Category 6™

Bitter cold in Alaska and Europe; Alaska's -79°F reading bogus

By: JeffMasters, 4:08 PM GMT on January 31, 2012

Bitter cold temperatures gripped much of Alaska again this morning, and the month of January is setting numerous records for coldest January on record for much of northern Alaska. According to the Fairbanks weather office, here are the likely final rankings for January temperatures at select locations in Alaska during 2012:

Nome: coldest
Kotzebue: 2nd coldest
Barrow: not in top ten coldest
Galena: coldest
Bettles: coldest
Fairbanks: 5th coldest (coldest since 1971)

A major atmospheric jet stream pattern change is underway this week, though, which will bring more seasonable temperatures to Alaska by late in the week.

Figure 1. Departure of temperature from average as analyzed by the GFS model, for January 30, 2012. Remarkably cold air was present over northern Alaska, Eastern Europe, and Southern Asia, while very warm air was over the Central U.S. and much of Siberia.

European cold wave kills 58
Alaska isn't the only place suffering exceptionally cold temperatures this week. At least 58 people have died in the European cold wave over the past week, according to ABC News. Hardest hit was the Ukraine, where 30 people, most of them homeless, died.

Alaska's -79°F reading bogus
I reported in yesterday's post that a personal weather station located about 180 miles north of Fairbanks, the Jim River DOT site, apparently recorded a low temperature of -79°F Saturday morning (January 28, 2012). This is very close to the coldest temperature ever recorded in the U.S., a remarkable -80°F (-62.2°C) reading from Prospect Creek, AK (about a mile away from Jim Creek), on January 23, 1971. However, it turns out the that the electronic temperature sensor on the weather station at Jim Creek is only rated to -40°F. Furthermore, the voltage on the lithium battery that powers the stations drops dramatically below -50°F, resulting in bogus low temperatures. Here is the official work on the low temperatures at Jim River from the NWS:

252 PM AKST MON JAN 30 2012





Jeff Masters

Winter Weather

Bitter cold -65°F temperatures hit Alaska

By: JeffMasters, 5:13 PM GMT on January 30, 2012

If you're wondering who's getting all the cold air the lower 48 states is missing during this non-winter of 2012, the answer during the past week has been Alaska. Our 49th state is used to intense winter cold, but not like what they've experienced during the past week. Friday night and Saturday night, temperatures plummeted to -50°F and -51°F in Fairbanks, marking the first time since 1999 the city had seen back-to-back minus fifty nights. The low temperature so far today at the Fairbanks International Airport has been -44°F, giving the city sixteen days of -40°F temperatures so far this month. Since 1906, there have only been three years (1906, 1934, and 1971) with more 40 below days during the month of January. At forty below zero, the air is so cold that the water vapor condenses out into ice crystals, which float in the air creating a low-visibility fog. A large area of Alaska experienced bitter cold temperatures of -50 to -65°F Sunday morning:

FORT YUKON CO-OP..............65 BELOW
BETTLES.................................60 BELOW**
HUSLIA.....................................60 BELOW
CHICKEN CO-OP.....................59 BELOW
GALENA AIRPORT....................58 BELOW
TANANA...................................58 BELOW
DELTA 20 SE CO-OP...............58 BELOW
COLDFOOT................................57 BELOW
EAGLE CO-OP.........................57 BELOW
KALTAG...................................56 BELOW
ARCTIC VILLAGE..................54 BELOW
NENANA..................................54 BELOW
SALCHA..................................54 BELOW
LAKE MINCHUMINA.................50 BELOW
MCGRATH.................................50 BELOW


The cold snap is expected to continue through mid-week, with more -65°F temperatures possible in the interior valleys north of Fairbanks. Warmer air is expected to arrive state-wide by Thursday.

Figure 1. It's a tradition! Photo taken Sunday, January 29, 2012, by one of our more adventurous wunderphotographers. Image credit: wunderphotographer TerezkaSunshine.

All-time U.S. low temperature record threatened?
The coldest temperature ever recorded in the U.S. was a -80°F (-62.2°C) reading from Prospect Creek, AK (about 180 miles north of Fairbanks) on January 23, 1971. A weather station just a few miles from Prospect Creek, the Jim River DOT site, appears to have recorded a low temperature between -78°F and -79°F Saturday morning (January 28, 2012), shortly before the weather station lost power. Keeping the power going at -70 is very tough, and it is not a surprise to see that the station lost power during this extraordinary cold snap. Power just returned this morning to the site, where the temperature was -66°F at 7 am AKST. Wunderground's weather historian Christopher C. Burt is corresponding with Alaska's state climatologist to get more information on whether the data during the power outage will be recoverable, and how reliable these near-record low temperatures might be.

Jeff Masters

Winter Weather

2011: Earth's 11th warmest year; where is the climate headed?

By: JeffMasters, 5:22 PM GMT on January 27, 2012

The year 2011 tied with 1997 as the 11th warmest year since records began in 1880, NOAA's National Climatic Data Center said last week. NASA rated 2011 as the 9th warmest on record. Land temperatures were the 8th warmest on record, and ocean temperatures, the 11th warmest. For the Arctic, which has warmed about twice as much as the rest of the planet, 2011 was the warmest year on record (between 64°N and 90°N latitude.) The year 2011 was also the 2nd wettest year over land on record, as evidenced by some of the unprecedented flooding Earth witnessed. The wettest year over land was the previous year, 2010.

Figure 1. Departure of global temperature from average for 2011. The Arctic was the warmest region, relative to average. Image credit: NASA Earth Observatory.

How much of the warming in recent decades is due to natural causes?
The El Niño/La Niña cycle causes cyclical changes in global temperatures that average out to zero over the course of several decades. La Niña events bring a large amount of cold water to the surface in the equatorial Eastern Pacific, which cools global temperatures by up to 0.2°C. El Niño events have the opposite effect. The year 2011 was the warmest year on record when a La Niña event was present. Global temperatures were 0.12°C (0.2°F) cooler than the record warmest year for the planet (2010), and would very likely have been the warmest on record had an El Niño event been present instead.

Figure 2. Departure from average of annual global temperatures between 1950 - 2011, classified by phase of the El Niño-Southern Oscillation (ENSO). The year 2011 was the warmest year on record when a La Niña event was present. ENSO is a natural episodic fluctuation in sea surface temperature (El Niño/La Niña) and the air pressure of the overlying atmosphere (Southern Oscillation) across the equatorial Pacific Ocean. Over a period of months to a few years, ENSO fluctuates between warmer-than-average ocean surface waters (El Niño) and cooler-than-average ocean surface waters (La Niña) in that region. Image credit: National Climatic Data Center.

Correcting for natural causes to find the human contribution
We know that natural episodes of global warming or cooling in the distant past have been caused by changes in sunlight and volcanic dust. So, it is good to remove these natural causes of global temperature change over the past 33 years we have satellite data, to see what the human influence might have been during that time span. The three major surface temperature data sets (NCDC, GISS, and HadCRU) all show global temperatures have warmed by 0.16 - 0.17°C (0.28 - 0.30°F) per decade since satellite measurements began in 1979. The two satellite-based data sets of the lower atmosphere (UAH and RSS) give slightly less warming, about 0.14 - 0.15°C (.25 - .27°F) per decade (keep in mind that satellite measurements of the lower atmosphere temperature are affected much more strongly by volcanic eruptions and the El Niño phenomena than are surface-based measurements taken by weather stations.) A 2011 paper published by Grant Foster and Stefan Rahmstorf, Global temperature evolution 1979 - 2010, took the five major global temperature data sets and adjusted them to remove the influences of natural variations in sunlight, volcanic dust, and the El Niño/La Niña cycle. The researchers found that adjusting for these natural effects did not change the observed trend in global temperatures, which remained between 0.14 - 0.17°C (0.25 - 0.31°F) per decade in all five data sets. The warmest years since 1979 were 2010 and 2009 in all five adjusted data sets. Since the known natural causes of global warming have little to do with the observed increase in global temperatures over the past 33 years, either human activity or some unknown natural source is responsible for the global warming during that time period.

Figure 3. Departure from average of annual global temperatures between 1979 - 2010, adjusted to remove natural variations due to fluctuations in the El Niño-Southern Oscillation (ENSO) cycle, dust from volcanic eruptions, and changes in sunlight. The five most frequently-cited global temperature records are presented: surface temperature estimates by NASA's GISS, HadCRU from the UK, and NOAA's NCDC, and satellite-based lower-atmosphere estimates from Remote Sensing Systems, Inc. (RSS) and the University of Alabama Huntsville (UAH.) Image credit Global temperature evolution 1979- 2010 by Grant Foster and Stefan Rahmstorf, Environ. Res. Lett. 6, 2011, 044022 doi:10.1088/1748-9326/6/4/044022.

Commentary: what do climate scientists think?
Some scientists have proposed that previously unknown natural causes could be responsible for global warming, such as a decrease in cloud-producing galactic cosmic rays. Others have proposed that the climate may be responding to the heat-trapping effects of carbon dioxide by producing more clouds, which reflect away sunlight and offset the added heat-trapping gases. These theories have little support among actively publishing climate scientists. Despite public belief that climate scientists are divided about the human contribution to our changing climate, polling data show high agreement among climate scientists that humans are significantly affecting the climate. A 2008 poll of actively publishing climate scientists found that 97% said yes to the question, "Do you think human activity is a significant contributing factor in changing mean global temperatures?" In my personal experience interacting with climate scientists, I have found near-universal support for this position. For example, I am confident that all 23 climate scientists and meteorologists whom I am personally acquainted with at the University of Michigan's Department of Atmospheric, Oceanic, and Space Science would agree that "human activity is a significant contributing factor in changing mean global temperatures." It is good that we have scientists skeptical of the prevailing consensus challenging it, though, because that is how scientific progress is made. It may be that one of the scientists making these challenges will turn out to be the next Einstein or Galileo, and overthrow the conventional scientific wisdom on climate change. But Einsteins and Galileos don't come along very often. The history of science is littered with tens of thousands of discredited scientific papers that challenged the accepted scientific consensus and lost. If we rely on hopes that the next Einstein or Galileo will successfully overthrow the current scientific consensus on climate change, we are making a high-stakes, low-probability-of-success gamble on the future of civilization. The richest and most powerful corporations in world history, the oil companies, have spent hundreds of millions of dollars to push us to take this gamble, and their efforts have been very successful. Advertising works, particularly when your competition has little money to spend to oppose you.

Where is the climate headed?
The 2007 United Nations-sponsored IPCC report predicted that global temperatures between 2007 and 2030 should rise by an average of 0.2°C (0.36°F) per decade. The observed warming over the past 30 years is 15 - 30% below that (but within the range of uncertainty given by the 2007 IPCC climate models.) Most of the increase in global temperatures during the past 30 years occurred in the 1980s and 1990s. The 2000s have seen relatively flat temperatures, despite increasing CO2 emissions by humans. The lower-than-expected warming may be partially due to a sharp decrease in stratospheric water vapor that began after 2000. The missing heat may also be going into the deep ocean waters below about 1,000 feet (300 meters), as part of a decades-long cycle that will bring extra heat to the surface years from now. Regardless, the laws of physics demand that the huge amount of heat-trapping gases humans are pumping into the atmosphere must be significantly altering the weather and climate, even if we are seeing a lower than predicted warming. As wunderground's climate change blogger, Dr. Ricky Rood said in a recent post,Changing the Conversation: Extreme Weather and Climate: "Given that greenhouse gases are well-known to hold energy close to the Earth, those who deny a human-caused impact on weather need to pose a viable mechanism of how the Earth can hold in more energy and the weather not be changed. Think about it."

Our recent unusual weather has made me think about this a lot. The natural weather rhythms I've grown to used to during my 30 years as a meteorologist have become significantly disrupted over the past few years. Many of Earth's major atmospheric circulation patterns have seen significant shifts and unprecedented behavior; new patterns that were unknown have emerged, and extreme weather events were incredibly intense and numerous during 2010 - 2011. It boggles my mind that in 2011, the U.S. saw 14 - 17 billion-dollar weather disasters, three of which matched or exceeded some of the most iconic and destructive weather events in U.S. history--the "Super" tornado outbreak of 1974, the Dust Bowl summer of 1936, and the great Mississippi River flood of 1927. I appeared on PBS News Hour on December 28 (video here) to argue that watching the weather over the past two years has been like watching a famous baseball hitter on steroids--an analogy used in the past by climate scientists Tony Broccoli and Jerry Meehl. We're used to seeing the slugger hit the ball out of the park, but not with the frequency he's hitting them now that he's on steroids. Moreover, some of the home runs now land way back in the seats where no one has ever been able to hit a home run before. We can't say that any particular home run would not have occurred without the steroids, but the increase in home runs and the unprecedented ultra-long balls are highly suspicious. Similarly, Earth's 0.6°C (1°F) warming and 4% increase in global water vapor since 1970 have created an atmosphere on steroids. A warmer atmosphere has more energy to power stronger storms, hotter heat waves, more intense droughts, and heavier flooding rains. Natural weather patterns could have caused some of the extreme events we witnessed during 2010 - 2011, and these years likely would have been naturally extreme years even without climate change. But it strains the bounds of credulity that all of the extreme weather events--some of them 1-in-1000-year type events--could have occurred without a significant change to the base climate state. Mother Nature is now able to hit the ball out of the park more often, and with much more power, thanks to the extra energy global warming has put into the atmosphere.

Extreme weather years like 2010 and 2011 are very likely to increase in frequency, since there is a delay of several decades between when we put heat-trapping gases into the atmosphere and when the climate fully responds. This is because Earth's oceans take so long to heat up when extra heat is added to the atmosphere (think about how long it takes it takes for a lake to heat up during summer.) Due to this lag, we are just now experiencing the full effect of CO2 emitted by the late 1980s; since CO2 has been increasing by 1 - 3% per year since then, there is a lot more climate change "in the pipeline" we cannot avoid. We've set in motion a dangerous boulder of climate change that is rolling downhill, and it is too late to avoid major damage when it hits full-force several decades from now. However, we can reduce the ultimate severity of the damage with strong and rapid action. A boulder rolling downhill can be deflected in its path more readily early in its course, before it gains too much momentum in its downward rush. For example, the International Energy Agency estimates that every dollar we invest in alternative energy before 2020 will save $4.30 later. There are many talented and dedicated people working very hard to deflect the downhill-rolling boulder of climate change--but they need a lot more help very soon.

Jeff Masters

Climate Change Climate Summaries

14 billion-dollar weather disasters for the U.S. in 2011

By: JeffMasters, 3:28 PM GMT on January 26, 2012

The tally of billion-dollar weather disasters in the U.S. during the crazy weather year of 2011 has grown to fourteen, and may reach fifteen, NOAA's National Climatic Data Center announced last week. The fourteen billion-dollar weather disasters in 2011 easily surpass the previous record of nine such disasters, set in 2008. Since 1980, the U.S. has averaged 3.5 billion-dollar weather disasters per year. The two new billion-dollar disasters of 2011:

Tropical Storm Lee, early September, 2011: Wind and flood damage across the southeast (LA, MS, AL, GA, TN) but considerably more damage from record flooding across the northeast (PA, NY, NJ, CT, VA, MD). Pennsylvania and New York were most affected. Total losses exceed $1.0 billion; 21 deaths.

Rockies and Midwest Severe Weather, July 10-14, 2011: An outbreak of tornadoes, hail, and high wind caused damage east of the Rockies and across the central plains (CO, WY, IA, IL, MI, MN, OH). Total losses exceed $1.0 billion; 2 deaths.

The total costs of these fourteen disasters is $55 billion, tying 2011 with 2004 for fourth place for most costly year for billion-dollar weather disasters in history. The only costlier years were 2005 (Hurricanes Katrina, Rita, and Wilma); 1988 (Midwest drought); and 2008 (Hurricanes Ike and Gustav.) NCDC says they are still analyzing the late-October snowstorm that hit New England to see if it was a billion dollar disaster. Insurance broker AON Benfield puts damages from this event at $3 billion, so it is likely that NCDC will add at least one more billion-dollar disaster to 2011's tally.

For those interested, NOAA has a full description of the 14 billion-dollar weather disasters of 2011, plus a list of their Top Ten Global Weather Events of 2011 and Top Ten U.S. Weather Events of 2011.

Figure 1. Front Street Bridge on the Susquehanna River in Vestal, NY, immediately following the flood of September 8, 2011, caused by the remnants of Tropical Storm Lee. Image credit: USGS, New York.

My other posts looking back at the remarkable weather events of 2011
Extreme temperatures of 2011: 7 national all-time heat records; 1 cold record
U.S. weather in 2011: unprecedented rains and wet/dry extremes
Top ten global weather events of 2011
2011: Year of the Tornado
Deadliest weather disaster of 2011: the East African drought
Tropical Storm Lee's flood in Binghamton: was global warming the final straw?
Wettest year on record in Philadelphia; 2011 sets record for wet/dry extremes in U.S.
Hurricane Irene: New York City dodges a potential storm surge mega-disaster

Figure 2. The new "Blue Marble" image of Earth on January 4, 2012, as seen by the VIIRS instrument on the new Suomi NPP satellite. Image credit: NASA.

Spectacular "Blue Marble" image of Earth released
A new polar orbiting satellite has returned a stunning true-color image of the Earth taken on January 4, 2012. The Suomi NPP satellite, launched on October 28, 2011, is the first one designed to both take measurements to improve short-term weather forecasts, and collect data to increase understanding of long-term climate change. The VIIRS instrument on the satellite collected a series of true-color images of the Western Hemisphere on January 4 that were stitched together to create a new "Blue Marble" image of Earth, like the ones taken by the Apollo astronauts in the 1970s.

The image is very interesting meteorologically, and extremely strange. It is obvious that it is a winter image, as revealed by the large area of stratocumulus clouds off the U.S. East Coast all the way to South Florida, caused by cold Canadian air blowing offshore. However, the U.S. and Canada are virtually snow-free and cloud-free, which is extremely rare for a January day. The lack of snow in the mountains of the Western U.S. is particularly unusual. I doubt one could find a January day this cloud-free with so little snow on the ground throughout the entire satellite record, going back to the early 1960s. NOAA's Advanced Hydrologic Prediction Service shows that only one state--Washington--had areas where precipitation accumulated more than 0.25" on January 4, 2012, which is an extraordinary occurrence for a January day.

Jeff Masters

Extreme Weather

Heavy rains drench Texas

By: JeffMasters, 5:03 PM GMT on January 25, 2012

Big smiles greeted heavy rains in Texas this morning, where an upper-level low pressure system brought significant soaking rains to eastern portions of the state. The rain was heavy enough to cause minor flooding of some creeks and rivers, and the NWS has posted flash flood watches and warnings for most of Eastern Texas. High water rescues have occurred on the streets of Haltom City, Texas. It's been a while since we've seen our severe weather map light up in green colors for Texas! Austin, Texas received 5.66" of rain this morning, setting a record for the date, and rainfall amounts of 2 - 4 inches have been common across most of East Texas. The storm has triggered severe thunderstorms over Texas yesterday and this morning, and two possible tornadoes were reported in Edwards County near Houston yesterday. NOAA's Storm Prediction Center has placed much of East Texas and Western Louisiana in their "Slight Risk" region for severe weather today, and tornado watches are posted. Some 24-hour rainfall amounts from the storm, for the period ending at 6am CST January 25:

Dallas Love 3.17"
Dallas/Fort Worth Airport 3.08"
San Antonio 3.13"
Waco 2.68"
Victoria 0.96"

FIgure 1. Radar-estimated rainfall for the 24 hours ending at 10:23am CST January 25, 2012.

Above-average rains for Texas this winter
Despite predictions that this winter would be unusually dry in Texas due to the on-going La Niña event in the Eastern Pacific, Texas has seen more rain than average. Today's storm is the second major soaking Eastern Texas has received this month. December also had plentiful rains, with the state recording its 19th wettest December in 117 years of record keeping. However, 2011 was the driest year in Texas history, and many regions still have a long way to go before drought conditions abate. The January 17, 2012 Drought Monitor showed 62% of Texas in two worst categories of drought--extreme to exceptional. That's quite an improvement from the 97% of the state that was in extreme to exceptional drought back on September 27, 2011, though. The latest GFS model forecast shows mostly dry conditions returning to Texas next week, with the possibility of more heavy rain for East Texas on February 3.

Category 4 Tropical Cyclone Funso moves away from Mozambique
The most powerful tropical cyclone of 2012 is Tropical Cyclone Funso, which intensified to a Category 4 storm with 140 mph winds early this morning. Funso is located in the Mozambique Channel between Madagascar and Mozambique, and is expected to remain offshore and move slowly southwards. The outer spiral bands of Funso dumped torrential rains on Mozambique early this week, triggering floods that killed at least twelve people. Flooding from Funso was made worse by the saturated soils left by Tropical Depression Dando, whose rains caused flooding that killed ten people in the country last week.

Figure 2. Image of Tropical Cyclone Funso taken by the MODIS instrument on NASA's Terra satellite on January 25, 2012, at 07:40 UTC. At the time, Funso was a Category 4 storm with 135 mph winds. Image credit: NASA.

Largest solar storm since October 2003 hits Earth
On January 23 near 03:39 UTC, big sunspot 1402 erupted, sending a coronal mass ejection (CME) headed towards Earth. The CME arrived at Earth on January 24 near 15 UTC, setting off the biggest solar storm since October 2003. Bright auroras were observed at many northern locations, and a G1-class geomagnetic storm is in progress. For more info, see NOAA's Space Weather Prediction Center or

Figure 3. Solar flare as observed by the Atmospheric Imaging Assembly (AIA) on NASA’s Solar Dynamics Observatory (SDO) at 03:27, 03:42, and 04:12 UTC January 23, 2012. Note the brightening of the solar surface as gas was superheated and magnetically supercharged. By the third (right) image, a stream of solar material is seen flowing off into space above the hot spot, likely solar protons and a coronal mass ejection (CME). Image credit: NASA Earth Observatory.

Jeff Masters

Drought Flood

Category 4 Funso kills 12 in Mozambique; deadly Alabama tornado rated an EF-3

By: JeffMasters, 2:48 PM GMT on January 24, 2012

Earth's first major tropical cyclone of 2012 is Tropical Cyclone Funso, a Category 4 storm with 135 mph winds located in the Mozambique Channel between Madagascar and Mozambique. Conditions for intensification have been favorable over the past few days, with light wind shear of 5 - 10 knots, water temperatures of 29°C, and a pocket of high oceanic heat content with warm waters extending to great depth located under the center of the storm. Funso is expected to intensify further and have sustained winds of 145 mph by Wednesday. Fortunately, the center of the storm is expected to remain offshore as the storm moves slowly southwards. The outer spiral bands of Funso have dumped torrential rains on Mozambique the past several days, triggering floods that have killed at least twelve people. The floods have swept across the main north-south highway in the country, cutting off the capital of Maputo from the north and center of the country. Flooding from Funso was made worse by the saturated soils left by Tropical Depression Dando, whose rains caused flooding that killed ten people in the country last week.

Figure 1. Image of Tropical Cyclone Funso taken by the MODIS instrument on NASA's Terra satellite on January 23, 2012. At the time, Funso was a Category 3 storm with 115 mph winds. Image credit: NASA/GSFC.

Yesterday's deadly Clay, Alabama tornado rated an EF-3
A damage survey by the NWS confirmed that the tornado that hit Clay, Alabama yesterday, killing two and injuring over 100, was a strong EF-3 tornado with 150 mph winds. A second EF-3 tornado with 140 mph winds touched down yesterday near Koffman, Alabama, and tore off the roof of a house and a barn. These are the only two EF-3 tornadoes of the year so far. There have been no EF-4 or EF-5 tornadoes yet. NOAA's Storm Prediction Center has placed portions of Southern Texas in their "Slight Risk" region for severe weather today, and portions of East Texas and Western Louisiana in the "Slight RIsk" region for Wednesday, and a few isolated tornadoes are possible in Texas and Louisiana over the next two days.

Jeff Masters

Hurricane Tornado

Rare January tornado outbreak kills two, injures 100 in Alabama

By: JeffMasters, 4:46 PM GMT on January 23, 2012

The calendar says it's the coldest month of winter, but today's weather is more typical of March, as a vigorous spring-like storm system has spawned a rare and deadly January tornado outbreak. Twenty tornadoes were reported in Arkansas, Alabama, Mississippi, and Tennessee last night and this morning, killing at least two, injuring 100, and causing major damage. Two deaths were reported in Canter Point and one unconfirmed death in Oak Grove in Alabama, from a tornado that ripped through the area near 3:30 am EST. The deaths were the first of the 2012 tornado season. In Clanton, about 50 miles south of Birmingham, Alabama, a separate tornado hit near 8:12 am EST this morning, trapping people in overturned trailer homes, destroying the WKLF radio studio, and toppling a 302-foot high transmission tower.

Figure 1. Satellite image taken at 9:45 am EST Monday January 23, 2012, of the major spring-like storm that spawned tornadoes over the Southern U.S. Image credit: NASA/GSFC.

Figure 2. Radar reflectivity image of the tornado that hit Clanton, Alabama this morning, trapping people in overturned trailer homes, destroying the WKLF radio studio, and toppling a 302-foot high transmission tower.

Significant historical January tornado outbreaks
Historically, January has been the least active month for tornadoes in the U.S. According to the Tornado History Project, during the 61-year period 1950 - 2010, 1223 January tornadoes occurred--an average of twenty per year. There have been two Januarys with no reported tornadoes--2003 and 1986. Thus far in 2012, there have been 44 preliminary tornado reports, so we are already at double the historical January average, with a week still to go in the month. NOAA's Storm Prediction Center has put Alabama and Georgia in their "Slight Risk" area for severe weather the remainder of today, so it is likely we will add a few more tornadoes to this month's tally before the outbreak is finished. January 2012 appears likely to become one of the top-five busiest months for January tornadoes in recorded history. Only four years since 1950 have had more than 50 January tornadoes:

January 1999 218
January 2008 88
January 1975 54
January 1997 50

The most recent significant January tornado outbreak occurred last year on January 1, 2011, when seven tornadoes, including two EF-3s, touched down in Mississippi, injuring two people.

The most prolific January tornado outbreak on record occurred January 21 - 22, 1999, when 126 tornadoes, including one violent F-4, hit Arkansas, Missouri, Mississippi, Louisiana, Tennessee, Kentucky, Illinois, Texas, and Alabama, killing nine people. A separate outbreak four days earlier, on January 17, spawned 22 tornadoes.

On January 7 - 11, 2008, a series of 75 tornadoes hit the U.S. This second busiest-ever U.S. January tornado outbreak hit southwestern Missouri, northwestern Arkansas and the surrounding areas the hardest. A strong supercell in northern Illinois and southeastern Wisconsin produced that region's first January tornadoes since 1967. Four people were killed, and the tornadoes did $88 million in damage. Fifteen strong EF-2 and EF-3 tornadoes were reported.

The deadliest January tornado since record keeping began in 1950 occurred on January 23, 1969, when an F-4 tornado hit a 5-county region south of Jackson Mississippi, killing 32 people.

Spring-like thunderstorms hit Chicago
Thunderstorms along the cold front from the storm that spawned today's deadly tornadoes rumbled through Chicago, Illinois last night, dropping over one-half inch of rain on ground covered by four inches of snow. Spring-like January thunderstorms in Chicago used to be a rare occurrence, but have become increasingly common in recent years. During the 50-year period 1947- 1996, Chicago's O'Hare Airport recorded ten days with thunder, on days when the high temperature reached at least 40°F. In the 16-year period 1997- 2012, there have been nine such days, so January spring-like thunderstorms have roughly tripled in frequency in Chicago in recent years. January 2008 set the record for most January thunderstorm days in Chicago, with three.

Big solar flare headed toward Earth
This morning at 03:39 UTC, big sunspot 1402 erupted, sending a coronal mass ejection (CME) headed towards Earth. This CME is expected to set off a solar storm on January 24 - 25. NOAA's Space Weather Prediction Center is advising that high-latitude power systems may experience voltage alarms; long-duration storms may cause transformer damage. Satellite orientation irregularities may occur; possible changes in satellite drag affect orbit predictions. HF radio propagation can fade at higher latitudes, and aurora may be seen as low as New York, Idaho, mid-Aleutians. According to NOAA, this is the strongest solar storm since May 2005.

Jeff Masters


Flooding, heavy snow, ice storm, and fires hit the Western U.S.

By: JeffMasters, 12:39 PM GMT on January 20, 2012

A state of emergency has been declared in Oregon and Washington, where a powerful winter storm brought deadly floods, heavy snows of up to 4 feet, a severe ice storm, and damaging winds Wednesday and Thursday. Heavy rains of 3 - 8 inches have fallen over a wide swath of Western Oregon since Monday, causing major to record flooding on multiple rivers and creeks. In Albany, Oregon, a family of four drove out of a supermarket parking lot and into a flooded Perwinkle Creek Wednesday night, and were swept away. Two people were rescued, but a 20-month-old boy and his mother drowned. The Marys River in Philomath rose to its highest flood on record yesterday, and will remain at major flood stage today before gradually receding tonight. The rains have tapered off over much of the region today, but renewed rains are expected later today and intermittently into early next week. The storm also brought strong winds to Reno, Nevada, fanning a brush fire that tore through the Reno area, destroying more than 20 homes and forcing thousands to evacuate. Reno experienced sustained winds of 44 mph, gusting to 70 mph, during the afternoon Thursday. The city didn't get any precipitation, and has received just 0.03" of precipitation this year. That fell on Monday, breaking a 56-day streak with no precipitation--the longest wintertime dry streak in city history. Strong winds gusting to 55 mph are expected during the day today, keeping the fire danger high, but heavy rain is expected tonight, which should ease the fire danger. The storm also brought a significant freezing rain event to northern Oregon and Western Washington yesterday, and up to an inch of ice accumulated in some areas, contributing to power outages that affected at least 275,000 people.

Figure 1. Satellite image taken at 7 pm EST Thursday, January 19, of the West Coast winter storm. A second storm, now approaching the coast, can be seen at the left of the image. Image credit: NASA/GSFC.

Some select snow amounts between 2 pm PST Monday January 16, and 1am PST Friday January 20, as compiled in the latest NOAA/NCEP/HPC Storm Summary:


KETCHUM 22 NW 38.5
STANLEY 28 NE 32.9
BURLEY 30 SW 22.2

HERON 15.3


ALTA 16.0 9662 FT
SNOWBIRD 11.0 8100 FT


AFTON 12.0

And some select rainfall amounts from the same time period:



Figure 2. The Marys River in Philomath, Oregon crested at its highest flood height on record Thursday, and remains at major flood level today. Image credit: NOAA.

The short-term forecast
The storm door will remain open for California and the Pacific Northwest through the weekend and into mid-week, as two more moisture-laden storm systems pound the region. By the time the active weather pattern calms down by mid-week, rainfall totals of 10 - 20 inches are expected along the Oregon coast. Snowfall totals of 4 - 6 feet are likely in the Cascade Mountains of Washington and Oregon, in the Northern Sierra and Shasta/Siskiyou Mountains in California, in the Northern Wasatch and Uinta Ranges of Utah, and in the Northern Rockies from far eastern Idaho/Western Wyoming through Central and Northern Idaho, Northwestern Montana, and Northeastern Oregon. Damaging strong winds will affect the coast from Northern California to Northern Washington during the weekend and into early next week, as well.

Record dry spell ends for California and Nevada
In San Francisco, the first significant rains since November 20 fell yesterday, a modest 0.08". The two-month period November 20 - January 19 saw just 0.26" of rain fall in the city, making it the longest two-month winter dry period in the city since records began in 1850, according to wunderground's weather historian, Christopher C. Burt. More rain is expected Friday through Saturday.

The long-range forecast
A major atmospheric pattern shift is responsible for the big storm in the Western U.S. The ridge of high pressure that brought Northern California its driest two-month winter period on record Nov 20 - Jan 19 has retreated to the northwest towards Alaska, allowing the subtropical jet stream to dive underneath the ridge and bring a plume of moisture called an "atmospheric river" to the coast. This shift was possible thanks to a weakening of a pressure pattern known as the Arctic Oscillation (AO). During December and the first half of January, the AO took on its second most extreme configuration on record. The pressure difference between the Azores High and the Icelandic Low reached its most extreme value since records began in 1865, keeping the winds of the jets stream flowing very rapidly. This pattern bottled the jet stream far to the north in Canada, and prevented cold Arctic air from spilling southwards into the U.S . The combination of a near record-strength AO and a borderline weak/moderate La Ninña event in the Eastern Pacific combined to keep a powerful ridge in place over the Western U.S., deflecting all the winter storms into Canada and Southern Alaska. The AO index has become much less extreme over the past two weeks, though, and is now close to average strength. This has allowed the polar jet stream to sag southwards from Canada into the northern U.S., giving the northern tier of states their first real sustained winter-like weather of the season this week (it's about time!) However, the polar jet is expected to remain far enough north so that no major snow storms will occur in the U.S. during the remainder of January--except perhaps in the Pacific Northwest. It's likely that the lack of storms will make January 2012 one of the top five driest January months on record. This month is also likely to be a top-ten warmest January, but won't be able to challenge January of 2006 for the top spot. That January was an incredible 8.5°F above average in the contiguous U.S., and so far, we are running about 4 - 5°F above average. The AO index is predicted to remain near average or potentially change signs and go negative by the beginning of February, which would allow cold air to spill southwards into the U.S. bringing more typical winter-like weather.

It's too early to say what type of winter weather February might bring, but it might be instructive to look at the last time we had winter like this year's. Like the winter of 2011 - 2012, the winter of 2006 - 2007 started out exceptionally warm, with the AO index reaching its all-time most extreme positive value on record during December and early January. New York City hit 72°F on January 6, 2007, the city's all-time warmest January day. The rest of January 2007 saw a gradual lessening of the extreme AO pattern, much like we are seeing this year, and the AO returned to normal in February 2007. That month was a classic winter month, ranking as the 34th coldest February on record, with several notable snow storms.

Auroras possible this weekend
From Active sunspot 1401 erupted Jan. 19th, for more than an hour around 16:00 UT. The long-duration blast produced an M3-class solar flare and a Coronal Mass Ejection that appears to be heading toward Earth. Forecasters say strong geomagnetic storms are possible when the cloud arrives during the late hours of Saturday, Jan. 21st. High-latitude (and possibly middle-latitude) sky watchers should be alert for auroras this weekend.

Wunderground's weather historian Christopher C. Burt has a new post titled, The Pacific Northwest’s Greatest Storm: The ‘Storm King’ of January 1880.

Have a great weekend everyone, and I'll be back with a new post on Monday.

Jeff Masters

Winter Weather

Major flooding in Oregon, heavy snows in Washington and California

By: JeffMasters, 4:07 PM GMT on January 19, 2012

A major atmospheric pattern change is underway, and the Pacific storm door is open. A major winter storm supported by an atmospheric river of high moisture is pounding Oregon, California, and Washington today, bringing record flooding, heavy snows, freezing rain, and damaging winds. The ridge of high pressure that had brought much of Northern California its driest winter period on record during the past two months has retreated to the northwest towards Alaska, allowing the subtropical jet stream to dive underneath the ridge. The subtropical jet is bringing a plume of moisture called an "atmospheric river" to the coast between Northern California and Southwestern Washington, resulting in heavy rains near the coast and snow measured in feet to the mountains. Heavy rains of 2 - 5 inches have affected much of Western Oregon over the past 24 hours, and the Marys River in Philomath has risen to its highest flood on record. Additional rains of 1 - 3 inches are expected today over the region, and damaging major flooding is expected along several Oregon rivers.

Figure 1. Radar-estimated precipitation for Oregon shows a wide swath of greater than 8 inches of rain has fallen since January 16 over Western Oregon.

Figure 2. The Marys River in Philomath, Oregon crested at its highest flood height on record this morning. Image credit: NOAA.

Heavy snow, ice storm hit Seattle
Yesterday in Seattle, Washington, 6.8" of snow fell, making it their greatest 24-hour snowfall since November 1985. Winds gusting to 85 mph in the mountains to the east of Seattle closed some ski areas, but heavy snows of 38" in 36 hours fell at White Pass, and the this weekend will see the best skiing of winter in Washington. The problem will be getting to the ski areas--an ice storm this morning has closed the Sea-Tac airport and snarled traffic.

Record dry spell ends for California and Nevada
Skiiers, take heart: Tahoe's Ski Season From Hell will end this weekend. A series of three snowstorms will pound the Sierra Mountains of California and Nevada, bringing the first heavy snows since November. According to Tahoe weather historian Mark McLaughlin, December 2011 was the second driest in the Sierra Mountains since record keeping began in 1920. He based this on an aggregate of data from eight locations from Highway 50 in the south to Mt. Shasta in the north in the central and northern Sierra Nevada. This winter has seen the longest winter dry spell in history in Reno, Nevada (56 days). The dry spell ended on January 16, when .03" of precipitation fell. The previous longest dry spell was 54 days, ending on January 24, 1961. Farther to the south in Minden, Nevada, the record dry spell ended at 72 days on January 16. Nevada's Carson River Basin snowpack is at 8% of normal, compared to 224% last year at this time. In San Francisco, the first significant rains since November 20 are expected to begin later today. The past two months have seen just 0.26" of rain in the city, making it the longest two-month winter dry period in the city since records began in 1850, according to wunderground's weather historian, Christopher C. Burt. Fresno, Califonia has seen no rain at all since November 20, and that dry spell should end today or Friday. Today's storm in Northern California will be followed by a new storm on Friday, which will bring 100 mph wind gusts and 1 - 2 feet of snow to the Sierras (2 - 3 inches of rain equivalent). A third storm with more snow is expected on Sunday night.

Figure 3. Satellite estimated water vapor in the atmospheric expressed as how much rain would fall if the entire amount of vapor were condensed in a vertical column. Where this "Total Precipitable Water" exceeds about 25.4 mm (1 inch), heavy precipitation can occur. An "Atmospheric River" extending from Hawaii with very moist air harboring precipitable water values near 1.5 inches (38 mm, light blue colors) is impacting the coast near the California/Oregon border, bringing heavy rains and snows. Image credit: University of Wisconsin SSEC.

I'll have a new post on Friday.

Jeff Masters

Winter Weather

Major winter storm pounds Pacific Northwest

By: JeffMasters, 3:24 PM GMT on January 18, 2012

A ferocious winter storm is pounding the Pacific Northwest, bringing heavy snow, flooding rains, and winds near hurricane force over coastal waters. The snow is falling in earnest in Seattle this morning, where 3 - 5 inches are expected. The storm's heaviest snows have fallen in Southwest Washington, just north of Portland, Oregon, where Toutle, Washington received 18" as of 6 am PST this morning. The storm also brought 2 inches of snow to Portland, Oregon overnight. The wet, heavy snow brought down numerous trees and power lines, causing power outages to 30,000 people. Portland averages just 6.5 inches of snow per year. Very heavy snows of 1 - 3 feet have fallen in the Cascade Mountains east of Seattle, causing extreme avalanche danger. From the latest NWS Seattle forecast discussion:

Strong winds and heavy snow have overloaded fragile snow layers weakly attached to old crusts and produced increasingly large and sensitive avalanches. Field reports late Tuesday already indicated lots of natural and human triggered slides ranging from about 1 to 3 feet deep. Avalanche warnings already in effect for high danger...and with warming...further winds and additional heavy to very heavy snow...some quite dense...avalanche activity should become larger and more severe on Wednesday. This should lead to extreme danger above about 5000 feet with increasing high danger below. Due to very dangerous conditions getting worse...back country travel should be avoided Wednesday.

At sea, the National Weather Service has issued a hurricane force wind warning for the Southern Oregon coastal waters. Hurricane force winds of 70 - 75 mph, gusting to 90 mph, are expected today, with waves of 22 - 25 feet.

Figure 1. Heavy snow in Mt. Vernon, Washington on January 17, 2012. Image credit: wunderphotographer spiritjoy.

Seattle snow history
Seattle only averages 8 inches of snow each winter, and so today's storm is a major event for them. According to wunderground's weather historian, Christopher C. Burt, the last major snowfall for Seattle (Sea-Tac Airport location) was 12.0" over the week of Dec. 18 - 25, 2008. It appears the max. 24-hour fall during that event was 6.0" on Dec. 20 - 21. Prior to 2008, it appears Nov. 1985 had 17.5", but what the biggest storm 24-hour total then is not clear. Seattle's record 24-hour snowfall was 21.5" on Feb. 2, 1916, and 32.5" fell as a storm total between Jan. 31 - Feb. 2, 1916. Much deeper snow was reported during the famous Storm King event of January 9 - 12, 1880 when "four to six feet" accumulated according to press reports.

Figure 2. Satellite estimated water vapor in the atmospheric expressed as how much rain would fall if the entire amount of vapor were condensed in a vertical column. Where this "Total Precipitable Water" exceeds about 25.4 mm (1 inch), heavy precipitation can occur. An "Atmospheric River" extending from Hawaii with very moist air harboring precipitable water values near 1.5 inches (38 mm, light blue colors) is impacting the coast near the Washington/Oregon border, bringing heavy rains and snows. Image credit: University of Wisconsin SSEC.

I'll have a new post on Thursday.

Jeff Masters

Winter Weather

Bill Read to retire as director of the National Hurricane Center

By: JeffMasters, 4:28 PM GMT on January 16, 2012

Bill Read, the director of the National Hurricane Center (NHC) since 2008, announced Saturday that he will be retiring on June 1, ending four and one-half years as the nation's most visible meteorologist. Read took the post of NHC director after Bill Proenza stepped down following a stormy six-month tenure where much of staff revolted against him. In the wake of the turmoil stirred up by Proenza, Read brought stability to the Hurricane Center. Conversations I've had with staff at NHC indicated that Read was an excellent manager of people, and was well-respected among his employees. His management ability, easy-going style, and solid communication skills made Read an excellent choice for director of NHC, and he will be missed. “I will have been in charge just shy of four and a half years on June 1,” Read wrote in a letter to hurricane center staff . “I had no idea I would ever be considered for such an honor. It’s been quite a ride and I’m blessed to hit the exit ramp in my career after working with you all.”

Previously, Read served as director of Houston's National Weather Service office, a post he took in 1992. Read was called in to work at NHC three times between 1992 and 2005 to help out with hurricane emergencies. Prior to his job in Houston, Read served in the U.S. Navy, where his duties included an assignment as an on-board meteorologist with the Hurricane Hunters. He began his career in 1977 with the National Weather Service test and evaluation division in Sterling, VA.

Figure 1. Bill Read at the National Hurricane Center forecast desk. Image credit: NOAA.

National Hurricane Center Directors:
Gordon Dunn, 1965 - 1967
Robert Simpson, 1967 - 1973
Neil Frank, 1973 - 1987
Bob Sheets, 1987 - 1995
Robert Burpee, 1995 - 1997
Jerry Jarrell, 1998 - 2000
Max Mayfield, 2000 - 2007
Bill Proenza, January - July, 2007
Ed Rappaport (interim), July 2007 - January 2008
Bill Read, 2008 - 2012

Who will the next director of NHC be?
The retirement of Bill Read means that a search for NHC's eleventh director must be complete before hurricane season arrives. While I haven't had time to ask them if they are interested, here are four candidates who would make excellent directors of NHC:

Dr. Ed Rappaport, Deputy Director of NHC since 2000. Dr. Rappaport served as interim director of NHC during the hurricane season of 2007, and did a great job. He did not want to be the permanent director, though, and it is uncertain if would want the position now. In a Q and A interview posted on the NHC web site last year, Dr. Rappaport said, "The responsibilities are immense and, to date, the circumstances have not been right for me to be the director full time. But I will consider it the next time the opportunity arises. For such a critical position, one which has such important responsibilities, great visibility, many challenges and the long periods of travel, everything has to be aligned right within your professional and personal life to make the commitment that is required to do the job well." I have to believe that if he wants the job, the next director of NHC will be Ed Rappaport.

James Franklin, Branch Chief of the NHC Hurricane Specialists Unit. Since 2008, Franklin has been responsible for the quality of hurricane forecasts coming out of NHC, a tough, high-pressure job that he has handled remarkably well. Before arriving at NHC, Mr. Franklin worked as a hurricane research scientist for NOAA's Hurricane Research Division.

Dr. Chris Landsea, NHC Science and Operations Officer since 2005. Between 1995 - 2004, Dr. Landsea worked as a hurricane research scientist for NOAA's Hurricane Research Division. Dr. Landsea has testified in front of Congress several times on the issue of hurricanes and global warming, and has excellent public communication skills.

Dr. Rick Knabb, tropical weather expert for the Weather Channel. Dr. Knabb served as a senior hurricane specialist at NHC from 2005 - 2008, then took a position as deputy director and director of operations of the Central Pacific Hurricane Center (CPHC) and NWS Forecast Office in Honolulu, Hawaii. In 2010, he joined the Weather Channel.

Jeff Masters

Hurricane Politics

Extreme temperatures of 2011: 7 national all-time heat records; 1 cold record

By: JeffMasters, 4:14 PM GMT on January 13, 2012

The year 2011 was the tenth warmest year on record for the globe, but the warmest year on record when a La Niña event was present (Ricky Rood has a discussion of this in his lastest post.) Seven nations and one territory broke all-time hottest temperature records. This is a far cry from 2010 (which tied for the warmest year on record), when twenty nations (plus one UK territory) set all-time hottest temperature records. One all-time coldest temperature record was set in 2011; this was the first time since 2009 one of these records was set. The all-time cold record occurred in Zambia, which ironically also set an all-time hottest temperature record in 2011. Here, then, are the most most notable extreme temperatures globally in 2011, courtesy of weather records researcher Maximiliano Herrera:

Hottest temperature in the world in 2011: 53.3°C (127.9°F) in Mitrabah, Kuwait, August 3
Coldest temperature in the world in 2011: -80.2°C (-112.4°F) at Dome Fuji, Antarctica, September 18
Hottest temperature in the Southern Hemisphere: 49.4°C (120.9°F) at Roebourne, Australia, on December 21
Coldest temperature in the Northern Hemisphere: -67.2°C (-89°F) at Summit, Greenland, March 18. This is also the coldest March temperature ever recorded in the Northern Hemisphere.
Hottest undisputed 24-hour minimum temperature in world history: A minimum temperature of 41.7°C (107°F) measured at Khasab Airport in Oman on June 27

Figure 1. Seven countries and one territory set all-time hottest temperature records in 2011, and one nation set an all-time coldest temperature record. Image credit: Ilissa Ocko, Princeton University.

New country hottest temperature records set in 2011
Iraq recorded its hottest temperature on record on August 3, 2011 in Tallil (Ali military airbase), when the mercury hit 53°C (127.4°F). The previous record was 52.3°C recorded at Diwanya FOB airbase a few days before.

Armenia recorded its hottest temperature on record on July 31 in Meghri, when the mercury hit 43.7°C (110.7°F). The previous record was 43.1°C in Meghri on July 17, 2005.

Iran recorded its hottest temperature in its history on July 28, 2011, when the mercury hit 53°C (127.4°F) at Dehloran. The previous previous record was set just one day earlier at Omidieh and Shoshtar, when the mercury hit 52.6°C (126.6°F). Older hotter temperatures have been measured in Iran using automated stations, but these temperatures have been found to be overestimated.

Kuwait recorded its hottest temperature on record on August 3, 2011, when the mercury hit 53.3°C (127.9°F) at Mitrabah. The previous record was 53.1°C in Sulaibiya on June 15, 2010. The Kuwait Meteorological Center confirmed the reading as authentic, though the temperature sensor had problems between 2009 and July 2010. Some temperatures as high as 53.5°C measured at the Kuwait City Airport during 2011 were in error. The 53.3°C (127.9°F) at Mitrabah thus represents:

1) The hottest temperature measured on Earth in 2011
2) New official national record for Kuwait
3) Second highest (undisputed) temperature ever recorded in Asia
4) Highest temperature ever recorded in an Arabic country
5) Third hottest location in the planet together with Lake Havasu City, AZ (after Death
Valley, CA and Moenjodaro, Pakistan)
6) A new world record for August

China broke its national heat record for both uninhabited and inhabited locations on July 14, 2011, when the temperature soared to 50.2°C (122.4°F) at a automatic station near Adyngkol Lake (just south of Turfan), and 49.4°C (120.9°F) at the town of Tuyoq. A higher reading of 50.7°C at Aydingkol Mirabilite on 23 July 1986 has not been verified as official by the Chinese.

Republic of the Congo set a new all-time extreme heat record on March 8, 2011, when the temperature hit 39.2°C (102.6°F) at M'Pouya. Congo's previous all-time hottest temperature was 39.0°C (102.2°F) at Impfondo on May 14, 2005.

Zambia set an all-time national heat record of 109.0°F (42.8°C) at Mfuwe, on October 26, 2011, breaking the previous national record of 108.1°F (42.3°C) also set at Mfuwe, on November 17, 2010. A no longer functioning station at Lusitu, Zambia measured a higher temperature in November 1990, but surrounding stations were all about 10°C cooler, so the Lusitu 1990 reading is considered unreliable.

The French Southern and Antarctic Lands Territory tied its all-time hottest temperature record when Europa Island recorded 35.6°C (96.1°F) on November 12, 2011. The previous record was set at Juan de Nova Island on March 31, 1997.

New country coldest temperature records set in 2011
For the first time since 2009, a new national extreme cold temperature record was set. Zambia set an all-time national cold record of -9°C (16°F) at Choma on June 27, 2011, breaking the previous national record of -8°C (18°F), set on July 10, 1898, at Nalisa Western Province.

Special mention:
Russia had its hottest temperature on record at a regular synoptic reporting staion on July 30, 2011, when the mercury hit 44.3°C (111.7°F) at Divnoe in Russia's Kalmykia Republic. Three hotter temperatures have been recorded at automated stations: 45.4°C in 2010 at a hydrological station at Utta, plus readings of 45°C at El'ton and 44.5°C at Verhjnky Baskunkak in August 1940.

Weather records researcher Maximiliano Herrera is the primary source of the weather records listed here and has worked tremendously hard to research them. He maintains a comprehensive list of extreme temperature records for every nation in the world on his website. If you reproduce this list of extremes, please cite Maximiliano Herrera as the primary source of the weather records.

Other posts looking back at the remarkable weather events of 2011
U.S. weather in 2011: unprecedented rains and wet/dry extremes
Top ten global weather events of 2011
2011: Year of the Tornado
Deadliest weather disaster of 2011: the East African drought
Tropical Storm Lee's flood in Binghamton: was global warming the final straw?
Wettest year on record in Philadelphia; 2011 sets record for wet/dry extremes in U.S.
Hurricane Irene: New York City dodges a potential storm surge mega-disaster

Figure 2. Portlight volunteers help distribute bottled water in the aftermath of Hurricane Irene in Raleigh, North Carolina.

Weather Underground renews as National Sponsor of Portlight Disaster Relief
This week, wunderground put out a press release in concert with Portlight Strategies, Inc.--a national grassroots non-profit organization--that Weather Underground, Inc., will again be a National Sponsor of Portlight Disaster Relief.

Hundreds of members of the blog community have teamed with Portlight Strategies, Inc., throughout the last three and a half years to provide much needed relief services and supplies to victims and survivors of several natural disasters, both domestically and internationally.

These relief efforts focused on helping people with disabilities, as well as people in small towns and rural areas often marginalized by the larger institutional relief infrastructure.

Portlight Strategies, Inc., has committed to building on the stunning success of this collaborative, grassroots initiative.

"Weather Underground stepping up to be one of our National Sponsors again in 2012 is a huge honor", said Paul Timmons, Jr., Portlight Strategies, Inc., Board Chair.

"We are very pleased to continue our support of Portlight Strategies because they make a real difference to otherwise neglected communities that are affected by weather-related disasters around the globe", added Alan Steremberg, President and co-founder of Weather Underground.

Visit the Portlight blog on wunderground to learn more. Donations are always welcome!

Have a great weekend everyone, and I'll be back Monday with a new post.

Jeff Masters

Climate Summaries Extreme Weather

U.S. weather in 2011: unprecedented rains and wet/dry extremes

By: JeffMasters, 3:07 PM GMT on January 11, 2012

Rains unprecedented in 117 years of record keeping set new yearly precipitation totals in seven states during 2011, NOAA's National Climatic Data Center revealed in its preliminary year-end report for 2011. An extraordinary twenty major U.S. cities had their wettest year on record during 2011. This smashes the previous record of ten cities with a wettest year, set in 1996, according to a comprehensive data base of 303 U.S. cities that have 90% of the U.S. population, maintained by Wunderground's weather historian Christopher C. Burt. Despite the remarkable number of new wettest year records set, precipitation averaged across the contiguous U.S. during 2011 was near-average, ranking as the 45th driest year in the 117-year record. This occurred because of unprecedented dry conditions across much of the South, where Texas had its driest year on record.

Figure 1. Precipitation rankings for U.S. states in 2011. Seven states had their wettest year on record, and an additional ten states had a top-ten wettest year. Texas had its driest year on record, and four other states had a top-ten driest year. Image credit: NOAA's National Climatic Data Center.

Figure 2.Wettest, driest, and warmest year records set during 2011 for major U.S. cities. No major cities had their coldest year on record during 2011. Image credit: NOAA's National Climatic Data Center.

2011 sets a new U.S. record for combined wet and dry extremes
If you weren't washing away in a flood during 2011, you were probably baking in a drought. The fraction of the contiguous U.S. covered by extremely wet conditions (top 10% historically) was 33% during 2011, ranking as the 2nd highest such coverage in the past 100 years. At the same time, extremely dry conditions (top 10% historically) covered 25% of the nation, ranking 6th highest in the past 100 years. The combined fraction of the country experiencing either severe drought or extremely wet conditions was 58%--the highest in a century of record keeping. Climate change science predicts that if the Earth continues to warm as expected, wet areas will tend to get wetter, and dry areas will tend to get drier--so 2011's side-by-side extremes of very wet and very dry conditions should grow increasingly common in the coming decades.

Figure 3. Percentage of the contiguous U.S. either in severe or greater drought (top 10% dryness) or extremely wet (top 10% wetness) during 2011, as computed using NOAA's Climate Extremes Index. Remarkably, more than half of the country (58%) experienced either a top-ten driest or top-ten wettest year, a new record. Image credit: NOAA/NCDC.

23rd warmest year on record, and 2nd hottest summer for the U.S.
The year 2011 ranked as the 23rd warmest in U.S. history, with sixteen states recording a top-ten warmest year on record. Delaware had its warmest year on record, and Texas its second warmest. However, these statistics don't convey the extremity of the summer of 2011--the hottest U.S. summer in 75 years. The only hotter summer--and by only 0.1°--was the Dust Bowl summer of 1936, when poor farming practices had turned much of the Midwest into a parking lot for generating extreme heat. The June - August 2011 average temperatures in Texas and Oklahoma were a remarkable 1.6°F and 1.3°F warmer than the previous hottest summer for a U.S. state--the summer of 1934 in Oklahoma. The U.S. Climate Extremes Index (CEI), which is sensitive to climate extremes in temperature, rainfall, dry streaks, and drought, indicated that an area nearly four times the average value was affected by extreme climate conditions during summer 2011. This is the third largest summer value of record, and came on the heels a spring season that was the most extreme on record. When averaged over the entire year, 2011 ranked as the 8th most extreme in U.S. history, since the fall weather was near-average for extremes. The CEI goes back to 1910.

Figure 4. Average temperatures for the summer in Texas and Oklahoma, at 86.8 degrees F (30.4 degrees C) and 86.5 degrees F (30.3 degrees C), respectively, exceeded the previous seasonal statewide average temperature record for any state during any season. The previous warmest summer statewide average temperature was in Oklahoma, during 1934, at 85.2 degrees F (29.6 degrees C). Image credit: National Climatic Data Center.

Wunderground's weather historian Christopher C. Burt has a more detailed look at the U.S. extremes observed during 2011 in his latest post. His selection for the most remarkable yearly record set during 2011:

Perhaps, most astonishing is the total annual rainfall of just 1.06” at Pecos, Texas (normal annual precipitation is 11.61”). If confirmed this would be a Texas state record for least amount of precipitation ever recorded in a calendar year, the current record stands at 1.64” at Presidio in 1956.

Other posts looking back at the remarkable weather events of 2011
Top ten global weather events of 2011
2011: Year of the Tornado
Deadliest weather disaster of 2011: the East African drought
Tropical Storm Lee's flood in Binghamton: was global warming the final straw?
Wettest year on record in Philadelphia; 2011 sets record for wet/dry extremes in U.S.
Hurricane Irene: New York City dodges a potential storm surge mega-disaster

I'll have a new post on Friday.

Jeff Masters

Climate Summaries

Heavy rains, snows, and season's first tornadoes hit Texas

By: JeffMasters, 2:41 PM GMT on January 10, 2012

The nation's first major winter storm rumbled through Texas yesterday, bringing much appreciated heavy rains. The storm set also spawned the year's first two tornadoes, and brought record-setting heavy snows to West Texas. A wide swath of 3 - 5 inches of rain fell over much of Eastern Texas and Southern Louisiana, bringing isolated flooding to the drought-ravaged region. Houston, Texas received 4.06" of rain, breaking the previous record rainfall for the date of 2.54". It was the heaviest rainfall for Houston since the 4.87" that fell October 15, 2007. Drought-stricken Texas has now received the heaviest precipitation, relative to average, of any state in the U.S. during 2012, thanks to a highly abnormal jet stream pattern that is keeping the northern polar branch of the jet stream far to the north in Canada. The latest GFS model forecast predicts that this unusually dry pattern will persist for at least the next ten days, with the possibility of it breaking down during the last week of January.

Figure 1. Radar-estimated precipitation ending Tuesday morning, January 10, 2012, shows a wide swath of 3 - 5 inches for much of Eastern Texas and Southern Louisiana.

Figure 2. Departure of precipitation from average for the 7-day period January 2 - January 9, ending at 7 am EST. Texas has been the wettest state in the U.S., and the rest of the country has been incredibly dry. Image credit: NOAA/Advanced Hydrologic Prediction Service.

Year's first tornado hits Texas City
The first tornado of 2012 touched down near 1pm CST in Texas City yesterday. The twister hit the Mall of the Mainland, damaging its roof and blowing out windows of parked cars. No injuries were reported, but the storm flooded the mall with 2 - 3 inches of water, and the mall remains closed today. A separate tornado affected Fort Bend County, Texas, but caused no damage or injuries. January is typically the quietest month of the year for tornadoes in the U.S.; during the past three years, we've averaged seventeen tornadoes in the month of January. A few more tornadoes are possible today, as NOAA's Storm Prediction Center predicts that a slight chance of severe weather will continue along the cold front of the storm that spawned yesterday's tornadoes. New Orleans, the Florida Panhandle, and most of Mississippi and Alabama are at risk of seeing a few tornadoes and damaging winds from severe thunderstorms.

Heavy snow in West Texas sets all-time snow records for Midland
Yesterday's storm dumped 10.6 inches of snow on Midland, Texas, setting a record for the heaviest 1-day snow in city history. The previous record was the 9.8" that fell December 10 - 11, 1998. Midland's total snowfall for the winter of 2011 - 2012 is now 19.5". With winter not even half over, this smashes their previous seasonal snowfall record of 13.9", set in the winter of 1946 - 1947. Remarkably, Midland (population 111,000) has had more snow this year than America's four snowiest cities with population greater than 75,000--Syracuse, Rochester, and Buffalo (in New York's lake-effect snow belts), and Duluth, Minnesota:

Heavy snows hit Southern Alaska
If you're wondering where all of the snow that usually hits California's Sierras and the northern tier of U.S. states is going, the answer is Southern Alaska. This winter's highly abnormal jet stream pattern is slamming an unending series of heavy snow storms into Southern Alaska, where the snow totals are mind-bending. A snow storm on Sunday dumped 15.2" of snow on Valdez, Alaska, bringing the total snow this season to 290.5". That's 24.2 feet (7.4 meters), and is 12 feet (3.7 meters) above what the city normal has by January 10. The city is still a ways from breaking their monthly or seasonal snowfall records--their highest monthly snowfall was 180" in February 1996, and their highest seasonal total was 550.7", set during the winter of 1989 - 1990. Valdez received 152.2" of snow during December 2011, setting a new December snowfall record (records go back to 1949.) According to wunderground's weather historian Christopher C. Burt, Valdez is the snowiest low-level location in the world and averages about 328" every winter season. The Alaska state snowfall record is 974.1" (81.2', or 24.7 meters) at Thompson Pass in 1952-1953, just up the highway from Valdez. This record is beyond reach, since the site is no longer is no longer operating. The latest forecast for Valdez calls for another 10 - 15 inches of snow today.

I'll have a new post on Wednesday or Thursday.

Jeff Masters

Winter Weather Drought

Remarkably dry and warm winter due to record extreme jet stream configuration

By: JeffMasters, 4:06 PM GMT on January 06, 2012

Flowers are sprouting in January in New Hampshire, the Sierra Mountains in California are nearly snow-free, and lakes in much of Michigan still have not frozen. It's 2012, and the new year is ringing in another ridiculously wacky winter for the U.S. In Fargo, North Dakota yesterday, the mercury soared to 55°F, breaking a 1908 record for warmest January day in recorded history. More than 99% of North Dakota had no snow on the ground this morning, and over 95% of the country that normally has snow at this time of year had below-average snow cover. High temperatures in Nebraska yesterday were in the 60s, more than 30° above average. Storm activity has been almost nil over the past week over the entire U.S., with the jet stream bottled up far to the north in Canada. It has been remarkable to look at the radar display day after day and see virtually no echoes, and it is very likely that this has been the driest first week of January in U.S. recorded history. Portions of northern New England, the Upper Midwest, and the mountains of the Western U.S. that are normally under a foot of more of snow by now have no snow, or just a dusting of less than an inch. Approximately half of the U.S. had temperatures at least 5°F above average during the month of December, with portions of North Dakota and Minnesota seeing temperatures 9°F above average. The strangely warm and dry start to winter is not limited to the U.S--all of continental Europe experienced well above-average temperatures during December.

Figure 1. Flowers sprouting on January 1, 2012 in Keene, New Hampshire, thanks to unusually warm December temperatures and lack of snow. Image credit: Wunderphotographer lovne32.

Figure 2. Departure of snow depth from average on January 6, 2011. More than 95% of the country that normally has snow at this time of year had below-average snow cover (yellow and orange colors.) Image credit: NOAA/National Operational Hydrologic Remote Sensing Center.

December 2011 jet stream pattern the most extreme on record
The cause of this warm first half of winter is the most extreme configuration of the jet stream ever recorded, as measured by the North Atlantic Oscillation (NAO). The Arctic Oscillation (AO), and its close cousin, the North Atlantic Oscillation (which can be thought of as the North Atlantic's portion of the larger-scale AO), are climate patterns in the Northern Hemisphere defined by fluctuations in the difference of sea-level pressure in the North Atlantic between the Icelandic Low and the Azores High. The AO and NAO have significant impacts on winter weather in North America and Europe--the AO and NAO affect the path, intensity, and shape of the jet stream, influencing where storms track and how strong these storms become. During December 2011, the NAO index was +2.52, which was the most extreme difference in pressure between Iceland and the Azores ever observed in December (records of the NAO go back to 1865.) The AO during December 2011 had its second most extreme December value on record, behind the equally unusual December of 2006. These positive AO/NAO conditions caused the Icelandic Low to draw a strong south-westerly flow of air over eastern North America, preventing Arctic air from plunging southward over the U.S. and Europe.

Figure 3. December 2011 temperatures in Europe and the U.S. were well above average, thanks to a positive phase of the Arctic Oscillation (AO). Compare the U.S. plot with the plot of typical departures of temperature from average due to the positive phase of the AO (Figure 4.) The two patterns are nearly identical. Image credit: NOAA/ESRL.

Figure 4. The departure of temperature from average in Centigrade during the November - December - January period during various phases of the Arctic Oscillation (AO). Positive AO conditions lead to warm winters in the U.S., while negative AO conditions lead to cold winters. Image credit: NOAA/Climate Prediction Center.

Wild swings in the December Arctic Oscillation
This winter's remarkable AO/NAO pattern stands in stark contrast to what occurred the previous two winters, when we had the most extreme December jet stream patterns on record in the opposite direction (a strongly negative AO/NAO). The negative AO conditions suppressed westerly winds over the North Atlantic, allowing Arctic air to spill southwards into eastern North America and Western Europe, bringing unusually cold and snowy conditions. The December Arctic Oscillation index has fluctuated wildly over the past six years, with the two most extreme positive and two most extreme negative values on record. Unfortunately, we don't understand why the AO varies so much from winter to winter, nor why the AO has taken on such extreme configurations during four of the past six winters. Climate models are generally too crude to make skillful predictions on how human-caused climate change may be affecting the AO, or what might happen to the AO in the future. There is research linking an increase in solar activity and sunspots with the positive phase of the AO. Solar activity has increased sharply this winter compared to the past two winters, so perhaps we have seen a strong solar influence on the winter AO the past three winters. Arctic sea ice loss has been linked to the negative (cold) phase of the AO, like we observed the previous two winters. Those winters both had near-record low amounts of sunspot activity, so sea ice loss and low sunspot activity may have combined to bring a negative AO.

Figure 5. The December Arctic Oscillation (AO) index has fluctuated wildly over the past six years, with the two most extreme positive and two most extreme negative values on record. Image credit: NOAA/Climate Prediction Center.

The forecast for the remainder of January
We will (finally!) get the first major storm of 2012 in the U.S. early next week, when a low pressure system will develop over Texas and spread heavy rains of 1 - 3" along a swath from Eastern Texas to New England during the week. This storm will pull in a shot of cold air behind it late in the week, giving near-normal January temperatures to much of the country, and some snow to northern New England. Beyond that, it is difficult to tell what the rest of winter may hold, since the AO is difficult to predict more than a week or two in advance. The latest predictions from the GFS model show the current strongly positive AO pattern continuing for at least the next two weeks, resulting in very little snow and warmer-than-average temperatures. If we don't get significant snows during the latter part of winter, the odds of a damaging drought during the summer in the Midwest will rise. The soils will dry out much earlier than usual without a deep snow pack to protect them, resulting in a much earlier onset of summer-like soil dryness. Water availability may also be a problem in some regions of the west due to the lack of snow melt. Fortunately, most Western U.S. reservoirs are above average in water supply, due to the record-breaking snows of the previous winter.

Jeff Masters

Winter Weather

Damage losses and climate change

By: JeffMasters, 10:58 PM GMT on January 03, 2012

During 2011, a series of violent tornado outbreaks hit the Plains and Southeast U.S., bringing an astonishing six billion-dollar disasters in a three-month period. The epic tornado onslaught killed 552 people and brought three of the five largest tornado outbreaks on record in a six-week period, including the largest and most expensive tornado outbreak in U.S. history--the April 25 - 28 Super Outbreak, which did $10.2 billion dollars in damage. Insured losses due to thunderstorms and tornadoes in the U.S. were at least $25 billion in 2011, more than double the previous record set in 2010. Damages from thunderstorms and tornadoes since 1980 have shown a clear increase since 1980 (Figure 2.) Disaster losses world-wide from weather-related natural disasters have also shown a significant increase in recent years, as has the number of these disasters. But how much of this is due to a change in the climate, and how much might be due to increases in population, wealth, and other factors?

Figure 1. Damage in Tuscaloosa, Alabama after the April 27, 2011 EF-4 tornado. Image credit: NOAA.

Not enough evidence to judge if climate change is affecting tornadoes
As I discussed last week in my post, 2011: Year of the Tornado, as far as we can tell, the number of damaging tornadoes has not increased in recent years, though the quality of the data set is to poor to know for sure. This is largely due to the fact that we never directly measure a tornado's winds--a tornado has to run over a building before we can make an EF-scale strength estimate, based on the damage. As tornado researcher Chuck Doswell said in a 2007 paper, "I see no near-term solution to the problem of detecting detailed spatial and temporal trends in the occurrence of tornadoes by using the observed data in its current form or in any form likely to evolve in the near future." My 2008 post, Are tornadoes getting stronger and more frequent?, discussed how a better way to assess how climate change may be affecting tornadoes is to look at how the large-scale environmental conditions favorable for tornado formation have changed through time. The most important ingredients for tornado formation are usually high atmospheric instability (as measured by the Convective Available Potential Energy, or CAPE), and high amounts of wind shear between the surface and 6 km altitude. Not enough work has been done on the subject to judge whether or not climate change is affecting severe thunderstorms and tornadoes, though.

Figure 2. Insured losses due to thunderstorms and tornadoes in the U.S. in 2011 dollars. Data taken from Property Claims Service MR NatCatSERVICE. Image credit: Munich Re.

Are the number of weather-related disasters increasing?
At a talk given last month at the American Geophysical Union meeting in San Francisco, Mark Bove of Munich Re insurance company examined trends in both damages and number of natural disasters since 1980. These numbers have shown significant increases since 1980. After we take out the increase in disasters reported due to an increasing population, greater wealth, and more advanced communications, is there a trend due to climate change? One way to check is to compare natural disasters due to geophysical events--earthquakes, tsunamis, and volcanic eruptions--to weather-related disasters. Geophysical disasters should remain relatively constant in number in a changing climate (unless sea level rise is occurring so rapidly that it is causing significant changes in stress on earthquake faults, something that is theoretically possible, but has not yet been observed.) If we then look at trends in the number of geophysical disasters versus weather-related disasters reported, it should give us an idea of how much of the recent increase in weather-related disasters may be due to climate change. Between 1980 and 2010, geophysical disasters increased by about a factor of 1.5, while weather-related disasters increased by a factor of 2.7 to 3.5 (Figure 3.) Bove stated that he thought weather-related disasters were likely subject to a higher increase in reporting rate than geophysical disasters, but not enough to account for the huge difference. Climate change was the likely reason for a large portion of the increase in weather-related disasters in recent years, he argued. His talk concluded, "there is quite some probability that natural catastrophe losses are driven already by human-caused climate change."

Figure 3. The number of natural disasters reported has increased markedly worldwide since 1980, particularly for weather-related disasters. Image credit: Munich Re.

However, this conclusion is controversial. A 2010 paper in the Bulletin of the American Meteorological Society by Netherlands researcher Laurens Bouwer titled, "Have disaster losses increased due to anthropogenic climate change?", looked at 22 disaster loss studies world-wide, published between 2001 and 2010. All of the studies showed an increase in damages from weather-related disasters in recent decades. Fourteen of the 22 studies concluded that there were no trends in damage after correcting for increases in wealth and population, while eight of the studies did find upward trends even after such corrections, bringing up the question whether or not climate change could be responsible for the increased disaster losses. However, Bouwer found that "studies that did find increases after normalization did not fully correct for wealth and population increases, or they identified other sources of exposure increases or vulnerability changes or changing environmental conditions." In all 22 studies, increases in wealth and population were the "most important drivers for growing disaster losses." He concluded that human-caused climate change "so far has not had a significant impact on losses from natural disasters."

Using storm surge to evaluate damage normalization studies
Damage from landfalling storms can be used to estimate if hurricanes are growing stronger with time, but damage estimates must first be corrected to account for changes in wealth and population over time. A 2008 study by Pielke et al. found that although hurricane damages had been doubling every ten years in recent decades, there were no increases in normalized hurricane damages in the U.S. from 1900 - 2005. They used census and economic data to adjust for how increases in populations and wealth may have affected hurricane damages over time. However, Grinsted et al. (2012) questioned whether or not this was done correctly. They found that storm surge heights of U.S. hurricanes and tropical storms correlated very well with metrics that looked at storm intensity, when looking at many decades of data to see long-term trends. However, the researchers found that while short-term trends in normalized hurricane damage estimated by Pielke et al. (2008) did correlate well historical storm surges, these normalized damages had poor correlation with the storm surge record, when looking at decades-long time scales. This implies that the corrections were biased. Dr. Stephan Lewandowsky of the University of Western Australia makes the case that efforts such as the one done by Pielke et al. (2008) to normalize disaster losses are probably biased too low, since they only look at factors that tend to increase disaster losses with time, but ignore factors that tend to decrease disaster losses. These ignored factors include improvements in building codes, better weather forecasts allowing more preparation time, and improved fire-fighting ability. He writes, "Most normalization research to date has not accounted for those variables because they are extremely difficult to quantify. (And most researchers have been at pains to point that out; e.g., Neumayer & Barthel, 2011, pp. 23-24.) In effect, normalization research to date largely rests on the oddly inconsistent pair of assumptions that (a) we have built up enormous wealth during the 20th century but (b) did so without any technological advance whatsoever." For example, during a severe October 2013 windstorm that did over $1 billion in damage to France, England, Germany, the Netherlands, and Denmark, "The insured losses for the St. Jude's Day storm would have been significantly higher but for the accuracy in weather forecasting several days ahead of the storm's formation", said financial information services company Fitch Services, since "policyholders have more time to protect their property from potential damage, while government agencies, utility firms and transport companies can make logistical arrangements to minimize disruption to power supplies and transport networks."

Studies showing no increase in normalized damage from storms have high uncertainty, and it is possible that higher economic damages due to stronger storms is indeed occurring, though the current research does not show this. Looking at disasters losses to make an argument that climate change is affecting our weather is difficult, due to the rarity of extreme events, and the changes in wealth and population that also affect disaster losses. We are better off looking at how the atmosphere, oceans, and glaciers are changing to find evidence of climate change--and there is plenty of evidence there.

Tornado researcher Dr. Harold Brooks has a May 2012 op-ed in New Scientist that discusses the difficulty in predicting how climate change will impact tornadoes.

Bouwer, L, 2010, "Have disaster losses increased due to anthropogenic climate change?", BAMS, January 2011, DOI:10.1175/2010BAMS3092.1

Doswell, C.A., 2007, "Small Sample Size and Data Quality Issues Illustrated Using Tornado Occurrence Data", E-Journal of Severe Storms Meteorology Vol 2, No. 5 (2007).

Del Genio, A.D., M-S Yao, and J. Jonas, 2007,
Will moist convection be stronger in a warmer climate?, Geophysical Research Letters, 34, L16703, doi: 10.1029/2007GL030525.

Grinsted, A., J. C. Moore, and S. Jevrejeva, 2012, "A homogeneous record of Atlantic hurricane surge threat since 1923," PNAS 2012, doi:10.1073/pnas.1209542109

Marsh, P.T., H.E. Brooks, and D.J. Karoly, 2007, Assessment of the severe weather environment in North America simulated by a global climate model, Atmospheric Science Letters, 8, 100-106, doi: 10.1002/asl.159.

Neumayer, E. & Barthel, F. (2011). Normalizing economic loss from natural disasters: A global analysis Global Environmental Change, 21, 13-24.

Pielke et al., 2008, "Normalized Hurricane Damage in the United States: 1900–2005", Natural Hazards Review, Volume 9, Issue 1, pp. 29-42.

Riemann-Campe, K., Fraedrich, K., and F. Lunkeit, 2009, Global climatology of Convective Available Potential Energy (CAPE) and Convective Inhibition (CIN) in ERA-40 reanalysis, Atmospheric Research Volume 93, Issues 1-3, July 2009, Pages 534-545, 4th European Conference on Severe Storms.

Trapp, R.J., N.S. Diffenbaugh, H.E. Brooks, M.E. Baldwin, E.D. Robinson, and J.S. Pal, 2007, Severe thunderstorm environment frequency during the 21st century caused by anthropogenically enhanced global radiative forcing, PNAS 104 no. 50, 19719-19723, Dec. 11, 2007.

Jeff Masters

Climate Change Extreme Weather

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.

Category 6™


Cat 6 lead authors: WU cofounder Dr. Jeff Masters (right), who flew w/NOAA Hurricane Hunters 1986-1990, & WU meteorologist Bob Henson, @bhensonweather