Category 6â„¢

Air Quality Awareness Days

By: JeffMasters, 8:41 PM GMT on June 30, 2005

The EPA has designated June 29 - July 1, "Air Quality Awareness Days". This designation is well-timed--the past two weeks have seen an unusual number of very hot days with light winds across large areas of the U.S. This, combined with June's high levels of UV light (which is needed to drive the chemical reactions that make smog), have conspired to produce some of the highest levels of air pollution across the U.S. in many years. Ground level ozone, the primary pollutant of concern in the summer, has been a particular problem. The EPA standard for ozone pollution is 80 ppb for an 8-hour period. If three or more violations of this standard occur in a year, the offending city must take action to reduce emissions or pay fines. There are a lot of cities that will be paying big bucks to reduce emissions, thanks to this June's hot weather. A sampling of who's been violating can be seen in the animation below. Everywhere the image is orange (AQI greater than 100), is an ozone air quality violation.

Chicago has had multiple sampling sites violate the ozone standard on 7 consecutive days.

Houston or Dallas (or both) have exceeded the ozone standard nearly every day the past week, with Houston posting a very unhealthy 103 ppb over an 8-hour period on June 28.

Denver recorded ozone violations at 2 locations on June 18.

California continues to lead the U.S. in air quality violations. If we take a look at the list of the 10 U.S. cities with the most ozone air pollution violations for 2004, five of the top seven cities are in California:

Number of 2004
City ozone violations
Bakersfield,CA 103
Riverside, CA 88
Los Angeles, CA 65
Houston, TX 37
Sacramento, CA 25
Fresno, CA 23
Dallas, TX 20
Ventura, CA 17
Ft. Worth, TX 15
Orange County, CA 12

As part of Air Quality Awareness Days, the EPA urges everyone to be more aware of the types of air pollution their area encounters. They also have suggestions on what to do to protect your health during a high pollution event, and how you can cut down our contribution to air pollution levels. I highly recommend the EPA Airnow web site for those interested to learn more.

The good news is that overall, we have been making progress on reducing ozone pollution in the U.S. Nationally, 2003 levels were 9% lower than 1990 levels and 21% lower than 1980 levels. However, these statistics were unadjusted to reflect variations in meteorology, and the real ozone improvements are less than this. Certainly, this summer's hot weather will skew the statistics, perhaps so far as to make it so no net progress in ozone levels may be seen when compared to 10 years ago.

Dr. Jeff Masters

Air and Water Pollution

Tropical Storm Bret

By: JeffMasters, 11:29 AM GMT on June 30, 2005

OK, blink and you'll miss this tropical storm. Tropical Storm Bret formed last night in the Bay of Campeche off Mexico, and is already on its way ashore. By tonight, it should be well inland and not even classifiable as a tropical depression.

Bret is the 2nd troical storm to form in the Atlantic this June, which is an unusual amount of activity for June. Since 1851, there have only been 12 occurrences of two or more tropical storms in the month of June, most recently in 1986. Does this portend an active hurricane season? Well, if we look at the plot of hurricane activity for 1986, we see that although that year had two June tropical cyclones, the rest of the year was well below average, with a total of only 6 tropical cyclones (11 is average). I remember the year well, it was the first year I flew into hurricanes as a member of the Hurricane Hunters. I was excited about doing a lot of flying that year, and my first flight of my career happened in June of that year. I flew into Hurricane Bonnie, a weak category one hurricane that hit Texas. The sight of huge waves crashing into the oil rigs we flew over, all lit up at night by Bonnie's lightning, made for an unforgettable first flight. But unfortunately for me, (and fortunately for the residents of the Atlantic Seaboard) the rest of the season was a dud, and we ended up having to fly down to Puerto Vallarta to chase hurricanes over the Eastern Pacific. In those days, the NOAA hurricane hunters were given 100 - 200 flight hours to use for hurricane research, and if there were no worthy Atlantic storms, we often worked storms off of Mexico in the Eastern Pacific. Actually Puerto Vallarta was not so bad a place to work out of! We stayed at a great beach front hotel (cheap since it was the off-season), and watched huge waves from Hurricane Paine smash down the 10-foot seawall protecting our hotel's swimming pool and push the debris into the pool.

Examination of other Junes reveals that there is no significant correlation between June tropical storm activity and the rest of hurricane season. However, the position and intensity of the Bermuda High and sea surface temperatures in the tropical Atlantic are more typical of what things should be like a month from now. We are already beginning to see strong tropical waves with impressive satellite presentations come off the coast of Africa, and that is unusual for June. In fact, the GFS model takes one of those waves and develops it into a hurricane next week as it sweeps north of the Leeward Islands, past Bermuda around July 6, then out to sea. It will be interesting to see if the GFS model is correct. If so, this would likely be the harbinger of an active hurricane season.

The Keeling Curve

By: JeffMasters, 2:46 PM GMT on June 27, 2005

Dr. Charles D. Keeling, whose pioneering work on measurement of atmospheric carbon dioxide levels helped draw attention to the global warming issue, died June 20, 2005, at his home in Montana. He was 77. The cause was a heart attack after a short hike, acording to the Scripps Institution of Oceanography in San Diego, where Dr. Keeling had long worked.

In 1955, Keeling became the first researcher to take measurements of atmospheric CO2 and establish that levels were the same regardless of the location. Mountaintops or polluted cities, California or Hawaii, it didn't matter--the magic number 315 parts per million (ppm) invariably came up. Keeling did note a seasonal fluctuation--CO2 values increased steadily during the winter, peaking at about 318 ppm, then fell back to 314 ppm with the onset of Spring. He corrected attributed the behavior to the fact that in Spring, plants suddenly take up a large amount of CO2, then gradually release it back to the atmosphere in Fall and Winter as the leaves fall and rot, releasing their stored carbon.

Beginning in 1958, Keeling took regular CO2 measurements at the top of Mauna Loa volcano in Hawaii. As the measurements progressed over the years, Keeling noted a steady increase of about 1.5 ppm per year. His plot of the increase, now called the "Keeling Curve", represents the most telling evidence of human impact on Earth's climate. While many other scientific findings on global climate change have come under attack, no one has challenged the steady and significant increase in CO2 found by Dr. Keeling--an increase solely attributable to human-caused burning of fossil fuels.

"I don't think I'm aware of any controversy about Dave's measurements, and that's really kind of remarkable," said Dr. Walter Munk, an oceanographer and colleague of Dr. Keeling at Scripps for 30 years, in an interview with CNN. "Dave was a stickler for every detail in connection with his experimental work."

The Keeling Curve continues it inexorable march upward at 1.5 ppm per year, and was at 378 ppm at the end of 2004. The rate of increase took an unexpected jump to 2.4 ppm per year for the years 2002 and 2003, sparking fears that a major change in emissions had transpired. But the Keeling Curve returned back to normal for 2004, with another 1.5 ppm increase in CO2. Scientists attributed the 2-year increase to natural processes, possibly tied to droughts and fires, or such factors as global temperatures, rainfall amounts and volcanic eruptions. In 1996, Dr. Keeling and colleagues showed that seasonal swings of carbon dioxide levels in the Northern Hemisphere were becoming larger, possibly a sign that the growing season is beginning earlier because of global warming.

One humorous note, taken from Gale Christianson's interesting 1999 book, Greenhouse: The 200-year Story of Global Warming, relates the story of CO2 measurements Keeling took in California during 1955. He traveled all across the West Coast, taking CO2 measurents in remote mountainous areas. He kept all his notes and measurements in a thick green notebook, and awoke horrified one night in Yosemite National Park to find a hungry mule deer scampering away from his campsite with the precious notebook clutched in its teeth. Keeling charged out into the snow-covered woods with his flashlight, desperately seeking the notebook with months of irreplacable data in it. Finally, a glint of color caught his eye, and he found his notebook, binding torn away and pages indented by a large set of teeth. He repaired the damage with a few strips of tape and was back in business. The moral of the story: back up your hard drive!

Charles David Keeling was born in Scranton Pa, earned his bachelor's degree in chemistry from the University of Illinois in 1948 and his doctorate in chemistry from Northwestern University in 1954. Dr. Keeling was elected to the National Academy of Sciences in 1994 and received the National Medal of Science in 2002.

Dr. Jeff Masters

Climate Change

Update on the National Weather Service Duties Act of 2005

By: JeffMasters, 8:42 PM GMT on June 20, 2005

From the Wichita, KS Eagle:

In several earlier blogs, I discussed that it may soon be illegal for the National Weather Service to issue non-severe weather forecasts under the provisions of the National Weather Service Duties Act of 2005, Senate Bill S.786, introduced April 14 by Sen. Rick Santorum, R-Pa. The bill's key provision (Section 2b) states that the National Weather Service cannot provide "a product or service...that is or could be provided by the private sector", with the exception of severe weather forecasts and warnings needed to protect life and property. Secretary of Commerce Carlos Gutierrez is given sole authority on how to interpret what NWS products and services should be restricted.

Since that discussion, the outcry against this piece of legislation has been widespread; a search for "Santorum National Weather Service" at reveals a large number of opinion pieces in various news reports, nearly all of them unfavorable to the bill. In particular, many criticized the timing of Santorum's release of the bill, which came 2 days after he received a $2000 donation from Joel Myers, the CEO of Accuweather, at a fundraiser. "I don't think there's any coincidence between the two," Santorum said. "It's just that I happened to have a fundraiser in the town he was in."

Sen. Santorum has been defending the legislation in a number of radio spots broadcast in Pennsylvania the past two months, but has taken substantial criticism in Pennsylvania for the bill. This may be part of the reason that June 2005 polls show him running 15 points behind in his 2006 election campaign against Democratic challenger Robert P. Casey, Jr. Two powerful unions, the National Weather Service Employee's Union and the Aircraft Owner's and Pilot Association, have been active in lobbying against the bill.

So what is likely to happen to the National Weather Service Duties Act of 2005? The bill is still sitting in the Committee on Commerce, Science, and Transportation, and has no co-sponsor in the Senate. The unpopularity of the bill makes it unlikely that the Committe will act upon the bill anytime soon. The most likely way the bill would make it into law is if Sen. Santorum manages to sneak the bill in as an amendment or rider to some other important piece of legislation. Given that he is the number three man in the Senate leadership, this is a distinct possibility. I will keep you all informed on the situtation and let you know if this happens, when your emails, faxes, and phone calls to oppose the bill will be needed.

It is interesting to note that Congress is working on wording in current legislation to "urge" (but not require) the NWS to not compete with the private sector. The House Science, State, Justice, Commerce and Related Agencies Appropriations Bill for 2006 includes the following language:

"The Committee urges the National Oceanographic and Atmospheric Administration and the National Weather Service to take maximum advantage of capabilities and services that already exist in the commercial sector to eliminate duplication and maximize the accomplish of the core mission of the National Weather Service."

This is the same language that was adopted by both the House and Senate as part of the report to the 2005 Omnibus Appropriations Bill last November, and seems like a far more reasonable way to foster non-competition between the NWS and the private sector than Sen. Santorum's bill.

One other note--the June 2005 issue of Business 2.0 magazine has an interesting 4-page article about Accuweather titled, "Stormy Weather." The article criticizes Accuweather for its adverserial relationship with the NWS: "And yet, when you ask Myers [Accuweather CEO] to assess the competetive landscape, he still can't seem to focus on the Weather Channel, the upstart company that has taken him to the cleaners. 'Our main competition,' he says, without a hint of irony, 'is the National Weather Service.' " Dr. Myers should heed this advice, and stop wasting everyone's time trying to push legislation to restrict the flow of National Weather Service information. The NWS works pretty well, and the taxpayers are mostly happy with it--so let's leave it alone.

Dr. Jeff Masters

How to oppose The National Weather Service Duties Act of 2005. The National Weather Service Duties Act of 2005 is currently before the Senate Commerce Committee, and will have to make it out of there before the full Senate votes on it. The time to kill this bill is now! Write your Senator if he or she is on the Senate Commerce Committee:


The benefits of hurricanes

By: JeffMasters, 1:12 AM GMT on June 23, 2005

My cousin, who is a soybean farmer in Northwest Indiana, complained to me this past Memorial Day weekend that he had never seen conditions so dry this time of year. The water level of the Tippecanoe River was the lowest he could remember, and the soybeans he'd planted were in serious danger of sharply reduced yields due to the drought.

Help came to his crops from an unusual source for Indiana--a tropical storm. While hurricanes and tropical storms make up an important part of the yearly rainfall budget in places like the Southeast U.S. and Japan, it is rare for the moisture from these storms to make a difference in inland locations, like Indiana. However, the image below, taken from the National Drought Mitigation Center, shows that Arlene, which dropped 2 - 3 inches of rain over much of Indiana on June 11, sharply reduced drought conditions there and in surrounding states.

Hurricanes and tropical storms are usually seen as terrible destructive forces of nature. However, they are an integral part of nature, and life in hurricane-prone areas has evolved to adapt to these great storms and even benefit from them. As we've seen, they can bring drought-busting rains. They can also perform the same cleansing function as forest fires in maintaining the conditions needed for healthy coastal forests, particulary in swampy mangrove forests. The intense rainfall of tropical cyclones causes high soil runoffs, resulting in high sediment levels being deposited in estuaries threatened by rising sea levels. Hurricane storm surges also carry substantial amounts of sediments and nutrients in coastal marshes. Studies show that hurricanes cause little long-term damage to marshes. While foliage may be stripped, the stimulation from new nutrients brought by the hurricane quickly returns the marshes to their original condition.

That being said, my cousin has a reason to be concerned about the negative impacts of Tropical Storm Arlene on his crops. The reason? Tropical cyclones are notorious spreaders of non-native invasive plants--in this case, a damaging fungus called soybean rust. Soybean rust, which spread from Asia to the Caribbean in recent years, first appeared in Alabama, Florida, Georgia, and six surrounding states in November 2004. It is thought to have been blown in from the Caribbean by Hurricane Ivan. There is concern that the winds of Arlene may have been strong enough to spread the spores as far north as Indiana, so my cousin's crops may have to adapt to deal with both the good and bad effects of Arlene.

Dr. Jeff Masters

Here comes Arlene!

By: JeffMasters, 6:55 PM EDT on June 08, 2005

Arlene is gone, leaving behind little in the way of damage, no deaths or injuries, and some beneficial rainfall to areas north of the landafall point that needed it. Overall, I thought the NHC did a nice job forecasting and not overhyping the storm, and the media definitiely overhyped the storm. It's best not to get too excited about June tropical storms! A few rainfall totals from Arlene:

Location Storm total
Panama City FL 5.4
Naples FL 5.3
Fort Myers FL 4.8
Mobile al 4.5
Pace FL 4.4
Homestead FL 4.2
Columbus MS 4.2
West Kendall FL 3.4
Pensacola FL 3.4
Milton FL 3.3
Atmore al 3.3
Macdill AFB FL 3.3

Additionally a cooperative observer near Royal Palm Beach FL
reported 6.8 inches of rain between 7 am June 9 and 7 am CDT June11.

Check out the regional radar landfall loop for Arlene.

Dr. Jeff Masters

Blog Entry for Saturday, June 11
Arlene is finally starting to resemble a hurricane, with a well-defined eye developing, and deep convection starting to wrap around the eye on the north and west sides. There is still a lot of dry air surrounding the storm, though, and that has prevented Arlene from becoming a hurricane. Dry air is frequently the nemesis of June tropical storms, since in June the jet stream is still far enough south that there is plenty of dry continental air being pulled south over the Gulf of Mexico by mid-latitude low pressure systems.

Arlene will likely hit land before much intensification can occur, so the residents of Alabama and Florida will dodge this blow for the most part. It's amazing how close the track of Arlene is to Hurricane Ivan's track!

Looking ahead to the next few days, strong winds over the Caribbean should keep the tropical wave in the eastern part from developing into anything until perhaps Monday or Tuesday, when the winds will relax and potentially allow a new tropical depression to form. Let's put the odds of this happening at about 25%.

Blog Entry from Friday, June 10
Arlene has been strengthening today, with maximum sustained winds at 5pm EDT of 65 mph. But again, the storm looks pretty unimpressive on satellite imagery, with an exposed center with deep convection just beginning to wrap around the center. The main weather is in a narrow band to the northeast of the center, and the central pressure is a very high 997 mb, only 6 mb lower than when the storm formed. Arlene still has a ways to go before it reaches hurricane status--75 mph winds and a well-defined eye--and not much time to get its act together before landfall Saturday. The Florida Panhandle will probably get some minor damage from the storm (less than $10 million), but Arlene may end up being more of a boon than a bane, since it will provide a substantial amount of rainfall to areas that need it. Tropical storms provide a important part of the rainfall the Southeast U.S. needs each year, and area agriculture would suffer greatly without the rains these storms provide.

Blog Entry from Thursday, June 9
Well, we have the first tropical storm of the season, Arlene. As is typical for early-season June storms, Arlene is disorganized and pretty unimpressive looking, with its center devoid of deep convection and tropical storm force winds present only in one modest band northeast of the center. The prospects for the storm to attain hurricane strength appear dim. Upper level winds on the west side of the storm are a little too strong to allow the storm to build up a nice inner core--the winds are disrupting things before they have a chance to get started. Add to this the fact that the sea surface temperatures are still relatively cool, and the storm is only expected to remain over sea until Saturday morning, and you arrive at the conclusion that hurricane status is unlikely for Arlene.

Although the official NHC forecast takes the center of Arlene west of the Florida Panhandle, the Panhandle should take the worst of the storm, since most of the strong winds are in a band northeast of the center. Let's hope that Florida taking the brunt of this first storm of the season is not a portent of things to come--the 2004 hurricane season was quite enough for Florida!

Blog Entry from Wednesday, June 8
Well, the disturbance in the Western Caribbean got its act together enough to become Tropical Depression One. Since the system is moving slowly, and has plenty of warm water and light vertical wind shear to contend with, it is likely to become Tropical Storm Arlene in the next 36 hours. The current NHC forecast brings the storm northward into the Gulf of Mexico, which as we can see by looking at the Historical Map, is typical for a June storm that forms in this location. The polar jet stream is still active this time of year, and creates many southward-extending troughs of low pressure that steer tropical cyclones northward.

It is interesting to note that the 5 tropical cyclones that formed in June in the Western Caribbean all hit the west coast of Florida. The current best guess NHC forecast takes the storm west of the Florida Panhandle, but includes Florida in its cone of probability, so Florida could be picking up where it left the 2004 hurricane season--in the bullseye.

First Atlantic tropical depression forming?

By: JeffMasters, 12:40 PM EDT on June 07, 2005

Take a look at the gathering clouds over the western Caribbean Sea, just north of Honduras. All the ingredients are in place for the first tropical depression of the season to form--surface pressures are starting to fall, upper level winds are creating a favorable outflow pattern of high cirrus clouds, and there is low vertical wind shear and warm 87 degree Fahrenheit water. I'd estimate that Western Caribbean systems at this stage of organization this time of year form into tropical depressions about 30% of the time. It is not well understood why so many of these type of systems fail to form into tropical depressions when all the ingedients needed are seemingly in place; this is an area of intensive research.

If a tropical depression does form, the GFS computer model predicts it will move north into the Gulf of Mexico and possibly threaten the U.S. Gulf Coast. However, this computer model is very unreliable at predicting the motion of tropical systems that haven't formed yet. For the most reliable information on developing tropical systems, read the National Hurricane Center's
Tropical Weather Outlook
, which is updated daily at 11am, 5pm, 11pm, and 5am EDT during hurricane season.

Dr. Jeff Masters

Tornado Drought

By: JeffMasters, 4:57 PM GMT on June 06, 2005

This weekend saw the largest tornado outbreak of the year, with 37 tornadoes reported on Saturday--primarily across Oklahoma, Kansas, Missouri, and surrounding states, and 17 more tornadoes across the northern Midwest on Sunday. However, no deaths or major damage was reported with any of these tornadoes, continuing the trend of this unusually kind 2005 tornado season.

Only five people have died since January 1, and none in April, May, or June, usually the worst months for tornado activity. The record fewest number is 15, set in 1986. So, 2005 could challenge this record, with the busiest part of tornado season already behind us (however, note that 2002 also was looking this way, with only 11 tornado deaths by June, but 37 fatalities occurred in November of that year). For comparison, tornadoes kill an average of 51 people a year, with 19 of these deaths in May, the deadliest month. For the continental Unites States, May had a preliminary tornado count of 129--the thirteenth lowest on record.

And for the first time ever, Oklahoma went the entire month of May without a tornado. Oklahoma's average is 21 tornadoes in May. The previous low was two tornadoes, in 1988. The record is 90, set in 1999 (the May 3 Oklahoma City tornado of 1999 marked the last F5 tornado to affect the U.S., and remains the fourth most expensive tornado ever--over $1 billion in damage--and the tornado with the highest winds ever measured--318 mph).

Why so few tornadoes this year? A very cold upper-level low pressure system over the Great Lakes and Northeast has provided unseasonable cool weather from the northern Plains to the mid-Atlantic states and prevented much middle-level moisture from moving northward from the Gulf of Mexico. This moisture is the key fuel needed to energize tornadic thunderstorms.

What's the outlook for the remainder of tornado season? The next 10 days of June look to be pretty normal, as far as tornado activity goes. The cold upper-level low pressure over the Northeast is gone now, and has been replaced with a typical jet stream pattern of frequent low presure systems passing across the country that favor the usual amount of tornado activity. Two separate weather systems embedded in this jet stream pattern could trigger tornadoes today over New York and surrounding states, as well as North Dakota and Montana.


Hurricane season begins

By: JeffMasters, 11:19 AM EDT on June 01, 2005

Atlantic Hurricane season officially begins today, Wednesday, June 1, and runs through November 30. This year's season is expected to continue the trend of above-normal activity seen since 1995. Both NOAA and Colorado State Professor Bill Gray's team predict a much more active than usual season. NOAA expects a 70% chance of an above-normal hurricane season, a 20% chance of a near-normal season, and only a 10% chance of a below-normal season. Long-term averages for the number of named storms and hurricanes are 10 and 6, respectively. Bill Gray's team predicts 15 named storms and 8 hurricanes, with a 77% chance of at least one major hurricane (Category 3 or higher) hitting the U.S.

Among the factors expected to cause a more active hurricane season are:

1) The absence of El Niño. According to NOAA's Climate Prediction Center, last year's weak El Niño conditions ended in April 2005, and El Niño conditions are not expected to recur during this year's hurricane season. There is a well-known link between El Niño and Atlantic hurricane activity, with El Niño favoring fewer hurricanes and La Niña favoring more hurricanes.

2) Much warmer than average sea surface temperatures (SSTs). Atlantic SSTs are at their highest in over 50 years, and are close to being the highest on record. This means plenty of high-octane "fuel" for hurricanes.

3) We are in the middle of a multi-decadal period of high Atlantic hurricane activity. Atlantic hurricane seasons have decades-long periods of generally above-normal or below-normal activity. These fluctuations are tied to a complicated set of natural cycles that occur in the winds and ocean currents over the Atlantic. Beginning with 1995 all of the Atlantic hurricane seasons have been above normal, with the exception of two El Niño years (1997 and 2002). This contrasts sharply with the generally below-normal activity observed during the previous 25-year period 1970-1994.

If you live in Florida, it's going to be tough to match last year's hurricane season, though. I compute the odds of at least four hurricances hitting Florida (3 of them major hurricanes) as happened in 2004 as a once in 300 year event. Two years back-to-back like that would happen once every 90,000 years.

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 6â„¢


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