Scientific Forecaster Discussion
fxus65 kvef 290904
Area forecast discussion
National Weather Service Las Vegas Nevada
204 am PDT sun Mar 29 2020
Synopsis...a weak weather system will bring scattered showers
and isolated thunderstorms to areas mainly north of Las Vegas
today. For next week, high pressure will rebuild over the region
allowing temperatures to climb several degrees each day and
trending above normal by mid week and into the weekend.
Discussion...through next week.
Weak upper level trough will drift across the Great Basin today,
accompanied by a pool of -20 to -25c air at 500mb. This will
result in some marginal instability and promote scattered shower
activity through the day, mainly north of Las Vegas, as well as
the potential for a few lightning strikes. Convective allowing
guidance focuses most of the activity across Lincoln County and
the Sierra into the southern Great Basin region. However, a few
showers may drift as far south as Clark County and northern Mohave
County during the afternoon and evening hours, with dry conditions
with any further southward extent.
The aforementioned trough will shift eastward tomorrow with
rebounding heights and gradually warming temperatures through the
week ahead. Still looks on track for the first appearance of 80
degree weather in Las Vegas by midweek, before slightly stronger
troughing develops over the northern rockies and knocks regional
heights down a bit.
Confidence in forecast details begins to degrade by the weekend,
with GFS and European model (ecmwf) model means tending to favor at least some
degree of ridging (dry & warm) despite the latest operational
solutions suggesting renewed troughing (cooler & unsettled).
Cluster analysis supports the idea of stronger ridging being favored,
but will need to monitor trends for the potential of cooling
conditions by early next week.
Aviation...for McCarran...light winds expected through the
morning with a push of southwest winds expected this afternoon with
occasional gusts to around 20 knots. Lower cigs expected to continue
through Sunday with ceilings dipping to around 5-7 kft later this
morning. Slight chance for isolated to scattered showers in and
around the Las Vegas Valley later this afternoon through the
evening, mainly between 20-05z today. Low confidence, but if a
shower moves over klas, ceilings may drop to around 5 kft. Outside
chance of a few lightning strikes with some of the stronger storms
this afternoon as well. Dense cloud cover will move east by around
06-07z tonight, leaving only few aoa 10 kft. Sky clear expected by 10-12z
Monday. Possible wind shift to the northwest later this evening but
confidence is low winds would be much more than 7-8 knots with this
brief wind shift. Light winds following typical diurnal trends
expected to return early Monday morning.
For the rest of southern Nevada, northwest Arizona and southeast
California...light winds expected through the morning with a push of
southwest winds expected this afternoon with gusts to around 20.
Stronger winds expected at kdag where gusts to around 25 knots are
possible. Scattered showers and a few storms are possible across
southern Nevada and parts of the Mojave Desert this afternoon, primarily
impacting kbih and the Las Vegas Valley taf sites. Broken mid to
high clouds expected to remain through much of the day today across
the region with cigs expected aoa 8-10 kft. Dense cloud cover will
move east later tonight, leaving mostly clear skies. Winds expected
to relax this evening and typical diurnal winds will return Monday.
Spotter information statement...spotters are encouraged to report
any significant weather or impacts according to Standard operating