Winter Weather Advisory 4, NWS Las Vegas, NV

Area Forecast Discussion
National Weather Service Las Vegas NV
735 PM PST Wed Mar 10 2021

.SYNOPSIS...A large and slow moving Pacific storm system will
begin to affect our region and bring cool showery weather through
Friday. Scattered to numerous showers are possible each day with
mainly light snow accumulations in the higher terrain above 4000
feet. Dry conditions return over the weekend with moderating
temperatures.
&&

.UPDATE...Radar continues to show scattered showers across eastern
Clark and northern Mohave County this evening. Some isolated light
showers are also being detected west of Las Vegas over the Spring
Mtns. Shower movement continues toward the northeast. Elsewhere,
loss of daytime heating has brought a significant decrease in radar
returns. For the rest of tonight, guidance shows most of the light
showers activity persisting across northern Mohave County then
wrapping back westward across Lincoln, central Nye and Esmeralda
Counties. Light flurries will continue over the Spring Mtns and
Sheep Range. Any new accumulations will likely be less than 1".

Cold upper low presently over northern California will slowly sag
south across southern California and the southern Great Basin by
late Thursday afternoon. Conditions will be very similar to today as
the air mass destabilizes under steepening lapse rates under cold
pool aloft. Would expect to see some of our stronger, but brief
storm cores occur southeast of I-15 tomorrow afternoon/early
evening. Gusty winds and small hail are possible.
&&

.DISCUSSION...Tonight through Wednesday.

The weather pattern through the rest of the week will be dominated
by a closed upper level low drifting across the Southwest US. This
will bring several rounds of showers and cooler temperatures to the
region.

The current area of showers should continue to rotate northeast this
evening and overnight. Coverage should also decrease with the loss
of daytime heating and general diffuse forcing instead of any
specific focused forcing like we have this afternoon. Best chances
tonight should be over the southern Great Basin.

The main low will shift eastward on Thursday. Expecting an uptick in
showery activity again tomorrow afternoon, with at least some chance
for precipitation across the entire area as temperatures aloft will
be cooler than today. Basically, there will be a lot of hit and miss
showers, with the most widespread activity over the higher terrain
as well as through northern Mohave through Lincoln and Nye counties.
Much like today, precipitation amounts should be light with a few
moderate bursts but with showers moving along quickly- it likely
wont result in any impacts. With cold core processes, a few
thunderstorms will also be possible, mainly north of I-15. Show
should be confined to above about 3500-4000ft.

The models continue to highlight the slower trend for the exiting low
Friday. Precipitation chances have increased since the previous
forecast, especially in Clark, Lincoln, and Mohave counties. Lower
confidence in the QPF for Friday since models are having a hard time
resolving the exit of the system, however anticipating similar
precipitation totals to today and tomorrow. Also lower confidence in
isolated thunderstorms developing Friday afternoon, but included a
mention of thunder in areas south of the I-15.

The system should finally exit the area Saturday. Behind the low,
increasing north winds are likely. Winds should increase in
Esmeralda and northern Inyo Friday, as they will have the best
chance for the system clearing the region and northerly flow will
take over. More widespread northerly winds are expected Saturday,
though models remain inconsistent on the strength of the winds.
Currently not seeing anything that would suggest high impact winds.

Low confidence in the long range forecast continues as an active
pattern continues next week. Increasing confidence that there will
be a lull on Sunday with dry weather and moderating temperatures
after well below temperature through Friday. After that, a series of
systems will likely impact the region but unsure when and what kind
of impacts would result.
&&

.AVIATION...For McCarran...

Gusty southwest winds will continue into the evening hours until
about 03Z when southerly wind will become less gusty after sundown
with wind remaining around 10 kt through the night.  Periods of CIGS
around 10kft can be expected.  Periods of VCSH or -RA are likely
through the TAF period. During showers, we could see CIGS drop to
5kft.  light and variable winds return after 15Z Thursday before
picking up again from the southwest around mid day with gusts to 20
kt.

For the rest of southern Nevada, northwest Arizona and southeast
California...

South to Southwesterly winds continue across the Mojave Desert this
afternoon with gusts of 25-30 kts for the Las Vegas Valley sites and
KDAG. Southerly winds are gusting from 20-25 kts along the Colorado
River Valley. These winds will continue into the evening hours when
we lose daylight after about 03Z when wind will decrease a little
and become less gusty. Isolated showers are expected through the TAF
period at every TAF site. Where showers develop, terminals can
expect gusty, erratic winds from the direction of the showers as
well as a CIG drop to 3-5 kft.
&&

.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&

UPDATE...Pierce

DISCUSSION...Nickerson
AVIATION...Berc

For more forecast information...see us on our webpage:
https://weather.gov/lasvegas or follow us on Facebook and Twitter

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LAS VEGAS NV
850 PM PST WED MAR 10 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0455 PM     NON-TSTM WND GST HENDERSON EXECUTIVE AIR 35.98N 115.13W
03/10/2021  M58 MPH          CLARK              NV   AWOS

            PEAK WIND GUST OF 58 MPH.

&&