Area Forecast Discussion
Issued by NWS Las Vegas, NV

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FXUS65 KVEF 261014

Area Forecast Discussion
National Weather Service Las Vegas NV
314 AM PDT Mon Oct 26 2020

.SYNOPSIS...Today features high winds and a stark drop in
temperatures areawide as a strong storm system pushes eastward out
of the region. Quiet weather with temperatures warming back to
seasonal averages expected Tuesday onward.

.DISCUSSION...Today through Sunday.
The strong weather system responsible for the sudden drop in
temperatures and gusty winds will close off and push eastward out of
the Desert Southwest today and tomorrow.

This system has certainly been interesting to forecast, with
precipitation chances trending slowly downward and wind gust
potential trending slowly upward through the week. Yesterday
morning, the unfortunate forecast result for our rain-lovers was a
near-zero precipitation chance for most of the region. Though a
couple of cloud flashes were observed over northeast Clark County,
nothing in the way of measurable precipitation fell over the
forecast area today. The Arizona Strip likely saw virga showers this
afternoon and evening, but certainly did not receive the wetting
rains for which we had hoped.

North winds will remain elevated areawide through this evening,
enhancing down the Colorado River Valley where the Wind Advisory has
been upgraded to a High Wind Warning. As mentioned in yesterday`s
briefing, the GFS LAMP continues to be bullish on wind gust speeds
along the Colorado River Valley, while the NBM and ECMWF Ensembles
feature gusts closer to high-end Wind Advisory speeds. As of this
discussion (0314am PDT), gusts of 59 mph at Laughlin, NV and at
the Hoover Dam, NV mark the peak gust of this event so far,
validating the High Wind Warning. Increased forecast wind speeds
through the overnight hours along the Owens Valley and Colorado
River Valley based on current trends. As we continue to monitor
gusts through the region, the High Wind Warning may need to be
downgraded back to a Wind Advisory before the expiration time.
Will make this decision if we see winds solidly trending downward.
Otherwise, the Wind Advisories across the area look in good shape
through 9pm this evening. Winds will remain elevated Tuesday
along the Colorado River Valley, but will be sub- advisory.
However, due to the lack of precipitation, relative humidity
values will remain critical, resulting in the potential for
increased fire danger Tuesday afternoon for lake zones.

This morning, the Owens Valley is under a Freeze Warning. Though
Bishop had their first freeze of the season yesterday morning, with
a low of 31F, lower elevations across the Valley will experience
theirs this morning with forecast lows in the low-20s expected. For
this reason, we have kept the Freeze Warning in place. Numerous
locations this afternoon will surpass or flirt with record cold high
temperatures. More detail can be found in the CLIMATE section.
Tomorrow morning, additional locations including Kingman in Arizona
and Indian Springs, Mesquite, and Borax in Nevada will experience
their first freezes as well, where their Freeze Warnings look in
good shape. Locations including northern Mohave County, Esmeralda,
south-central Nye, and northern Lincoln counties who have already
had their first freeze will experience morning low temperatures in
the upper-teens to mid-20s Tuesday morning. Residents in these
locations are encouraged to take precautions to protect plants,
pipes and pets.

As the closed low pushes eastward through the rest of the work week,
an area of high pressure will set up over northern Mexico. This
ridging will allow temperatures to rebound back to seasonal averages
by the end of the week, making for a very comfortable Halloween
night with trick-or-treating temperatures in the upper 50s to mid-
60s across the region.

For the long term, a zonal flow will take hold over the CONUS,
resulting in light winds, average temperatures, light high clouds
and a persistent lack of precipitation.

.FIRE WEATHER...Gusty north winds will continue through this evening
with gust speeds 35-50 mph and isolated gusts to 60 mph. Red Flag
Warnings look to be in good shape. RH values will stay at critical
levels through the duration of the warning. That said, RHs will fail
to improve much overnight tonight, remaining in the low teens for
much of the region. As a result, an extension of the Red Flag
Warning may be warranted along the Colorado River Valley where
enhanced winds around 20 kts may persist through Tuesday afternoon.
Because of the borderline nature of the forecast winds, holding off
for now due to lack of confidence.


                  FORECAST   RECORD
Las Vegas, NV        58*    56 (1951)
Desert Rock, NV      56*    57 (1996)
Bishop, CA           60     48 (1996)
Barstow, CA          60*    63 (1996)
Needles, CA          61*    64 (1919)
Kingman, AZ          51*    55 (1940, 1996)
Death Valley, CA     75     70 (1921)

*-Current forecast breaks or is close to current record values.

.AVIATION...For McCarran...Strong north winds will be the main
aviation concern today, with wind gusts to 35 knots possible through
the early evening hours. Wind direction will favor due north this
morning, possibly shifting more north-northeast this afternoon.
Pockets of blowing dust may result in brief visibility reductions
but nothing of significant impact. Winds will decrease in speed
after sunset this evening but northerly winds will remain elevated
overnight with speeds of 10-15 knots.

For the rest of southern Nevada, northwest Arizona and southeast
California...Strong northerly winds will be the main aviation impact
today, with the stronger winds gusting to 40-50 knots possible along
the Colorado River near KIFP and KEED.  Winds will decrease in
intensity after sunset but remain elevated and out of the north for
most TAF sites. Pockets of blowing dust may also result in brief
visibility reductions.

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



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