Area Forecast Discussion
Issued by NWS Las Vegas, NV

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000
FXUS65 KVEF 211709
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
1009 AM PDT Thu Mar 21 2024

.SYNOPSIS...A weak weather disturbance passing across central
Nevada today will lead to locally gusty winds otherwise, expect
another warm day with above normal temperatures and sunny skies.
Friday afternoon, gusty southwest winds pick up across the
forecast area as a weekend weather system approaches. Gusts will
peak on Saturday with a drop in temperatures and the return of
precipitation chances extending through Sunday.

&&

.UPDATE...High pressure over the area today with few concerns
weather wise. High temperatures should be similar or a bit warmer
than yesterday with mostly sunny skies once the cirrus moves
through. A weak shortwave passing across the area today will
produce some afternoon gustiness. In general, southwest winds 10-20
mph is expected with localized areas of 20 to 30 mph, mainly in
the western parts of San Bernardino County. No updates will be
needed this morning.

&&

.PREV DISCUSSION...237 AM PDT Thu Mar 21 2024...

.SHORT TERM...Today and Friday.

A ridge of high pressure will allow temperatures to remain between 5
and 7 degrees above seasonal averages today with breezy southwest
afternoon winds between 10 and 20 mph as a result of a weak
shortwave moving through the ridge. The mixing from the winds
coupled with the heating from lack of cloud cover may be enough for
Las Vegas to reach the first 80F day of the year today, with a 30%
chance of occurrence. If Las Vegas reaches 80F today, this would not
reach a record. In fact, the record high temperature for March 21st
is 92 degrees set in 2004. The record earliest 80-degree day
occurred on February 1st, 2003. The average date of the first 80-
degree day in Las Vegas is March 14th.

Chances of 80F for Las Vegas persist into Friday, with a 25% chance,
though through the day, heights will drop over the region as a
trough associated with a strong area of low pressure digs through
the western CONUS. That said, gradients will tighten across the
forecast area with the approach of this trough, which may allow for
enough wind-driven mixing to put the first (or second) 80F of the
year in jeopardy once again. Gusty south-southwest winds will pick
up through the afternoon on Friday, with highest speeds expected in
the higher elevations of southern Inyo, western San Bernardino,
southern Nye, and western Clark counties. No wind-related headline
expected, as speeds will generally range from 20 to 30 mph.

.LONG TERM...Saturday through Wednesday.

The center of a strong area of low pressure will remain off the
coast of the Pacific Northwest on Saturday, though the associated
trough and 170 kt 250mb jet will push into the Mojave Desert through
the day. Changes in the surface pressure gradient across our area
will increase winds in the afternoon as a surface low develops in
the lee of the Sierra. The strongest winds are forecast within a
belt stretching from western San Bernardino County / southern Inyo
County through Clark County into southwestern Utah. Gusts of 40 to
50 mph are highlighted in these areas, with gusts approaching 60 mph
in the mountains of Clark County. Peak gust locations and speeds
continue to change with each model run, as these parameters highly
depend on the position and strength of the trough as it moves into
the Desert Southwest. That said, Saturday has just entered the hi-
resolution domain, so confidence will continue to increase here
forward. Holding off on wind-related headlines for now as we work
out the details, but can guarantee that Saturday and Saturday night
will boast gusty southwest winds in our forecast area as the trough
axis slides through the southwestern United States.

Precipitation amounts continue to increase with each forecast run.
That said, little-to-no accumulating precipitation is forecast in
the lower deserts due to the inland trajectory and minimal moisture
associated with this system. Lower deserts can expect less than
0.25" of rainfall, with amounts between 0.50" and 0.75" across
northern Lincoln County, the eastern Sierra slopes, and the Spring
Mountains. These values are subject to change with minor
fluctuations in the trajectory of the trough, as much of the
moisture will be intercepted by the Sierra Nevada with the current
expected path.

Snow levels will drop from 7500 ft to 4500 ft through this event,
resulting in 4 to 8 inches of snow possible in the mountains of
Lincoln and Clark counties as well as along the eastern Sierra
slopes. 1-2 feet of snow possible in the peaks of the Sierra above
9000 ft.

Temperatures drop through the weekend, and will bottom out on Sunday
with 10-12 degrees below seasonal averages before rebounding through
the first half of next week.

&&

.AVIATION...For Harry Reid...Variable winds this morning
increase and turn to the southwest this afternoon, becoming gusty.
Wind speeds will rise to over 10 knots with gusts in excess of 15
knots likely in the late afternoon. After sunset, wind speeds fall
to less than 10 knots but remain out of the southwest. FEW to SCT
mid and high level clouds stream through the area and should have
little impact on aviation.

For the rest of southern Nevada, northwestern Arizona and
southeastern California...Breezy southerly to southwesterly winds
develop in the Las Vegas Valley and Colorado River Valley this
afternoon with speeds in excess of 10 knots and gusts around 15
knots. Likewise, northwesterly winds with peak gusts up to 15
knots develop at KBIH this evening. Overall winds decrease
overnight. At KDAG, westerly to southwesterly winds over 10 knots
persist throughout the TAF period, with gusts picking up in the
morning through the evening. FEW to SCT mid and high level clouds
stream through the area and should have little impact on aviation.

&&

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

&&

$$

UPDATE...Salmen

SHORT TERM...Varian
LONG TERM...Salmen
AVIATION...Meltzer

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