770
FXUS65 KVEF 050226
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
726 PM PDT Sat May 4 2024

.SYNOPSIS...A potent storm system will move across the region
tonight and Sunday bringing widespread strong winds and much cooler
temperatures. High elevation snow in the southern Sierra will spread
across parts of southern Nevada tonight and Sunday leading to a
dusting of snow in the mountains. Light winds will return Monday
then breezy periods with temperatures a little below normal can
be expected for much of the upcoming week.

&&

.UPDATE...Areas northwest of Las Vegas have seen advisory level
winds all afternoon but in the valley, the stronger gusts have
been slow to develop. The trends of the past few days have
suggested a slower onset of strong winds until the evening and
overnight hours and as we approach 7 pm, we are beginning to see
these stronger winds push into the valley. Gusts this evening and
overnight will generally be in the 35-45 mph range across much of
the Las Vegas Valley with further strengthening expected near
daybreak when gusts could approach or exceed 50 mph for several
hours. However, the strongest winds tonight are likely to be near
the mountains over the far western and southwestern parts of the
valley.

Elsewhere, more of the same with strong winds continuing
overnight. Temperatures will cool much more rapidly tonight with
low temperatures in the morning ending up about 10-15 degrees
cooler than this morning. Shower chances will be mostly confined
to the Sierra through the early morning hours then showers are
expected to develop across southcentral Nevada later tonight.

&&

.PREV DISCUSSION...1253 PM PDT Sat May 4 2024...

.SHORT TERM...Through Monday night.

Winds were ramping up across the region and will continue to
increase from the south-southwest through this afternoon then will
peak during the evening/overnight hours as a cold system plunges
down from the northwest. The trajectory and strength of the low will
result in one of the more significant wind events this season as
strong deep layer winds in its base spread over our region tonight.
This will be favorable for high downslope winds from the southern
Sierra/White Mountains of Inyo County to the Spring Mountains in
southern Nevada this evening and overnight. Gusts of 60-80 mph are
indicated by high res model cross sections and supported by NBM
point probability forecasts. NBM probabilities of gusts over 40 mph
range from 80-100 percent across most of our forecast zones under a
Wind Advisory, especially between 03Z and 15Z Sunday as a
concentrated wind belt traverses the area from northwest to
southeast.

A noteworthy trend from the latest model ensembles is a fairly
rapid decrease in wind speeds across the Spring Mountains between
16Z and 18Z. The valid time of the High Wind Warning for the Spring
Mountains was shortened to end at 11 am PDT. Wind speeds will be
decreasing across much of southern Nevada and northwest Arizona
late Sunday morning through early afternoon, but may hang on around
the Barstow/Twentynine Palms area through late afternoon. No change
to the expiration time of 5 PM for the Wind Advisory for these
zones, but the potential for widespread gusts over 40 mph will be
diminishing through early Sunday afternoon.

Most of the precipitation associated with the system will be
intercepted by the southern Sierra through this evening. The
forecast of 2-3" of new snow at Aspendell remains largely unchanged
and more significant snow amounts will be confined near the crest.
There will be sufficient moisture, instability and dynamic forcing
for light showers to develop across south central Nevada tonight and
Sunday. There is a chance for a light dusting of snow as far south
as the Spring Mountains. Less than 1" expected in some of the higher
valley floors of central Nye and northern Lincoln Counties.

A high temperature drop of 15-20 degrees will occur for Sunday as
the cold system moves overhead. West-northwest breezes spreading
over the region on the back side of the exiting systems late Sunday
afternoon will diminish fairly quickly overnight leaving fairly
light winds for Monday. High temperatures will rebound about 8-10
degrees by Monday afternoon.

.LONG TERM...Tuesday through Friday.

The area will be under a mostly zonal flow with a touch of a NW
component through much, if not all, of the work week as persistent
troughing remains just to our north. At the surface, this results in
breezy afternoons with highs roughly 3-8 degrees below normal across
the area. We`ll remain dry as the troughing to our north has very
little moisture to work with. PoPs stay below 10% through Friday.

&&

.AVIATION...For Harry Reid...Winds continue to increase with the
expectation of wind gusts 30 to 40 knots by mid afternoon lasting
into the overnight hours. Sustained winds 20 to 30 knots will
transport dust from the southwest, which may result in reduced
visibilities from mid afternoon through tonight, though confidence
is low on reductions below 4 to 5 sm. The potential for sustained
winds 35 knots or greater and/or wind gusts 48 knots or greater
is generally 15-30%. In addition to winds, mid level clouds will
overspread southern Nevada by this evening, generally around
15kft. Winds will gradually decrease and eventually turn northwest
from late morning through the afternoon Sunday as a front moves
through the area.

For the rest of southern Nevada, northwest Arizona and southeast
California...Strong and gusty winds to affect all terminals through
the afternoon and into the overnight hours. Winds will generally be
from the southwest with gusts 30 to 40 knots. Winds will initially
be more southerly at KBIH within the Owens Valley. Additionally, as
precipitation develops along the Sierra crest, there is the
potential for some spillover into the Owens Valley and have
maintained VCSH for KBIH this afternoon into tonight. Any
precipitation that reaches the valley floor will be light. Skies
will become broken to overcast as a cold front sweeps northwest to
southeast across the region, though ceilings generally look to
remain above 10kft. Winds will turn north to northwest on Sunday,
first at KBIH and then southward into the afternoon/evening as a
cold front moves through the region. Winds will diminish in
intensity, but remain elevated 15-25 knots in the wake of the front.

&&

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

&&

$$

UPDATE...Salmen

SHORT TERM...Adair
LONG TERM...Salmen
AVIATION...Austin

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