621
FXUS65 KVEF 020857
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
157 AM PDT Wed Apr 2 2025

.SYNOPSIS...Scattered showers and isolated thunderstorms will
develop today and Thursday as an upper level system shifts through
the region, with the most widespread precipitation expected this
afternoon. Impacts will be limited with small hail and sudden
gusty winds possible, as well as light to briefly moderate snow
above 5000ft. Temperatures will remain cold today, about 15-20
degrees below normal. Temperatures will begin to recover on
Thursday, and return to near normal over the weekend. Winds will
be lighter than the have been over the past few days.

&&

.SHORT TERM...Today through Thursday.

Through the early morning hours, satellite showed an area of cloud
enhancement and cooling cloud tops through southern Nevada and
northern Inyo County. Radar returns in these areas of better
organized clouds were meager, however surface observations verified
that something was happening under these clouds as rain was reported
in a few locations. Also worth noting- current mesoanalysis suggests
there is weak instability across the southern Great Basin which
correlated well with the cooling clouds and rain reports/light radar
returns...but almost none of the high res models had instability
over the region through the morning. Relied on current analysis,
model satellite, and the few models that were doing decent with the
current situation (which was the NAMNest and HiRes-ARW) for the
forecast through the morning hours. This approach would suggest an
area of light precipitation developing and moving into southern
Inyo, eastern San Bernardino, and western Clark counties early this
morning. This would be associated with a shortwave digging into
east-central California currently, with strong vorticity advection
moving into the area ahead of the feature. Impacts from this early
morning precipitation should be minimal as anything that falls will
be light, however brief graupel and gusty winds to 30 MPH will be
possible under anything that develops. In the Spring Mountains, brief
light to moderate snow will be possible at times through 10 AM PT
above 5000ft.

This reinforcing shortwave will dig through California and shift
into Arizona this afternoon, deepening as it makes this transition.
In addition to increased forcing, this feature will also drag colder
air into the area. Widespread lift and cold air aloft will allow for
scattered showers to develop through the day. Moisture will increase
slightly over the region as PWATs nudge closer to normal ahead of
the shortwave. Overall, today`s precipitation should be more
widespread and have a better chance for rain to reach the ground
compared to yesterday. The peak of precipitation activity will be
this afternoon as weak instability develops with diurnal heating-
expecting widespread showers and thunderstorms this afternoon in
southern Nevada and western Arizona where HREF shows the best
potential for surface based CAPE to develop and SPC highlights under
General Thunder in their convective outlook for today. Freezing
levels will be a bit lower than yesterday and with steep mid level
lapse rates developing this afternoon, there is an even better
chance for small hail and graupel today. In addition, dry low levels
could result in sudden gusty outflow winds from showers and
thunderstorms today, though not all forecast sounding show dry
midlevels which could inhibit outflow potential. While rain may be
more efficient to reach the ground today, it will still struggle
with dry low levels and meager overall moisture so rain impacts are
not expected. Snow levels will drop to 4000-5000ft this afternoon
and a quick few inches of snow is possible in the Spring Mountains
as well as light accumulations up to an inch in places such as US-93
in Lincoln County and Fort Rock on I-40 through Mohave County.

Winds this morning have been gusty at times, mainly in San
Bernardino County where west winds were gusting 30-40 MPH at times.
Elsewhere, west to southwest winds were gusting up to 25 MPH. There
has been a downward trend in winds in the past few hours though, and
this trend is expected to continue through the morning. The best
pressure gradient and low levels winds will shift south of the area
by sunrise and the probability for impactful winds is low today. The
wind advisory in the Western Mojave Desert and Yucca Valley expired
at 2 AM PT and no need to extend the wind headline.Isolated westerly
gusts to 40 MPH are possible for a few more hours around Barstow and
Yucca Valley, however the strongest winds and most widespread
impacts have ended. By sunrise, much lighter winds are expected area
wide. Winds will become north to northwest through the day behind
the shortwave, however they will not be strong.

Precipitation the develops this afternoon will slowly diminish
tonight, with showers lingering the longest in northeast CLark
County into northern Lincoln County where the upper level low will
be centered. On Thursday, the upper level system will remain
entrenched over the region and wont move significantly from where it
sets up tonight. Additional scattered showers and thunderstorms are
expected in southern Nevada and western Arizona Thursday, with the
best chance for dry conditions being in California where dry
anticyclonic flow should be set up and will prohibit precipitation
development. Moisture will be decreasing and the mid levels should
warm up slightly compared to this afternoon, so precipitation
activity and impacts should be lower than what is able to develop
today. Snow levels on Thursday will also be higher, around 5000-
6000ft, so the potential for snow impacts will also be lower even
though the chance for precipitation may be better on Thursday in the
Kingman and Fort Rock, AZ area than today. Winds on Thursday will
continue to be from the northwest and remain lighter than what we
have seen for winds the past few days. Temperature today will be
colder than yesterday, remaining 15-20 degrees below normal. On
Thursday, temperatures will warm a few degrees compared to today but
will still remain at least 10 degrees below normal for this time of
the year.

.LONG TERM...Friday through Wednesday.

The broad area of upper-level troughing will finally close off over
southern Nevada on Thursday before it starts to push eastward on
Friday. Expect gusty north winds across the forecast area on Friday
and Saturday afternoons as a result of the trough shifting east and
a growing ridge of high pressure building over the southeastern
Pacific Ocean to our west. Chances of wind gusts over 40 mph remain
confined to the higher terrain as well as north-south oriented
valleys such as the Colorado River Valley. Expect impacts to east-
west thoroughfares as well as to area lakes, with wave heights at or
above 2 feet possible. Slight PoPs persist in our far northern and
eastern zones Friday afternoon, though accumulation is likely to be
little-to-none.

Through the weekend and start of next week, skies clear and
temperatures increase above seasonal normals as a ridge of high
pressure builds in the Pacific across the Desert Southwest. Monday
and Tuesday have a 60% and 90% chance, respectively, for reaching 80
degrees here in Las Vegas. HeatRisk increases back to "Low" (Level 1
on a scale of 0-4) for desert valleys over the weekend including Las
Vegas, Moapa Valley, Death Valley, Pahrump Valley, and the Colorado
River Valley.

[Note] "Low" HeatRisk does not mean that chances of heat-related
illness are low for any one individual - it means chances are low
for the general population. People who should take extra precautions
during "Low" HeatRisk days include those out of town from cooler
locations, those consuming alcohol, caffeine, or other drugs, and
those without adequate means of hydration or air conditioning.

Meanwhile, chances of 90 degrees return to Las Vegas and 100 degrees
return to Death Valley mid-to-late week as the southeastern Pacific
ridge continues to build into the extended forecast. HeatRisk climbs
to "Moderate" (Level 2 on a scale of 0-4) for our lowest valleys on
Wednesday.


&&

.AVIATION...For Harry Reid...For the 06Z Forecast Package...West-
southwesterly winds this evening will shift to the northwest by
early Wednesday morning, becoming elevated and gusty with gusts to
around 20KT expected. Similar to today, scattered showers are
expected to develop across the Las Vegas Valley and surrounding
mountains after 15Z, persisting through sunset. Precise timing of
these showers and associated impacts at KLAS remains in question,
though the time period between 16Z-22Z looks to be the most likely
for showers to impact the terminal. Erratic gusty winds are
expected in the vicinity of any showers and associated outflow
boundaries, along with briefly lowered ceilings to around 6kft as
well as potential visibility reductions in rain and/or graupel.
After 00Z, showers will begin to diminish and move east as winds
return to the west-southwest. Dry conditions are forecast after
sunset, with winds becoming light and variable as ceilings
gradually improve and scatter out.

For the rest of southern Nevada, northwest Arizona and southeast
California...For the 06Z Forecast Package...Las Vegas Valley
terminals will follow similar trends to KLAS, with both KVGT and
KHND realizing a northwesterly wind shift Wednesday morning, with
gusts to around 20KT expected at both terminals from mid morning
through mid afternoon. After 00Z, winds at KVGT will become light,
though at KHND, gusty winds will back to the southwest,
continuing through the end of the period. KBIH, similarly will see
gusty northwesterly winds by mid to late morning, with gusts to
around 25KT expected through late afternoon before winds diminish,
veering more to the north or north-northeast. Winds at KEED and
KIFP will be more variable, though are expected to be gusty out of
the west for at least the first few hours of the period, shifting
to the northwest at KEED by mid morning, but generally remaining
southerly to southwesterly at KIFP. At both terminals, gusts
largely diminish between 18-20Z, with winds becoming light after
03/01Z. Westerly winds persist at KDAG for the duration, with
sustained speeds around 25-30KT and gusts to 35-40KT. In addition
to winds, scattered showers are expected to develop across the
area on Thursday, potentially impacting all terminals except KDAG.
Erratic gusty winds can be expected in the vicinity of any
showers or associated outflow boundaries, as well as brief MVFR
conditions due to lower ceilings or reduced visibility in rain
and/or graupel through mid afternoon. Showers diminish and move
east after 00Z with improving ceilings to follow.

&&

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

&&

$$

SHORT TERM...Nickerson
LONG TERM...Soulat
AVIATION...Phillipson

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