822
FXUS65 KVEF 040619
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
1115 PM PDT Tue Jun 3 2025

.SYNOPSIS...Scattered showers and isolated thunderstorms are
expected each day this week, but chances and coverage decrease each
day. Flash Flood Watch in effect for San Bernardino, Clark, and
Mohave counties today, as stronger storms will have very high rain
rates. In addition to heavy rain, frequent lightning and gusty
erratic winds can be expected this afternoon. The region will
gradually dry out through the remainder of the week as temperatures
climb into the weekend.
&&

.UPDATE...

Scattered thunderstorms continue this evening across southeastern
Inyo, San Bernardino, and Mohave Counties. PWAT values still around
200 to 250 percent of normal have led to exceptional efficiency when
it comes to rainfall production, with the primary concern with these
storms through tonight being heavy rainfall leading to flooding and
flash flooding. Multiple Flash Flood Warnings remain in effect, and
given minimal shear, storm propagation will largely be dictated by
outflow boundaries. The severe threat has diminished with the loss
of insolation and waning instability, but a few strong gusts are
still possible, especially behind storms where subsidence is
increased and DCAPE around 1200-1400 J/kg persists. Overall, the
forecast is on track this evening, with only minor updates needed
to PoP and Sky grids to account for current observations and near-
term trends.

&&

.SHORT TERM...Today and Wednesday.

A cut-off low off the southern California coast will push inland and
through our forecast area tonight into Wednesday as it weakens into
an open wave. Meanwhile, remnant anomalous moisture over the region
(250-300% of normal) will couple with clear skies and daytime
heating to increase afternoon instability to over 1000 J/kg of CAPE
across portions of the Mojave Desert. Thunderstorm activity has
already begun over the mountains of our forecast area this
afternoon. Activity will increase in coverage through the day, with
best chances in a line from Ridgecrest through Las Vegas into
central Mohave County. These best chances will then shift southward
through the remainder of the afternoon and evening as the center of
the low begins to push through Sonora, adding additional dynamics to
the atmosphere. These thunderstorms will be very moisture-efficient,
quickly turning our +1 inch of PWAT into heavy rain. As a result, a
Flash Flood Watch has been issued for San Bernardino, Clark, and
Mohave counties through 5am tonight / Wednesday morning. The largest
flash flood concerns will exist on lake beaches, in slot canyons,
and for communities living within concrete washes. In addition to
heavy rain, SPC Mesoanalysis shows very high forecast DCAPE (over
1500 J/kg)) over the next few hours in southern Inyo / northern San
Bernardino counties due to continued dry low levels. While strong
gusty winds from thunderstorms are expected areawide, the greatest
chances for severe-level wind gusts exist in these areas.

This open wave will push into Arizona overnight tonight into
Wednesday, putting us in the top west quadrant of the low. Though
this position of the low won`t lend to as great of dynamics in the
Mojave Desert as today, the amount of remnant moisture (200-250% of
normal) combined with daytime heating will return scattered showers
and isolated thunderstorms to much of the forecast area Wednesday
afternoon. Additionally, the resultant northwest flow aloft will
allow for a shortwave trough to push into the southwestern Great
Basin on Wednesday. The associated weak cold front will provide
additional dynamics to the southern Great Basin, returning isolated
thunderstorm chances to that region as well. Will continue to assess
the need for a Flash Flood Watch for portions of our forecast area
tomorrow, with the best chances existing in Mohave County.

.LONG TERM...Thursday through Monday.

General troughing with embedded shortwaves continues across the
Desert Southwest through the remainder of the work week as two areas
of high pressure build around us. This troughing will allow for
continued precipitation chances each afternoon as anomalous moisture
slowly scours out of the region, with chances confining to eastern
Lincoln and dropping below 10 percent by Friday. The ridging
surrounding us will allow heights to rise despite our troughing,
resulting in temperatures climbing through the weekend. Expect
widespread "Moderate" (Level 2 on a scale of 0 to 4) HeatRisk by
Sunday, with "High" HeatRisk in the lowest valleys.
&&

.AVIATION...For Harry Reid...For the 06Z Forecast Package...
Thunderstorms have ended for the overnight period and it is likely
that no additional wind shifts from outflow boundaries will impact
the valley. Overnight winds will be southwest around 7-10 kts along
with SCT clouds around 12k feet. Additional convection is likely in
the area Wednesday after 18Z in and around the valley which would
produce similar impacts to today. East to southeast winds will set
up Wednesday afternoon but could again be influenced by convection
and outflows after 21Z.

For the rest of southern Nevada, northwestern Arizona and
southeastern California...For the 06Z Forecast Package...Scattered
showers and thunderstorms will persist into the early morning hours
across the lower Colorado River Valley. Brief heavy rain and gusty
winds to 35 kts are possible at IFP and EED through 09z before
storms begin to weaken. Elsewhere, SCT-BKN clouds along with winds
generally less than 10 kts into Wednesday morning. Additional
showers and thunderstorms are expected Wednesday afternoon with
gusty outflow winds, brief heavy rain, and lower CIGS. Greatest
threat for storms will be after 19z and last into the evening.

&&

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

&&

$$

UPDATE...Phillipson
DISCUSSION...Soulat
AVIATION...Gorelow

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