Severe Thunderstorm Warning 19, NWS Las Vegas, NV

Area Forecast Discussion
National Weather Service Las Vegas NV
947 AM PDT Thu Jun 5 2025

.SYNOPSIS...Isolated-to-scattered showers and thunderstorms are
expected across southern Nevada and northwest Arizona this afternoon
with lesser chances in southeastern California. Gusty outflow winds,
frequent lightning, and moderate-to-heavy rain will be threats with
any storms that develop. Things will begin to dry out and heat up as
we head into the weekend.

&&

.UPDATE...A line of weakening thunderstorms is currently moving east
through northern Clark and Mohave counties. Along with frequent
lightning, these generally produced between .2 and .6 inch of
precipitation over the last six hours, including .55 inch at
Mesquite and .43 inch at Colorado City. High resolution guidance
shows redevelopment of thunderstorms along high terrain in southern
Nevada and northwestern Arizona by late morning, becoming more
numerous and moving into the valleys in the afternoon. Rain rates of
an inch per hour are possible which could lead to flooding impacts.
High resolution guidance is still showing the potential for outflow
winds up to 50 mph with the stronger storms, which makes sense given
1500 J/kg DCAPE this afternoon near the California/Nevada state
line. Storms will have up to 1000 J/kg SBCAPE to work with later
today. Lacking shear should reduce the hail threat. Most of the
storm activity should end in the evening.

&&

.SHORT TERM...Today.

Elongated troughing stretching from the eastern Pacific through
southern California into southern Nevada and northwest Arizona will
allow for vorticity advection into the region today. This advection
combined with daytime heating and precipitable water values over 200%
of normal will allow for another round of showers and thunderstorms
across much of the area this afternoon. Convection will favor areas
of higher terrain for development beginning later this morning.
Showers and thunderstorms will move off the higher terrain, tending
to move from west to east with the upper-level flow. Southern Nevada
and northwest Arizona will have the best chances at seeing scattered
showers and thunderstorms this afternoon as this is where CAPE
values around 500 to 1,000 J/kg overlap with 0.75 to 1.0 inches of
precipitable water. Convection in San Bernardino and Inyo counties
will be more isolated in nature. Anomalous moisture across the area
will allow for moderate-to-heavy rain capable of resulting in
isolated flash flooding will be possible with stronger storms.
Frequent and dangerous lightning and 30 to 40 mph outflow wind gusts
will be possible with any storms that develop; 50 mph outflow wind
gusts will be possible with stronger storms. With lower CAPE values
than we had on Tuesday and lack of sufficient wind shear, 1 inch
hail is not expected to be a threat today. However, more robust
convection may produce graupel or small hail (pea, nickel, or dime
sized). Convection will begin to die down across the region after
sunset with the exception of northern Lincoln County where showers
and thunderstorms may linger later into the evening.

.LONG TERM...Friday through Wednesday.

Friday through early next week, a return to more typical early June
hot and dry conditions is on tap for southern Nevada, southeastern
California and northwestern Arizona. Ensemble guidance and cluster
analyses remain in good agreement regarding a strengthening ridge
over the region, which will facilitate a decrease in moisture and
gradually warming temperatures, with a return to above normal
temperatures on Friday, warming to well above normal Sunday through
at least Tuesday. Fairly widespread highs in the 90s and lower 100s
are expected Sunday through Tuesday, with Monday and Tuesday looking
to be the hottest days of the forecast. Along with the warming
temperatures will be increasing HeatRisk, with "Major" HeatRisk
returning to Death Valley and the Lower Colorado River Valley on
Saturday, gradually expanding across other lower elevations through
early next week, with "Extreme" HeatRisk possible for the lowest
Valleys Monday and Tuesday. Thereafter, ensemble members begin to
diverge, with some indications that a weak trough may try to
undercut the ridge heading into midweek, but with little in the way
of moisture, this trough would have little impact other than
tempering the hot temperatures by a couple of degrees, and producing
some breezy conditions. Stay tuned.

&&

.AVIATION...For Harry Reid...For the 18Z Forecast
Package...Convection will develop today and is expected to be more
widespread than yesterday and may impact all terminals.
Thunderstorms in and around the valley could produce gusty erratic
winds with gusts over 30KT, especially between 20Z and 02Z. In
addition- storms today could produce lightning, small hail, moderate
to heavy that could reduce visibility to 6sm, and CIGs to 8000ft.
Outside of convection influence, southeast winds are expected this
afternoon around 8KT with intermittent gusts to around 15KT.

Precipitation will diminish after 03Z this evening. Winds may be
erratic for a few hours after thunderstorms end depending on how
outflow impact the valley this afternoon, but diurnal winds trends
with light winds speeds are expected to set up by 08Z at the latest.
Light winds following typical trends will then persist through the
rest of the TAF period. On Friday, isolated showers and
thunderstorms may develop after 20Z but the chance for convection
and convective impacts is much lower on Friday compared to today. It
is less likely that gusty outflows will impact the valley on Friday
with the most likely scenario being light diurnal wind trends
continuing through the afternoon.

For the rest of southern Nevada, northwest Arizona and southeast
California...For the 18Z Forecast Package...Scattered showers and
thunderstorms will develop this afternoon in Clark, Lincoln, and
northern Mohave counties, as well as in the Sierra. Convection today
could produce erratic wind gusts over 30KT, moderate to heavy rain,
reduced visibility due to heavy rain or blowing dust, lightning, and
CIGS below 10kft. Precipitation will diminish after 03Z, with dry
conditions expected across the region by 08Z. After a dry night,
additional showers and thunderstorms should develop after 18Z on
Friday in southern Nevada and western Arizona, however convection on
Friday will be less widespread and less likely to produce impacts
compared to today.

Outside of convective influence, expected south to southwest winds
around 10KT to develop this afternoon across the region with the
strongest winds expected in the Colorado River Valley where gusts up
to 20KT are likely. Winds will diminish after sunset with typical
light wind patterns expected tonight and Friday. &&

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

&&

UPDATE...Meltzer
SHORT TERM...Stessman
LONG TERM...Phillipson
AVIATION...Nickerson

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