998
FXUS65 KVEF 122203
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
303 PM PDT Wed Aug 12 2026

.KEY MESSAGES...

* This afternoon offers widespread chances for storms with an
  increased risk for flooding in Mohave County AZ, with a Flash
  Flood Watch issued from noon through midnight.

* Daily afternoon to evening isolated thunderstorm chances will
  continue through the late week, with the greatest chances over
  higher terrain and some storms spreading into adjacent valleys.

&&

.DISCUSSION...Through Tuesday.

Today is shaping up to be one of the most active monsoon days of
the season thus far. Latest SPC mesoanalysis shows the 1" PWAT
contour extending all the way up into the southern Great Basin.
With mostly sunny skies west of the Colorado River and a subtle
trough approaching off the Pacific, all the ingredients are there
for scattered storms across the area. Main concerns will be flash
flooding and gusty outflow winds. Morning convection in central
Mohave County produced impressive rain rates/totals, but will
likely limit (or at least delay) additional activity in this area
as the atmosphere has been worked over. This could set up an
instability gradient for afternoon storms to run along, pushing
them down the lower Colorado River Valley. SPC has highlighted
this area with a marginal risk of severe winds. Activity may
linger in the southern Great Basin and lower Colorado River Valley
this evening, but things should largely be on the downtrend
around sunset.

Tomorrow, the trough moves a bit closer and flow aloft
strengthens. This will speed up storm movement, reducing the
risk of flash flooding outside of training storms. However, this
stronger flow aloft will also produce an uptick in vertical wind
shear, potentially allowing for more organized convection. This
signal is most clear in the southern Great Basin where the latest
HREF indicates 70-90% probabilities of 30+ knot thunderstorm winds
and a 10-20% chance of 50+ knots. Wouldn`t rule out the potential
for hail as well thanks to modestly rotating updrafts depicted in
some CAMs. Storm coverage across the Mojave Desert should be more
isolated in nature on Thursday. On Friday, the southwesterly flow
pushes moisture mainly into southeastern NV and northwestern AZ,
where isolated to scattered convection is yet again possible in
the afternoon hours. Drier conditions with just isolated activity
possible over the weekend.

&&

.AVIATION...For Harry Reid...For the 18Z Forecast Package...Light
and variable winds becoming southerly by late morning. Convection is
expected to develop Wednesday afternoon with more coverage than
previous days. 30%-40% chance of thunderstorms at the terminals
which could result in brief heavy rain, visibility under 5SM, sudden
gusty winds, and CIGs below 8000ft. Outside of convection, south to
southeast winds around 12KT with occasional gusts over 20KT are
expected. Light and variable winds will develop toward sunset. VFR
conditions with SCT-BKN clouds over 10kft are expected overnight. A
20-30% chance of thunderstorms on Thursday afternoon with similar
CIGs and VSBYs.

For the rest of southern Nevada, northwest Arizona and southeast
California...For the 18Z Forecast Package...The initial round of
showers and thunderstorms may shift in eastern Mohave County will
diminish by early afternoon. Convection will develop again Wednesday
afternoon across much of the region. Any storms could produce
lightning, heavy rain, sudden gusty winds, and CIGs below 8000ft.
Outside of convective influences, south to southwest winds around 10-
15KT will develop Wednesday afternoon. Wind and convection will
diminish after sunset Wednesday. Although coverage will be less,
thunderstorms will develop again on Thursday afternoon.

&&

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

&&

$$

DISCUSSION...Woods
AVIATION...Czyzyk

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