949
FXUS65 KVEF 271117
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
417 AM PDT Wed Aug 27 2025

.KEY MESSAGES...

* Isolated shower and thunderstorm activity continues through the
  rest of the work week, with decreasing chances and coverage each
  day, becoming negligible over the weekend.

* Drying conditions will allow temperatures to climb back to above-
  normal through the weekend and start of the next work week before
  moisture is reintroduced to the Desert Southwest midweek.

&&


.DISCUSSION...Today through Wednesday.

We have been watching an incoming shortwave trough approach the
southern California coast over the last 24 hours, which has helped
to deamplify ridging over the Desert Southwest and return a dry
southwesterly flow to the region aloft. Moisture has already begun
to ease out of the region today, with PWATS dropping from 150-200%
of normal to 100-150%. Since moisture across the area is still at-or-
above normal for this time of year, the upper-level support in the
form of a 75-85 kt 300mb jet and the advection of various cyclonic
vorticity maxima will return chances of isolated showers and
thunderstorms to the forecast area this afternoon. Skies will clear
efficiently through the remainder of the morning, allowing for
daytime heating to increase surface-based CAPE values areawide. As
such, convection will start over the higher terrain before becoming
more widespread as the afternoon progresses. Primary threats remain
gusty winds, frequent lightning, and flash flooding beneath training
storms or flash flooding with storm activity over already-moist
soils from rain over the past few days. As we progress through the
work week into the weekend, we watch Tropical Storm Juliette over
the southeastern Pacific. This storm will weaken, posing no direct
threat to land; however, mid-to-upper level moisture will shear off
from the remnants of Juliette, queuing itself right into our
southwesterly flow aloft. As a result, expect increased cloud cover
late tonight through Thursday. Chances of precipitation will
continue to decrease each day, with now negligible chances Saturday
and Sunday.

Heights will rise over the forecast area as our aforementioned weak
shortwave translates eastward out of the region. Temperatures will
increase to slightly-above normal through the weekend into the start
of the next work week, as a result. Early-to-mid week, a closed area
of low pressure pushing into the Pacific Northwest will once again
deamplify the Four Corners ridge. The corresponding brief southerly
flow into the region will advect additional monsoonal moisture,
which will then be accompanied by increased upper-level dynamics
from this Pacific NW trough as it pushes through the Intermountain
West. As such, slight PoPs return to the forecast in the long term.
&&


.AVIATION...For Harry Reid...For the 12Z Forecast Package...Quiet
weather expected this morning. A few thunderstorms should again
develop over the mountains around noon, but coverage and intensity
should be less than in previous days. There is a small (less than
20%) chance for outflow winds to reach the terminal. Thunderstorms
should quickly wane around 01Z. VFR conditions expected at the
terminal today and Thursday. Temps remain below 100F.

For the rest of southern Nevada, northwestern Arizona and
southeastern California...For the 12Z Forecast Package...Scattered
mid-level clouds this morning, followed by thunderstorm development
over the higher terrain around noon, primarily across the southern
Great Basin and the I-40 corridor. Thunderstorm coverage and
intensity should be less than in previous days, with the main threat
being erratic, gusty winds. Thunderstorms should wane around sunset.
VFR conditions expected outside of thunderstorm areas.
&&


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


$$

DISCUSSION...Soulat
AVIATION...Morgan

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NWS Flagstaff Office