309
FXUS65 KVEF 040454
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
953 PM PDT Sun Aug 3 2025

.KEY MESSAGES...

* Mainly dry conditions and near to slightly above normal
  temperatures will continue through early next week.

* A warming trend sends temperatures well above normal mid to late
  week, with Moderate to Major HeatRisk in desert valleys. An
  Extreme Heat Watch remains in effect for southern areas
  Wednesday and Thursday.

* Wildfire smoke will keep hazy conditions over southern California
  and southern Nevada at least into Tuesday.

&&

.DISCUSSION...

The region remains beneath southwesterly flow aloft, entrenched
between ridging over the Four Corners Region and troughing over
the Pacific Northwest, with slightly above normal temperatures and
dry conditions expected through Sunday. Heading into early next
week, the aforementioned Pacific Northwest trough will translate
inland, with the deamplification and eastward shift of the ridge
expected to result in a subtle decrease in thicknesses, allowing
temperatures to cool a few degrees closer to normal for early
August. While there remains some uncertainty regarding how far
east the ridge will shift, and thus, how much monsoonal moisture
will be able to return to the region, there are indications for
PWATs to recover to around 75% of normal for southern Nevada and
northwestern Arizona. Ensemble PWATS range from around 0.60" to
0.75" across the Colorado River Valley and Mohave County midweek
onward, though PoPs remain paltry, only around 5-10% for far
eastern Mohave County Wednesday through Friday. Convection, if it
occurs, would be likely to favor the higher terrain.

The main focus of the forecast remains on temperatures mid to late
week, with the aforementioned ridge expected to build and
retrograde westward, resulting in a quick warm-up to temperatures
5 to 8 degrees above normal Wednesday through Friday. An Extreme
Heat Watch remains in effect for Southern Mohave County, southern
San Bernardino County, and the Colorado River Valley Wednesday and
Thursday, where these sharply warmer temperatures are expected to
result in development of widespread Major HeatRisk (Level 3 of 4)
and localized Extreme HeatRisk (Level 4 of 4) Wednesday, and
especially on Thursday. The hot temperatures will continue Friday,
though will see the beginning of a comparative cooling trend with
another trough progged to translate eastward across the Pacific
Northwest into the Rockies, serving to once again deamplify the
persistent ridge. However, with the ridge remaining in the
vicinity of the Four Corners Region/northern Mexico, the trend of
mainly dry conditions with southwesterly breezes will continue,
with only low-order PoPs for far eastern Mohave county through the
weekend.

&&

.AVIATION...For Harry Reid...For the 06Z Forecast
Package...Southwest winds this evening around 7-9 kts, but gusts to
around 20 kts are forecast to return after 08z, although there is
uncertainty in the persistence of gusts overnight. Like we have seen
over the past few days, expected to see southwest winds increase
Monday afternoon with gusts to around 25 kts. VFR conditions are
expected, but there could be some denser areas of smoke through
Monday afternoon, but surface visibilities are not expected to drop
below 6sm. Temperatures will drop below 100F by 04Z this evening,
and warm above 100F after 19Z Monday and continuing until 04z. Temps
expected to peak around 105.


For the rest of southern Nevada, northwest Arizona and southeast
California...For the 06Z Forecast Package...Winds have diminished
over most areas this evening, but some intermittent gusts to around
20 kts are possible overnight at KDAG and the Las Vegas Valley TAF
sites. Expect winds generally less than 10 kts at the remaining TAF
sites. Southwest winds will increase over all areas Monday afternoon
with gusts 20-25 kts. Wildfire smoke could potentially impact KDAG
and the Las Vegas TAF sites overnight and early Monday. While
visibility reductions to less than 6sm are unlikely, some lower
layers of smoke are possible.
&&

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

&&

$$

DISCUSSION...Phillipson
AVIATION...Gorelow

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