448
FXUS65 KVEF 211207
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
1051 PM PDT Thu Aug 20 2026

.KEY MESSAGES...

* Warm temperatures continue with above-normal afternoon highs and
  near-record morning lows into next week.

* Thunderstorm chances continue today but decrease over the weekend
  and remain lower through the first half of next week.


&&

.DISCUSSION...Through next Thursday.

Above-normal temperatures will continue today as a 500mb ridge
remains in place across the region. An increase in moisture over
southern Mohave County and the lower Colorado River Valley will
allow readings to cool a few degrees from Thursday`s highs, although
temperatures will still average 2 to 3 degrees above normal in most
locations. Moisture levels will decrease over the weekend, allowing
temperatures to warm a degree or two on both Saturday and Sunday.
The Extreme Heat Warning remains in place for most of the southern
two-thirds of our area through tomorrow evening. Pockets of Major
HeatRisk (level 3 out of 4) will persist through the weekend in some
of the lower desert valleys, and an extension of heat products may
be needed. Warm conditions will continue into early next week as the
ridge remains in place over the Southwest, with afternoon highs
staying a few degrees above normal and overnight lows remaining
unusually warm.


As previously mentioned, moisture will remain in place across
southern Nevada and northwest Arizona today, allowing for another
round of showers and thunderstorms during the afternoon and evening.
Storms once again will favor formation over the higher terrain, and
some may move into adjacent valleys. However, a trough approaching
the California coast will allow upper-level flow to turn more
southwesterly, ushering in drier air and potentially hindering
convective development. Any storms that do develop will be capable
of producing locally heavy rainfall and sudden gusty winds. Drier
air will continue to spread across the area over the weekend,
decreasing storm chances, with any activity generally confined to
the higher elevations of the Sierra and southern Great Basin. Drier
conditions should persist into the first half of next week, although
some uncertainty remains regarding how quickly moisture may return
as the trough and ridge evolve. Some long-range guidance suggests
the ridge may eventually shift back east, potentially allowing
monsoonal moisture and thunderstorm chances to increase again by the
second half of next week.

&&

.AVIATION...For Harry Reid...For the 12Z Forecast Package...
Overnight convection has since moved well northwest of the Valley,
bringing conditions back to normal diurnal wind patterns. Light and
variable winds continue through around 17z, then a more consistent
SSE-S direction sets up. By 20z, S-SSW wind shift is expected with
gusts 15-20 kts likely through sunset. Light southerly flow to
persist after sunset. Hi-res guidance depicts isolated convection
around Clark and Mohave counties this afternoon which have the
potential to develop outflow around the Valley. Leftover boundaries
from storms earlier this morning can favor convective development
near the terminal. At the moment, do not think KLAS will be impacted
by a storm during this TAF period, but will watch how convection
evolves later today and watch if outflow boundaries near the Valley.
For now, keeping VCSH after 20z and will update the TAF accordingly.
Temperatures exceed 100 degrees from 18z-04z.


For the rest of southern Nevada, northwest Arizona and southeast
California...For the 12Z Forecast Package...Mainly daily diurnal
wind patterns expected at all terminals outside of any convective
activity. Light winds this morning become southerly and increase in
the 17-19z timeframe with gusts 15-25 kts expected through sunset.
KDAG is the exception as usual as west winds decrease during the day
and become variable during the afternoon, favoring a NE direction.
Expect the evening westerly push at KDAG after 00z with sporadic
gusts over 20 kts. For terminals around Las Vegas and in the CRV, Hi-
res guidance depicts isolated convection around Clark and Mohave
counties this afternoon which have the potential to develop outflow
boundaries. Not currently expecting much impact at the terminals,
but will watch how storms evolve this afternoon and update TAFs if
there is high confidence in any impacts.


&&

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

&&

$$

DISCUSSION...Planz
AVIATION...Moore

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