446
FXUS65 KVEF 190923
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
223 AM PDT Tue Aug 19 2025

.KEY MESSAGES...

* Hotter than normal temperatures are on tap for the region this
  week with Extreme Heat Warnings and Heat Advisories in effect
  Wednesday through Saturday.

* Moisture will return to the region during the second half of the
  week, bringing increased precipitation chances to the area.

&&

.DISCUSSION...through next Tuesday.

Temperatures will continue to increase each day through the end of
the week as we find ourselves under higher than normal 500 mb
heights courtesy of the Four-Corners High. Afternoon high
temperatures will top out around 5 degrees above normal as
temperatures peak on Thursday and Friday. While 5 degrees above
normal might not sound too bad, there will be little overnight
relief with this heatwave as overnight low temperatures will be
around 6 to 12 degrees above normal each night during the second
half of the week. This combination of hotter than normal
temperature during the day and anomalous overnight temperatures
will result in widespread Moderate (Level 2 of 4) to Major (Level
3 of 4) HeatRisk with pockets of Extreme (Level 4 of 4) HeatRisk
during the second half of the week. As such, A Heat Advisory is in
effect for Esmeralda County, central Nye County, the Spring
Mountains, and the Sheep Range from 8:00 am Wednesday through
11:00 pm Saturday. An Extreme Heat Warning is in effect for the
Owens Valley, Death Valley, San Bernardino County, Mohave County,
Lincoln County, and Clark County from 8:00 am Wednesday through
11:00 pm Saturday. While the heat headlines run through Saturday,
one potential caveat is that convective cloud cover and
precipitation could limit afternoon temperatures for portions of
the region.

As the high pressure ridge settles over the Four Corners Region,
we will find ourselves in our typical monsoonal pattern with
southeasterly flow aloft helping to transport moisture into our
area. Moisture will begin to increase today, but the only evidence
of this moisture will be increased cloud cover for portions of
the region. Precipitation chances will begin to increase in the
eastern portions of Mohave County on Wednesday afternoon, slowly
pushing further west on Thursday afternoon as moisture continues
to increase. Chances for afternoon showers and thunderstorms will
become more widespread across northwestern Arizona, southern
Nevada, and southeastern California beginning Friday and
continuing into the weekend. Lightning, gusty outflow winds, and
localized heavy downpours will be threats with any convection that
develops. Forecast confidence decreases as we head into next week
due to discrepancies regarding a potential trough and the return
of dry southwesterly flow. The timing of this shift to drier flow
aloft will determine how long we will see moisture linger across
the region as it recirculates beneath the ridge.

&&

.AVIATION...For Harry Reid...For the 06Z Forecast Package...Light
easterly winds late this evening will turn to the typical southwest
direction by midnight.  Winds tomorrow will be similar to what was
experienced today, with variable winds in the morning, followed by
light east to southeast winds during the afternoon and early
evening.  Southwest winds will return after sunset.  VFR conditions
will prevail through tomorrow.  Temperatures will top out near 106
degrees, with readings exceeding 100 degrees between 20Z and 04Z.

For the rest of southern Nevada, northwestern Arizona and
southeastern California...For the 06Z Forecast Package...Winds
across the region will follow typical diurnal direction trends
tonight and tomorrow, with speeds generally remaining less than 12
knots.  The exceptions to this will be in the Owens Valley, where
southerly winds with gusts to 30 knots are possible during the
afternoon.  VFR conditions will prevail through tomorrow across the
region.

&&

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

&&

$$

DISCUSSION...Stessman
AVIATION...Planz

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