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580
FXUS65 KVEF 020254 CCB
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
754 PM PDT Mon Jul 1 2024

.SYNOPSIS...A dangerous long-duration heat wave is on the way to the
Mojave Desert and southern Great Basin. Excessive Heat Warnings go
into effect beginning Wednesday and Thursday and continue into next
week. Monsoonal moisture lingering over northwest Arizona through
this evening will be pushed away to the east by Tuesday.
&&

.UPDATE...
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Another quiet, warm, and breezy evening across the area as
monsoonal activity remains east of us. This remains true through the
forecast period, with PoPs below 10% for the entire CWA. The main
story continues to be the coming excessive heat as a strong ridge
builds over the Western US. The worst of the heat looks to arrive
this weekend and into early next week. Daily and all-time records
will be challenged in some locations, leading to widespread Major
and Extreme HeatRisk. Those with outdoor plans during this time
should strongly consider moving them inside, or at the very least,
limit their time outside. Unfortunately, the excessive heat is
likely to continue through next week, possibly longer.
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&&

.SHORT TERM...through Wednesday.

The main weather story is the heat wave building over our forecast
by Wednesday and continuing through the holiday weekend into next
week. Temperatures will only increase 1-3 degrees across our
forecast area Tuesday as the trough over the Intermountain Region
slowly pulls away and allows the large Eastern Pacific ridge to
begin nosing inland. This will boost temperatures an additional 3-5
degrees Wednesday and begin a long heat wave as the ridge amplifies
and parks over the western states. The Excessive Heat Warning
remains in effect for much of southeast California and southern
Nevada Wednesday through Monday then expands to include the Colorado
River Valley and much of Mohave County Thursday through Monday.

A lesser concern is moisture over eastern Mohave County which now
looks to be quite limited due to dry westerly flow aloft associated
with the aforementioned trough. Isolated light showers or a brief
thunderstorm can`t be completely ruled out, but chances are only
about 10 percent this afternoon. Increasingly dry flow will impede
convection Tuesday over Mohave County and the surface dewpoints in
the 50s and 60s today will drop into the 30s and 40s Tuesday.

.LONG TERM...Thursday through Monday.

The aforementioned ridge is forecast to be centered along the West
Coast Thursday then model ensembles are in good agreement that it
will slowly become centered over Nevada Saturday through Monday.
Preceding the ridge will be a dry north-northwest flow over our
region with very little potential for any moisture to work its way
in. This is the hottest synoptic pattern that we see and this is
reflected in the NBM forecast high temp of 117 in Las Vegas Sunday
and Monday...which would tie our all-time record high that we have
reached five other times. Although this is not a certainty, there is
a 56 percent probability that Las Vegas will reach 117 degrees
during this time, so there is no good reason to adjust this downward
simply because it is a fairly rare occurrence. Death Valley should
be about 10 degrees higher...around 127. The NBM indicates a 25
percent probability that Furnace Creek could reach 130 degrees. 115-
119 degrees can be expected from Laughlin to Lake Havasu during this
time.

There is no indication of a break in the heat for our region through
the middle of next week among the medium range ensembles.
&&

.AVIATION...For Harry Reid...South to southwest winds with
occasional gusts to 25kts will persist across the valley through
sunset.  Wind will drop below 10kts overnight, and speeds are
expected to remain less than 10kts through Tuesday.  VFR conditions
are expected through the week under mainly clear skies. Temperatures
will increase throughout the week, with readings around 115F or
higher, likely by the weekend.

For the rest of southern Nevada, northwestern Arizona, and
southeastern California...Gusty south-to-southwest winds will
continue across the Las Vegas Valley, Colorado River Valley, and
western Mojave Desert, including KDAG, through this evening.  KBIH
will see light northerly winds, becoming variable or even southerly
for a period late this afternoon and evening.   All sites should see
winds fall below 10kts overnight, and remain less than 12kts on
Tuesday.  VFR conditions are expected through the week under mainly
clear skies.  Temperatures will increase through the week, with
readings rising to 110F-120F by the weekend.
&&

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

$$

UPDATE...Woods
SHORT TERM/LONG TERM...Adair
AVIATION...Planz

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