745
FXUS65 KVEF 170452
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
952 PM PDT Sun Jun 16 2024

.SYNOPSIS...A shifting weather pattern will bring a cooling trend
to the area through the middle of the week in addition to breezy
winds. Temperatures are forecast to increase late in the week as
high pressure builds over the region with very hot conditions
expected over the weekend. Increasing confidence for the
reintroduction of major heat impacts by next weekend for many valley
locations.
&&


.UPDATE...The Red Flag Warning in effect for Mohave County today has
been allowed to expire on time at 8pm PDT. Southwest winds have
decreased across the region, but isolated gusts between 20 and 25
mph are still possible through the early part of the overnight
hours. Winds will return tomorrow late-morning. These winds coupled
with very dry conditions will return the Red Flag Warning for Mohave
County from 11am - 8pm tomorrow. There will be additional
consideration to include parts of the southwestern Great Basin in
this warning, but will likely wait until the morning to make any
formal decision to coordinate with fire weather partners.
Temperatures will cool off somewhat tomorrow for the start of the
work week with temperatures hovering within a couple of degrees of
seasonal averages. No changes made to the forecast this evening as
it looks to be in good shape.
&&

.PREVIOUS DISCUSSION...1250 PM PDT Sun Jun 16 2024/


.SHORT TERM...Tonight through Monday night.

Broad upper level troughing will remain over the region tonight
through Monday night. This will result in dry conditions, breezy
winds, and cooler temperatures compared to what we have been
experiencing recently.

A reinforcing piece of energy will dig south through the mean
cyclonic flow Monday afternoon and overnight which will bring
increasing winds to the region. Monday afternoon winds should be
generally uneventful as probabilities for impactful wind gusts over
40 MPH remain low. There are scattered pockets of high probabilities
(80% or higher) Monday evening overnight as the shortwave swings
through central Nevada. West winds around Barstow, CA into Yucca
Valley should increase in response to the increasing gradient and
enhancement flow through the terrain. Higher probabilities (over
70%) for wind gusts over 40 MPH through this area mainly highlight
the terrain then briefly the Twentynine Palms area after 8 PM,
however winds should be short lived by that time and thus impacts
will be limited. Brief periods of difficult driving conditions and
patchy blowing dust will be possible on portions of the I-40 as well
as around Yucca Valley Monday evening into the early overnight.

Further north, a cold front will sweep through the area Monday
night, reaching at least the Colorado River Valley by Tuesday early
morning, which will bring increased north winds. Again, seeing
pockets of higher probabilities for wind gusts over 40 MPH through
southern Nevada and parts of Death Valley; however, the higher
probabilities are only for an hour or two. Synoptically, low level
wind profiles and the overall strength of the incoming wave would
suggest winds should not overachieve or be overly strong. Winds may
jump up to 40 MPH as the front passes through the area, but should
not last more than a hour or two and thus wind impacts will be
limited.

Outside of winds, the only other weather to note will be cooler
temperatures. High temperatures Monday afternoon will remain near or
slightly below normal, but will be comparatively cooler than the heat
we have been experiencing recently. Moderate HeatRisk will be limited
to Death Valley and the lower Colorado River Valley on Monday.

.LONG TERM...Tuesday through Saturday.

Tuesday will be the "coolest" day of the week with afternoon high
temperatures topping out 3 to 5 degrees below normal for mid-June.
Troughiness will linger across the Western US through the end of the
work week as the upper-level trough that brought us our brief
reprieve from the heat weakens. These rising 500 mb heights will
allow for temperatures to quickly recover back up to 5 to 10 degrees
hotter than normal by the end of the week. By Friday, widespread
Moderate HeatRisk will have returned to southeastern California,
northwestern Arizona, and southern Nevada. Major HeatRisk will
return to the Las Vegas Valley, Death Valley, and the Amargosa
Valley on Saturday as temperatures continue to climb.
&&


.AVIATION...For Harry Reid...Breezy south to southwest winds with
occasional gusts to 25 knots will continue into tonight. Winds
should diminish to around 10 knots before sunrise, and a period of
light and variable winds is expected tomorrow morning before gusty
southwest winds return. A weak front is expected to move across the
region tomorrow evening after 03Z, bringing gusty northwest-to-north
winds to the valley. Skies will be mostly clear through Monday
afternoon, although some light haze or smoke from the Post Fire
north of Las Angeles may reduce slantwise visibilities at times.

For the rest of southern Nevada, northwest Arizona and southeast
California...South to southwest winds with occasional gusts of 20 to
30 knots will continue at most regional TAF sites into this evening,
and then again on Monday. Further north in the Owens Valley,
including KBIH, winds will favor a more north-to-northwest direction
with occasional gusts this afternoon and Monday. All areas, except
KDAG, should see winds fall below 15 knots overnight.  Skies will be
mostly clear through Monday afternoon, although some haze or smoke
from the Post Fire north of Las Angeles may reduce slantwise
visibilities at times, especially across the western Mojave Desert
and lower Colorado River Valley.
&&


.FIRE WEATHER...Very dry conditions are expected through the week
Monday with minimum relative humidity dropping below 10% this
afternoon and again Monday afternoon. For Arizona fire zones 101 and
102, poor RH recovery is expected tonight with some improvement
Monday night. A Red Flag Warning is in effect for AZZ101-102 today
and Monday due to very dry conditions and increased winds resulting
in high fire start and spread risk. Widespread wind gusts may
struggle to reach or exceed gust thresholds but sustained winds will
likely exceed 20 mph both days. Elsewhere, it will be dry but winds
will struggle to jump to impactful levels for an extended period of
time and fuels through out much of the area remain marginal. NVZ460
could reach Red Flag Warning criteria Monday evening and early
overnight; however, it is uncertain if fuels are sufficient for
considerable wild fire risk.
&&


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

&&

$$

UPDATE...Soulat
SHORT TERM/FIRE WEATHER...Nickerson
LONG TERM...Stessman
AVIATION...Planz

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