785
FXUS65 KVEF 100738
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
1238 AM PDT Mon Jun 10 2024

.SYNOPSIS...Temperatures will remain five to 10 degrees above normal
through next weekend, with Tuesday and Wednesday the hottest days of
the period. Conditions will remain dry with periodic cloud cover and
occasional breezy afternoon winds.
&&

.SHORT TERM...through Wednesday night. Midnight satellite loop
showed just a few mid and high level clouds drifting over the
region. Surface obs showed light winds and temperatures averaging
around five degrees cooler than 24 hours ago, but still above normal
for early June. Dewpoint temperatures had dropped sharply - as much
as 20 to 30 degrees in the past 24 hours over much of the area. The
overall pattern was evolving as expected, with our area under a
ridge axis between low pressure heading east across the northern
Rockies and a cut off low sagging south well offshore of southern
California. Under this ridge axis, the respite from the heat will be
brief, only lasting one more day before temperatures jump on Tuesday
and Wednesday. This leads to the main concern for this forecast -
the Excessive Heat Watch. Forecast HeatRisk values have come down a
tiny bit since yesterday, with a speckled mix of Moderate and Major
in the Watch area. Forecast high temperatures are also down a degree
or so. However, digging into the NBM at several points within the
Watch area shows that the deterministic forecast highs and lows are
in the lower half of the distribution in most cases, and in some
cases even below the 25th percentile. Another factor worth
considering is that we just came out of an excessive heat episode,
and the two day "break" is both short in time and not much of a
break at all since temperatures only came down to about five degrees
above normal. Thus, folks who are vulnerable to the heat may be
coming into this episode already carrying some leftover stress from
the previous episode. With these factors in mind, upgraded the Watch
to a Warning. Expect dry conditions and light winds under the
building ridge aloft.

.LONG TERM...Thursday through Sunday.

Not much change in the overall expectations late this week through
the weekend. A cut off low off the Baja California coast will weaken
as it ejects northeast into the Southern Plains Thursday through
Saturday. Long range models are in decent agreement with the
progression of this feature, with the main difference in model camps
being in how strong the low will be as it moves through. No matter
what solution occurs, this low will pass through with minimal to no
weather impacts. Afternoon breezy winds are expected but there are
no indications on model ensembles for impactful winds as the
probability for wind gusts remains less than 20% through the period.
Any moisture associated with the low will be lost to the terrain in
California, so significant rainfall is not expected either. In
general, the main noticable difference in weather will be cooler
temperatures compared to Tuesday and Wednesday`s heat.

For Sunday into the beginning of the work week, there is significant
disagreement between models on how an incoming West Coast trough
will interact with a ridge trying to build in from the south. The
temperature spread on ensembles for Sunday through next week is
massive for that time period ranging from potentially impactful heat
levels to below normal temperatures. It should remain dry through at
least the weekend, and even if the incoming trough does dig this far
south it would mainly be potential wind impacts and precipitation
would be not of concern due to limited moisture.
&&

.AVIATION...For Harry Reid...Light and variable winds this morning
will give way to southeast breezes this afternoon. Speeds should
largely remain in the 6-10 knot range, but there is a 25% chance of
winds over 10 knots at times. By late afternoon or early evening,
wind direction is forecast to shift to the south-southwest, and
persist through the night. Similar pattern expected tomorrow, but
winds will be slightly weaker. Mostly clear skies with just a few
high clouds.

For the rest of southern Nevada, northwest Arizona and southeast
California...Yet another day of south-southeast breezes across much
of the area, though wind magnitude will be weaker. Peak gusts this
afternoon are forecast to be in the 12-18 knot range. KDAG remains
the exception to the wind direction described above, with light
easterly or variable winds this afternoon and the typical westerly
push this evening. Mostly clear skies at all TAF sites with just a
few mid and high clouds.
&&

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

$$

SHORT TERM...Morgan
LONG TERM...Nickerson
AVIATION...Woods

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