831
FXUS65 KVEF 131929
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
1229 PM PDT Thu Jun 13 2024

.SYNOPSIS...A weak low pressure system brings slightly cooler
temperatures to the area as well as potential for precipitation in
the Sierra and northwest Arizona today. Temperatures rise on Friday
and Saturday but start to fall next week as a broad trough moves
into the western United States.

&&

.SHORT TERM...Tonight through Sunday

The low pressure system moving through southern California and
Arizona today advects moisture northward and brings isolated
precipitation chances to northwest Arizona this afternoon and early
evening. Convection should taper off after sundown as surface
heating ends. Limited CAPE means lightning is unlikely but a few
strikes cannot be ruled out. The main concern is strong outflow
winds that are usually associated with high based storms and dry air
near the surface. Convection may also occur over the Sierra crest in
northern Inyo County, but these should be low impact and limited in
range to the mountains. POPs are in the 10 to 30 percent range and
precipitation totals should be light.

The low moves east and ridging resumes starting Friday. Temperatures
continue to be around 5 to 10 degrees above normal through the end
of the week. By Saturday, HeatRisk Level 2 (Moderate) will spread
across the area with patches of Level 3 (Major) near Las Vegas, the
Colorado River Valley, and southern San Bernardino County.  There is
a 75 percent chance of a high of at least 110 degrees in Las Vegas
on Saturday. This level of heat is dangerous to those without
adequate cooling or hydration. Be sure to plan ahead if spending
time outside this weekend. Surface temperatures should start to
decrease again on Sunday as a trough moves into the western United
States and heights aloft fall. Because of the limited spatial and
temporal extent of the heat, especially compared to the previous two
extreme heat events this summer, there will be no headlines issued
for the heat this weekend at this point.

A westerly low level jet develops ahead of the trough, bringing
gusty surface winds to the Sierra and western San Bernardino County.
The current NBM run shows the strongest winds limited to high
terrain on Saturday, but coverage spreads to lower elevations of
western San Bernardino County on Sunday. Will continue to monitor
these winds to determine the necessity of a headline.

.LONG TERM...Monday through next Thursday

A cooler weather patten is likely for the beginning of next week as
a trough digs into the Western US. ECMWF EFIs highlights this well
with a increasing signal for below normal max and min temperatures
Tuesday and Wednesday. There remains some uncertainty still in exact
temperatures models continue try to resolve how strong and deep the
trough will dig, but a trough of some flavor is being highlighted on
all long range model camps so cooler temperatures are expected.

Winds are the other concern with the trough. While exact wind
impacts will depend on the exact setup of the upper level trough,
increasing winds possible early next week. Fire weather will also be
a concern as it will remain dry with the increasing winds. Pinning
down exact wind strength and the time period for the strongest winds
is still uncertain, though there is a decent signal in probabilities
for win gusts over 40 MPH in  the Barstow area and western Mojave
Desert. Stay tuned!

&&

.AVIATION...For Harry Reid...Winds between 180-200 degrees with
occasional gusts of 15-20 knots are expected through the afternoon
and early evening.  Wind speeds will diminish to less than 10 knots
after sunset and become light and variable by tomorrow morning.
Northeast winds (040-070) are possible tomorrow morning after 16Z,
but speeds are expected to remain 8 knots or less.  Southeast to
south winds will redevelop tomorrow afternoon.  No significant cloud
cover is forecast through the TAF period.

For the rest of southern Nevada, northwest Arizona and southeast
California...South to southwest winds are expected across most of
the region through the afternoon and early evening, with occasional
gusts of 20 -25 knots common. Isolated showers will develop over
northwest Arizona after 20Z and showers and a few embedded
thundershowers are expected along the Sierra after 21Z.  Winds will
diminish in most areas overnight, and lighter winds following
similar directional trends are forecast for Friday.  VFR conditions
will prevail at all regional TAF sites through the period.

&&

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

&&

$$

SHORT TERM...Meltzer
LONG TERM...Nickerson
AVIATION...Planz

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