177
FXUS65 KVEF 150904
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
104 AM PST Fri Nov 15 2024

.SYNOPSIS...Conditions will turn unsettled today and Saturday
as the region will be under an area of low pressure. Strong winds
with gusts exceeding 40 mph will occur in the western Mojave Desert
of southern California today. Also, isolated to scattered showers
will favor the higher terrain both days, while Saturday will be the
coldest day. Another system clips the area early next week keeping
temperatures on the cool side, and setting the stage for persistent,
gusty north winds down the lower Colorado River Valley through the
middle of next week.
&&

.SHORT TERM...Through Saturday night.

Trough axis moving inland across central/southern California early
this morning. Showers starting to expand in coverage along the
windward side of the southern Sierra Nevada and Tehachapis. A few
short-lived thunderstorms are occurring as well.

Little has changed in to progression of the trough across the
southern Great Basin and Mojave Desert through Saturday night.

Precipitation: With the system lacking any significant moisture tap,
total QPF the next two days will be negligible, less than a 0.10"
most spots, the exception would be along the southern Sierra crest
where guidance paints a 0.25"-0.33". As lapse rates steepen this
afternoon under cold pool aloft with H5 temps -26C to
-28C, isolated to scattered showers will blossom primarily over the
higher terrain of southern Nevada and Inyo County. With the loss of
daytime heating, shower coverage should shrink tonight. Saturday
should play out quite similar to today. Isolated to scattered
showers will develop throughout the day along and east of the trough
axis across southeast Nevada, northwest Arizona and southeast
California. Snow levels drop to around 5000 feet but do not expect
much in the way of accumulation except on vegetative surfaces as
road surface may still be too warm.

Wind: Wind Advisory from 7 am to 7 pm for the western Mojave Desert
of San Bernardino still look good. Both the GFS/NAM MOS guidance for
Barstow show wind speeds peaking between 10 am and 4 pm. The
probability for impactful wind gusts over 40 mph are 80% or greater.
There will be some pockets of 30-40 mph gusts extending eastward
into the higher terrain of the Mojave National Preserve, Clark and
Mohave counties as well. Wind speeds diminish tonight and Saturday,
before north winds begin to increase Saturday night behind the
exiting trough.

Temperatures: Below normal temperatures both days with high running
about 10 degrees normal Saturday.

.LONG TERM...Sunday through Thursday.

Not much change in the extended forecast. Still looking at our
weekend trough closing off over southern Arizona and northwestern
Mexico on Sunday. This will mark the end of precipitation chances
from this system, but induce breezy north across the area. Strongest
gusts expected in the lower Colorado River Valley, where there
remains a 50-70% chance of 40+ mph gusts on Sunday. Forecast highs
continue to be 5-10 degrees below normal for mid-November.

Quick on the heels of the weekend system is a broader, progressive
trough that swings through on Monday. There has been some change in
this system`s evolution among ensemble guidance, with the EPS
trending towards the weaker/more-progressive GEFS mean solution.
This doesn`t impact Monday`s PoPs or winds very much. Latest NBM
PoPs continue to be low and largely confined to northeastern
portions of Lincoln and Mohave counties, where they range from 10-
30%. Meanwhile, NBM 40+ mph gust probabilities have ticked up
slightly on Monday across western San Bernardino County (pre-frontal
winds) and our northwestern CWA (post-frontal winds) to where they
now range from 40-70%. However, the more-progressive and less-
amplified trend shown in ensemble guidance would result in a weaker
N-S pressure gradient in the wake of Monday`s trough, meaning weaker
northerly winds Tuesday-Thursday. The trend can be seen in NBM 40+
mph gust probabilities on Tuesday, which have dropped to 50-60%
between Needles and Laughlin. Should the aforementioned trends
continue, these probabilities may decrease further. The potential
for wind impacts outside of the Colorado River Valley on Tuesday is
less than 40%. North winds are forecast to gradually weaken
throughout the rest of the week as a strong ridge begins to dominate
the Western US. Temperatures will also slowly warm during this time.
&&

.AVIATION...For Harry Reid...Diurnal wind patterns will continue
through the start of the forecast period, however an approaching
system will result in a quick uptick in southwesterly winds with
gusty conditions developing by daybreak. Sustained wind speeds
around 15-20KT with gusts to 25-30KT are expected thereafter through
the afternoon. Along with the increasing winds, high clouds will
give way to a SCT deck with bases around 10kft, mainly during the
afternoon and evening. In this scenario, localized blowing dust will
be possible across the Valley, though low probability of impacts at
KLAS precludes inclusion in the TAF. After sunset winds will begin
diminishing and veer to the west, with the eventual northwesterly
wind shift now looking to hold off until near or just beyond the end
of the forecast period.


For the rest of southern Nevada, northwest Arizona and southeast
California...Winds remain light across the region with mainly
diurnal wind patterns forecast through the start of the period. The
trend will be for increasing westerly to southwesterly winds at all
terminals except KBIH, with the uptick in westerly winds expected by
around 09Z at KDAG and KHND, and toward 15-19Z for other terminals.
KBIH will see gusty northerly winds through the period, with
intermittent light rain or rain/snow showers with ceilings around
10kft, mainly during the late morning and afternoon. Wind gusts to
20-30KT will be common, though will begin diminishing after sunset
with KIFP quickly returning to diurnal wind patterns by the end of
the period. KBIH will see a continuation of gusty northerly winds,
while KVGT will see a northwesterly wind shift late in the period
with gusts maintained by local terrain enhancements. Dry conditions
are forecast for all but KBIH, with passing mid and high clouds
through the period.
&&

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

$$

SHORT TERM...Pierce
LONG TERM...Woods
AVIATION...Meltzer

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