084
FXUS65 KVEF 242141
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
141 PM PST Sun Nov 24 2024

.SYNOPSIS...After quiet conditions today, the next weather system
will begin to impact the region Monday. This will result in a
major snowfall event for the Sierra between Monday and Tuesday
night. Elsewhere, precipitation chances will spread across the
region, particularly along and northwest of the I-15 corridor.
Cooler and drier northwest flow will develop by Thanksgiving Day
with another weak system moving through the region between Friday
and next weekend.

&&

.SHORT TERM...Tonight through Tuesday night.

Winds have continued to ease today from north to south. Some stray
sprinkles/flurries were beginning to wane across Lincoln County.
Otherwise quiet conditions through the rest of today.

Attention now turns to an upper level trough currently situated
of the Pacific Northwest Coast that will gradually weaken and
slide southeast Monday through early Wednesday. This will direct
an atmospheric river squarely at the southern Sierra, resulting
in significant precipitation totals. As we approach the onset of
this system, more details are beginning to come into view.

For the Sierra, snow levels will begin around 6000 feet at the
onset of the system in the Sierra Monday morning but quickly climb
to between 8000-9000 feet by Monday evening and remain in that
range until mid-day Tuesday when they begin to fall once again. As
the precipitation ends Wednesday morning, snow levels will once
again be in the 6000-7000 foot range. Snowfall rates between 1-2
inches per hour are expected during the peak of this system Monday
night into Tuesday morning and when combined with winds gusting
20-30 mph could create areas of blowing snow and blizzard-like
conditions at times at the high elevations. Snowfall totals will
be measured in feet, especially above about 8000 feet in
elevation.

The White Mountains will also likely see significant snow with
this event, however totals will be far lower with the Sierra
intercepting much of the moisture.

For the lower elevations, chances for rain will be present,
mainly along and northwest of the I-15 corridor. The Owens Valley
will likely see the highest amounts. However, confidence in the
details of exact amounts there is relatively low. The most likely
scenario for the Owens Valley is storm total numbers on the order
of 1.0-1.5 inches of rain, however there is much wider
variability in the guidance with several inches dividing the low-
end from high-end scenarios. It`s worth noting that if observed
QPF falls on the higher end of the spectrum, small stream flooding
will certainly be possible within the Owens Valley.

Precipitation should be tapering off late Tuesday through
Wednesday morning as the trough weakens and moves east of the area
leaving us in dry northwesterly flow.

.LONG TERM...Wednesday through Saturday.

Precipitation will be ending Wednesday morning with generally
drier and cooler conditions expected Wednesday and Thursday as
northwest flow develops. The next feature of interest will be a
weak upper level low feature that will gradually shift east across
the region in the Friday through Saturday timeframe.

The latest 12z cluster analysis has come into much better
agreement with the pattern evolution late in the week. Unlike the
00z analysis, the 12z has no clusters where the upper low
interacts with the exiting trough.Regardless, QPF totals  This
should allow for a break between systems of at least 24 hours or
longer. The differences between the clusters mainly come down to
the strength and track of the low as it progresses east. The
implications for the region will primarily be minor differences in
precipitation placement and timing. Regardless, any precipitation
that falls would be largely beneficial (outside of the impact of
wet roadways across the region).


&&

.AVIATION...For Harry Reid...Light and variable winds will continue
through mid-afternoon when winds will increase slightly and settle
in from the southwest. Even with the slight increase in magnitude,
sustained winds will be around 10 knots or less. These southwesterly
winds will continue into the late evening, when winds will once
again become light and variable. Light and variable winds are
expected to continue through Monday afternoon. Showers will begin to
develop in the higher terrain surrounding the valley late Monday
morning with a 20 to 40% chance of showers impacting the terminal on
Monday afternoon and evening. Low CIGS will accompany these showers
with a 75%+ chance of CIGS below 6.5 kft  and a 25 to 50% chance for
CIGS of 5 kft or lower beginning early Monday afternoon.

For the rest of southern Nevada, northwest Arizona and southeast
California...Winds at KVGT will remain light and variable through
Monday morning. Winds at KHND will tend to favor a southerly to
southwesterly direction with sustained speeds of 8 to 12 knots
through early Monday morning when winds will become light and
variable. KDAG will continue to favor a westerly direction through
Monday. 20 to 30 knot wind gusts will gradually decrease throughout
the evening and overnight hours, with gusts dropping off completely
early tomorrow morning. Winds at KEED will remain under 10 knots and
will favor a west-southwesterly direction into the overnight hours
when winds will become light and variable. KIFP will see sustained
wind speeds of 10 knots or less and will favor a southerly direction
through Monday morning. Light and variable winds will remain light
while settling in from the northwest during the early evening hours
at KBIH. These northwesterly winds will continue through the evening
hours with winds becoming light and variable during the overnight
hours as showers develop in the higher terrain around KBIH. Light
rain and 5 kft CIGS will have the potential to impact KBIH beginning
early Monday morning and continuing into the afternoon. This showery
activity will work its way west across southeastern California,
southern Nevada, and northwestern Arizona during the day on Monday,
bringing chances for light rain and lower CIGS to KDAG, the Las
Vegas Valley TAF sites, and KIFP on Monday and Tuesday.

&&

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

&&

$$

DISCUSSION...Wolcott
AVIATION...Stessman

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