Atolia, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

959
FXUS65 KVEF 232107
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
107 PM PST Tue Dec 23 2025

.KEY MESSAGES...

* Widespread rainfall with isolated flash flooding, snow at the high
  elevations, and gusty winds will impact Christmas travel.

* Heavy mountain snow expected in the Sierra and White Mountains
  amounting to several feet of new accumulation in the highest
  elevations by the end of the week.
&&

.DISCUSSION...through next Tuesday. Midday satellite loop showed mid
and high level clouds blanketing our CWA. Area radars showed virga.
Surface obs showed locally gusty south winds and temperatures a few
degrees cooler than 24 hours ago thanks to the opaque cloud cover.

Mid level water vapor loop showed a very striking presentation of
the incoming storm. The mid and high level moisture over our area
today was streaming north from the tropics well ahead of the main
storm, which was located near 30N 137W. In between those two
features were multiple shortwave troughs showing up as comma shapes,
with very strong mesoscale vertical motion shown by deep convection
ahead of the wave axes and sharp drying immediately behind them.

As has been advertised for a while now, this storm and its
associated heavy rain are on the way. High resolution models show
light precip breaking out along and southeast of Interstate 15 as
early as this evening, followed by the main rain band pushing into
Inyo and Esmeralda counties late tonight and sweeping east across
the entire CWA Wednesday and Wednesday night. In general, rain
totals of one half to one and a half inches should be common across
the deserts, with much higher totals of four to six inches on the
south slopes of mountains where orographic lift will be maximized.
All of this supports the Flood Watch which is in effect. Due to the
unseasonably warm nature of this storm system, snow levels will be
extremely high, starting off at 7500 to 9000 feet in the northwest
CWA and over 10,000 feet in the southeast CWA tonight. Cooler air
will begin to push in from the west Wednesday evening, knocking snow
levels down to 6000 to 7000 feet in the western CWA by Christmas
morning. This will allow substantial snow to accumulate in the
Sierra Nevada and White Mountains of Inyo County on Christmas Day,
with multiple feet likely on the Sierra crest. Thus, the Winter
Storm Warnings look good. As snow levels drop on the Spring
Mountains Christmas Day, a few inches of snow will likely bring a
white Christmas to the communities there, but it appears that the
heaviest precip will have exited stage right by then. A weaker
atmospheric river could try to push in from the southwest Friday, so
more winter weather products may be needed after the first wave has
passed. Winds will also be a factor. Southerly winds were already
increasing over the southern Great Basin and should become more
widespread later this evening, so the Wind Advisory there looks
good. One concern is that precipitation drag could tamp down the
wind speeds as the rain moves in, but even if that occurs, stronger
winds could surface both before and after the rain, as well as
during any breaks in the rain. On Wednesday, strong southerly flow
ahead of the rain band should allow gusty winds to surface in Mohave
County and the Colorado River Valley, so the Wind Advisory there
looks good as well. The same caveats about precipitation drag apply.

Models are slowly starting to come into better agreement for the
post-Christmas period, showing lingering low pressure off the West
Coast directing another (weaker) AR toward our area Friday, leading
to chances for more rain and mountain snow before the low weakens,
cuts off, and retrogrades southwestward Saturday onward, allowing
drier air to take over. We will need to watch this closely, as some
of the ensemble members show this low eventually pulling another
slug of moisture back northward toward our area in the middle of
next week.
&&

.AVIATION...For Harry Reid...For the 18Z Forecast Package...Winds
to remain rather light then shift to the southeast by early to mid
afternoon. A few wind gusts of 15-20 knots may occur during the
afternoon and early evening hours, but otherwise winds to remain
10 knots or less. A few showers will develop late afternoon into
early evening, potentially bringing virga and some gusty winds,
though confidence remains too low to mention in TAF. The more
substantial aviation impacts are expected overnight into Christmas
Eve, initially with lowered ceilings of 5-6 kft or less with
persistent light to moderate rains after 17z. There is a low
probability of ceilings below 3 kft and reduced visibilities to
5 sm or less, though this is toward the end of the current TAF
period so will refrain from mention in TAF at this time.

For the rest of southern Nevada, northwest Arizona and southeast
California...For the 18Z Forecast Package...A complex forecast
period is anticipated as widespread low ceilings and rain are
expected to move from west to east, affecting all terminals from
around 09z Christmas Eve into Christmas Day. This will bring
bouts of gusty winds, especially at KBIH, where wind gusts of
20-35 knots are expected late this afternoon into tonight.
Elsewhere, winds to generally remain below 15-20 knots outside of
any heavier showers. Low ceilings will also become more prevalent
with time, developing overnight into Christmas Eve morning and
persisting into Christmas Day. Broken to overcast skies of 4-6
kft can be expected with at least a low probability of ceilings as
low as 1500 ft, and visibility impacts due to rain and fog.
Future TAF issuances will likely invoke some of this as confidence
on timing and impacts becomes more clear.
&&

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

$$

DISCUSSION...Morgan
AVIATION...Austin

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