Twentynine Palms, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

629
FXUS65 KVEF 270355
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
755 PM PST Thu Dec 26 2024

.SYNOPSIS...The largely dry and mild pattern resumes to end 2024.
Systems passing by to our north and east will bring periods of
elevated winds with minor impacts possible in the Barstow area
Friday. Light precipitation chances also accompany these systems,
but are confined to the Sierra and our northern zones.

&&

.UPDATE...Dense swaths of high clouds were spreading down from
northern California and the Pacific Northwest ahead of a fast moving
shortwave trough which will slide across the Sierra and northern
Great Basin late tonight and Friday morning. The main effect on our
forecast area will be strong winds developing across the southern
Sierra and western Mojave Desert late tonight through Friday. High
resolution models continue to indicate strong winds will remain
confined to the southern Sierra ridgetops and conditions are not
favorable for strong downslope into the Owens Valley. Western San
Bernardino County will see the strongest surface winds with gusts 40
to 50 mph and a Wind Advisory remains in effect between 7 AM and 7
PM Friday. No immediate changes needed from the forecast trends
detailed in the previous discussion. -Adair &&

.PREV DISCUSSION...
1237 PM PST Thu Dec 26 2024

.DISCUSSION...through New Year`s Day.

Lots of high clouds around today with a window of sunshine expected
this afternoon. This should help boost temps to above-normal values
once again. Lighter winds today due to a more zonal pattern. A few
weak shortwaves pass to our north today and tonight, bring light
precipitation chances to the Sierra and northern fringes of the CWA.
Snow levels in the Sierra rise from ~8000` - 9000` throughout the
window for precipitation. Combined with limited spillover, not
expecting any notable impacts in the Aspendell area with a ~40%
chance of 1" of snow and ~10% of 2". For the northern fringes of the
CWA, snow levels hover around 6000` throughout, potentially bringing
(50% probability) a dusting of snow to portions of US-93 in northern
Lincoln County. Chances for 1" of snow are ~10%. Other than these
locations, the forecast area remains dry.

An additional, weaker disturbance is forecast to slide down the
Sierra Crest and into SE California tomorrow, tightening the E-W
pressure gradient across our western deserts. The forecast gradient
has strengthened over the last 24 hours of model cycles, resulting
in stronger winds. Both NBM and HREF guidance paints western San
Bernardino County with 60-90% probabilities for 40+ mph gusts. Thus,
a Wind Advisory has been issued for the Barstow zone from 7AM - 7PM
Friday. Main concerns are hazardous crosswinds on N-S roads and
areas of blowing dust.

The pattern remains progressive over the weekend with broad ridging
moving in on Saturday, returning drier and calmer conditions across
the area. By Sunday, the next shortwave is passing through the Great
Basin, flattening the ridge and spurring increased winds (mainly in
our western zones). Precip chances are confined to the central
Sierra with this system.

As we head into next week and next year, the pattern remains
progressive in a general zonal or WNW flow. However, discrepancies
continue regarding a potential system around NYE. Dry conditions are
likely (90% confidence), but the wind and temperature forecast is
more uncertain. About 50% of the Grand Ensemble members (mostly
GEFS and GEPS) show a trough digging into our area around the new
year, but the other ~50% (mostly EPS) keep the trough farther
east. The former would promote stronger north breezes and cooler
temperatures, while the latter would be calmer and warmer.

&&

.AVIATION...For Harry Reid...No operationally significant clouds,
winds, or weather expected through Saturday.

For the rest of southern Nevada, northwest Arizona and southeast
California...Westerly winds will increase over the Sierra and in the
Barstow area tonight and Friday, with gusts up to 60 knots over the
crest and 30 to 40 knots in the Barstow area. Snow will also spread
over the Sierra and far northern Lincoln county tonight and Friday
morning, with associated low ceilings and terrain obscuration, while
VFR conditions persist in the Mojave Desert. Conditions will improve
Friday afternoon and evening, with no operationally significant
clouds, winds, or weather expected Saturday.

&&

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

&&

$$

DISCUSSION...Woods
AVIATION...Morgan

For more forecast information...see us on our webpage:
https://weather.gov/lasvegas or follow us on Facebook and Twitter