Joshua Tree, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

567
FXUS65 KVEF 231031
AFDVEF

Area Forecast Discussion
National Weather Service Las Vegas NV
230 AM PST Sat Nov 23 2024

.SYNOPSIS...Gusty west-southwest winds will spread across much of
the region today and tonight in response to a Pacific System slowly
moving inland then pulling away over the Rockies Sunday. The
strongest winds will occur near the Southern Sierra and the Spring
Mountains. High elevation snow will be confined near the Sierra
crest. Another system will move across the region through the first
half of next week, resulting in chances for widespread rain and
mountain snow.
&&

.SHORT TERM...Today through Sunday Night.

The powerful Pacific System moving slowly inland today and tonight
will spread gusty west-southwest winds across much of our forecast
area though impacts will be primarily related to favorable
conditions for high downslope winds on the east facing slopes of the
Southern Sierra and Spring Mountains. Damaging downslope winds
occured in the Owens Valley as a couple big rigs were blown over
along Highway 395 near Olancha shortly after midnight. Automated
nearby sensors were recording gusts over 58 mph. The Wind Advisory
for the Eastern Sierra/Owens Valley was replaced with a High Wind
Warning valid until 4 AM PST Sunday. Gusts reached 69 mph at Angel
Peak in the Spring Mountains at 130 AM and the strongest are yet to
come through today. The latest HREF/NBM have indicated a slight
decrease in speeds for general winds not enhanced by the terrain for
places like the central Las Vegas Valley where gusts of 25 to 35 mph
can be expected. The 140-150 knot 250 mb jet across northern CA/NV
will slowly dip over the southern Great Basin tonight while decrease
to 110-120 knots. 700 mb winds of 40-50 knots will be common through
the period which will interact with the high terrain. No other
changes are planned for wind headlines and speeds will diminish late
tonight into early Sunday morning which supports High Wind
Warning/Wind Advisory expiration times of 4 AM PST sunday.

The tail end of the atmospheric river will slide off the Southern
Sierra this morning, but additional batches of moisture may lead to
additional snow near the crest. Any precipitation which manages to
spill onto the lower slopes and Owens Valley is expected to be quite
light.

Temperatures will be noticeably warmer today, especially in the Las
Vegas Valley, as winds mix the boundary layer leading to highs in
the lower 70s. HIghs will drop about 8-10 degrees Sunday behind the
trough axis.

.LONG TERM...Monday through Friday.

A tricky long term forecast period with a lot of uncertainty
embedded within it. High confidence in the cooling trend continuing
into Monday as the low-amplitude ridge breaks down and exits to the
east and troughing starts to dominate the pattern. As far as the
overall pattern goes, uncertainty significantly increases by
Wednesday when 21% of global ensemble members delay the onset of the
positively-tilted trough moving through the region until Thursday at
the earliest with some solutions offering an even later passage. The
solution will obviously have a significant impact on both
temperatures and precipitation. A Winter Storm Watch has been issued
for 10 PM Sunday through 10 AM Wednesday for the Eastern Sierra
Slopes to encapsulate both the increased confidence in higher
snowfall totals/lower snow levels and the uncertainty in the exact
timing of the greatest impacts. Outside of the Eastern Sierra
Slopes, it gets tricky in terms of how much moisture will be
available and when. The current forecast has PoPs increasing Monday
morning through Tuesday morning, and then just lingering through at
least Wednesday. Highest PoPs are in the Southern Great Basin,
diminishing to the south with dismal PoPs in the Eastern Mojave
Desert and Colorado River Valley. The determining factor in terms of
precipitation to the east of the Sierra will be to what extent the
Sierra erodes the system before it gets there.
&&

.AVIATION...For Harry Reid...Winds will be light and diurnal through
the early morning hours. Mid-to-late morning, gusty southwest winds
(directional variability between 190 and 240) will pick up between
25 and 35 kts with a 30 percent chance of occasionally exceeding 35
kts until sunset. Speeds will gradually drop overnight before
gaining a westerly component Sunday morning. Gusts will remain in
the TAF through the TAF period with SCT-BKN between 15 and 20 kft.

For the rest of southern Nevada, northwestern Arizona, and
southeastern California...Mid-to-late morning, gusty southwest winds
will pick up across the Las Vegas Valley with speeds between 25 and
35 kts and directional variability between 190 and 240. Uncertainty
at KBIH, as gusty southeast winds battle gusty west-southwest
downslope winds along the Owens Valley. Additionally, there`s a 30
percent chance of light rain showers overnight tonight reaching the
terminal, so expect quite a bit of directional variability and
occasional gusts between 15 and 25 kts at KBIH as a result, with
winds subsiding after sunset. Late-morning through the rest of the
TAF period, KDAG will gust from the west between 25 and 35 kts.
Persistent south gusts will struggle to materialize along the
Colorado River Valley, but expect sustained winds around 8 kts and
occasional gusts between 15 and 20 kts through the day. SCT-BKN
between 15 and 20 kft across the forecast area with the exception of
KBIH, where cigs associated with light showers could drop as low as
5 kft at times.
&&

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

&&

$$

SHORT TERM...Adair
LONG TERM...Sarment
AVIATION...Soulat

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