Temecula, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

159
FXUS66 KSGX 122046
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
146 PM PDT Mon May 12 2025

.SYNOPSIS...
Cooler conditions are expected today and Tuesday. In addition to
cooler conditions, winds will increase over the mountains and into
the deserts today with elevated winds continuing into Wednesday
morning. There are slight chances of light showers on the coastal
mountain slopes and drizzle for the coast and valleys on Tuesday.
Conditions will warm for Wednesday, but remain slightly below
average into the weekend.

&&

.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...

Cloud coverage will continue to increase as a trough of low pressure
moves across the Pacific Northwest this afternoon and evening.
Tuesday is expected to be the coolest day of the week, with
temperatures cooling an additional 10 to 15 degrees for inland
locations. Winds over the mountains and deserts at 1 PM were mainly
gusting in the 40 to 50 mph range. Stronger winds will continue over
the mountains and into the deserts through early Wednesday morning.
Winds will be strongest on the desert mountain slopes, through
passes, and into the deserts. Peak gusts of 40 to 55 mph expected in
the deserts, with local gusts closer to 65 through wind prone passes
like the San Gorgonio Pass. On the desert mountain slopes, peak
gusts will be 50 to 60 mph.

As the trough digs south into the Great Basin tonight into Tuesday,
the marine layer will deepen. Widespread low clouds can be expected
from the coast to the mountain slopes. The moisture will be deep
enough that when a shortwave moves through the mean flow on Tuesday
morning and when the trough axis passes Tuesday evening light
showers may develop. Any shower development is most likely on the
coastal mountain slopes, with the potential for some drizzle west of
the mountains mainly on Tuesday morning/early afternoon. Ensemble
guidance is showing a 40 to 60 percent chance of rainfall
accumulations reaching or exceeding 0.10" on the coastal mountain
slopes, with a 20 to 40 percent chance of rainfall accumulations
reaching or exceeding 0.20" on the coastal mountain slopes. For the
coast and valleys there is a less than 10 percent chance for
accumulations to reach or exceed 0.20". Local high resolution WRF
guidance and HRRR guidance continues to indicate rainfall rates less
than 0.10" per hour Tuesday morning and evening, with only a 10
percent chance of rainfall rates exceeding 0.10" per hour on the
coastal mountain slopes.

The main trough axis will be to our east by Wednesday, which will
allow for the winds to weaken, dry conditions to return, and for
high temperatures to warm 5 to 10 degrees, locally up to 15 degrees
warmer in the mountains. Most guidance indicates we will maintain an
overall troughing pattern over the western United States for the
remainder of the week, with a ridge of high pressure building over
the Eastern Pacific. The overall troughing pattern will keep high
temperatures just below the seasonal normal, maintain at least night
and morning low cloud coverage, and elevated afternoon sea breezes.
Over the weekend, there becomes some disagreement in the upper level
pattern which will impact whether we get warmer conditions and a
squashed marine layer or increased cloud coverage, winds, and cooler
conditions. For example on Saturday, 40 percent of solutions show a
weak trough passing through the Intermountain West, 40 percent of
solutions show a deeper trough, and 20 percent show ridging over the
West Coast. By Sunday, 50 percent of solutions indicate ridging with
30 percent of solutions indicating a deeper trough.

&&

.AVIATION...
122040Z...Coast/Valleys...BKN low clouds based near 2000 ft MSL are
slowly filling in near the San Diego Co coast at this hour. Bases will
rise closer to 2,500-3,500 feet overnight and after 05Z in Orange
County and the Inland Empire.  Low clouds mostly clearing for
northern areas, but will  struggle to clear in San Diego County
in the afternoon hours.

.Mountains/Deserts...SCT-BKN High clouds AOA 20000ft through
tonight, but otherwise, VFR conditions through tonight. Winds becoming
more widespread and increasing 30-45 kts this afternoon and evening
up to 55 kt along desert slopes and through mountain passes with STG
UDDFS possible. BLDU in windier corridors,  primarily in the deserts.
Gusty winds continue on Tuesday.

&&

.MARINE...
Strong west-northwest winds will continue through Tuesday, with
sustained winds of 15 to 20 kt and gusts to 25 kt across the outer
coastal waters leading to hazardous conditions for small craft,
strongest winds near San Clemente Island. A Small Craft Advisory
remains in effect through late Tuesday night. Winds briefly diminish
late tonight through Tuesday morning, but will strengthen again
Tuesday afternoon and evening. Winds taper off by Wednesday morning.

&&

.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.


&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory until 5 AM PDT Wednesday for Apple and Lucerne
     Valleys-Riverside County Mountains-San Bernardino County
     Mountains-San Diego County Deserts-San Diego County
     Mountains-San Gorgonio Pass near Banning.

PZ...Small Craft Advisory until 11 PM PDT Tuesday for Waters from San
     Mateo Point to the Mexican Border Extending 10 to 60 nm out
     including San Clemente Island.


&&

$$

PUBLIC...CO
AVIATION/MARINE...APR