La Mesa, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

585
FXUS66 KSGX 231047
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
247 AM PST Sat Nov 23 2024

.SYNOPSIS...
Increasing moisture and clouds this morning as an atmospheric
river currently bringing rain to central California slowly makes
its way into southern California. It will also bring lower
temperatures and gusty west winds to the mountains and deserts.
Light precipitation could start as early as this afternoon in
northern Orange County, western Riverside County and southwestern
San Bernardino County but is more likely this evening and tonight.
Another wave of moisture will bring better chances of
precipitation for Monday through Wednesday. Chances for rain will
end late Wednesday, with warmer and drier conditions returning
for the end of next week.

&&

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

This morning...The atmospheric river continues to bring rain and
high elevation snow to central California while marine layer low
clouds are increasing in coverage in the coastal areas of SoCal.

The AR is slowly making its way southeast but by the time it
reaches the areas south and east of LA, it will have lost much of
its energy and moisture. As a result, most areas will receive one
tenth of an inch or less of rainfall between this afternoon and
Sunday morning. The rainfall distribution will favor the coastal
mtn slopes, especially in the San Bernardino Mountains where
orographic effects could bring up to one half inch of rain.
Through Sunday afternoon, snow levels will remain near or above
7,000 ft with little or now snow accumulations below that
elevation.

This system will also bring stronger onshore flow with gusty west
winds in the mtns and adjacent desert slopes. The favored mtn
passes and canyons could get wind gusts of 35 to 40 mph. Winds
will weaken by Sunday afternoon.

The cool, cloudy conditions will keep daytime high temperatures
west of the mtns mostly 5-10 degrees below seasonal averages
through Wednesday.

Another surge of moisture will likely arrive on Monday and last
through Wednesday. It will continue the cool, cloudy conditions
with periods of rain. The details are still uncertain but the
cluster analysis shows that at least a percentage of ensemble
members across model platforms show some precipitation each day
from Monday through Saturday. After Wednesday however, the pattern
changes as the closed upper low moves inland over the northern
Great Basin and a weak high pressure ridge builds over the
southwest U.S. This will make it much less likely that any
precipitation will materialize for Thursday through Saturday. The
ridge will bring a warming trend, with temperatures west of the
mtns becoming slightly above average for Thursday, Friday and
Saturday.

&&

.AVIATION...
231030Z...Coast/Valleys...Areas of low clouds with bases 500-1200 ft
MSL with tops to 1300 ft MSL will continue through 17Z-19Z Sat,
mainly within 20 mi of the coast. Local VIS 0-3 mi will occur in the
coastal valleys through 16Z Sat. Generally SCT clouds with local BKN
clouds near the coast will occur 19Z-23Z Sat, with BKN-OVC low
clouds increasing 22Z Sat-02Z Sun in all coastal/valley areas with
bases 1200-2000 ft MSL and tops 4000-7000 ft MSL and with areas of
terrain obscurations in clouds/-SHRA. Local VIS 3-5 miles will occur
in -SHRA mainly 00Z-12Z Sun. Most areas will clear 16Z-18Z Sun.

Mountains...Areas of terrain obscurations will occur 22Z Sat-08Z Sun
in the San Bernardino County/Riverside County mountains and 01Z-12Z
Sun in the San Diego County mountains due to clouds/FG/-SHRA,
especially on the coastal slopes, with cloud tops mostly to
around 8000 ft MSL.

Deserts...Mostly clear skies with unrestricted VIS will prevail
through Sun morning.

&&

.MARINE...
No hazardous marine weather conditions expected through Wednesday.

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.

&&

$$

PUBLIC...PG
AVIATION/MARINE...Maxwell