Winchester, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

085
FXUS66 KSGX 261023
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
223 AM PST Thu Dec 26 2024

.SYNOPSIS...
A series of Pacific storms will pass by to the north today
and Friday bringing gusty westerly winds in the mountains and
deserts. An upper ridge will build from the southwest late Friday
through the weekend. This will result in mild days, a shallow
marine layer, and cool nights this weekend. Some offshore flow
could develop early next week after another trough of low pressure
passes by to the north and northeast.

&&

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

Scattered high clouds continue to move across the region early
this morning as a mostly zonal Pacific jet remains aimed at
central and northern California. A pair of short waves will move
by to the north today and Friday, maintaining mild weather,
though highs remain several degrees above normal in the deserts.
Gusty westerly winds will develop across the mountains and deserts
late Thursday night into Friday, peaking Friday afternoon and
evening with gusts around 35-45 mph on the wind prone desert
mountain slopes and below the passes. Winds will diminish Friday
night. Increasing onshore flow will also bring the return of the
marine layer along the coast late tonight or Friday morning,
though with the passing trough it should deepen fast enough to
mitigate any dense fog concerns. In fact, by Friday evening it
could even be deep enough for some spotty drizzle west of the
mountains.

The subtropical high to our southwest will slowly shift eastward
and expand into Southern California this weekend, bringing warmer
weather and causing the marine layer to become more shallow. Highs
in the inland valleys through the deserts will be around 7 to 15
degrees above normal, with highs closer to normal for the coastal
areas and western valleys as some marine layer influence remains.
By Sunday morning the marine layer could be shallow enough for
another round of dense fog in the coastal areas.

Surface pressure gradients begin to trend offshore on Monday
following the passage of another wave to our north. There are some
timing and strength differences in the ensembles, but for now it
looks likely for a period of weak to potentially moderate (20%
chance) Santa Ana event sometime in the Monday-Wednesday time
frame, bringing warmer and much drier conditions. NBM 90th
percentile high temperatures have highs reaching the low 80s in
the valleys on New Year`s Day.

&&

.AVIATION...
261000Z....SCT-BKN high clouds at or above 20,000 ft MSL will
continue to stream south across the region through this evening. Low
clouds develop tonight, remaining mostly offshore, with minimal
chances for CIGs at any site (10-20% chance) through Friday morning.
Periods of stronger westerly winds up to 25 knots possible in the
high deserts and near the mountains with mod up/downdrafts on
Friday.

&&

.MARINE...
After the current swell wanes this morning, another series of long
period west-northwesterly swells pick up Friday and continue through
the beginning of next week. Seas will be generally 5-9 feet in the
outer coastal waters and 3-6 feet in the inner waters. Northwest
flow will strengthen slightly late Friday afternoon, with areas of
gusts around 20 knots near San Clemente Island. Otherwise, no marine
hazards are expected through Monday.

&&

.BEACHES...
As the long period west-northwest swell fades, surf heights continue
to wane, but locally high surf of 5-9 feet remains possible for west
facing beaches in San Diego County through this afternoon. This will
make swimming hazardous and pose a minor coastal flooding threat.
See the High Surf Advisory for more details.

After a brief lull late today into Friday, another long period (15
to 17 seconds) northwesterly (280 degree) swell of 3-5 feet arrives.
Elevated surf to 4-6 feet is expected late Friday through early next
week with localized sets to 7-8 feet possible on west-northwest
facing beaches. Minor coastal flooding is possible for vulnerable
areas during morning high tides as tides increase through this
weekend coinciding with the elevated surf.

&&

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


&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...High Surf Advisory until 4 PM PST this afternoon for San Diego
     County Coastal Areas.

PZ...None.

&&

$$

PUBLIC...SS
AVIATION/MARINE/BEACHES...Zuber