Boulevard, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

506
FXUS66 KSGX 180413
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
813 PM PST Fri Jan 17 2025

.SYNOPSIS...
Onshore flow will continue to bring cooler weather and partly
cloudy skies west of the mountains during the nights and mornings
into Monday. Offshore flow will develop Monday and dry Santa Ana
Winds are expected late Monday through Tuesday, and possibly
again Thursday.

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

It was a cool onshore day with higher humidity. Partial low
clouds hung around most areas west of the mountains. Saturday
will be quite similar with partly low cloudy skies from coast to
mountains, but mostly sunny in the afternoons. Weak offshore flow
forces a halfway retreat of the coastal low clouds for Sunday and
Monday for less coastal cloudiness overall. Nights will continue
quite chilly. Northerly flow aloft continues with a deep trough
over the central U.S. while a ridge is aligned along the West
Coast. A shortwave drops southward out of Canada through SoCal
late Monday. This will enhance the upper support, the northerly
wind flow aloft, at the same time that offshore surface pressure
gradients tighten: the recipe for Santa Ana Winds. Like recent
episodes, it will continue cool, but it will spread very dry into
all areas Monday night and Tuesday. This looks like a solid
moderate strength event, with top isolated gusts approaching 60
mph. After that shortwave passes through Tuesday, winds will
gradually subside. Then we turn our attention to the next possible
(probable?) Santa Ana episode Wednesday and/or Thursday. A
similar shortwave drops south out of Canada, and well, you know by
now how it works. Nearly all guidance shows a strong offshore
pressure gradient, but a minority of ensemble solutions do not
bring strong upper support to coincide with the surface flow and
contribute to wind strength. As my wishy-washy language suggests,
we obviously have lower confidence on the timing and strength of
that second episode. I would count on some offshore winds at
least; stay tuned for word on how strong. With higher pressure
aloft, daytime temperatures will get back into the 70s Tuesday and
beyond. Now, if you like to read fantasy, read on. A good portion
of model guidance brings another shortwave trough out of the
north on the weekend of 25-26 January. But with this wave, a lot
of ensemble members detour it over the ocean where it can grab
some moisture before moving it into SoCal and, dare we jinx it,
bringing rain.

&&

.AVIATION...
180345Z...Patchy low clouds have started to redevelop both offshore
and in the eastern valleys this evening. These will continue to fill
into coastal and valley areas overnight. Clouds will be more
widespread tonight than last, but some patchiness with occasional,
intermittent clearing is still expected. Cloud bases at 1800-2500 ft
MSL overnight. Low clouds will then gradually clear 15-18Z Saturday.
Clouds that redevelop and move inland after about 19/05Z will have
lower bases than tonight, around 1000-1500 ft MSL initially, and
will lower further overnight.

NWS San Diego is aware of limited communications of observations
from KTRM since January 8th. We are working with the FAA to address
this issue.

&&

.MARINE...
No hazardous marine conditions are expected through Tuesday.

&&

.FIRE WEATHER...
The next Santa Ana event late Monday into Tuesday will bring very
dry air into the entire region, and strong winds to foothills,
adjacent inland valleys, and into interior Orange County.
Strongest gusts in foothills will be 45-60 mph Monday night and
Tuesday, with humidity plunging to 5-15% away from the coast
Tuesday. A Fire Weather Watch is in effect for Monday through
Tuesday. After a temporary decrease in winds late Tuesday and
Wednesday, with very little humidity recovery, another Santa Ana
episode is looking to redevelop for Wednesday night and Thursday.

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Fire Weather Watch from Monday morning through Tuesday evening
     for Orange County Inland Areas-Riverside County Mountains-
     Including The San Jacinto Ranger District Of The San
     Bernardino National Forest-San Bernardino County Mountains-
     Including The Mountain Top And Front Country Ranger
     Districts Of The San Bernardino National Forest-San
     Bernardino and Riverside County Valleys  -The Inland Empire-
     San Diego County Inland Valleys-San Diego County Mountains-
     Including The Palomar And Descanso Ranger Districts of the
     Cleveland National Forest-San Gorgonio Pass Near Banning-
     Santa Ana Mountains-Including The Trabuco Ranger District
     of the Cleveland National Forest.

PZ...None.

&&

$$

PUBLIC/FIRE WEATHER...MM
AVIATION/MARINE...CSP