Fountain Valley, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

469
FXUS66 KSGX 051721
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
921 AM PST Fri Dec 5 2025

.SYNOPSIS...
Weak Santa Ana winds will continue across the mountains and
foothills today, followed by weak onshore flow on Saturday. Fog,
potentially dense, could return to the coastal areas Sunday and
Monday mornings. Gradual warming through the middle of next week
and little change through the end of the week with high
temperatures as much as 10-15 degrees above normal and periods of
weak to locally moderate Santa Ana winds.

&&

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

.Morning Update...

Offshore flow continues at this hour with widespread wind gusts
15-25 MPH across the region, locally near 40 MPH in mountain
passes. Classic offshore flow winter pattern was observed this
morning with lows in the 30s across wind sheltered valleys, with
elevated breezier areas seeing lows only in the lower 50s.
Strengthening high pressure aloft will contribute to a warming
trend by Sunday into next week with highs well above average. No
changes currently to the forecast.

.Previous Discussion (429 AM Friday)...

Weak Santa Ana winds will continue through the morning, then
gradients and winds weaken through the afternoon. An upper level
east- west ridge axis associated with the high over the East
Pacific begins to nudge into So Cal today bringing warming across
the region. Highs will generally be in the upper 60s to low 70s
across the coastal areas, valleys, and low deserts, low 60s in the
high deserts, and 50s in the mountains - around 2 to 4 degrees
above normal.

Pressure gradients become neutral to the east and very weakly
offshore to the north on Saturday, allowing a return of a more
prominent sea breeze in the afternoon. This won`t do anything in
terms of moderating temperatures with the upper ridge continuing
to nudge in from the west, but it could lead to the redevelopment
of fog, first over the coastal waters during the afternoon
Saturday, then spreading into the coastal areas Saturday night.
Weak offshore flow develops again by Sunday morning as surface
high pressure develops over the eastern Great Basin and Rockies,
which could help push the fog back out to sea relatively early in
the morning. Winds weaken again Sunday afternoon with another
night of potential fog at the coast before offshore flow returns
again Monday morning. Otherwise warmer on Sunday with highs around
5-10 degrees above normal.

The remainder of next week will be decidedly warm and dry with
periods of weak to locally moderate Santa Ana winds. While there
is high certainty in the overall upper level pattern with the
ridge slowly shifting east, becoming directly overhead around
Thu/Fri, ensembles have a bit of spread in the amplitude of the
ridge. This will affect the track of any short waves to our north
and the subsequent surface high pressure and Santa Ana wind
strength behind them, as well as temperatures. Current forecast
has temperatures peaking at around 10-15 degrees above normal
Tuesday through Friday, reaching the low 80s in the valleys and
low deserts. The CW3E West-WRF ensemble shows Santa Ana winds
peaking Monday and Tuesday when there is around a 65% chance of a
weak-to-moderate event, lowering to around a 40% chance on
Wednesday. This translates to gusts around 30-45 mph in the wind
prone passes, canyons, and foothills, locally around 50 mph in the
favored spots. Ensembles are starting to hint at the East Pac
ridge breaking down and precipitation returning around the middle
of the month, but we`ll have to see how well that holds up.

&&

.AVIATION...
051615Z....Mostly clear skies and VFR conditions are expected
through early Sat.

&&

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

&&

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


&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement until 10 AM PST this morning for Orange
     County Coastal Areas-San Diego County Coastal Areas.

PZ...None.

&&

$$

UPDATE...APR
PUBLIC...SS
AVIATION/MARINE...Westerink