Fallbrook, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

648
FXUS66 KSGX 142144
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
144 PM PST Sun Dec 14 2025

.SYNOPSIS...
Areas of dense fog on the coastal mesas and western valleys again
tonight into Monday morning. Well above normal high temperatures
through Thursday, with periods of weak offshore flow through
Tuesday. Gradual cooling with more widespread night and morning
low clouds and fog for Friday into next weekend.

&&

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

Mostly clear this afternoon with a few high clouds and areas of
low clouds persisting at the immediate coast. Temperatures are
generally lower but within a few degrees of what they were at this
time yesterday. Inland high temperatures will be well above
seasonal averages but the marine layer presence will keep
temperatures near the coast closer to normal.

This pattern of low clouds and fog will likely repeat for tonight
into Monday morning even as the upper level trough moves eastward
into AZ, although the low clouds may be a little higher and low
visibility not as widespread. After the upper trough moves east,
high pressure aloft begins to build in from the west and offshore
flow develops on Monday, with winds gusting to around 30 mph below
the passes and canyons. Weak offshore flow under high pressure
aloft will persist into Tuesday and mitigate or nullify the
influence of the marine layer so that low clouds and fog are
unlikely to return for Mon night/Tue morning or Tue night/Wed
morning. It will also bring drier and warmer conditions into the
coastal areas, resulting in daytime high temperatures on Tuesday
as much as 10 degrees above seasonal averages in the coastal
areas, and up to 20 degrees above average in the far inland
valleys. Tuesday is likely to be the warmest day overall, with
high temperatures reaching the 80s in the inland valleys and lower
deserts.

Onshore flow returns on Wednesday as a shortwave trough moves
inland to the north and the upper level ridge weakens and flattens
out. This could bring some cooling to the coastal areas and far
western portions of the inland valleys, and potentially a return
of low clouds and fog to the coastal areas Wed night. However,
this is a fast-moving trough and offshore flow quickly returns on
Thursday as a sfc high follows the departing trough into the Great
Basin. The offshore winds will bring drier and warmer conditions
but are unlikely to be strong enough to produce any other impacts.

As we approach next weekend, a more vigorous trough will displace
the upper high to the south, establishing a high-zonal pattern
over CONUS. This pattern is expected to bring a weak atmospheric
river to central and northern CA next weekend but SoCal will
likely remain dry but cooler with more of a marine layer presence
as onshore flow returns. Temperatures for next Sat and Sun will
range from near normal at the coast to about 10 degrees above
normal in parts of the inland valleys.

&&

.AVIATION...
142130Z...Coast/Valleys...Low clouds, now based around 900-1100ft
MSL have finally cleared out of the coastal areas by 21z this
afternoon, though lingering clouds along the beaches and within a
mile of the coast remain possible through the afternoon.
Outside of the clouds, trapped moisture and particles within
portions of the coast and inland valleys are leading to HZ this
afternoon, with pockets of 6SM and locally near 5SM VIS possible.
Low clouds will push back inland again as early as 00-02z this
evening. Cloud bases initially near 700-1000ft MSL this evening
should settle to 400-900ft MSL by 06z. VIS down to 0-3SM for inland
areas as low clouds/fog move in with VIS for coastal areas down to 2-
5SM. Clouds/fog expected to clear a bit earlier Monday morning,
around 17-19z.

Mountains/Deserts...Clear skies and VFR conditions expected through
the Monday afternoon.

&&

.MARINE...
Low clouds have lifted over the waters this afternoon, but should
settle back down this evening, with areas of light fog bringing
visibilities of 2-5 nautical miles. Otherwise, no hazardous
marine conditions are expected through Thursday.

&&

.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...Munyan