Grossmont, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

239
FXUS66 KSGX 240426
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
926 PM PDT Mon Jun 23 2025

.SYNOPSIS...
A few degrees cooler today with below average temperatures. Tuesday
will be a few degrees warmer with gradual warming trend continuing
through the end of the week. The marine layer will bring night and
morning low clouds to coastal areas through the week. Low clouds are
expected to reach into the valleys at times, most likely during the
first half of the week.

&&

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

Update: Low clouds are continuing to fill in along the coast and
penetrate further inland throughout the evening. With the trough
axis moving over, there could possibly be some areas of drizzle for
the coastal and inland valleys, and especially for the foothills.
All of these clouds should begin to scatter out tomorrow morning
from east to west. Some of these clouds could hang around the
coastal areas for the entirety of the day. It will still be rather
cool tomorrow, with highs still in the upper 70s to mid 80s within
the IE. By Wednesday, as the trough exits and the ridge begins to
move back in over the region, it will be notably warmer, and this
gradual warming trend will continue into the weekend and early
next week with little change in the longwave pattern overall.

(Previous discussion submitted at 127 PM):

A weak coastal eddy continues to spin in the California Bight. A few
patches of low clouds remain along the immediate coast as of 1 PM.
High resolution model guidance is indicating the possibility of
patchy drizzle developing tonight into Tuesday morning, mainly along
the coast. The marine layer is expected to remain 2000 to 2500 ft
deep through Wednesday while we remain under cyclonic flow aloft as
a trough moves across the West Coast.

A few degrees of warming will occur on Tuesday, but highs will
remain about 5 to 10 degrees below average. An additional 4 to 8
degrees of warming is expected for inland areas on Wednesday. This
will bring conditions back to within 5 degrees below normal for
Wednesday.

An area of high pressure will build in from the southeast Thursday
into the weekend. Current ensemble guidance is showing the ridge
axis setting up mainly over the low deserts. This would bring more
noticeable warming there Friday through Monday. Chances of the low
deserts exceeding 110 degrees are highest on Sunday and Monday at 60
to 80 percent. There are some indications that the position of the
high pressure would allow for a moisture surge from the southeast
into the low deserts over the weekend. If that were to occur, that
would keep high temperature readings lower. Conditions are expected
to warm up west of the mountains, with temperatures in the valleys
reaching into the 90s. Chances of the Inland Empire exceeding 100
degrees on Sunday and Monday are mostly 20 to 30 percent, locally up
to 50 percent in the eastern portion of the Inland Empire. The
building high pressure aloft should keep the marine layer shallower
and more confined to coastal areas.&&

.AVIATION...
240200....Coast/Valleys/Coastal Mountain Slopes...Low clouds based
1500-2000 ft MSL have developed over the nearshore waters and
coastal SD County. These clouds will push inland and into Orange
County starting 03-06z. Most of the IE should eventually fill in
overnight. 40% chance of BKN CIGs reaching KSBD. -DZ and BR
possible, especially near the coast. Highest likelihood from 11-15z
Tuesday morning. Otherwise, low clouds retreat to the coast 16-19z.
Clearing will likely occur at the beaches Tuesday afternoon. Clouds
redevelop Tuesday evening, pushing into coastal land areas after 03z
Wednesday.

.Mountains/Deserts...Clear skies and largely unrestricted VIS
through Tuesday evening. Wind gusts 25-35 kts this afternoon and
evening. Stronger gusts begin to subside by 04-06z Tuesday.

&&

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

&&

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


&&

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

&&

$$

UPDATE...Stewey
PUBLIC...CO
AVIATION/MARINE...KW