571
FXUS66 KSGX 091916
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
1216 PM PDT Mon Mar 9 2026

.SYNOPSIS...
Cooler weather can be expected through Tuesday as onshore winds
begin to take hold. The area of low pressure to south has the chance
to bring light showers over San Diego through this evening. High
pressure will move over the area by Wednesday into the first half of
next week, bringing record setting heat and increased heat risk.

&&

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

A different day out there with much cooler weather today. Greater
onshore flow and moisture continue to be pulled in from an area of
low pressure to the south that has been stalled over Baja the past
couple of days. Light rain showers have been reported in downtown
San Diego and points east along the border this morning. Southern
areas of the county will continue to see cloudier skies with
scattered showers through the evening, with everyone drying out
overnight. Similar temperatures can be expected into Tuesday with
highs near to slightly above normal as the low pressure system slowly
begins to move east into Sonora/Chihuahua and eventually Texas. The
marine layer will deepen the next couple of nights to bring low
clouds/fog from the coast to the coastal slopes each night/morning,
where the most cloud coverage will be expected by Tuesday morning.

Cool weather lovers, we hope you enjoy the next couple of days,
because it`s about to get hot hot hot! A ridge of high pressure to
our west over the Pacific has been patiently waiting to get its
groove on. By Wednesday, the ridge of high pressure will move
eastward. This will increase high temperatures near 5-15 degrees
from Tuesday to Wednesday, greatest change over the inland valleys
with highs in the 80s and a chance to hit 90 across the Coachella
Valley.

This will only be the start though, as the ridge becomes anchored
just off the coast with 850mb temps rising near 20C (10-12C above
normal). Another large increase in warming can be expected as the
ridge strengthens, with hot temperatures expected by Thursday into
at least the first half of next week, starting a period of prolonged
heat. Wednesday to Thursday will see another large warm up with
temperatures increasing 10-15 degrees for the coast into the western
valleys, with a 5-10 degree warm up for the mountains and deserts.
NBM chances for reaching 100 degrees on Thursday are around 20-40%
for northern Orange County and the eastern  Coachella Valley.

By Friday, temperatures will increase further with some areas nearing
not only daily record territory but for the entire month of March.
Ramona`s monthly record, for instance, is 94 degrees. NBM model
chances to break this record are quite good, around 75%. NBM chances
to see 100 degrees are near 25-50% for northern OC, western IE,
parts of East County San Diego and likely triple digit heat across
the entire Coachella Valley. Not even the immediate coast will
retreat from the heat, with highs well into the 80s. The mountains
will also continue to warm into the 70s and 80s. Please use this
time to prepare for the heat if you work outdoors, have elderly
neighbors or will be recreating outside.

The ridge will not back down into the weekend, though a weak area of
low pressure to southwest may provide a slight increase in greater
onshore flow and cooling for areas mainly near the coast with areas
staying in the 70s instead of 80s. All other areas will be with a
couple of degrees of Thursday/Friday, so the heat will continue. By
early next week, ensemble model clusters are in fairly good
agreement on the ridge restrengthening and slowly moving inland over
the Desert Southwest. This will bring continued hot weather across
the region into at least the first half of next week. As the dome of
high pressure heats further, the chance grows for more of our climate
sites to see record high temperatures for the month of March. To put
this in perspective, the March record high for Palm Springs is 104
degrees, where NBM shows near a 70-80% chance to break this by next
Monday.  There is of course still room for modifications to the
forecast, but the overall message is that very hot temperatures 15-
25+ above normal, so please take the precautions now so that you are
prepared. As always, please keep up to date on the latest forecast
on our social media pages and at weather.gov/sandiego.

&&

.AVIATION...
091730Z...SCT-BKN clouds AOA 10000 feet MSL through the afternoon in
San Diego County, except down to 8000 feet in any -SHRA near the
Mexico border. Gradual clearing to occur after 02Z. Patchy low
clouds to develop generally after 08Z into Tuesday morning, but with
low confidence of cigs impacting coastal airports for much time,
most likely at KSNA and 30% chance at KONT. Any cigs would be based
around 2000-2500 feet MSL.

&&

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

&&

.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...APR
AVIATION/MARINE...MM

NWS San Diego (SGX) Office