La Mesa, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

759
FXUS66 KSGX 291718
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
1018 AM PDT Thu May 29 2025

.SYNOPSIS...
A deep marine layer brought us areas of drizzle for portions of
the San Diego County coast and valleys overnight. Low clouds will
clear from inland towards the coast by early afternoon. Strengthening
high pressure aloft over California will bring much warmer
weather for inland areas through Friday, with high temperatures
today 5 to 10 degrees warmer than Wednesday and another 5 to 10
degrees warmer on Friday. Friday high temperatures could be as
much as 10 to 15 degrees above average for the Inland Empire. This
will be followed by a cooling trend for Saturday through Tuesday,
with Tuesday high temperatures as much as 10 to 15 degrees below
average for the mountains. A closed upper level low pressure
system off the coast of northern and central Baja will draw some
tropical moisture northward into the area during the weekend with
the relatively greater chances for showers over the mountains and
on Sunday. A warming trend will follow for the latter half of next
week.

&&

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

This morning...The marine layer is deeper than yesterday at about
3500 ft, with a thick saturated layer. This brought us a few hundredths
of an inch of drizzle overnight in the San Diego County valleys
and coastal areas. The low clouds are beginning to clear at the
inland edges at this hour. The inversion at the top of the marine
layer is not as strong as yesterday so it`s more likely that the
low clouds will clear better than yesterday and more areas west of
the mountains will see some sunshine this afternoon.

High pressure aloft over California will bring 5 to 10 degrees of
warming for inland areas today while the marine layer continues to
moderate temperatures closer to the coast. A further 5 to 10
degrees of warming is expected on Friday for the inland areas.
Friday will be the warmest day this week with high temperatures
as much as 10 to 15 degrees above average for the Inland Empire. High
temperatures will range from the lower to mid 70s near the coast
to the 90s to around 100 for the Inland Empire with 102 to 108 for
the lower deserts. A cooling trend will begin on Saturday as a
closed upper low to the southwest moves northeast.

For the weekend, a closed upper level low pressure system off the
coast of northern and central Baja will draw some tropical
moisture northward into the area with precipitable water values
peaking on Sunday. There is a chance of showers over the weekend
with the relatively greater chances on Sunday and over the
mountains of San Diego County. On Saturday, there is about a 45
percent of measurable precip (0.01 inch) over the San Diego
County mtns and about a 25 percent elsewhere. On Sunday those
chances rise to about 70 percent and 50 percent respectively.
Chances for precip end on Monday morning as the upper low moves
north of SoCal.

The cooling trend will continue through Tuesday with Tuesday high
temperatures as much as 10 to 15 degrees below average for the
mountains. Highs on Tuesday will range from the lower to mid 60s
near the coast to the lower to mid 70s for the Inland Empire with
the upper 80s to mid 90s for the lower deserts. This will be
followed by a warming trend for Wednesday through the end of next
week. A greater return of night and morning coastal low clouds is
expected for Sunday night into Monday morning with the low clouds
extending well inland and across much of the valleys. The deeper
marine layer will persist through Tuesday, then become gradually
shallower for the latter half of next week.

&&

.AVIATION...
291540Z...Coasts/Valleys...Low clouds based around 1500-2000 feet
MSL and tops to 3,200 feet MSL will slowly clear the inland valleys
this morning. Scatter out expected 17-19Z. Confidence in low cloud
coverage for tonight into Friday morning is low to moderate. Highest
confidence in VCTY KSAN and KSNA becoming BKN after 02-04Z, but
areas of far inland Orange County and Inland Empire may remain FEW-
SCT during this period. Bases slightly lower 1200-1800 ft MSL with
vis restriction in the valleys across higher terrain.

Other areas...FEW-SCT clouds AOA 20K ft MSL and VFR conditions today
into Friday.

&&

.MARINE...
No hazardous marine conditions are expected today through Sunday.
Slight chance of showers across the area by the weekend.

&&

.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...APR