Strong Wind in California, May 4, 2025

Area Forecast Discussion
National Weather Service San Diego CA
916 AM PDT Sun May 4 2025

.SYNOPSIS...
A area of low pressure will impact the region through early this
week bringing cool weather with scattered showers, along with
thunderstorms across the high desert and Coachella Valley later
this afternoon and evening. Rain chances stick around for inland
areas by Monday and become limited by Tuesday as the weather
system moves out. A building area of high pressure will usher in
warmer and drier weather by the middle and end of next week.

&&

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

.UPDATE...
Ongoing light rain/drizzle continues across most of
the coastal and inland areas, with nothing currently making it
over to the deserts. Radar shows at least some light showers are
moving up just east of the Coachella Valley, so this will likely
change in the next few hours. Limited accumulations have occurred
thus far with 12hr rain totals coming in around 0.10" for the
coasts/valleys to closer to 0.50" for the Inland Empire,
foothills, and mountains. While any additional precipitation today
is expected to remain light, chances for thunderstorms will exist
this afternoon generally across the mountains and deserts with
brief, heavy rainfall and gusty winds possible at times.
Rain/storms will mostly end or move eastward by midnight tonight,
although light rain/snow showers may prevail in the mountains
through Monday morning. Moisture, and the potential for some light
rain showers in the mountains, will prevail through Tuesday.
Warming through the rest of the week, with little to no
precipitation chances after Tuesday.

&&

.PREVIOUS DISCUSSION...
.SHORT TERM (Through Tuesday)...

An potent area of low pressure is circulating over SoCal. Most
rainfall over the area has been light and will continue to be
mainly confined to the coastal slopes as well as western San Diego
County. As the low as the low progresses eastward today, cold air
aloft with adequate instability will give way for a chance of
thunderstorms for parts of the Coachella Valley and high desert
later this afternoon and early evening. Hi-res models indicated
storms will produce near 1/4" an hour rainfall rates, with some
stronger storms closer to 1/2" per hour in parts of the high
desert. As storm activity begins in the north, it will weaken as
it moves southward, which may give some heavier showers to parts
of the eastern Inland Empire and SBD/RIV Co mts. While most of
Orange County will see minimal rainfall, off and on showers will
continue into parts of San Diego County into the afternoon and
evening. Most areas will see less than one quarter of an inch of
rainfall except across the mountains and anywhere that sees a
thunderstorm form. Though this storm is cold, snow levels will
remain mainly above 6,500 feet, so most resort levels will see
under one half inch or no snowfall from this system.

The low will continue to slowly push eastward on Monday as
another weak embedded shortwave keeps the trough overhead. This
will allow for another chance of showers for the mountains and
deserts Monday afternoon and evening. Instability will be further
limited, but thunder may rumble in parts of the high desert once
again. Areas closer to the coast will gradually clear with some
sunshine by Monday afternoon. Mostly sunny and dry conditions will
move into the region by Tuesday, though areas near Big Bear may
see a stray shower.

It will be rather cool out there today with highs 10 to 20 degrees
below normal for inland areas and near 5 degrees below normal at
the coast. Most of the mountains will remain in the 40s to near
50 degrees today with much of the coastal basin and high desert
staying in the 60s with cloudy and wet conditions. Ramona's
forecast high of 61 and Borrego Springs' high of 74 today would
tie the daily record for coolest high temperature in both cities.
Temperatures will warm slightly by Monday, with more noticeable
warming on Tuesday.

&&

.LONG TERM (Wednesday Onward)...

A weak area of high pressure will move in off the coast by
Wednesday. This will bring temperatures near normal for the day.
Models indicate the high strengthening through the end of the week
which will lead to a warming trend. By Friday into next weekend,
highs may near 10 degrees above normal with 90 degree readings
possible in the high desert and Inland Empire, along with triple
digit heat into the lower deserts.

&&

.AVIATION...
041530..Coasts/Valleys/Coastal Slopes...Clouds with varying bases
but largely between 2000-3000 ft MSL are in place across the coastal
basin this morning. Areas of BR/DZ and locally -SHRA are bringing
areas of reduced VIS to 2-5 SM with bases below 1000 ft MSL. BR/DZ
this morning will transition to SCT showers this afternoon. 10-15%
chance for ISO TSRA in the eastern Inland Empire after 20Z today.
Isolated showers are possible overnight into Monday morning, locally
reducing VIS to 2-5 SM.

Desert Mtn Slopes/Deserts...Strong southwest to west winds will
continue through the mountain passes and into the deserts through
late this morning, with surface gusts 25-35 kt, locally up to 45 kt
below the passes. MOD-STG up/downdrafts and areas of LLWS possible
over and east of the desert slopes this morning. SCT TSRA will
develop over the deserts and mtns north of San Diego County after
about 19Z today (including a 20% chance for TSRA at KPSP and KTRM),
with lesser chances (10-15%) for the desert mtn slopes and desert of
San Diego Co. Strong up/downdrafts and vis restrictions will be
possible with any storm that develops. TSRA taper off late this
evening, though SCT SHRA will continue overnight into early Monday.

&&

.MARINE...
Sustained winds 10 to 20 knots over the coastal waters through this
afternoon, from the northwest in the outer waters and from the
southwest nearshore. In addition to this, combined steep seas of 8-
11 feet in the outer coastal waters and 6-8 feet in inner coastal
waters this morning before gradually lowering this afternoon into
Monday. The Small Craft Advisory remains in effect and contains more
details.

&&

.BEACHES...
West swell of 8-11 feet with a 7-10 second period will generate
elevated surf and a high risk of rip currents today, bringing
hazardous swimming conditions to all beaches. Surf of 5 to 8 feet
for San Diego County beaches, with local sets to 9 feet, and 3 to 6
feet for Orange County Beaches is expected. A High Surf Advisory is
in effect today. Surf dwindles Monday morning, though a building
long period southwest swell may keep surf elevated for both San
Diego and Orange counties (3-6 feet) through midweek.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...High Surf Advisory until 11 PM PDT this evening for San Diego
     County Coastal Areas.

PZ...Small Craft Advisory until 11 AM PDT this morning for Coastal
     Waters from San Mateo Point to the Mexican Border and out
     to 10 nm-Waters from San Mateo Point to the Mexican Border
     Extending 10 to 60 nm out including San Clemente Island.

&&

PUBLIC...Zuber
AVIATION/MARINE/BEACHES...Westerink