091
FXUS66 KSGX 040439
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
930 PM PDT Fri May 3 2024

.SYNOPSIS...
Mostly cloudy cool weather will prevail this weekend with gusty
winds in the mountains and deserts and periods of showers over and
west of the mountains. Southwest to west winds will increase in
strength through the day Saturday, peaking Saturday night and early
Sunday. Some drizzle may occur Saturday morning, but the best
chances of accumulating rain will be Saturday night and early
Sunday. Dry and warmer conditions will prevail Monday through most
of next week.

&&

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

Low clouds along the coast were already spreading into the valleys
at mid-evening, with stratus covering all valley areas by late
tonight with some drizzle forming as well. Current progs suggest the
timing of most of the measurable rain to be 11 PM Saturday through 9
AM Sunday, generally from northwest to southeast with the cold front
associated with the system. Rainfall still is forecasted to be
mostly light, under 1/4" except local amounts over 1/2" in a few
coastal-slope locations of the mountains. Like is typical with
spring systems, the wind will be a factor, with a few gusts around
70 MPH Saturday night through San Gorgonio Pass and along a few of
the desert mountain slopes.

From previous discussion...

A low pressure system is on track to move inland through
California on Saturday night and dig into the Great Basin on
Sunday. This system will bring cooler, cloudier, windier (in the
mountains and deserts), and wetter conditions (in and west of the
mountains) to Southern California this weekend. Southwest to west
winds will begin to increase Saturday afternoon, peaking in
strength Saturday night into Sunday, gradually diminishing into
Sunday night. Winds will be strongest on the desert mountain
slopes, through passes, and into portions of the deserts. Peak
gusts of 55 to 65 mph expected. There is a 30 to 40 percent chance
that a few isolated gusts to 70 mph are possible in wind prone
locations on the desert foothills of the San Bernardino mountains
and near the San Gorgonio Pass late Saturday night. Winds will
gradually weaken into Sunday night. For much of next week, a broad
troughing pattern over the United States will enhanced the
onshore pressure gradient, bringing periods of breezy westerly
winds to the mountains and deserts each afternoon and evening.

A weak coastal eddy is expected to help deepen the marine layer
overnight. This could result in patchy drizzle for the coast and
valleys tonight into Saturday morning. The best chance for showers
and accumulating rain is late Saturday night into Sunday morning.
Shower coverage will be scattered with mostly light amounts expected
to accumulate. A few hundredths to a tenth of an inch of rain are
expected for the coast and valleys. One-quarter to locally one-half
inch expected on the coastal slopes of the mountains with the
greater amounts most likely on the coastal slopes of the San
Bernardino County mountains. A trace of snow is expected above 7000
ft. This will be a quick moving system and dry conditions are
expected by early Sunday afternoon.

Highs Saturday are expected to be 3 to 5 degrees below average for
the coast and valleys, and near average for the deserts. Sunday will
be even cooler, especially for inland areas with highs 10 to 15,
locally up to 20 degrees below average for the valleys, mountains,
and deserts. Cold conditions expected Monday morning, especially in
the High Desert where lows are forecast to fall to the mid to upper
30s. The highs on Monday will make up for the cool conditions Sunday
and Monday morning, with temperatures as much as 10 to 15 degrees
warmer than Sunday for the mountains and High Desert. Conditions are
expected to gradually warm into the end of next week.

&&

.AVIATION...
040350Z...Coasts/Valleys/Foothills...Patchy low clouds with bases
2000-2500 FT MSL are occurring this evening. Clouds will fill in
across the coast/western valleys through 07z Sat, reaching the
Inland Empire/foothills after 10z Sat. Bases may lower a few hundred
feet overnight. Terrain obscurations where low clouds and terrain
intersect. Scatter out 17z-20z Sat across the valleys, with coastal
sites seeing intermittent cigs through the afternoon.

Mountains/Deserts...W-SW winds developing after 20z Sat with the
strongest winds occurring after 00z Sun. Expect W-SW winds 20-35 kt
with gusts of 45-60 kt. Areas of MOD-STG up/downdrafts and LLWS
over/east of mtns.

Otherwise...Clear skies with unrestricted VIS will continue into Sat
morning, with increasing high clouds AOA 15,000 FL MSL on Sat.

&&

.MARINE...
No hazardous marine conditions are expected through Saturday
morning. Gusty northwest wind gusts of 25 to 30 knots will occur
Saturday evening through Sunday evening, which will generate
hazardous boating conditions, especially in the outer waters.
Northwest wind gusts up to 20 knots will be possible over the outer
waters each afternoon and evening Monday through the middle of next
week.

&&

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


&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory from noon Saturday to 8 PM PDT Sunday for Apple
     and Lucerne Valleys-San Bernardino County Mountains-San
     Gorgonio Pass Near Banning.

     Wind Advisory from 3 PM Saturday to 8 PM PDT Sunday for
     Coachella Valley-Riverside County Mountains-San Diego
     County Deserts-San Diego County Mountains.

PZ...Small Craft Advisory from 3 AM to 10 PM PDT Sunday for Coastal
     Waters from San Mateo Point to the Mexican Border and out
     to 30 nm.

     Small Craft Advisory from 6 PM Saturday to 3 AM PDT Monday for
     Waters from San Mateo Point to the Mexican Border Extending
     30 to 60 nm out including San Clemente Island.


&&

$$

PUBLIC...Maxwell (Update)/CO (Previous Discussion)
AVIATION/MARINE...EA