953
FXUS66 KSGX 051553
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
853 AM PDT Sun May 5 2024

.SYNOPSIS...
Light rain showers across central San Diego County will diminish
over the next hour or two, giving way to a cool day with passing
clouds. Strong winds over the mountains and deserts will continue
through this evening. Dry weather with slow warming will prevail
through most of the upcoming week.

&&

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

Update...
A 543 DM low is progressing into the Great Basin this morning, and
a shortwave is rounding the base of the trough over the Mojave
Desert. A weak front produced generally light rain showers earlier
this morning, with most locations across the coast and western
valleys picking up a few hundredths of an inch to a quarter of an
inch of rain, and higher amounts along the foothills and
mountains. Clouds are clearing out pretty quickly behind the
front, with most coastal and valley areas seeing only passing
clouds. Mountain waves are clearly visible on satellite imagery,
signifying strong winds over the mountains and desert slopes. Peak
wind gusts of 50-55 mph will occur through this evening before
diminishing.

Today will be the coolest day of the week for most areas, with
highs topping out 3-6 degrees below normal across the coast and
western valleys, and 10-20 degrees below for the foothills,
mountains and deserts. Much warmer conditions are expected
tomorrow.

Previous Discussion (Issued 253 AM PDT Sun May 5 2024)...
.SHORT TERM (Today-Tuesday)...

Once the front moves through, the remainder of the day will be
partly cloudy and cool. Highs will reach the 60s for the coastal
areas and valleys, 40s in the mountains, upper 50s to low 60s in
the high desert, and mid to upper 70s in the low deserts.

The upper level low moves out on Monday with drier northwest flow
into Tuesday. Monday will be significantly warmer, followed by
minor warming on Tuesday, though still a few couple degrees below
normal. Breezy west winds develop in the mountains and deserts
each afternoon into late night, though are forecast to remain
below advisory strength. Some patchy marine layer low clouds will
develop along the coast each night, especially on Tuesday with the
development of a coastal eddy. The marine inversion will be fairly
weak though, so expect decent clearing each day even at the coast.

&&

.LONG TERM (Wednesday-Saturday)...
Minor warming continues into Wednesday as we remain under weak
cyclonic flow wedged between the upper ridge off the West Coast
and a large upper low over the northern Great Plains. Both
deterministic and ensemble models are coming into better agreement
with the evolution of this pattern into the latter half of the
week. A positively-tilted short wave on the back side of this low
will amplify late Wednesday, eventually splitting from the parent
low and retrograding southwestward into Thursday and Friday.
There is the potential for weak offshore flow Wednesday morning as
the short wave drives south and surface high pressure begins to
build over the Great Basin.

There are still differences in the placement and strength of the
low late in the week, resulting in increasing spread in the
temperature forecast. Since models have trended to the further
west solution, forecast now has temperatures remaining fairly
steady/not as warm for the latter half of the week. Marine layer
low clouds will continue for the coastal areas and portions of the
valleys each night and morning, potentially deepening and
spreading further inland next weekend if the upper low continues
to drift west or southwest as some ensemble members and the
deterministic models suggest.

&&

.AVIATION...
051530Z...Coasts/Valleys/Foothills...-SHRA continues across
southeastern San Diego County this morning. Skies will briefly clear
this morning followed by FEW-SCT clouds, locally BKN-OVC with bases
2500-3500 FT MSL through this afternoon and early evening. Skies
clearing generally between 06-09z tonight. Some patchy low clouds
possible overnight but CIGs are unlikely. W-NW winds increasing
later this morning and afternoon, with peak wind gusts of 25-30 kts
possible along the immediate coast.

Mountains/Deserts...Expect another round of strong W-SW winds 20-35
kt with gusts of 45-60 kt after 18Z. Areas of MOD-STG up/downdrafts
and LLWS over/east of mtns. SCT-BKN clouds at/abv 10000 ft MSL
through this evening.

&&

.MARINE...
Northwest winds gusting 25 to 30 knots will continue through this
evening, which will generate hazardous boating conditions,
especially in the outer waters. Northwest winds gusting up to 20
knots will be possible over the outer waters each afternoon and
evening for 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 until 8 PM PDT this evening for Apple and Lucerne
     Valleys-Coachella Valley-Riverside County Mountains-San
     Bernardino County Mountains-San Diego County Deserts-San
     Diego County Mountains-San Gorgonio Pass Near Banning.

PZ...Small Craft Advisory until 10 PM PDT this evening for Coastal
     Waters from San Mateo Point to the Mexican Border and out
     to 30 nm.

     Small Craft Advisory until 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...EA/SS
AVIATION/MARINE...Adams