003
FXUS66 KSGX 121231
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
401 AM PST Wed Feb 12 2025

.SYNOPSIS...
One round of precipitation will spread southeastward across the
area for today and tonight with another round of heavier
precipitation for Thursday and Thursday night. Showers will
continue on Friday and end from the northwest Friday night. There
will also be periods of stronger and gusty southwest to west winds
at times into Friday. Drier with warming for the weekend, then
slightly cooler early next week.

&&

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

.SHORT TERM (Today through Friday)...
Lighter precipitation will spread southeastward across the area
early this morning, becoming more widespread from the coast to the
mountains for late this morning through tonight. For Thursday and
Thursday night, heavier precipitation will spread southeastward
across the area. Showers will continue on Friday and end from the
northwest Friday night. Please see the hydrology section below for
more details on the snow levels and on the precipitation timing
and amounts.

Stronger and gusty west winds in the San Diego County deserts will
diminish during the late morning. For Thursday and Thursday night,
there will be periods of stronger and gusty southwest to west
winds. For the mountains and deserts, gusts to 40 to 50 mph are
expected with the stronger gusts along the lower desert slopes of
the San Bernardino Mountains for the the desert slopes of the
mountains in southern San Diego County to 70 to 80 mph. For the
coast and valleys, winds could gust to 25 to 35 mph on Thursday
evening.

&&

.LONG TERM (Saturday through Tuesday)...
Drier with a warming trend for the weekend with high temperatures
on Sunday a few to around 5 degrees above average, in the lower to
mid 60s near the coast to the mid 60s to lower 70s in the valleys
with the lower deserts in the mid to upper 70s. Then slight
cooling spreading inland for Monday and Tuesday as a low pressure
system moves inland to the north.


&&

.AVIATION...
121030Z...Coast/Valleys/Foothills...SCT-BKN layer of clouds at 2500-
4000 feet MSL with tops to 6000 feet will lower and become more
uniform in coverage as -RA overspreads the region after 16Z today
and continuing tonight. This will reduce vis to 3-6SM and cigs 800-
2000 feet MSL, lowest in SHRA. Lowest cigs/vis after 06Z tonight
into Thursday.

Mountains/Deserts...Strong westerly winds on desert slopes of
mountains and into deserts through 16Z. Surface gusts 25-40 kts at
times will lead to moderate up/downdrafts in lee of ridges. Areas of
higher terrain above 3500 feet obscured in FG, with obscurations
more widespread as -RA arrives after 16Z. Cigs and reduced vis will
develop in the high desert after 17Z with -RA moving in. Cloud bases
vcnty PSP will drop below 5000 feet MSL after 00Z with -RA
and reduced vis arriving after 06Z.

&&

.MARINE...
Hazardous winds in the outer waters will taper off this morning and
a Small Craft Advisory is in effect until 7 AM. Periods of stronger
winds and choppy seas are expected later today through Friday. Brisk
southerly winds will increase along the coast this afternoon into
early Thursday. Southwest winds will increase across the coastal
waters Thursday afternoon then diminish Thursday night. Finally,
westerly winds will increase Friday before diminishing Friday night.
Each of these periods of winds could briefly generate hazardous
conditions. No additional hazardous marine conditions are
anticipated Friday night through Sunday.

&&

.BEACHES...
A large westerly swell with a long period will arrive Friday,
generating large surf late Friday through Saturday. Surf of 4 to 6
feet with sets up to 9 feet can be expected, highest on west facing
beaches. There will be a high rip current risk and hazardous
swimming conditions.

&&

.HYDROLOGY...
Snow levels will rise from around 4500 feet early this morning to
6000 to 6500 feet around noon, 7000 to 7500 by late this
afternoon, and to around 8000 feet by Thursday morning.

Lighter precipitation will spread southeastward across the area
early this morning, becoming more widespread from the coast to the
mountains for late this morning through tonight. For Orange and
southwestern San Bernardino Counties through tonight, rainfall and
liquid-equivalent above the snow level is expected to range from
one-third to two-thirds of an inch near the coast to 0.75 to 1.25
inches in the mountains with snowfall of 2 inches above 6000 to
6500 feet and 3 to 6 inches above 8000 feet. For San Diego County,
rainfall through tonight is expected to range from one-half to one
inch near the coast to 1.5 to 2.5 inches in the mountains. For
today and tonight, the NBM probability for Palomar Mountain to
receive 2 or more inches of rainfall is 70 percent.

For Thursday and Thursday night, heavier precipitation will
spread southeastward across the area with additional rainfall
and liquid-equivalent above the snow level for Orange and
southwest San Bernardino Counties from around 1.5 inch near the
coast to 3 to 5 inches in the mountains with local amounts to
around 6 inches. For northern San Diego County and western
Riverside Counties, amounts are expected to range from 1 to 1.5
inches near the coast to 2 to 4 inches in the mountains with
amounts across southern San Diego County from around 0.75 inch
near the coast to around 1.5 inches in the mountains. A snow level
around 8000 feet on Thursday will lower to around 6500 to 7000
feet for early Friday morning.

For today through Friday night, rainfall and liquid-equivalent
above the snow level for Orange, southwestern San Bernardino,
western Riverside, and northern San Diego Counties is expected to
range from 2 to 2.5 inches near the coast to 4 to 7 inches in the
mountains with local amounts exceeding 8 inches. Amounts will
decrease from north to south across San Diego County with amounts
across southern San Diego County ranging from around 1 inch near
the coast to 2 inches in the mountains. For the lower deserts,
amounts are expected to range from around one-quarter inch for
locations bordering Imperial County to around 1 inch for the
northern Coachella Valley. For high desert areas, amounts are
expected to range from one-half to one inch farther inland from
the mountains to 1 to 2 inches on the foothills near the desert
slopes of the mountains. Additional snowfall could be as much as 1
to 2 feet above 8000 to 8500 feet with 4 to 8 inches from 6500 to
7500 feet. For today through Friday, NBM probabilities for 5
inches or more of rainfall are highest for the eastern San Gabriel
Mountains at 85 to 95 percent.

For Thursday and Thursday night, there could be hourly rainfall as
much as 0.75 to 1 inch on the coastal slopes of the mountains with
the most likely time for heavier rainfall rates on Thursday
evening when there is also a slight chance of thunderstorms.

Both the San Diego River at Fashion Valley and the Santa Margarita
River at Ysidora are forecast to reach Monitor Stage late Thursday
night into Friday morning, with only an 8% chance of the San Diego
River reaching Minor Flood Stage.

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Flood Watch from Thursday morning through late Thursday night
     for Orange County Coastal Areas-Orange County Inland Areas-
     Riverside County Mountains-San Bernardino County Mountains-
     San Bernardino and Riverside County Valleys-The Inland
     Empire-San Diego County Coastal Areas-San Diego County
     Mountains-San Diego County Valleys-Santa Ana Mountains and
     Foothills.

     Wind Advisory until 10 AM PST this morning for San Diego County
     Deserts.

PZ...Small Craft Advisory until 7 AM PST this morning for Waters from
     San Mateo Point to the Mexican Border Extending 30 to 60 nm
     out including San Clemente Island.

&&

$$

PUBLIC/HYDROLOGY...17
AVIATION/MARINE/BEACHES...MM