550
FXUS66 KSGX 132205
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
205 PM PST Thu Nov 13 2025

.SYNOPSIS...
An incoming winter storm system will continue to bring clouds,
cooler weather and increased chances for precipitation today into
the weekend. The storm system will bring the best chances for
rainfall across northern areas tonight into Friday, with all areas
expected to receive moderate to heavy rainfall by Friday night
through early Sunday, increasing the flood threat. This system
will be a warmer one, so expect we can expect most mountain
communities to only see light snowfall accumulations. The storm
door will remain propped open into at least the first half of next
week as a weaker storm system moves closer to our region.

&&

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

A defined area of low pressure is currently spinning just of the
coast of the Oregon-California border with an associated frontal
boundary draped across the Central Coast. This is bringing locally
heavy rainfall this afternoon across this region northward toward
the Bay Area. The low and frontal boundary will move southward
closer to our region tonight into Friday as the trough stalls and
elongates. We can see weak echoes on radar west of LA, so
increasing clouds and light showers will be possible over northern
areas by this evening and overnight. Model projections depict much
lighter amounts for much of Friday across San Diego County into
the lower deserts.

A Flood Watch has been issued for all areas for much of Saturday
as this storm system moves over the region. This is when most
areas will see the heaviest rainfall, including a chance for
thunderstorms. Any area that sees these thunderstorms or heavier
rainfall over this longer period will see an increased risk for
flooding, including near burn scars. Model agreement is fair in
having the system depart on Sunday, leaving us with off and on
light showers and breaks in the clouds. Cool conditions will also
be accompanied with this storm system with highs 60-65 degrees for
areas west of the mountains and 40s/50s across the mountains.

Ensemble model guidance is in better agreement of another area of
low pressure moving southward over SoCal by Monday and Tuesday of
next week. Though the details on this are still quite uncertain,
confidence is growing in a continued cooler and wetter weather
pattern. As of now, it looks increasingly likely that this system
will not be as wet as the one we will be seeing this weekend.
Models diverge some by the latter half of next week, but consensus
continues to lead to a continued active weather pattern.


&&

.HYDROLOGY...
A Pacific storm will bring increasing chances for showers
beginning tonight as increasing clouds and light showers are seen
this afternoon.The frontal boundary looks to stall some on Friday,
so most of the precipitation that occurs on Friday morning and
afternoon will be concentrated the LA Basin and surrounding
mountains. Rain rates with this time frame look to be under one
half inch. The San Diego metro may remain fairly dry for much of
the day on Friday.

Once the system pushes southward and inland over our area by
Friday night and Saturday, widespread heavier rainfall can be
expected over all of Southern California. This has warranted a
Flood Watch for all areas as there is an increased risk of
flooding. There is also a chance of thunderstorms for Friday
night into Saturday evening. Scattered lighter showers will
continue into Sunday.

Through Sunday, rainfall for Orange and southwestern San
Bernardino Counties is expected to range from around 3 inches
near the coast to 3 to 5 inches for the mountains, locally
exceeding 7 inches on the south facing coastal slopes. For San
Diego County into the lower deserts, the forecast is a bit
trickier with the rainfall totals. Most areas near the San Diego
metro will receive 2 inches of rain in total, though some areas
may see closer to 1.5 inches. The Riverside and San Diego County
mountains will be seeing near 3 to 4 inches with locally greater
amounts. For the high desert, 1.5 to 2.5 inches of rainfall is
expected with near 1 inch for the lower deserts.

These rainfall amounts, along with the potential for periods of
higher intensity rainfall for late Friday night through Saturday,
could produce debris flows in burn areas, significant ponding of
water on roads and highways, and urban and small stream flooding.
The current forecast for the San Diego River has the river at
Fashion Valley rising above the 7.5 foot monitor stage from 9 AM
Saturday to 9 PM Sunday, sufficient to flood low-water crossings.

Snow levels above 10000 feet will lower to around 8000 feet for
late Saturday and 6500 to 7500 feet on Sunday. There could be 3
to 6 inches of snowfall for Saturday night and Sunday, mostly
above 7500 feet with accumulations near one inch for areas below
7000 feet, including the Big Bear Lake region.

&&

.AVIATION...
132145Z...Coasts/Western Valleys...VFR conditions prevail through
the day with increasing mid level clouds based around 6000-7500ft
MSL ahead of an incoming storm system. Lower clouds with varying
bases from 2000-4000ft increase after 09z but confidence/timing of
any long duration CIGs is low. Increasing chances of isolated areas
of -RA after 06z Friday.

Otherwise...VFR conditions will continue through Friday afternoon.
Mid and high clouds at 5-15 kft will gradually increase.

&&

.MARINE...
A storm system will approach Friday and move through Saturday and
Sunday, boosting southerly winds and seas. Prefrontal winds could
bring wind gusts of 20-30 kts across the waters on Saturday.
Occasional heavy rain Saturday could reduce visibility. There is a
slight chance of thunderstorms Friday night through Saturday night.
A Marine Weather Statement is now in effect for these thunderstorm
chances for Friday afternoon through late Saturday and contains more
details.

&&

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


&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Flood Watch from late Friday night through Saturday evening for
     Apple and Lucerne Valleys-Coachella Valley-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 Deserts-San Diego
     County Mountains-San Diego County Valleys-San Gorgonio Pass
     near Banning-Santa Ana Mountains and Foothills.

PZ...None.

&&

$$

PUBLIC...APR
AVIATION/MARINE...Munyan