Snow Valley

000
FXUS66 KSGX 060001
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
501 PM PDT Sat Sep 5 2026

.SYNOPSIS...
Patchy marine layer low clouds and fog can be expected overnight and 
in the morning as high level clouds from Tropical Cyclone Marie move 
over the area this weekend. Periods of light to locally moderate 
precipitation are possible, highest chances on Sunday. There is a 
slight (5-10%) chance of thunderstorms, mainly over the San 
Bernardino Mountains and High Desert on Sunday afternoon. Warming 
high and low temperatures through the middle of next week. Slight 
chance of mountain showers and thunderstorms return for mid-week.

&&

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


...UPDATED AVIATION DISCUSSION FOR 00Z TAF PACKAGE...

Tropical Cyclone Marie is about 800 miles south of San Diego, CA 
this morning. A swath of high clouds and moisture from the cyclone 
have made their way into Southern California. The only radar returns 
over SoCal as of 11 AM were in Imperial County. As Marie continues 
to track north and west this weekend, additional moisture will be 
pushed into the area increasing chances of showers. The highest 
chances are tomorrow north of San Diego County. Total rainfall 
amounts may reach over a half an inch over the San Bernardino 
Mountains, and generally 0.20 to 0.30 inches for the Inland Empire, 
with slightly lesser amounts to the coastal areas of Orange County, 
tapering off to lesser amounts over San Diego County. It's possible 
some areas in southern San Diego County may not see any accumulating 
rainfall. There is a 5 to 10 percent chance of thunderstorms over 
the San Bernardino Mountains and High Desert Sunday afternoon. Drier 
conditions expected for Monday and Tuesday. 

For this weekend, high temperatures will remain below average inland 
with highs near the coast running a few degrees above average. 
Overnight lows will also return to above average for this time of 
year by Sunday. By Tuesday, high temperatures will be within a few 
degrees of average for the mountains and deserts and 3 to 8 degrees 
above average for the coast and valleys. Above average low 
temperatures will be maintained into next weekend. Widespread minor 
to moderate HeatRisk is expected for inland areas Wednesday and 
Thursday. Temperatures will peak on Wednesday and gradually cool 
into Friday. 

The upper level flow turns southeasterly Wednesday and Thursday, 
which may allow for some additional moisture to creep into the area. 
There still remains some uncertainty in the upper level pattern with 
the position of the upper level ridge over the southwestern US and a 
trough off the US West Coast. A more easterly position of the trough 
would result in drier conditions with a more westerly position of 
the ridge allowing more moisture into the area. Current forecast 
follows the NBM which has 20 to 40 percent chance of showers and a 
15 to 20 percent chance of thunderstorms over the mountains 
Wednesday and Thursday afternoon.

&&

.AVIATION... 
060000Z...Coast/Valleys/Mountains...Mid and high level clouds around 
10,000-15,000ft MSL continue to stream into the area associated with 
the influx of tropical moisture. SCT-OVC mid/high clouds will 
continue for much of today and into Sunday. With this increasing 
cloud cover and moisture, marine layer clouds will struggle to 
develop, though some localized patches based near 2500ft MSL are 
possible overnight near the coasts. Shower activity will be largely 
focused across Orange County, the Inland Empire, and the mountains, 
with VCSH increasing by 12z Sunday. More steady -SHRA expected 
around 16-23z for the northern areas, with only VCSH expected across 
San Diego County for 16-23z. Brief instances VIS to 4-6SM and BR as 
well as BKN-OVC CIGs at 5000ft MSL or lower in areas of SHRA. In the 
mountains, pockets of TSRA may briefly occur, especially in the San 
Bernardino Mountains 18z Sunday through 00z Monday. Precipitation 
chances rapidly wind down by 00-03z Monday.

Deserts...Breezy southwest winds with intermittent gusts up to 35 
knots on the desert slopes of the mountains continue this evening. 
Winds weaken after 03z Sun. Mid-level clouds AOA 10,000ft MSL have 
increased today, and will persist into Sunday. VCSH possible in the 
deserts after 12z, with instances of -SHRA in the High 
Desert. Otherwise, VFR with no significant impacts expected.

&&

.MARINE...
No hazardous marine conditions are expected through Wednesday.

&&

.BEACHES...
A large south swell from Hurricane Marie has been building today, 
and is set to peak Sunday into Monday before gradually diminishing 
Tuesday. This will result in elevated to high surf and strong rip 
and longshore currents at majority of beaches. Additionally, waves 
will occasionally run much farther up the beach than expected, 
especially during increasing and high tides. 

For south and southwest-facing beaches, expecting high surf 6-10 
feet. This includes Orange County and north San Diego County 
beaches. For west-facing beaches, expecting elevated surf 4-7 feet. 
This includes most of southern San Diego County beaches. 

High surf combined with high astronomical tides 6.2 to about 6.8 
feet will lead to tidal overflow and coastal flooding through 
Tuesday during evening high tides, especially for south and 
southwest-facing beaches as well as low-lying areas.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Coastal Flood Advisory until 11 PM PDT Tuesday for Orange County 
     Coastal Areas-San Diego County Coastal Areas.

     High Surf Advisory until 11 PM PDT Tuesday for Orange County 
     Coastal Areas-San Diego County Coastal Areas.

PZ...None.

&&

$$

PUBLIC...CO
AVIATION/MARINE/BEACHES...Munyan