Area Forecast Discussion
Issued by NWS San Diego, CA

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000
FXUS66 KSGX 212056
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
155 PM PDT Thu Mar 21 2024

.SYNOPSIS...
Weak high pressure aloft will bring dry weather Friday with morning
marine layer clouds dissipating through midday. Over the weekend a
trough of low pressure will bring showers, colder weather, and gusty
winds. The storm moves east Monday followed by dry and warmer
weather Tuesday and Wednesday.

&&

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

Marine layer clouds cleared from the coast this morning and the
skies were sunny this afternoon. Low clouds will return tonight and
spread into the valleys through daybreak, then clear back to the
coast Friday afternoon.

The weekend will be colder, wetter and windier than the weather we
had today and the weather we will have on Friday. On Saturday
morning a cold 536 dm upper low west of Oregon will dig down the
coast Saturday afternoon through Sunday night. This long wave trough
will send a couple of shortwaves across SoCal that will bring
periods of rain and mountain snow this weekend.

The first shortwave drives the trough down the coast Saturday ahead
of an atmospheric river with an IVT of 300-400 kg/m/s. This upper
level moisture combined with increasing low level moisture from a
rapidly deepen marine layer to 5000 feet will bringing increasing
chances of precipitation over and west of the mountains through the
day. Snow is forecast in the mountains above 6500 feet.

On Sunday a second shortwave digs the trough even farther south for
more showers and lower snow levels. Gusty winds are forecast in all
areas this weekend, strongest in the mountains and deserts. Wind
Advisories will likely be needed this weekend, as are Winter Weather
Advisories for several inches of snow in the San Bernardino and San
Jacinto above 6,000 feet.

Monday will be a transition day as the trough exits the region. It
will be a cool day with below average temperatures. Tuesday and
Wednesday will be a few degrees warmer with weak ridging aloft.

&&

.AVIATION...
212000Z...Coasts/Valleys...SKC conditions will continue through the
daylight hours. Low clouds will push ashore and locally inland after
03-05Z Friday, although not as far inland. Bases/vis should be
similar to or slightly lower than ceilings this morning at around
1000ft MSL.

Mountains/Deserts: Mostly clear skies with unrestricted VIS today
and tonight, but with some cumulus buildups mainly over the
mountains at around 9000 feet MSL 20-01Z.

&&

.MARINE...
No hazardous marine conditions are expected through Saturday
morning. Strong winds will generate hazardous conditions for
Saturday afternoon through Monday. Strongest winds, including gales,
and highest seas are expected Sunday.

&&

.BEACHES...
Large short-period swell from the west-northwest will arrive early
Sunday, peak Sunday night, and subside Monday. This storm swell
could produce breaking surf of 8-10 feet Sunday night, highest in
southern San Diego County.

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.

&&

$$

PUBLIC...Moede
AVIATION/MARINE/BEACHES...Suk


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