SD Forecast Discussion

000
FXUS66 KSGX 302017
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
117 PM PDT Thu Jun 30 2022

.SYNOPSIS...
A cooling trend will continue through Monday as a trough of low
pressure strengthens off the West Coast. Night and morning low
clouds and fog will continue, spreading further inland into the
valleys each night. The low pressure will weaken starting Tuesday,
with high pressure building in from the east, resulting in a
warming trend for much of next week. Hotter conditions are
expected towards the end of next week, with monsoonal thunderstorm
activity potentially returning for next weekend.

&&

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

At 1 PM, visible satellite showed mostly clear skies across the
region, except for some mid-level clouds on the east-facing slopes
of the mountains, with cloud bases around 10,000 feet.
Temperatures continue on their downward trend today, with current
readings running a couple of degrees cooler in the valleys
compared to this time yesterday. Low clouds will reform and spread
back inland this evening, pushing into portions of the western
valleys.

A trough of low pressure currently situated off the West Coast
will continue to strengthen through early next week, resulting in
a cooling trend for SoCal. Temperatures look to be coolest on
Sunday and Monday, with highs only in the mid 80s for the Inland
Empire and 100 to 105 degrees for the lower deserts. Quite a
change from the recent heat! Coastal areas will be near seasonal
averages Sunday and Monday, while the valleys, mountains and
deserts will be 5 to 10 degrees below seasonal averages.

After Monday, the trough is expected to weaken and push inland,
with high pressure building in from the east into the Southwest
U.S. This will bring a warming trend beginning on Tuesday, with
temperatures reaching above seasonal averages by next Thursday. By
next weekend, some models and ensembles are showing monsoonal
thunderstorm activity making its way towards our region. However,
there are some differences in the ensembles in the location of the
high pressure by next weekend as well as the possible moisture
intrusions, so confidence is rather low in when monsoon
thunderstorms will return to Southern California.

&&

.AVIATION...
301940Z...Coast/Valleys...FEW mid level clouds 5000-8000 ft MSL with
FEW high clouds AOA 10000 ft MSL through the afternoon. BKN-OVC low
clouds with bases 800-1400 ft MSL will move inland after 02Z,
reaching coastal TAF sites between 05Z-07Z Fri. Vis restrictions of
3-5 SM in BR/HZ locally in the valleys and near higher coastal
terrain. Low clouds expected to scatter out 16-18Z Fri.

Mountains/Deserts...Cu have developed over portions of the
mountains, with bases around 10000 ft MSL. Cu will dissipate around
01Z Fri. Mostly clear with unrestricted vis in the deserts. West
wind gusts 25-35 kt over the mountains and locally into the deserts
through 10Z Fri. Another round of west winds with gusts 25-
35 kt expected around 21Z Fri.

&&

.MARINE...
Periods of gusty northwest winds near 20 kt in the outer waters each
afternoon through the 4th of July holiday.

&&

.FIRE WEATHER...
The cooling trend will continue for the remainder of the week and
into early next week as a trough of low pressure approaches the
West Coast. Increased southwest to west winds will occur each
afternoon and evening through the passes and across the desert
mountain slopes, with peak gusts 35 to 45 mph. Afternoon minimum
humidity will drop to 15 to 20 percent in those locations. The
combination of breezy winds and low humidity will create a few
hours of elevated fire weather conditions each afternoon and
evening in the mountains and deserts.

A warming trend will commence on Tuesday and continue through the
remainder of next week as high pressure builds back into the
region.

&&

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

&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...NONE.
PZ...NONE.
&&

$$

PUBLIC/FIRE WEATHER...Connolly
AVIATION/MARINE...CO

NWS SGX Office Area Forecast Discussion