Wildfire in California, May 22 to 25, 2023

Area Forecast Discussion
National Weather Service San Diego CA
151 PM PDT Mon May 22 2023

.SYNOPSIS...
One last day of isolated showers and thunderstorms in the
San Bernardino and Riverside County mountains and high desert.
For Tuesday through Friday, a trough of low pressure will develop
over the western states with drier southwest flow aloft and
stronger onshore lower level flow. There will be a cooling trend
through Friday with the marine layer deepening onto the coastal
slopes of the mountains. There will also be periods of stronger
and gusty southwest to west winds for the mountains and deserts.
That low pressure system will weaken and move inland with warming
for next weekend into early next week.

&&

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

Forecast Highlights:

* Isolated mountain/high desert thunderstorms this afternoon
* Cool, onshore flow pattern with marine layer clouds west of mtns

It's May and it's gray and it will stay. An incoming trough over
the west will amplify and be the dominating weather feature
impacting SoCal throughout the week. This will mean May Gray west
of the mountains with sunshine over the valleys each day, but not
likely near the coast. Temperatures will trend cooler with temps
averaging about 5 degrees below normal mid-late week.

One last day of isolated showers and thunderstorms today with the
activity over the SBD/Riverside County mountains and the high
desert, but not as robust as the past couple of days. Moisture
will be on a rapidly decreasing trend tonight through Tuesday as
west winds increase associated with the aforementioned digging
trough.

The trough axis will move east this upcoming weekend, allowing for
slow warming and a slightly shallower marine layer.

&&

.AVIATION...
221930Z...Coast/Valleys...Low clouds have been slow to clear the
western valleys today. Low confidence in complete clearing this
afternoon, especially along the coast. Low clouds are expected to
fill in the coastal basin again through 10Z Tue. Bases are expected
to be 600-1200 ft MSL, with local vis restrictions of 2-4SM in
BR/HZ. Slow clearing is expected again tomorrow with low confidence
in coastal areas clearing.

Mountains/Deserts...15-30 percent chance of TSRA (highest chance
again across SBD mts/deserts) through 01Z Tue. CB clouds AOA 10000
feet MSL with tops to 35 kft. Gusty erratic winds should be expected
in and around any storm.

&&

.MARINE...
No hazardous marine conditions are forecast through Saturday.

&&

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

&&

PUBLIC...Gregoria
AVIATION/MARINE...CO