National Weather Service Forecast Discussion

Dicussion provided by the National Weather Service Forecast Office located in San Diego, California

000
FXUS66 KSGX 272129
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
129 PM PST Mon Jan 27 2020

.SYNOPSIS...
High pressure aloft and weak offshore flow will create warmer and
dry weather to start the week. Santa Ana conditions will set up
for Wednesday through Saturday. Gusty north to northeast winds are
expected in the mountains, foothills, and valleys with widespread
above average temperatures west of the mountains. Well above
normal high temperatures are expected next weekend under high
pressure aloft, then a small chance of precipitation returns
Sunday night into Monday.

&&

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

At 1 PM, water vapor satellite showed an upper-level ridge to our
southwest and an upper-level low 900 miles west of the Washington
coast. Weak surface high over Nevada was creating north to
northeast wind gusts around 25 mph through mountain passes and
along coastal mountain slopes. Highs through Thursday will be
around 5 degrees above normal for most areas, with little to no
low clouds and fog at night along the coast.

The aforementioned upper-level low will move by to our northeast
as a trough the middle of the week. This will create brief onshore
flow across the region late Tuesday, but then switch to Santa Ana
conditions Wednesday morning. The trough passage and building
surface high pressure over the Great Basin will create
northeasterly wind gusts of 40 to 50 mph, with local gusts to 60
mph, along coastal mountain slopes and through mountain passes
into adjacent valleys. Strongest winds are expected Wednesday
night. Winds then diminish Thursday, but remain offshore and gusty
through Saturday.

Model ensembles are in good agreement with a H500 588 DM ridge
building over central CA by the weekend. This would create much
warmer weather across the region, with highs most areas 10 to 15
degrees above normal by Saturday and into Sunday, and portions of
the mountains even 20 degrees above normal. A few high temperature
records may be broken this weekend. From the current forecast,
Big Bear Lake is expected to break their record of 63 Sunday by a
degree, but temperatures could increase even more as confidence
increases.

The ridge is not expected to linger very long as a trough swings
across the region early next week. This would lower high
temperatures and redevelop low clouds along the coast. There is
also a small chance of precipitation with the system, so slight
chance of precipitation has been added to the forecast Sunday
night into Monday.

&&

.AVIATION...
272110Z...Mostly clear skies are expected through the evening with
high clouds AOA 20K FT MSL. Unrestricted VIS for most locales,
though 4-6 SM for the Inland Empire will see periods of continued HZ
through the evening. Calm winds and high clouds will prevail through
Tuesday.

&&

.MARINE...
No hazardous marine weather is expected currently through Friday,
although north winds will increase Wednesday and could produce
choppy and hazardous conditions. These winds will decrease early
Thursday morning.

&&

.BEACHES...
Elevated surf and strong rip currents will continue this week. Surf
approaching 7 feet in San Diego County mainly Tuesday.

&&

.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...JJT
AVIATION/MARINE/BEACHES...APR

NWS SGX Office Area Forecast Discussion