National Weather Service Forecast Discussion

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

000
FXUS66 KSGX 150402
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
902 PM PDT Thu Mar 14 2024

.SYNOPSIS...
Strong Santa Ana winds will slowly begin to diminish through this
afternoon and evening. Isolated showers and thunderstorms will be
possible this afternoon, mainly across the San Diego County
mountains and valleys, with precip chances increasing across our
northern mountains tonight. Higher chances of showers and
thunderstorms develop on Friday, with lesser chances Saturday and
Sunday afternoons. Drier and warmer early next week.

&&

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

.EVENING UPDATE...
The band of precipitation along the leading edge of the vort max
that produced lightning, small hail, and snow as low as 3300 ft
over part of San Diego County earlier this afternoon has weakened
and shifted south into northern Baja. No sooner than that ended
did more light showers wrapping around the north side of the upper
level low start moving into the high deserts and San Bernardino
Mountains. Big Bear City Airport has been reporting on and off
light snow this evening. Scattered showers will continue to move
across these areas overnight, possibly spreading into the
Coachella Valley, Riverside County Mountains, and portions of the
Inland Empire overnight. For the deserts and valleys accumulations
will generally be light, mostly a tenth inch or less. The
greatest accumulations are expected on the north slopes of the San
Bernardino Mountains where around 0.20-0.40 inch or more is
possible. The snow level remains near 4500 ft overnight. Given the
relatively drier air compared to our typical winter storms, snow
ratios will be higher than usual, leading to the potential for 2
to 4 inches of snow overnight, especially for places like Big Bear
which are typically favored in this weather pattern. Some
adjustments to PoPs and rain/snow amounts were made for tonight
into Friday to increase the coverage of precipitation as well as
amounts for the San Bernardino Mountains.

.PREVIOUS DISCUSSION...
Mid-level moisture wrapping around the periphery of the low
pressure system will remain through this weekend, with the deepest
moisture profile on Friday. This is when showers and isolated
thunderstorms will be possible region-wide, with the highest
chances occurring across the mountains and eastern valleys.
Chances will linger through this weekend, with slight chances
both Saturday and Sunday afternoon.

Snow levels will rise above 5500 feet later in the day on Friday.
Off and on snow showers will result in accumulations of 3-7
inches above 6500 feet in San Bernardino and Riverside Counties by
Friday evening.

Highs today will top out up to 5 degrees above normal at the
coast, but will be around 5-8 degrees below normal across the
valleys, and 8-15 degrees below normal in the mountains and
deserts. Highs will cool a few degrees on Friday before slow
warming develops Saturday into early next week. Highs will be
above normal by Monday.

Weakening upper level low pressure will linger somewhere in the
vicinity of the southwest states into early next week. Weak
onshore flow may return by the middle of next week and begin to
spread cooling into the coast and valleys on Wednesday.

&&

.AVIATION...
150335Z...Coast/Valleys...SCT-BKN050-150 through Friday afternoon
with areas NE winds 15-25 kt below the mountain passes. Scattered
-SHRA moving off the mountains westward into the valleys at times
tonight and Friday.

Mountains/Deserts...Mountains occasionally obscured in clouds and
snow tonight and Friday. Snow will be most widespread in the San
Bernardino and San Jacinto Mountains.

&&

.MARINE...Breezy northeast winds 10-20 kt from San Mateo
Point to San Clemente Island tonight through Friday morning with
mixed swells and choppy seas at times.

&&

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


&&

.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Winter Weather Advisory until 6 PM PDT Friday for Riverside
     County Mountains-San Bernardino County Mountains.

PZ...None.

&&

$$

PUBLIC...SS/EA
AVIATION/MARINE...Moede

NWS SGX Office Area Forecast Discussion