San Diego Weather at Mission Trails, CA

000
FXUS66 KSGX 120430
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
930 PM PDT Tue May 11 2021

.SYNOPSIS...
Building high pressure aloft will bring warmer days and a shallower
marine layer Wednesday and Thursday to inland areas. Temperatures in
the coastal areas will remain relatively unchanged due to the
persistent marine layer influence. A trough of pressure will bring
cooling this weekend along with a deeper marine layer, perhaps deep
enough to produce areas of drizzle west of the mountains Saturday
night into Sunday morning.

&&

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

Update:

Highs across our service area today ranged from 62 degrees at Del
Mar Beach to 99 degrees at Palm Springs and Thermal. A cloudy
morning across many areas west of the mountains turned sunny, but
the low cloudiness has re-developed and has filled in across much
of Orange County and the areas along the San Diego County coast
and into parts of the valleys north of downtown San Diego, but low
clouds will likely develop along the rest of the coast and much
of the valley regions overnight. The sky will continue clear over
the deserts. Pretty much status quo as the past several nights. No
changes were made to the forecast this evening.

Previous Discussion (Issued at 150 PM PDT Tue May 11 2021):

Marine layer clouds cleared to the coast by 1 PM today except over
La Jolla where clouds persisted. Coastal temperatures were unchanged
from yesterday, while the valleys, mountains and deserts were
several degrees warmer. This pattern repeats Wednesday. A weak ridge
over the Southwest will bring another couple degrees of warming to
the valleys, mountains and deserts, but areas within 5 miles of the
coastal won`t see much temperature change. The inversion aloft will
be a little stronger and that will keep morning low clouds from
clearing at the coast until early afternoon. Scattered to broken
clouds may linger at the beaches most of the day.

Friday through Sunday...A trough of low pressure over the Pacific
Northwest will move down the coast Friday and then across Southern
California Saturday and Sunday. It will deepen the marine layer to
around 4,500 feet Saturday night, perhaps deep enough for areas of
light rain or drizzle west of the mountains Saturday night through
Sunday morning. Broad cyclonic flow at 500 mb with embedded weak
shortwaves will enhance our precipitation chances. Ensemble
probabilities show a 60-70% chance of measurable rain of >0.01" in
the coastal and valleys zones Sunday morning, greatest amounts near
0.10" on the foothills and the west facing lower mountain slopes.

Temperatures will trend lower this weekend due to lower heights and
a deeper marine layer. By Sunday, highs will be 5 degrees below
average near the coast and in the deserts, and from 10-15 degrees
below average in the valleys and mountains. Stronger onshore flow
will result in gusty west winds in the mountains and deserts.

&&

.AVIATION...
120415Z...Coast/Valleys...Low clouds will continue to spread through
all coastal areas by 06Z and most valleys by 09Z with BKN/OVC bases
1400-1800 ft MSL and tops to 2500 ft MSL. Most vis will be 6+ miles
below the cloud bases, but higher terrain will be obscured. Clearing
will occur 16Z-18Z Wed in the valleys and 18Z-22Z Wed near the
coast, with some beaches likely not clearing. Stratus will spread
inland again Wed evening.

Mountains/Deserts...Mostly clear with unrestricted vis through Wed
evening.

&&

.MARINE...
No hazardous marine weather is expected through Sunday.

&&

.SKYWARN...
Skywarn activation will not be needed this week.


&&

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

$$

PUBLIC...Gregoria (Update)/Moede (Previous Discussion)
AVIATION/MARINE...Maxwell