Area Forecast Discussion
Issued by NWS San Diego, CA

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000
FXUS66 KSGX 231147
AFDSGX

Area Forecast Discussion
National Weather Service San Diego CA
447 AM PDT Tue Jul 23 2019

.SYNOPSIS...
Through Thursday, high pressure centered near the four corners
will maintain a flow of monsoonal moisture into southern
California. There will be scattered thunderstorms in the mountains
each day from late morning through early evening with smaller
chances elsewhere and at other times. High pressure will be
centered over southern California for the weekend. This will bring
some drying and inland warming, decreasing thunderstorm chances
for Friday into the weekend. Monsoonal moisture may return the
early to middle part of next week.

&&

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

.SHORT TERM (Today through Thursday)...
High pressure aloft will remain centered near the four corners
through Wednesday, then move slowly towards the south on
Wednesday. This will maintain the flow of monsoonal moisture into
portions of southern California.

Overnight, there have been some sprinkles and a few light
measurable amounts from bands of mid level showers moving
northward across portions of southwest California. This will
continue into this morning. Some thunderstorms have also developed
over northern Baja. These may move into southern San Diego County
early this morning as shown by the HRRR.

Higher precipitable water values, of around 1.8 to 1.9 inches,
will remain entrenched across the lower deserts into Thursday.
Lower level moisture remains shallow. Dewpoints in the lower 70s
extend as far north as the southern Coachella Valley, but with
dewpoints in the northern Coachella Valley in the 50s.

Scattered thunderstorms will continue in the mountains the next
few days, mainly during the late morning through early evening
hours with smaller chances and lesser coverage in the deserts and
inland valleys. High temperatures will remain around average.
Night and morning coastal low clouds will be patchy and not extend
inland much past some coastal areas.

&&

.LONG TERM (Friday through Monday)...
High pressure centered over southern Arizona on Friday will be
centered across southern California and northern Baja for the
weekend. This will bring some drying. Thunderstorm chances will be
decreasing on Friday. That drying along with warming and
subsidence aloft will most likely result in afternoon clouds near
the mountains, but no thunder, for the weekend. With drying of
lower level moisture, lower desert high temperatures should warm
to above 110, generally around 5 degrees above average.

For early next week, the center of high pressure may migrate back
towards the four corners with slight weakening of the high
pressure as well. This should bring a return of monsoonal moisture
for the early to middle part of next week.

&&

.AVIATION...
231000...Coast/Valleys...Stratus is slow to develop this morning due
to some virga and mid/high clouds moving across the area. Low
clouds, with bases 800-1000 ft MSL are currently patchy over the
coastal waters, but could develop along portions of the coast over
the next few hours as the mid and high clouds move out of the
region. Confidence is increasing that coastal and valley aerodromes
will remain free of low clouds through the morning. A few -SHRA will
develop across the region this morning.

Mountains/Deserts...Debris mid and high clouds from old
thunderstorms will continue across the area through the morning,
along with isolated -SHRA. SCT-BKN clouds AOA 10000 ft MSL expected
to form this afternoon and evening with isolated TSRA possible over
the mountains and desert mountain slopes. Gusty surface winds, small
hail, strong up/downdrafts and frequent lightning are all possible
near storms.

&&

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

&&

.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...17
AVIATION/MARINE...JJT


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