Area Forecast Discussion
Issued by NWS San Diego, CA
FXUS66 KSGX 302026
AREA FORECAST DISCUSSION
National Weather Service San Diego CA
126 PM PDT MON MAY 30 2016
High pressure aloft will strengthen over California, bringing a
warming trend this week. The marine layer will thin, but hold along
the coast as it heats up inland. Nocturnal low clouds and fog will
not extend as far inland after Tuesday. For next weekend...a weak
low pressure system in the vicinity of Southern California will bring
a cooling trend and a deepening of the marine layer.
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
Areas of light rain and drizzle were not reported after 9 AM PDT, but
the marine stratus was slow to burn off over western San Diego
County. by 1 PM PDT, skies were clearing over most of Orange County
and where clear elsewhere across the CWA, with only a few stray
cumulus over the mts. Temperatures were in the upper 60s and lower
70s west of the mts at Noon, but well into the 80s and lower 90s
across the deserts. The surface pressure gradients were 3-6 MBS
onshore KSAN to the deserts, with mostly light winds reported.
Expect the marine layer to thin by about 1500 feet Tue morning,
but still be deep enough to produce stratus well into the valleys.
Some patchy drizzle may develop as well, but should not be as
widespread, or accumulate to the degree it did this morning.
Clearing of the stratus layer should reach closer to the coast Tue,
but will likely be limited along the immediate coast.
A weak upper-level low over SW AZ this morning, will drift SE as a
high pressure ridge over the Pacific edges east. The ridge will
build over the SW through Fri, peaking at 593 DM before another low
pressure system approaches from the west. This will knock heights/
thickness back down and strengthen the onshore flow into next
weekend, building the marine layer back into the valleys. A weak
troughing pattern follows into next week.
Look for a warming trend this week, peaking about Fri inland. Along
the coast, some warming may be felt as the marine layer thins and
allows some afternoon sun at times, but it will be trivial compared
to the warming inland, where afternoon temperatures will climb
through the 90s and reach the century mark and higher in some areas.
Depending on the track of the incoming low pressure system this
weekend, a few shwrs/tstms could pop. But for now, the spread in
model solutions and lack of derived instability guidance limits
confidence that anything at all will materialize.
302030Z...Coast/Valleys: Areas of low clouds continue to impact
coastal TAF sites this afternoon, with BKN-OVC cigs 1700-2800 ft MSL
and tops to 4500 ft MSL. Coastal TAF sites could experience a few
hours of SCT low clouds blo 3000 ft MSL before low clouds redevelop
after 01Z this evening, spreading inland overnight. Expect less
inland extent than recent nights. Cigs will be mostly 1200-1500 feet
MSL tonight. More clearing is possible Tue than today, but
confidence is only moderate. Inland areas could also clear by 17Z
Tue with some low clouds lingering at the immediate coast Tue
Elsewhere: Mostly clear skies with unrestricted visibility
200 PM...No hazardous marine conditions are expected through Friday.
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.