Area Forecast Discussion
Issued by NWS San Diego, CA
FXUS66 KSGX 240355
AREA FORECAST DISCUSSION
National Weather Service San Diego CA
855 PM PDT TUE AUG 23 2016
High pressure off the coast will bring slight warming on Wednesday,
then cooler into the weekend as low pressure becomes reestablished
across the West. Marine clouds will be patchy along the coast
tonight and again Wednesday night with areas of fog likely, then
spread farther inland Thursday night into the weekend as the marine
layer deepens. Continued dry, with a warming trend Sunday through
early next week as high pressure builds aloft.
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
Skies were clear across the CWA this evening, except for some patchy
marine clouds over the coastal waters and near shore. The Miramar
sounding had a weak 3 degree C inversion based near 1600 FT. the
inversion height had changed little from yesterday. There was a
slight bump in moisture in the mid-levels, otherwise the column was
rather dry. At 8 PM PDT, weak to moderate onshore surface pressure
gradients were supporting isolated westerly wind gusts of 25 to as
much as 40 MPH through the passes and locally into the deserts,
otherwise winds were light.
High pressure centered off the coast will build heights/thickness
over the region tomorrow, resulting in a slight warm-up, but it will
be brief, as another long wave trough develops over the West Thu-
Sat. The trough will keep daytime temps below average, and the skies
mostly clear across the SoCal after night and morning coastal low
clouds and fog burn away.
Then, beginning on Sunday, high pressure will rebuild over the SW,
which should bring a warm-up through the first half of next week.
The GFS/ECMWF solutions have considerable spread, so confidence is
low at this point regarding just how warm it will get. But a model
blend indicates daytime highs could be from 4-8 degrees above
average by Tue. Both models keep the high in an unfavorable position
to allow any decent monsoonal flow into SoCal, so expect skies to
stay dry through month`s end.
240325Z...Coast/Valleys...Patchy stratus with bases 1000-1300 ft MSL
has begun to develop along the San Diego County Coast. Expect
stratus to develop along the Orange County coast after 06Z and
spread 10-15 mi inland overnight...reaching KSAN by 08Z and KSNA by
11Z. Bases lowering to around 700-1100 ft MSL with areas of vis 1-3
SM over higher coastal terrain and on the coastal mesas. Stratus
clearing to the coast 16-18Z.
Mtns/Deserts...S few cumulus clouds may develop over the mountain
ridges Wednesday afternoon. Otherwise mostly clear with unrestricted
vis through Wed night.
No hazardous marine weather is expected through Saturday.
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.