Area Forecast Discussion
Issued by NWS San Diego, CA
FXUS66 KSGX 261646
AREA FORECAST DISCUSSION
National Weather Service San Diego CA
946 AM PDT THU MAY 26 2016
Marine layer stratus was fully locked in west of the mountains
this morning, except for much of the Inland Empire. Even drizzle
occurred over portions of San Diego County with 0.01-0.02"
occurring at a few locales, including at our office in Rancho
Low temperatures this morning were in the 50s to lower 60s at
most locales. The range of temps across our service area this
morning was 36F at Big Bear Lake to 68F at Palm Springs.
The stratus is beginning to erode from east to west and expecting
this trend to continue with plenty of sunshine prevailing during
The upper level low, which was over Southern California yesterday,
is now over northern Arizona and pulling away. Subsidence on the
back side of this feature, along with a relatively dry atmosphere
will result in a tranquil day today with temps warmer than
yesterday over inland areas and especially the lower deserts where
lower 90s are forecast for the Coachella Valley.
See previous discussion below for further forecast details.
A weak trough of low pressure will persist over Southern
California through the holiday weekend. This will continue the
deep marine layer and the relatively cool weather. Higher
pressure next week indicates warmer weather.
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
Clouds have been slowly gathering in the coastal basin this
morning and we expect a mostly gray sunrise for the metro areas.
A weak low pressure trough will continue settled over the west
and this will keep our marine layer deep and healthy through the
holiday weekend. There will be some variations on the theme of
night and morning low clouds filling most of the coastal basin,
but days should be mostly sunny. On Saturday and Sunday the
trough deepens ever so slightly and some additional mid level
moisture arrives. That will form some cumulus clouds over the
mountains, but chances of precip are too slim to forecast for now.
Temperatures will continue below average through the weekend.
Model guidance shows a high pressure ridge to develop Monday
through Wednesday. Daytime temperatures will eventually reach
average for most spots by Memorial Day. The strengthening ridge
would tamp down the marine layer and push temperatures above
average for a change Tuesday and Wednesday.
261520Z... Coast/Valleys...Mainly bkn low clouds with bases 2000-
3000 feet MSL with tops to around 4000 feet MSL will continue
through mid morning. Slow improvement after 26/17Z beginning at the
coastline. Low clouds will re-develop this evening after 02z near
the coast this evening and move inland only 5-10 miles with bases a
bit lower compared to today, likely 1500-2500 feet MSL. Risk of low
cloud bases tonight below 2000 feet MSL is moderate-high. Confidence
in a solid low cloud base tonight is moderate to high also.
Mountains/Deserts...Mountain slopes obscured at times in clouds
below 4000 feet MSL this morning. West winds with gusts to 40 knots
at times will produce weak to moderate up/down drafts over and east
of the mountains through this evening.
800 AM...Wind gusts near 20 kts this afternoon and evening over the
outer waters, otherwise, no hazardous marine conditions are expected
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.