Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Diego California
425 am PDT sun Apr 19 2015
Synopsis...a weak low pressure system off the California coast will
move slowly southward through Monday...then move slowly inland
through Southern California Tuesday. This will bring slow cooling...
a deeper marine layer with areas of night and morning coastal low
clouds and fog...and locally gusty west winds in the mountains and
deserts. For Wednesday and Thursday...a second low pressure system
from the northwest will continue the cooler temperatures and also
bring a chance of showers. Another weak trough of low pressure from
the northwest may continue a slight chance of showers for late
Friday into early Saturday.
Discussion...for extreme southwestern California including
Orange... San Diego...western Riverside and southwestern San
Short term (today through tuesday)... a weak low pressure system
off the central California coast will move slowly southward through
Monday...then move slowly inland through Southern California
Tuesday. This will bring a slow cooling trend with deepening of the
marine layer and with stronger onshore flow bringing periods of
gusty west winds to the mountains and deserts. Satellite imagery
shows stratus coverage greatest over the inner coastal waters early
this morning with patchier coverage extending into coastal areas.
With deepening of the marine layer...stratus is expected to extend
into portions of the inland valleys for late tonight into Monday
morning and into the far inland valleys for Monday night into
Long term (wednesday through saturday)... for Wednesday and
Thursday...a second weak low pressure system from the northwest will
maintain cooler temperatures and also bring a chance of showers.
There continue to be some model to model and run to run differences
with the details. Current runs show Thursday as the most likely time
for somewhat greater coverage of showers. For late Friday into early
Saturday...another weak low pressure system from the northwest may
continue a slight chance of showers.
Aviation... 190930z...coastal areas...patchy stratus with bases 700-
1000 feet mean sea level and areas of visible 3-5sm continuing over the coastal
waters and up to 10 miles inland through about 17z. Stratus
returning to the coastal airports 20/03-06z with bases 1000-1500 feet
mean sea level...spreading 20-25 Michigan inland overnight. Otherwise a few clouds
at or above 20000 feet mean sea level and unrestricted visible through Monday morning.
228 am...no hazardous marine weather is expected through
Tuesday. A storm system moving into Southern California will bring a
chance of showers over the coastal waters Wednesday and Thursday.
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.