Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Diego California
913 am PDT Tuesday Oct 13 2015
gradually cooler through the weekend...with a chance of afternoon
and early evening showers and thunderstorms as a low pressure system
moves in from the southwest. Showers and thunderstorms will be
mainly in the mountains and deserts...beginning Wednesday afternoon
and continuing into Saturday. A second low pressure system from the
northwest could bring more widespread precipitation for Saturday
night into Monday...possibly heavy at times on Sunday.
Discussion...for extreme southwestern California including Orange...
San Diego...western Riverside and southwestern San Bernardino
Mostly sunny this morning...except for a few middle and high clouds.
Temperatures are generally a few degrees higher than this time
yesterday...except for some inland valley and mountain areas where temperatures
are a few degrees lower than this time yesterday.
From previous discussion...
a low pressure system to the southwest will drift slowly north off
the coast through Wednesday before moving inland through southern and
central California Thursday and Friday.
Deterministic models indicate some cooling in the lower levels today
and most areas are expected to have high temperatures a few degrees
lower than Monday. The gradual cooling will continue into the
weekend with high temperatures falling to around seasonal averages.
Overnight low temperatures will slowly decrease...but remain above
average...especially near the coast where sea surface temperatures
have warmed to just below their warmest levels of the Summer and
early fall season and well above average for October.
As the low pressure system from the southwest moves inland across
Southern California...there is a chance of afternoon and early
evening thunderstorms...mainly for the mountains and deserts
Wednesday afternoon into Saturday. Brief heavy rainfall is possible
with thunderstorms. Coverage and amounts are expected to be highly
variable but with overall coverage and amounts greater for San
For the weekend into early next week...a low pressure system from
the North Pacific is expected to move into Southern California
Saturday night into early next week. Due to model
inconsistencies...some uncertainty remains. However...this could
turn out to be a significant early season storm...with more
widespread precipitation...possibly heavy on Sunday. Snow levels
would be fairly high...mostly above resort levels.
131500z...mostly clear...with only some scattered clouds above 10000
feet mean sea level...and unrestricted visibilities. After about 14/12z late
tonight patchy low clouds at around 800 feet mean sea level with tops around
1200 feet mean sea level may develop over the coastal waters. The confidence in
keeping the low clouds out of the ksan taf for tonight is moderate
as the risk of broken low clouds at ksan overnight into Wednesday is
800 am...slight chance of thunderstorms Wednesday into Thursday.
Otherwise...no hazardous marine weather is expected through Saturday.