Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Diego California
155 PM PDT Wednesday Jul 30 2014
although a stray afternoon thunderstorm may be possible over the San
Bernardino County mountains and deserts this afternoon...drier
conditions will prevail across most areas through Thursday...with
above average temperatures for inland areas. Subtropical moisture
will then spread back into the area for this weekend...with a chance
of afternoon and evening thunderstorms...mainly in the mountains and
deserts. Drier weather will then return early next week.
Otherwise...the marine layer and weak onshore flow will bring patchy
late night and early morning low clouds and fog near the coast.
Discussion...for extreme southwestern California including Orange...
San Diego...western Riverside and southwestern San Bernardino
Water vapor imagery continues to show Southern California situated
between high pressure over the Desert Southwest and a trough off the
West Coast this afternoon. As a result...southwesterly flow aloft
continues to prevail. At this time...the brunt of the moisture for
the remnants of Hernan remains to our north and west...with
thunderstorms firing over the Central Valley and central Sierra.
Cumulus are starting to build over the higher mountain peaks...but
in truth...they are quite flat. There is still a chance that one of
these cumulus could build enough to form a brief shower or
thunderstorm late this afternoon. Otherwise...temperatures this
afternoon are running a little cooler along the coast and a little
warmer inland. This trend will continue into tomorrow as well...as
not expecting much if any change for tomorrow...as a shallow marine
layer reforms along the immediate coast.
Models are hinting at subtropical moisture spreading back across
Southern California by this weekend. In fact...several show the
potential for a disturbance moving through either late Saturday
night or on Sunday. For now...our forecast keeps the best chances
of showers and thunderstorms over our mountains and deserts for this
weekend...but will need to take a closer look at the rest of the 12z
runs for consistency sake. Drier conditions will redevelop then for
early next week...with a gradual warming trend possible.
302016z...coasts/valleys...unrestricted visibility and few-scattered
clouds at or above 20000 feet above mean sea level through 31/0600
UTC. 31/0600-1600 UTC...patches of stratus may gradually develop
within 5-8 miles of the coast...with bases of 700-1000 feet above mean
sea level and tops around 1200 feet above mean sea level. Visibility
may locally be reduced to 1 mile or less. Confidence in stratus
occurrence at ksan...kcrq and ksna is low. Any stratus/fog that
forms should clear by 31/1600 UTC.
Mountains/deserts...some cumulus clouds with bases around 9000 feet
above mean sea level developing over the mountains through 31/0200
UTC...with a thunderstorm or two possible over the San Bernardino
County mountains and high deserts. Thunderstorm tops could reach
35000 feet mean sea level. Otherwise...few-scattered clouds at or above 20000 feet
above mean sea level through Thursday morning.
116 PM PDT...no hazardous marine weather expected through
Sunday...although wind gusts may reach 25 knots near San Clemente
Island during the evening hours today and Thursday.
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.