Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Francisco Bay area
1044 PM PDT sun Jul 27 2014
Synopsis...a combination of monsoon and subtropical moisture will
continue to move across the forecast area into Tuesday. This will
result in periods of middle and high level clouds. There is also a
slight chance of isolated light showers or thunderstorms during
that time. Temperatures are forecast to remain near normal or
slightly above normal through the week.
Discussion...as of 8:37 PM PDT Sunday...showers and thunderstorms
have tapered off for the evening as low clouds begin to make
their way to the coast. It was another warm day today with
temperatures running 5 to 10 degrees above normal at many
locations. San Francisco International Airport reached a high of
77 with normal temperature of 72...Sonoma County Airport reached
92 with a normal temperature of 83 degrees and Salinas Airport
reached a high of 76 with a normal high of 71 degrees. Several
lightning strikes were observed around the area today due to the
monsoon/subtropical moisture and elevated instability. Roughly 72
lightning strikes were observed offshore with 3 strikes occurring
over land...1 near Hollister...1 near Gilroy and 1 in Carmel
The latest satellite water vapour image continues to show a
combination of monsoon and subtropical moisture pushing into
Southern California. The 1200z European model (ecmwf) and 1800z gfs40 have
initialized well with the current synoptic pattern and both
continue to advect the previously mentioned moisture into the
forecast area through Tuesday. Upper air analysis with the 1800z
nam12 shows elevated instability over the forecast area modified
totals around 32 hovering along the coast through Tuesday. The
combination of elevated instability and moisture will support
showers and isolated thunderstorms in the forecast for Monday and
By Wednesday the subtropical link moves to the west and the monsoon
moisture slides to the east leaving clearing skies over the
forecast area for the remainder of the forecast period. Onshore
winds and morning low clouds will help to maintain near normal
temperatures for the remainder of the week as well.
Aviation...as of 10:30 PM PDT Sunday...radar is quiet so looks
like the threat for showers is over for tonight. Stratus
continues near the coast and can be seen spreading inland through
a few of the coastal gaps. So stratus is more likely to spread
into sfo and the approach later tonight.
Vicinity of ksfo...MVFR/IFR ceilings after 10z.
Ksfo bridge approach...MVFR/IFR ceilings after 09z.
Monterey Bay area terminals...stratus covers the entire mry Bay
area. IFR ceilings through 18z.
Marine...as of 10:45 PM PDT Sunday...shower and thunderstorm
activity has diminished for the night. Another surge of middle and
high level moisture will bring thunderstorm chances Monday
afternoon through Tuesday. Otherwise light north to northwest
winds and seas will continue into early next week.
Public forecast: Larry
aviation/marine: west pi
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