Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Francisco Bay area
312 am PDT Thursday Aug 21 2014
Synopsis...warmer temperatures are expected away from the coast
the next few days. Otherwise little change is forecast through the
weekend with continued below normal temperatures expected...especially
for inland areas. Much warmer inland temperatures are possible by
the middle of next week.
Discussion...as of 3:00 am PDT Thursday...southerly flow in the
low levels has caused stratus to pile up in the North Bay this
morning. Local drizzle is possible in these areas during the early
morning hours. The marine layer is steadily compressing as upper
low over Southern California moves east and upper level high
over the eastern Pacific nudges into the state. This will allow
for more afternoon clearing and about 4-8 degrees of warming inland
on Thursday. Another upper trough will deepen over the Pacific
northwest tonight and Friday and will maintain a marine layer of
1500-2000 feet over the area. Upper level troffing will continue
over the Pacific northwest through the weekend behind the
original upper trough. As a result temperatures will cool off
slightly Friday through Sunday and be near or slightly below normal.
Previous model runs suggested significant warming around next
Tuesday as upper level high from the eastern Pacific moves
over the state. The latest models maintain this scenario except
the European model (ecmwf) holds off the heating until Wednesday. So the extended
forecast still calls for several degrees of warming for the
middle of next week.
Aviation...as of 10:45 PM PDT Wednesday...a moderately deep marine
layer and onshore winds will usher the stratus clouds back inland
Vicinity of ksfo...stratus forecast to arrive overnight. VFR
returns by late morning. West wind gusts should stay below 20
knots Thursday afternoon and evening.
Ksfo bridge approach...similar to ksfo.
Monterey Bay area terminals...low clouds tonight will scatter out
by late Thursday morning.
Marine...as of 3:00 PM PDT Wednesday...moderate northwesterly
winds expected across the northern outer waters tonight and over
portions of San Francisco Bay this afternoon. Otherwise generally
light winds and seas will continue. A moderate period south swell
will move into the region later this week due to storms in the
... Arena to pt Reyes 10-60 nm until 3 am
Small Craft Advisory...sf Bay north of the Bay Bridge from 2 PM
Public forecast: west pi
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