Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Francisco Bay area
1001 PM PST Monday Nov 30 2015
Synopsis...a weak weather system will leave behind some middle level
clouds through tonight. High pressure returns Tuesday and
Wednesday with dry and seasonable weather. A fast moving cold
front will arrive Thursday bringing a round of rain and wind to
the Bay area. Dry weather quickly returns Friday and Saturday
before the next chance of rain arrives Sunday or Monday.
Discussion...as of 9:00 PM PST Monday...a frontal system
dissipated as it moved over the area today but managed to drop
light sprinkles or rain showers during the afternoon hours. Parts
of the North Bay and sfo Bay area received measurable rain with
amounts less than .05 inches. Only trace amounts fell elsewhere.
Low and middle level moisture will linger over the area through
tonight but models are in agreement that the precipitation is over with.
Overnight lows will be 3-5 degrees warmer due to the cloud cover so
the string of cold nights will end.
A weak ridge of high pressure will move over the area Tuesday and
Wednesday. Drier air will bring clearing at the lower levels on
Tuesday while high clouds from the next system will be moving into
the area. Temperatures will trend warmer Tuesday and Wednesday.
The next system will slow down as it deepens off the coast so rain
from this system will hold off until Thursday. The system is
forecast to become negatively-tilted which is less favorable for
orographics. Rainfall amounts are expected to be 0.25-0.75 across
the district except less than .25 inches over the southern
After a few showers Thursday night dry weather returns Friday and
Saturday as the system moves rapidly inland and upper level ridge
returns. Medium range models indicate another chance for rain
around Sunday and another possibly middle of next week. Neither of
these systems look very wet at this point.
Aviation...as of 9:50 PM PST Monday...VFR conditions expected to
continue through tonight with middle and upper level clouds. Ksts
anticipated to see LIFR ceilings around 400 feet after 10z as a
result of lingering low level moisture. Winds will be light
offshore or locally variable tonight.
Vicinity of ksfo...VFR conditions through tonight. Mainly high
ceilings and light offshore flow.
Ksfo bridge approach...similar to ksfo.
Monterey Bay area terminals...VFR conditions through tonight. Mainly
high ceilings and light offshore flow.
Marine...as of 8:57 PM PST Monday...light to moderate winds will
continue through midweek over the coastal waters. Winds will
increase Wednesday night and Thursday as a storm system approaches
the region. A longer period swell will also impact the coastal
waters tonight. The period will gradually decrease through the
week...but a larger swell will arrive late in the week.
Public forecast: west pi
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