Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Francisco Bay area
1102 PM PDT sun may 24 2015
Synopsis...after a couple more days of cooler than normal
temperatures...warmer weather is expected during the second half
of the week...especially for inland areas. However...coastal
areas will remain seasonably cool as onshore flow persists.
Discussion...as of 8:25 PM PDT Sunday...except for some inland
valley and higher elevation locations...the expected warming did
not materialize today as moderate onshore flow continued to advect
cool marine air inland. In addition...a deep marine layer
resulted in slow clearing inland and little or no coastal
Little change is expected over the next couple of days.
Temperatures will hold near persistence or even cool slightly as
an upper low settles in the Pacific northwest. This troughing to
our north may act to deepen an already deep marine layer. In
addition...little change is expected in the strength of onshore
flow. High temperatures will remain anywhere from two to ten
degrees below normal. Widespread night and morning low clouds will
persist and many coastal areas will remain under the clouds
throughout the day on Monday and Tuesday.
The upper level ridge currently centered offshore along 135w is
forecast to shift eastward by midweek. Both the GFS and European model (ecmwf)
forecast the ridge axis to be aligned along the West Coast by late
Thursday. This will result in warming trend from Wednesday through
Friday. Most of the warming will occur across inland areas where
high temperatures will warm into the 80s in some spots for the
first time in nearly 4 weeks. Coastal areas will remain relatively
cool...however...as onshore flow persists. The marine layer will
become more shallow...but is expected to remain entrenched near
Aviation...as of 11:00 PM PDT Sunday...for 06z tafs. Stratus has
filled in across all terminals. Partial clearing is expected again
Monday. Ksfo and koak along with Monterey Bay terminals are not
expected to clear but rather will see ceilings lift temporarily in
the afternoon. Light to locally moderate onshore flow will
continue through tonight.
Vicinity of ksfo...MVFR ceilings will lower to IFR overnight. Ceilings
will lift after 20z Monday but area terminals are not expected to
clear. Light to locally moderate onshore flow will prevail.
Ksfo bridge approach...IFR ceilings around 1000 feet expected overnight.
Ceilings will clear from the south Monday morning but area terminals
will remain overcast around 1500 feet through the afternoon.
Monterey Bay area terminals...IFR ceilings will persist through the
tonight. Ceilings will lift after 18z-19z Monday but area terminals are
not expected to clear. Light onshore flow will prevail.
Marine...as of 10:40 PM PDT Sunday...northwesterly winds will
continue across the ocean waters through tonight. Winds will ease
on Memorial Day into Tuesday with fairly light seas. Some slightly
stronger northwest winds will return by late in the week but in
general expect a prolonged period of generally light wind and
... Arena to pt Reyes 10-60 nm
Public forecast: dykema
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