Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Francisco Bay area
250 PM PDT Friday Aug 22 2014
Synopsis...night and morning low clouds and slightly below
normal afternoon high temperatures are forecast through the
weekend. Warmer temperatures are possible inland by the middle of
Discussion...as of 3:00 PM PDT Friday...as expected mostly sunny
conditions across our County Warning Area except right at the coast from San Mateo
County northward with temperatures running close to what we saw on
Thursday. Right now inland locations are mostly in the middle 70s to
middle 80s with upper 60s to middle 70s at most coastal spots. Still
have plenty of clouds out over the water and with a favorable
westerly surface flow tonight plus a marine layer around 1500
feet, would expect clouds to return for many spots along with
patchy fog and some coastal drizzle.
For the weekend into the first part of next week, temperatures
will only vary by a few degrees each day as two upper level
systems rotate through to our NE which will keep US in a stable
northwest flow aloft. Temperatures may even a bit cooler than normal in this
setup for far inland locations that will often be into the 90s for
this time of year. Near the coast the warmer than normal SST
readings plus plenty of sunshine should help to keep temperatures at or
above normal for some spots. Only real item of concern will be
locally breezy and drier NE winds that are expected for Saturday
as the upper low moves into northern Nevada and a ridge of high
pressure at the surface builds to the north. This will create
elevated fire weather concerns.
For the second half of next work week, warming is forecast as a
ridge of high pressure builds back across our area. 850 mb temperatures
will increase to the 21-22c range (or a 2-3c increase from our
current values). Closer to the surface this will translate into
80s and 90s inland with upper 60s to upper 70s at the coast.
Finally, interesting to note that the operational GFS (plus around
30 percent of naefs members) brings subtropical moisture from
Tropical Storm Marie across the North Bay and northern California
for next weekend. At this time, this is not the favored solution.
Instead, CPC 6-10 and 8-14 day forecasts both keep the rain well
out of our area which is what the operational Gem and European model (ecmwf)
Aviation...as of 10:30 am PDT Friday...morning stratus is
starting to clear back to the coast. Look for afternoon seabreeze
winds and low clouds spreading back inland overnight.
Vicinity of ksfo...VFR today. Low clouds reforming after midnight. The
seabreeze will reach 15 to 20 knots this afternoon.
Ksfo bridge approach...similar to ksfo.
Monterey Bay area terminals...VFR. Low clouds reforming during the
evening. Seabreeze winds expected to reach 10 to 15 knots this
Marine...as of 3:00 PM PDT Friday...generally light to moderate
winds will continue across the coastal waters through much of the
forecast period. Strongest winds are expected over the northern
waters. A moderate period southerly swell...generated by tropical
storms...will continue into early next week.
... Arena to pt Reyes 10-60 nm
Small Craft Advisory...pt Arena to pt Reyes 0-10 nm until 3 am
Small Craft Advisory...pt Reyes to Pigeon pt 0-10 nm from 9 PM until 3 am
Small Craft Advisory...sf Bay north of the Bay Bridge until 10 PM
Small Craft Advisory...pt Reyes to Pigeon pt 10-60 nm until 10 PM
Public forecast: Bell
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