Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Francisco Bay area
936 am PST Thursday Feb 11 2016
Synopsis...dry weather will continue through the rest of the
week. Large westerly swell will begin to impact the coast today
raising the risk of sneaker waves at area beaches.
Discussion...as of 8:40 am PST Thursday...high clouds currently
streaming across most of our County Warning Area this morning. Should see break
throughout the day with highs forecast to be mostly 65 to 70 for
the North Bay, and upper 60s to middle 70s for the rest of the County Warning Area.
Outside of the high surf, no weather related hazards.
Latest guidance in continues to show quiet weather at least into
Tuesday with normal to above normal temperatures. Rain will return
Wednesday into Thursday. Current forecast appears on track with no
major updates planned.
Previous discussion...satellite imagery is currently showing a
mixture of low and high clouds over the district. Area surface
observations are not yet indicating any fog...however the temperature/dew
point spreads are once again narrowing to just a few degrees
..and there is fog developing in the San Joaquin Valley. High
clouds moving over the northern half of the district are keeping
temperatures a little warmer as compared to 24 hours ago...with
readings generally in the upper 40s to middle 50s. Offshore flow
still persists...with current surface pressure gradients of 6.2
between wmc and sfo...and 0.8 from SAC to sfo. After morning
patchy fog clears...expect high temperatures to warm to the 60s
The high pressure ridge over the western states will continue to
weaken with a gradual cooling trend extending through Saturday.
High pressure is prognosticated to rebuild off the West Coast for warming
conditions beginning on Sunday and continuing through early next
By midweek...an upper level trough approaching the coast will
bring rain chances back to the area. The 00z European model (ecmwf) spreads rain
across the entire County Warning Area beginning Wednesday night with showers
persisting into Thursday night as the trough moves through.
The 00z GFS brings rain in a little sooner...by midday Wednesday.
The current forecast reflects this GFS solution more closely with
the earlier precipitation. Much cooler temperatures are also expected on
Wednesday with this system.
Aviation...as of 9:35 am PST Thursday...high clouds are expected
to continue through most of the day although they should not cause
any aviation impacts. Winds will generally stay under 12 kts.
Vicinity of ksfo...VFR through the day with winds of 280 to 300 up
to 10 knots forecast for the afternoon into the early evening. High
Sfo bridge approach...similar to ksfo.
Monterey Bay area terminals...keeping a close eye on clouds still
well off the coast. WRF indicates they could make to kmry after
10z and likely not to ksns at all. For now went VFR through 10z
before bringing in ceilings at 010. Winds at kmry and ksns expected to
be under 10kt through the day. Medium confidence due to potential
Marine...as of 09:27 am PST Thursday...northwest winds will
increase through the weekend with the exception of the northern
outer waters where southwest winds will prevail. A large long
period northwest swell will begin to move into the area today and
persist into the weekend. This large swell will result in very
large breaking waves near offshore reefs and sand bars.
... Surf advisory...all coastal areas starting at noon.
Public forecast: Bell/Sims
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