Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Francisco Bay area
453 PM PDT Friday Oct 9 2015
Synopsis...dry weather with near normal to above normal
temperatures will continue into early next week. A low pressure
over northern Mexico will move west out over the Pacific waters
and may be a factor in our weather as early as Wednesday.
Discussion...as of 3:00 PM PDT Friday...a bit of a surprise
today as temperatures in many spots are actually running slightly
behind values from Thursday. Main reason may be due to the
slightly stronger onshore flow today (1.3 mb from the west
compared to just 0.4 mb) which has brought across a little more
ocean-cooled air to our region. Overall still should end up being
warmer than normal for most spots with a wide range -- 60s and 70s
at the coast with 80s to lower 90s inland. Lows tonight will most
be in the 50s to middle 60s with a few spots in the North Bay
forecast to drop into the upper 40s. Some fog may also for
overnight especially near the coast and into sf Bay.
The ridge of high pressure overhead will flatten over the weekend
leading to some minor cooling across our entire region although
man spots will remain a bit warmer than normal. Skies will remain
mostly sunny during the day with many areas staying clear
An upper level low well to our south will slowly meander to in a
clockwise fashion all next week which will put the center of
circulation just to the south of our County Warning Area by Thursday. Moisture
associated with the low will rotate from the southeast toward our
area and possibly bring a few showers into the souther part of our
County Warning Area. In general the models have been trending a bit dryer with the
system so probability of precipitation were kept at 20 percent or less.
Longer range outlook off the operational GFS continues to show a
wet system brining rainfall to our area (especially north of
Monterey bay) out in days 9 and 10. The operational European model (ecmwf) also
bring a system to the pacnw/norcal coast during a similar time
although with less rainfall. Will keep an eye on how it plays out.
Aviation...as of 4:42 PM PDT Friday...high confidence VFR
through the evening. Band of low clouds seen on visible imagery
from the Pacific northwest to the northern California coastal waters is
slowly progressing eastward...but the leading edge of clouds is
also tending to dissipate. Minor influx of marine based clouds
possible late tonight into Saturday morning as light onshore winds
continue and night-time cooling enhances above mentioned cloud
layer. VFR at all area terminals by late Saturday morning.
Vicinity of ksfo...VFR. Westerly wind gusts to 20-25 knots until
Ksfo bridge approach...similar to ksfo.
Monterey Bay area terminals...VFR. IFR ceilings developing between
06z-08z. VFR returns by late Saturday morning.
Marine...as of 3:00 PM PDT Friday...gradually increasing winds
today and through the week with the strongest winds expected along
the Big Sur coastline and southward. A moderate period west to
southwesterly swell generated by hurricane oho will enter the
waters this evening...lasting into the weekend.
... Pinos to pt Piedras Blancas 0-10 nm until 2 am
Public forecast: Bell
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