Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Francisco Bay area
401 am PST Sat Feb 13 2016
..warm weather to return tomorrow through Tuesday...
Synopsis...dry weather will continue through the weekend and
into early next week. Patchy fog and low clouds will continue in
coastal areas through the morning. Otherwise...mostly clear skies
are expected into early next week. Offshore flow will develop by
Sunday morning which will result in a warming trend from Sunday
into Tuesday. Rain is possible by the middle of next week. Large
long-period westerly swell will continue to impact the coast
through this evening...creating hazardous conditions at area
beaches...including sneaker waves.
Discussion...as of 3:00 am PST Saturday...satellite and observation shows
some patchy fog across our County Warning Area early this morning. Similar to
yesterday expect the fog to burn-off fairly fast with party to
mostly sunny conditions by the afternoon for all locations. One
minor difference from Friday is the addition of fog for some
inland valley locations. Observation indicate that fog has moved into part
of North Bay, sf Bay, Santa Clara Valley, and Salinas valley.
Highs are expected to mostly be in the middle 60s to the lower 70s.
Temperatures will start to warm on Sunday as a ridge of high
pressure builds back into our region. Guidance continues to
suggest that the warmest readings will be on Monday as the ridge
axis GOES overhead and both 500 mb heights and 850 mb temperatures peak.
Models have slightly backed off from the 500 mb heights, with 850
mb temperatures still forecast to peak around 17c. Therefore, forecast
highs were slightly lowered. However, still looks like a few
record highs may be set.
After another round of warm readings on Tuesday, cooler weather
will return back to our region as a longwave trough advances to the
coast. As was mentioned in the past couple of discussions, the
operational GFS has been bouncing around from fairly wet to mostly
dry while the other models plus ensembles have been more bullish
with rain chances. Latest models continue the trend with the 06z
GFS now favoring rain for our region. Therefore, probability of precipitation were
increased to the likely category for most of the County Warning Area. Rainfall
amounts are forecast to range from 1/2" to 1" for the coastal
hills with 1/4" to 1/2" for the rest of our area. Start time will
be late on Wednesday or early Thursday with the majority of rain
forecast to fall on Thursday. A few showers are possible going
Dry weather will return late Friday and likely continue for
several additional days.
Aviation...as of 3:50 am PST Saturday...patchy low clouds have
developed over inland areas as well as along the coast. High
clouds embedded in the southwesterly flow aloft will continue to
stream across the region this morning. Localized reductions in
slant- wise visibility possible around sunrise...as a result of
hazy and stable weather conditions. Light to locally moderate
winds persist through today. Winds will pick up slightly this
afternoon. Moderate to high confidence.
Vicinity of ksfo....IFR ceilings will come in and out through the
early morning before scattering out around 16z. Moderate west
winds will ease this morning then increasing again this afternoon.
Sfo bridge approach...similar to ksfo.
Monterey Bay area terminals...vlifr conditions expected to persist
till around 17z. Light winds will prevail through the morning then
increase this afternoon.
Climate...here is a list of record high temperatures from Sunday
February 14 through Tuesday February 16. The record high is listed
for each day along with the year the record was set (if the record
was set on more than one year...the most recent year is listed).
Sunday Monday Tuesday
location Feb 14 Feb 15 Feb 16
San Francisco Bay area...
Kentfield 84/1930 79/1930 77/1930
San Rafael 78/1977 78/1977 77/1977
Napa 81/1930 81/1943 81/1930
San Francisco downtown 78/1930 76/1930 75/1930
San Francisco Airport 74/1977 75/2015 69/2007
Oakland museum 80/1977 80/2015 75/2015
Oakland Airport 72/2013 73/1977 73/1977
Richmond 77/1977 75/1977 75/2015
Livermore 79/1977 80/1933 78/1977
Moffett field 82/1977 79/1977 73/1977
San Jose 80/1930 80/1930 78/1930
Gilroy 80/1996 81/1991 81/1977
Monterey Bay area...
Monterey 81/1943 79/1977 73/2013
Santa Cruz 82/2015 82/1916 85/1930
Salinas 83/2015 81/2013 80/1977
Salinas Airport 84/2015 81/2015 77/2013
King City 85/1977 86/1977 90/1977
Marine...as of 2:56 am PST Saturday...high pressure
strengthening over the eastern Pacific will gradually strengthen
through the weekend resulting in moderate to strong northwesterly
winds across the coastal waters. A large long period westerly
swell will continue into through today then gradually diminish. A
cold front will approach the coastal waters by late Wednesday or
... Surf advisory...all coastal locations through 8pm
Small Craft Advisory...Pigeon pt to pt pinos 0-10 nm
Small Craft Advisory...pt Arena to Pigeon pt 10-60 nm
Small Craft Advisory...pt pinos to pt Piedras Blancas 0-10 nm
Small Craft Advisory...Pigeon pt to pt Piedras Blancas 10-60 nm
Small Craft Advisory...pt Arena to pt Reyes 0-10 nm
Small Craft Advisory...pt Reyes to Pigeon pt 0-10 nm
Small Craft Advisory...rough bar advisory for sf bar
Public forecast: Bell
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