Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Francisco Bay area
936 PM PST Friday Feb 12 2016
..warm weather to return Sunday 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 Saturday 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 Saturday...creating hazardous conditions at area
beaches...including sneaker waves.
Discussion...as of 8:55 PM PST Friday...light onshore flow
resulted in slight cooling in most areas today. But a few
locations were as warm or even a bit warmer than yesterday and all
locations remained warmer than average today.
A weather system currently moving over the ridge and through the
Pacific northwest will suppress the ridge for one more day. Light onshore
flow will continue into Saturday along with patchy morning fog and
low clouds near the ocean. Patchy dense fog is likely in coastal
areas early on Saturday. Little change is expected in our
temperatures on Saturday.
The upper ridge will rebuild just offshore from late tomorrow
through Monday...with 500 mb heights forecast to increase to about
585 dm over our area by Monday morning. In addition...surface
high pressure will build to our north and east and result in the
development of moderate offshore flow across our region by Sunday
morning. Locally gusty north to northeast winds are expected in
the hills from late Saturday night through Monday. The combination
of a building ridge aloft and offshore flow will mean warmer temperatures
from Sunday through Tuesday. The warmest day will probably be
Monday when highs are forecast to be in the 70s to lower 80s.
Offshore flow will weaken by Tuesday which may mean slight cooling
near the coast...but inland areas will remain warm into Tuesday.
Record highs are possible early in the week. A complete list of
record highs for Sunday through Tuesday is included in a climate
section below. Some of the record highs during these three days
were set just last year.
There appears to be a reasonably good chance that wet weather will
return our area around the middle of next week. The European model (ecmwf) has
been consistent in forecasting widespread rainfall across our
region from late Wednesday into Thursday. The GFS has not been as
consistent with the midweek system...with the 12z GFS backing off
considerably on rainfall potential. However...the 12z GFS ensemble
mean still looked promising for wet weather and the 00z
operational GFS is just in and it has trended slightly wetter.
The midweek system may be our only chance at widespread rainfall
for the foreseeable future as the longer range models suggest
ridging redeveloping out near day 10. In addition...the climate
prediction center's 8-14 day indicates below normal precipitation across
all of California.
Aviation...as of 9:35 PM PST Friday...coastal stratus will
continue to fill in along the coast. High clouds embedded the
southwesterly winds aloft will continue to stream across the
region through tonight. Localized reductions in slant-wise
visibility possible around sunrise...as a result of hazy and
stable weather conditions. Patchy low clouds and patchy fog
expected to develop tonight/early Saturday morning over the North
Bay as well as over Monterey Bay terminals. Moderate west to
northwest winds will ease overnight becoming mainly light and
variable. Moderate to high confidence.
Vicinity of ksfo....VFR. Moderate west winds will ease overnight becoming
light and variable overnight.
Sfo bridge approach...similar to ksfo.
Monterey Bay area terminals...patchy low clouds and fog
anticipated to return to area terminals early Saturday morning.
Have included tempo ceilings between 13z-17z. Light and variable Wills
will prevail overnight. Moderate confidence.
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 09:29 PM PST Friday...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 Saturday then gradually diminish. A cold front will
approach the coastal waters by late Wednesday or Thursday.
... Surf advisory...all coastal locations through
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...Pigeon pt to pt pinos 0-10 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 Pigeon pt 10-60 nm
Small Craft Advisory...rough bar advisory for sf bar
Public forecast: dykema
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