Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Francisco Bay area
513 PM PST sun Jan 25 2015
Synopsis...dry weather and unseasonably warm temperatures will
persist through Monday as the region remains under a strong ridge
of high pressure. A weak storm system will then approach Southern
California Monday night into Tuesday and bring a chance of light
precipitation to the central coast.
Discussion...as of 2:48 PM PST Sunday...fog has cleared from all
areas in the County Warning Area...but even with afternoon sunshine...areas around the
greater San Francisco Bay have been very slow to warm up. The
coolest location as of 2 PM was Napa Airport at a clammy 54
degrees. Oakland and Hayward are 13 and 15 degrees cooler than
yesterday at this time...and are struggling to get out of the 50s.
The difference is in the wind. Yesterday much of the area
experienced down-sloping offshore winds while today winds have
switched to a light sea breeze. Meanwhile...locations from the
Monterey Bay southward have warmed to the the upper 70s and 80s.
Currently Watsonville and Salinas are reporting 80 and 81 degrees
respectively...and the high so far today at the weather office in
Monterey has been 77 degrees. Right now the only locations that
are in jeopardy of breaking high temperature records are in
Monterey or Santa Cruz counties. 2 PM temperatures at sfo and mry
airports are 23 degrees apart: 57 versus 80.
Beginning tomorrow the upper ridge will begin to weaken and shift
eastward as a disturbance over Southern California and Arizona
begins to move to the north and into central California. This is
expected to advect some moisture into the southern zones...thus a
slight chance of light rain is possible across mainly the southern
half of the district on Tuesday morning. By later in the day the
disturbance will eject to the east and shower chances will end.
Dry and mild conditions are indicated for the rest of the week as
the area remains under weak high pressure. Temperatures are
expected to warm again by the end of the week.
Aviation...as of 5:00 PM PST Sunday...offshore flow weakening but
airmass remains dry enough for VFR conditions. Central Valley fog
may still impact the interior north and East Bay valleys late
tonight. High clouds will move in from the south by Monday morning.
Vicinity of ksfo...VFR. Light offshore winds.
Ksfo bridge approach...similar to ksfo except areas of 5-6 mile
visibility in haze.
Monterey Bay area terminals...VFR.
Climate...record high temperatures are possible over the area today.
Here is the list of records along with the January warmest high
temperature readings and the latest year they occurred.
Sf Bay area...
Location today (1/25) January warmest
Kentfield 77/1934 79/1962
San Rafael 70/2014 82/1962
Napa 83/1899 85/1962
San Francisco 74/1899 79/1962
sfo Airport 68/2011 73/2014
Oakland 73/2014 78/2014
Oak Airport 70/2014 77/2014
Richmond 69/2011 76/1962
Livermore 73/1911 77/1911
Mountain View 72/2014 76/1948
San Jose 71/2014 79/1962
Gilroy 77/2014 80/2014
North central coast...
Monterey 78/1942 84/2014
Santa Cruz 80/1899 84/2014
Salinas 78/2014 87/2014
sns Airport 78/2014 86/2014
King City 77/2014 86/1976
Marine...as of 2:19 PM PST Sunday...light offshore flow near the
coast with southerly flow further offshore due to high pressure
over the Great Basin over the next 24 hours. Winds veer to the
south Tuesday with northerly winds returning late Wednesday.
Northwest swell will gradually diminish through the upcoming week.
Public forecast: Sims
aviation: west pi
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