Area forecast discussion 
National Weather Service San Francisco Bay area 
359 PM PST sun Dec 21 2014 


Synopsis...light rain and drizzle will diminish through the 
overnight hours as high pressure builds over the eastern Pacific. 
Higher than average tides will result in minor coastal flooding 
over the next several days. Temperatures warm through midweek 
before a storm brushing the area brings temperatures back down to 
seasonal normals. 


&& 


Discussion...as of 3:00 PM PST Sunday...moist flow remains across 
our entire County Warning Area this hour with many spots seeing dew points of 55 
to 60 and relative humidity readings of 80 to 95 percent. In addition...latest 
one hour rainfall totals shows quite a few spots in our area 
reporting tips. Decided to just do a minor grid update to add 
drizzle to all locations along with a slight chance of rain for 
much of the North Bay. 


A ridge of high pressure will build into California over the next 
several days allowing for warming along with dryer conditions and 
fewer clouds each day. Tuesday appears to be the warmest of the week 
as 850 mb temperatures jump from by about 8c to the 15-16 range on 
Tuesday and the ridge axis GOES across. With plenty of sunshine 
highs will move into the middle 60s to lower 70s. 


Cooler weather will return along with a very slight chance for 
showers Wednesday (christmas eve) as an inside slider skirts close 
to tthe northern portion of the County Warning Area. Any rainfall should be very 
light with the larger impact being temperatures cooling back 
closer to normal. Overnight lows are also expected to drop due to 
drier air. We will likely see 30s back in Interior Valley 
locations. 


Longer range guidance favors drier than normal conditions out to 
January 4th. Currently no sign of any major storms impacting our 
area the next two weeks. 


&& 


Aviation...as of 3:57 PM PST Sunday...high pressure will build 
over norcal during the period. There's plenty of leftover surface 
to low level moisture and increasing air mass stability will lead 
to areas of IFR ceilings and visibilities. Low level winds become 
more northerly late tonight through Monday which should help with 
clearing on Monday. 


Vicinity of ksfo...IFR ceiling presently reported and forecast to 
continue through 03z. MVFR 03z-09z followed by IFR. 


Ksfo bridge approach...similar to ksfo. 


Monterey Bay area terminals...MVFR...but localized IFR possible through 
the evening. Light winds. 


&& 


Marine...as of 3:00 PM PST Sunday...northwest winds will 
gradually increase over the southern and outer waters through 
tonight and persist on Monday as high pressure builds off the 
California coast. King tides will impact the coast and inland bays 
through Tuesday. King tide impacts for seafaring vessels will 
occur primarily during low tides...with the possibilities of boat 
keels touching Harbor bottom...strong currents in Harbor 
entrances...and additional breaking waves over offshore reefs. 
&& 


Mtr watches/warnings/advisories... 
... Flood Advisory...coastal and Bay Shore areas 
Small Craft Advisory...pt pinos to pt Piedras Blancas 0-10 nm 
Small Craft Advisory...pt pinos to pt Piedras Blancas 10-60 nm 
Small Craft Advisory...Pigeon pt to pt pinos 10-60 nm from 3 am 
Small Craft Advisory...rough bar advisory for sf bar until 8 PM 


&& 


$$ 


Public forecast: Bell 
aviation: canepa 
marine: rgass 


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