Scientific Forecaster Discussion

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Area forecast discussion 
National Weather Service San Francisco Bay area
236 PM PDT Sat Apr 19 2014

Synopsis...dry and mild weather will continue through Monday
afternoon. A weak storm system will impact the area Monday night
through Tuesday with a chance for light rain. Dry weather and
near normal temperatures return for the balance of the work week.

&&

Discussion...as of 02:30 PM PDT Saturday...sunny skies across the
area this afternoon except for patchy low clouds along portions of
the coast. A weak cold front is impacting the coast north of Point
Arena at this hour however ridging over the southern half of the
state will keep all but some increased cloud cover to the north.
Temperatures are fairly similar to yesterday in the middle to upper
60s...cooler near the coast.

Ridging continues to build over the area tomorrow increasing 850 mb
temperatures and decreasing the onshore pressure gradient. Widespread 70s
and low 80s are forecast away from the immediate coast.

Monday night into Tuesday another frontal system moves through
northern California. Rainfall is forecast to be very light with
this system. The GFS and European model (ecmwf) are hanging on to up to a tenth of
an inch at most in the northern reaches of Sonoma County while
the 12z NAM depicts barely any measurable precipitation. Have reduced quantitative precipitation forecast
in agreement with cnrfc to several hundredths total at most.
Temperatures cool quite a bit Tuesday as the cooler airmass
settles in.

Dry weather sets up and temperatures rebound Wednesday and Thursday as a
low amplitude ridge moves through ahead of another storm system.
Medium range models have been consistent in an end of the week
storm having a more significant impact. Gefs ensembles have over
90 percent probability of over a tenth of inch of rain in San
Francisco.

&&

Aviation...as of 10:50 am PDT Saturday...satellite imagery shows
that low clouds have cleared from all terminal sites. There are a
few high clouds streaming across the state at this time...and low
clouds off the coast. Expect low clouds to form again tonight.

Vicinity of ksfo...VFR today and tonight. Gusty west winds 20-28
knots are forecast for this afternoon and evening.

Ksfo bridge approach...similar to ksfo.

Monterey Bay area terminals...VFR. Expect MVFR conditions again
late tonight.

&&

Marine...as of 10:50 am PDT Saturday...gusty northwest winds in
the Small Craft Advisory criteria are still expected in the
southern waters today and tonight.

A high surf advisory has been issued from 5 am Sunday to 5 am Monday
morning for the coast from Sonoma County south to Monterey County.
Northwest swell will build to 13 to 15 feet with swell periods 15 to
16 seconds.

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Mtr watches/warnings/advisories...
... Surf advisory...the entire coast
Small Craft Advisory...pt pinos to pt Piedras Blancas 0-10 nm
Small Craft Advisory...pt pinos to pt Piedras Blancas 10-60 nm

&&

$$

Public forecast: ac
aviation/marine: Sims

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