Area forecast discussion
National Weather Service San Francisco Bay area
858 PM PDT Monday Jun 17 2013
Discussion...as of 9:00 PM PDT Monday...an upper level low approaching
the Pacific northwest brought cooler temperatures to the area
today. Highs today were about 5 degrees cooler than Sunday. With
the cooler air aloft and strong northwest pressure gradient...the
marine layer is not well defined. As a result stratus will only be
areal in coverage tonight and there could be patchy drizzle
along the coast. 500 mb heights drop some more on Tuesday as the
upper low approaches the Oregon coast so there will be a few
degrees more cooling.
The upper trough axis will swing inland on Wednesday bringing
warmer temperatures to the area. An upper level ridge starts to
build off the California coast Thursday through Saturday for
warmer temperatures. Because the upper trough will remain over the
Great Basin...northwest flow will persist and inland temperatures
are not going to get very warm with highs in the middle 80s to lower
90s in the north and East Bay interior and lower to middle 90s over
the southern interior.
From previous extended...European model (ecmwf) tries to build a warm ridge over the
state from the south next week while the GFS and Gem keep the
influence of the upper trough off the Pacific northwest coast in charge.
&&
Aviation...as of 5:10 am PDT Monday...skies remain mainly clear
over area terminals with the exception being ksfo that currently
has a broken ceilings of 1000 feet. Temporary clearing possible but
am going pessimistic with a prevailing ceilings through the evening.
Gusty winds will prevail across the region this evening into late
tonight as the onshore gradient from sfo-SAC has increased to over
5 mb. Stratus is expected to return over most area terminals
tonight with clearing anticipated between 16z-18z Tuesday morning.
Vicinity of ksfo...ceilings have already returned over ksfo with only
a slight possibility of the stratus pulling back temporarily this
evening. As stated above have gone pessimistic with this evenings
forecast and have kept prevailing ceilings in through this evening.
Gusty winds will also prevail this evening and through late
tonight as a strong onshore gradient continues.
Ksfo bridge approach...1000 foot ceilings will slowly fill into the
Bay this evening affecting the approach by 01z-02z. An early
clearing is in store again Tuesday with the bridge scattering out
around 15z. Gusty winds will persist through this evening then
gradually diminish overnight.
Monterey Bay area terminals...VFR through this evening with ceilings
returning around 03z over kmry. Ceilings will return over ksns after
midnight tonight. Clearing is expected around 16z over ksns and
18z over kmry. Gusty winds will continue through this evening then
diminish after sunset.
&&
Mtr watches/warnings/advisories...
... Pinos to pt Piedras Blancas 0-10 nm
Small Craft Advisory...sf Bay until 11 PM
Small Craft Advisory...Pigeon pt to pt Piedras Blancas 10-60 nm
&&
$$
Public forecast: west pi/rww
aviation/marine: CW
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