Area forecast discussion
National Weather Service San Francisco Bay area
1029 am PDT sun may 19 2013
Discussion...as of 9:05 am PDT Sunday...skies are mostly clear
across the region this morning as northerly flow mixes drier air
into the boundary layer. One patchy of low clouds remains in
Monterey Bay...from Moss Landing southwest to the Monterey
peninsula. These clouds should clear by late morning. Light
offshore flow should then keep skies clear across our entire
forecast area through at least Monday evening.
Temperatures are running at least a few degrees warmer compared to
24 hours ago...and up to 10 degrees warmer in the North Bay...as
subsidence warming increases under a building upper ridge. Afternoon
highs will be several degrees warmer today compared to yesterday
and about five degrees warmer than normal. The warming trend will
continue into Monday as the ridge axis moves inland over
California and weak offshore flow develops. Highs on Monday will
warm into the 70s near the ocean...80s around San Francisco
Bay...and low to middle 90s in the inland valleys.
Northerly winds will increase in the hills late today and reach
their peak overnight tonight with local gusts up to 40 miles per hour
possible in the north and East Bay hills. These winds...combined
with warm and dry conditions...will increase fire weather
concerns. However...this will be a short-duration event with winds
expected to rapidly decrease on Monday. Thus...red flag warnings
will not be needed.
A significant change in the weather is forecast Tuesday and
Wednesday as a cold upper trough plunges southeast out of the Gulf
of Alaska and into northern California. Strong and gusty northwest winds
will develop by late Tuesday afternoon as the initial shortwave
moves through. Winds near the coast and in the coastal hills may
be strong enough by late Tuesday to warrant wind advisories. Will
look at this more closely for the afternoon forecast package.
High temperatures will drop sharply on Tuesday as a much cooler
airmass begins to overspread the area and strong onshore flow
develops. Only the far southern interior will remain relatively
warm on Tuesday. But by Wednesday all areas will see temperatures
well below normal. Cool conditions will then continue through the
end of the week as an upper trough remains near the West Coast.
&&
Aviation...as of 10:25 am PDT Sunday...VFR conditions will
prevail through the forecast. Offshore drying winds this morning
will turn onshore by the early afternoon hours and continue into
the evening hours.
Vicinity of ksfo...VFR conditions through the forecast. Moderate
to strong west winds will be present this afternoon and
evening...with wind gusts to 30 knots possible. Moderate confidence.
Ksfo bridge approach...similar to ksfo.
Monterey Bay area terminals...VFR conditions will prevail through
at least 06z. Patchy stratus will be possible early this evening
at kmry...similar to the past few evenings. Otherwise...moderate
onshore winds this afternoon.
&&
Mtr watches/warnings/advisories...
... 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...sf Bay from 1 PM
Small Craft Advisory...mry Bay from 1 PM
&&
$$
Public forecast: dykema
aviation/marine: Riley
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