Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Francisco Bay area
403 am PST Friday Mar 6 2015
Synopsis...high pressure through the weekend will bring clear
skies and above normal temperatures. The high will continue
through Monday and Tuesday with near normal temperatures. By
late Tuesday night or Wednesday the next Pacific front will
approach the coast with a chance of some light rain.
Discussion...as of 3:10 am PST Friday...a 580 dm high is centered
over northern California this morning leading to clear skies and
mild temperatures with generally light winds. Some of the wind
protected valleys have cooled into the upper 30s such as Napa and
Livermore. The position of the high and associated surface
pressure gradients is leaving fairly light offshore winds in
place. However even in the absence of strong offshore flow expect
daytime highs into the 70s most locations today as the increasing
sun angle will allow for rapid warming after sunrise. Were
splitting hairs but in general it looks like today may be the
warmest day through the weekend. But any cooling over the weekend
look of little consequence with sunny skies and temperatures from the
upper 60s at the beaches...70s around the Bay and even some lower
80s for the inland valleys of Monterey/San Benito County. Looks
like an ideal weekend for outdoor activities across the Bay area
including the beaches.
The ridge will weaken slightly by Monday and Tuesday with perhaps
some increase in onshore flow near the coast but again no cooling
of note is forecast through at least Tuesday.
Next weather item of interest will be an incoming Pacific front.
Getting conflicting solutions from the models so confidence
remains low given its still 5-6 days out. In general the GFS model
is showing a very weak frontal passage by next Wednesday with little or
no rain. The Gem and European model (ecmwf) are notably wetter. Have kept probability of precipitation in
the low chance category for now given model discrepancies.
Aviation...as of 4:00 am PST Friday...flying conditions will be
favorable today with no significant change over yesterdays
weather. High pressure over the region will maintain VFR
conditions and light/variable winds.
Vicinity of ksfo...VFR. Weak late afternoon and early evening
seabreeze...otherwise light and variable winds.
Ksfo bridge approach...similar to ksfo.
Monterey Bay area terminals...VFR. Light winds.
Marine...as of 04:00 am PST Friday...high pressure dominates the
region through early next week resulting in generally moderate
north winds over the coastal waters through the weekend. A gentle
mixed swell will persist through the forecast period.
Public forecast: rww
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