Area forecast discussion
National Weather Service San Francisco Bay area
306 am PDT Friday may 24 2013
Discussion...as of 3:00 am PDT Friday...anothery fairly chilly
morning on tap for parts of our County Warning Area with a few areas expected to
drop into the lower 40s. Current cloud/fog satellite image shows
mostly clear conditions expect for a patch that extends from the
San Mateo coast down to around Monterey Bay. Current northerly
surface flow is still twice the westerly piece, so any cloud
formation this morning should be limited. With 850 mb temperatures
forecast to increase 1-3c for today compared to yesterday we
should see some minor warming at the surface especially for inland
spots. Highs will be in the upper 50s to middle 60s at the coast with
mostly low to middle 70s inland.
Synoptically...an upper level system currently over the pacnw/British Columbia
region will remain nearly stationary into the first half of next
week as pieces of energy become entrained in the flow and then
rotate around it. This combined with a northwest flow aloft across our
area will help to keep the cooler than normal temperatures going.
Over the weekend rain will stay to the north with the only threat
from the weather looking like pockets of low clouds and fog
Sunday morning especially for coastal areas. Highs on the weekend
will be close to where we end up today -- give or take a couple of
degrees.
On Monday a piece of energy from the North Pacific will begin to
dive to the south toward the pacnw/California coastal area. Each model run
as of late has continued to increase the amount of rain for the
San Francisco and Monterey Bay region with the main focus on
Monday night into Tuesday as the trough axis GOES through along with
an impressive area of positive vorticity advection. Pop values were increased from the
previous shift. Rainfall amounts will generally be light (under a
tenth), however the system does of precipitable water amounts to around 1.25" so
locally higher numbers cannot be ruled out.
Showers will taper off on Tuesday and by Wednesday the system will
be well off to our east. Guidance beyond that point is highly
variable although seems to be centered on the idea of a weak ridge
building back to our area. Kept dry conditions for the
Wednesday to Friday period. Temperatures will slowly rebound
for the second half of next week.
&&
Aviation...as of 10:38 PM PDT Thursday...clear skies persist
across the region. Patchy low clouds are expected to reform along
the coast late tonight/early Friday morning. Terminals will likely
remain clear through tonight. Winds will continue to diminish
overnight. Moderate and locally gusty winds are anticipated Friday
afternoon. Moderate confidence.
Vicinity of ksfo... winds will continue to ease overnight. Winds
are forecast to strengthen once again Friday afternoon with the
onset of the seabreeze. VFR conditions are anticipated through
tonight with patchy low clouds expected to reform but remain at
the coast. Moderate confidence.
Ksfo bridge approach...moderate winds will ease overnight with
VFR conditions expected to prevail.
Monterey Bay area terminals...VFR conditions expected through
tonight. Winds will continue to ease becoming light and variable
overnight. Moderate confidence.
&&
Mtr watches/warnings/advisories...
... Pt to pt pinos 0-10 nm
Small Craft Advisory...pt Arena to pt Reyes 0-10 nm
Small Craft Advisory...pt Reyes to Pigeon pt 0-10 nm
Small Craft Advisory...pt pinos to pt Piedras Blancas 0-10 nm
Small Craft Advisory...pt Arena to Pigeon pt 10-60 nm
Small Craft Advisory...Pigeon pt to pt Piedras Blancas 10-60 nm
Small Craft Advisory...mry Bay from 11 am
Small Craft Advisory...sf Bay from 1 PM
&&
$$
Public forecast: Bell
aviation/marine: CW
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