Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Francisco Bay area
347 am PST Monday Mar 2 2015
Synopsis...a quick moving weather system from the Pacific
northwest will drop down the coast bringing scattered showers and
isolated thunderstorms back to the area mostly south of San
Francisco Bay today and this evening. High pressure builds Tuesday
through next weekend with a return to dry conditions...mostly
clear skies and above normal daytime temperatures.
Discussion...as of 3:00 am PST Monday...WV and infrared satellite loops
show a system rapidly dropping down from the north. Clouds have
been on the increase this morning and in some spots winds are
starting to also increase. Similar to Saturday...showers will form
across our County Warning Area later this morning as the main low moves overhead.
This will lead to more destabilized atmosphere with favorable
lifted and cape values for thunderstorm and possible small hail.
Based on the track of the low...the most likely spot for showers
will be south of San Francisco Bay in particular Santa
Cruz...Monterey...and San Benito counties. Last few runs of the
hrrr also show convection firing up around San Jose by early
afternoon which will need to be monitored. Rainfall amounts are
expected to be light with the northern half of the County Warning Area looking at
less than a tenth of an inch. Around Monterey County local amounts
could exceed a quarter of an inch. Snow levels will remain low at
around 4000 feet. Minor accumulations are likely for portions of
Showers will come to end overnight as the low dives to the south
and off the northern Baja California coast Tuesday morning. Behind it a
ridge of high pressure will build back to the entire West Coast of
the Continental U.S. Through Vancouver Island leading to warmer weather and
dry conditions. Right now Thursday through next Monday looks very
nice for this time of the year with highs in the upper 60s to middle
Aviation...as of 3:47 am PST Monday...for 12z tafs. Quick moving
boundary rapidly approaching the region. Some low ceilings so far at
ksts and kwvi but in general just expecting high clouds. -Shra
expected over the hills this afternoon but not likely to impact
terminals so have used vcsh in tafs. Light southerly flow this
morning turning onshore this afternoon as the system passes to our
south. Clearing skies with light winds tonight into Tuesday.
Vicinity of ksfo...just expecting some middle and high clouds today
with west winds developing by around 19z today.
Ksfo bridge approach...similar to ksfo.
Monterey Bay area terminals...some low ceilings near kwvi and khaf
suggests potential for some low clouds to impact kmry this morning
ahead of boundary. In general though just expecting middle and high
level clouds. Expect -shra over the hills this afternoon and have
put vcsh in the tafs for kmry and ksns.
Marine...as of 3:47 am PST Monday...a fast moving cold front will
drop north to south over the waters today with some gusty northwest
winds...along with a chance of showers or an isolated
thunderstorm. Winds will gradually ease overnight into Tuesday
with generally light wind and seas forecast from midweek and
beyond as high pressure builds.
... Arena to pt Reyes 10-60 nm
Small Craft Advisory...pt Arena to pt Reyes 0-10 nm until 2 PM
Small Craft Advisory...Pigeon pt to pt pinos 10-60 nm until 2 PM
Small Craft Advisory...pt Reyes to Pigeon pt 10-60 nm
Public forecast: Bell
Visit US at weather.Gov/sanfrancisco
Follow US on facebook, twitter, and youtube at: