Scientific Forecaster Discussion
Area forecast discussion
National Weather Service San Francisco Bay area
336 am PST Sat Dec 7 2013
Discussion...as of 3:00 am PST Saturday...a vigorous cold front
continues to move rapidly southward across the district...and is
currently across Monterey and central San Benito counties. So far
rainfall amounts with this front have ranged from a few tenths to
over an inch of rain. Temperatures have risen ahead of the front...
and remain above freezing behind the front...at least at lower
elevation reporting stations. Latest higher elevation reports...
30s degrees at Mount Hamilton...and 32 at Chews Ridge. There will
be measurable snow at those locations...thus the Winter Weather
Advisory remains in effect for the southern two thirds of the
district at this time...but the Santa Cruz Mountains and East Bay
hills will expire at 6 am. Will examine the precipitation trends at
6 am and see if the Santa lucias need to be kept under an advisory
or not. If so...the existing 10 am expiration time should be
Expect shower activity to quickly diminish this morning as the
front continues to move south and east. The cool airmass in the
wake of the front will result in another chilly day across the
district with highs in the 40s to around 50. In fact...maximum
temperatures for the day at some locations could have occurred
already. Cold temperatures are anticipated tonight and a freeze
warning has already been posted for all areas except San Francisco
for tonight. Food for thought...however...the rainfall received
last night through this morning could keep dew point temperatures
warmer. Thus...Sunday night is expected to be the colder night
of the two.
Gradual moderation of temperatures is expected to occur next
week. A shortwave ridge will develop over our area early in the
week which will allow days to warm...but overnight lows in the
valleys will likely remain below freezing all the way through
midweek. Increased onshore flow from midweek on will finally
result in moderating nighttime temperatures. Also...precipitation chances will
return by about Thursday as a weakening system approaches the
coast. However...latest model guidance suggests that this system
will mostly dissipate by the time it reaches our area.
Aviation...as of 3:36 am PST Saturday...a fast moving cold front
has moved through the forecast area overnight. Gusty northwest
winds will be present at the terminals today as a result of cold
air filling in behind the departing front. Showers will linger in
the Monterey Bay area through late afternoon.
Vicinity of ksfo...VFR conditions are expected to prevail today
with gust northwest winds. Winds will reach 22 knots with gusts to 30
knots by late morning early afternoon.
Ksfo bridge approach...similar to ksfo.
Monterey Bay area terminals...VFR conditions are expected to
prevail today with ceilings bkn-ovc035-040. Light showers will be
possible through late afternoon. Gusty westerly winds will reach
15 knots with gusts to 22 knots possible.
... Weather advisory...mountains of Monterey and San
Benito counties above 2000 feet until 10 am.
Winter Weather Advisory...Santa Cruz Mountains and East Bay
hills above 2000 feet until 6 am.
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...Pigeon pt to pt pinos 0-10 nm
Small Craft Advisory...pt pinos to pt Piedras Blancas 0-10 nm
Small Craft Advisory...pt Arena to pt Reyes 10-60 nm
Small Craft Advisory...pt Reyes to Pigeon pt 10-60 nm
Small Craft Advisory...Pigeon pt to pt pinos 10-60 nm
Small Craft Advisory...pt pinos to pt Piedras Blancas 10-60 nm
Small Craft Advisory...San Francisco Bay north of the Bay Bridge until 1 PM
Small Craft Advisory...San Francisco Bay south of the Bay Bridge until 1 PM
Small Craft Advisory...mry Bay
Public forecast: Sims
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