FXUS66 KMTR 240038

Area Forecast Discussion
National Weather Service San Francisco Bay Area
438 PM PST Fri Feb 23 2018

.SYNOPSIS...Mostly sunny skies will prevail around the Bay Area
today. Another very cool night is forecast for Friday night. Dry
weather and slightly warmer temperatures are expected over the
weekend. Cooler, unsettled weather is expected to return by early
next week with another system bringing rain to the area later next


.DISCUSSION...as of 01:58 PM PST Friday...Abundant sunshine
blankets the Bay Area this afternoon and most of the state for
that matter. Despite the afternoon sunshine temperatures are still
running several degrees below normal. Max temps will likely top
in the lower to mid 50s for most locations. The higher peaks in
the region a much colder: Diablo low 30s, Mt Hamilton and Chews
Ridge mid-upper 20s. Afternoon MODIS imagery still shows some
lingering snow over the higher peaks in Monterey/San Benito

For tonight, clear skies will continue leading to another cold
night, especially away from the coast and major urban centers.
Lows tonight will be in the 20s to lower 30s across the interior
and inland valleys. Closer to the coast and major urban centers
will be mid 30s to lower 40s. Needless to say some frost will be

Dry weekend ahead as the Bay Area remains in a cold dry northwest
flow. There is a slight uptick in 500 mb heights and 850 mb temps,
especially on Sunday, leading to a slight warming trend. That
being said, temperatures will still be below normal for this time
of year, but interior locations may crack 60 degs by Sunday.
Overnight lows will still be cold and frost will be possible
again Saturday night.

Want to at least mention that embedded in the long wave trough a
weak short-wave trough slides through NE California on Saturday
afternoon/evening. Moisture seems limited to NE of the Bay Area.
Therefore, will not include any precip at this time.

Latest model guidance continues to bring another re-enforcing
upper trough late Sunday into Monday. Better dynamics and better
moisture will allow for an increased chance of precip. Current
forecast will bring showers into the North Bay early Monday and
then spread southward through the day and even into early Tuesday.
Rainfall amounts will generally be a few hundredths to a few
tenths over the higher peaks. Snow levels will initially be 2,500
feet and above and then gradually drop through the day. Similar to
the last few system minor snow accumulations will be possible
with the Santa Lucias receiving the most.

Brief break Tuesday into Wednesday with a short-wave ridge. If the
long are right, and they have been showing this solution for
several runs now, late next week could be interesting.
Deterministic and ensembles means bring one of the more "robust"
storm system into CA as of late. Lots of details will need to be
sorted out between now and then, but timing looks to be right at
the end of the month. Stay Tuned...


.AVIATION...as of 4:38 PM PST Friday...VFR. 24 hour trends indicate
much drier conditions settling in today, dewpoint temperatures
have tumbled downward double digits into the teens and 20s. W-NW
winds near 10 knots this evening will tend to shift to light land
breezes tonight as land temperatures become colder, more dense
compared to relatively milder, less dense temperatures over the
ocean and bays. Any lingering snow cover enhancing outgoing
longwave radiative cooling in the mountains of the Central Coast
may add to E-SE drainage winds overnight into Saturday morning in
the Salinas Valley.

Vicinity of KSFO...VFR. West to northwest winds 10 to 20 kt becoming
light later this evening.

SFO Bridge Approach...Similar to KSFO.

Monterey Bay Terminals...VFR through the period with mainly clear skies.
Onshore winds becoming E-SE tonight, possibly gusty in the Salinas Valley
overnight into Saturday morning.


.MARINE...as of 4:00 PM PST Friday...Gusty northerly winds will continue
across the waters through the weekend as high pressure sits over the
eastern Pacific. An upper level system will move through the region
on Monday bringing increasing winds, fresh swell, and scattered showers
to the coastal waters.



Here are the record low temperatures and the years they occurred for
Saturday, February 24.

Location Saturday

SF Bay Area

Healdsburg 29 in 1944
Santa Rosa 28 in 1920
Calistoga 29 in 1982
Kentfield 29 in 1955
San Rafael 34 in 2017
Napa 30 in 1919
San Francisco 40 in 1891
SFO Airport 35 in 1955
Half Moon Bay 33 in 2017
Oakland Airport 36 in 2015
Richmond 36 in 1955
Livermore 29 in 1987
Moffett Field 34 in 2017
San Jose 26 in 1897
Gilroy 28 in 1960

Monterey Bay Area

Santa Cruz 29 in 1925
Salinas 31 in 1982
Salinas Airport 30 in 1953
Monterey 37 in 1955
King City 24 in 1982


.Tngt...SCA...Pigeon Pt to Pt Pinos 0-10 nm until 10 PM
SCA...Pt Arena to Pigeon Pt 10-60 nm
SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm
SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm until 9 PM
SCA...Pt Arena to Pt Reyes 0-10 nm
SCA...Pt Reyes to Pigeon Pt 0-10 nm




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