Scientific Forecaster Discussion
fxus66 kmtr 132034
Area forecast discussion
National Weather Service San Francisco Bay area
134 PM PDT sun Oct 13 2019
Synopsis...temperatures are cooler today and the trend will
continue Monday. Tuesday will see a brief warm up for
temperatures before the next system moving in mid week. A chance
of light rain is possible late Wednesday into Thursday morning for
the North Bay. Breezy, dry conditions are expected after the
frontal passage for next weekend.
Discussion...as of 01:32 PM PDT Sunday...the upper level trough
over the eastern Pacific continues to dig southeastward toward
central California. Winds are onshore and temperatures are on
average 4 to 7 degrees cooler today than yesterday. Clouds have
decreased this afternoon with patchy stratus remaining off the
coast. The marine layer is expected to deepen, allowing the
stratus to return and move further inland tonight. Overnight lows
will once again be widespread in the 40s and 50s, with isolated
areas seeing the mid-to-low 30s. Patchy frost is possible in
isolated areas that drop into the 30s, but chances are low.
A weak ridge builds Tuesday and Wednesday allowing temperature to
warm slightly. However by Wednesday night, the next upper level
trough moves from the eastern Pacific over the Pacific northwest.
Models have trended downward in the troughs overall strength, but it
looks like it will be enough to make for breezy northwesterly wind
conditions and a chance of light rain for the North Bay early
Thursday morning. Breezy winds will continue after the passage of
the front and providing cooler drier conditions for next weekend.
Aviation...as of 10:31 am PDT Sunday...for 18z tafs. Satellite
imagery shows a few high clouds passing over the region with
patchy low clouds along the coast. VFR conditions to prevail
through late tonight before patchy low clouds develop as the
marine layer deepens thanks to the influence of an upper trough.
Patchy MVFR/IFR cigs to develop overnight and into tomorrow
morning, low confidence on timing and extent of low clouds.
Generally light winds this morning turning onshore this afternoon
Vicinity of ksfo...VFR to prevail through the period with patchy
low clouds in the vicinity early tomorrow morning. Not expecting
broken conditions to develop at ksfo at this time. Light winds this
morning to turn onshore this afternoon around 10-15 kt.
Sfo bridge approach...similar to ksfo.
Monterey Bay terminals...VFR through this evening before low
clouds are expected to develop over the Bay and the peninsula. Low
confidence on timing of extent of low clouds this evening. IFR
cigs expected overnight and early tomorrow morning. Locally breezy
southeast winds this morning down the Salinas valley. Winds to turn
onshore this afternoon around 10-15 kt.
Marine...as of 01:32 PM PDT Sunday...generally light
northwesterly winds will continue across the coastal waters today
with locally breezy winds over the northern outer waters north of
Point Reyes. Mixed seas will persist through early this week with
a light shorter period northwest swell and a light southerly
swell. Fresh wind generated short period waves combined with
swells will produce locally hazardous seas over portions of the
outer waters beginning this evening. A larger northwest swell will
arrive later this week.
... Arena to Pigeon pt 10-60 nm
Small Craft Advisory...Pigeon pt to pt Piedras Blancas 10-60 nm from 3 am
Public forecast: dk
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