Area Forecast Discussion
Issued by NWS San Francisco Bay Area, CA

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FXUS66 KMTR 201808

Area Forecast Discussion
National Weather Service San Francisco Bay Area
1108 AM PDT Fri Oct 20 2017

.SYNOPSIS...Now that shower activity has moved out of the area
dry weather will prevail through the forecast period. Cooler
temperatures and breezy onshore winds will persist today before a
warming trend begins over the weekend and into early next week.
Temperatures are forecast to be well above average through most of
next week.


.DISCUSSION...As of 8:40 AM PDT Friday...Last nights system
quickly moved through with rain beginning in the North Bay in the
evening and reaching San Francisco by around 11 PM. Rainfall
totals varied across the CWA with areas in the North Bay Mountains
receiving up to 0.91" at Middle Peak in Marin County to 0.40" in
Boulder Creek in the Santa Cruz Mountains down to only a few
hundredths of an inch for parts of Monterey County and far
eastern inland areas.

Cool temperatures are expected again today with highs forecast in
the upper 50s and 60s for most locations. Along with cool
temperatures, breezy onshore winds will persist throughout the day
reaching 15 to 25 mph in the afternoon, with higher gusts

The main forecast concern will be the warm temperatures for the
region early next week.


.PREV DISCUSSION...As of 3:05 AM PDT Friday...A warming trend
will begin during the weekend as an upper level ridge builds over
the state. Much warmer temperatures are then forecast early in the
work week as the upper ridge strengthens along the West Coast and
light offshore flow develops. On Monday and Tuesday expect
widespread high temperatures in the 80s to around 90, with these
warm temperatures developing not only inland, but in coastal areas
as well. Slight cooling is projected late in the week as the
ridge begins to weaken.


.AVIATION...As of 11:05 AM PDT Friday...For 18z Tafs. Moisture
feed aloft oriented NW to SE focused over the North Bay/East Bay,
bringing some low to mid level clouds. Post frontal convection
with weak vertical development also contributing to overall dirty
decks in the mid to low levels today, especially near KSFO KOAK
KSJC KHWD KLVK. Winds will generally be light, except along the
coast, where onshore afternoon sea breeze will become breezy with
occasional gusts into the low 20s by the afternoon. Improving CIGS
thru the TAF period with generally VFR for tonight.

Vicinity of KSFO....Generally VFR with a handful of FEW-SCT decks
in the low to mid levels through the morning, with improving cigs
by the afternoon. Winds increasing in the afternoon, becoming
sustained around 15mph with gusts to 20 to 25 mph.

SFO Bridge Approach...Similar to KSFO with a few extra clouds thru
the early afternoon.

Monterey Bay Terminals...VFR. Light winds, with increasing onshore
flow by the afternoon. Afternoon sea breeze 10 to 15mph with
gusts to around 20 mph.


.FIRE WEATHER...As of 3:05 AM PDT Friday...Rainfall which moved
across the district overnight brought wetting rains to many
locations. Highest rainfall amounts were in the North Bay
mountains, but many locations at lower elevations received around
a quarter of an inch. Rainfall should end in most areas by mid
morning. Today will be a cool day with brisk northwest winds.

A warming trend will get underway during the weekend as a high
pressure ridge begins to build over California. This ridge will
strengthen into early next week and result in warm and dry
conditions districtwide from Monday through Wednesday. Will need
to be wary of possible gusty offshore winds in the hills beginning
late in the weekend and continuing into Monday night.

&& of 11:00 AM PDT Friday...Lighter winds will persist
in the wake of a cold front that is  passing through the coastal
waters tonight. A long period  northwesterly swell will accompany
this system creating hazardous  seas for mariners operating small
crafts. Mariners are urged to  use extreme caution if out at sea
as hazardous seas are forecast  to persist over the next few days.


     .Tday...High Surf Advisory...CAZ006-505-509-529-530
             SCA...Pigeon Pt to Pt Pinos 0-10 nm
             SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm
             SCA...Pt Arena to Pigeon Pt 10-60 nm
             SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm
             SCA...Mry Bay
             SCA...Pt Arena to Pt Reyes 0-10 nm
             SCA...Pt Reyes to Pigeon Pt 0-10 nm
             SCA...Rough Bar Advisory for SF Bar




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