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000
FXUS66 KMTR 271823
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco Bay Area
1123 AM PDT Sun Oct 27 2019

.SYNOPSIS...The current strong and potentially historic offshore
wind event continues and will bring significant impacts to most
of the San Francisco Bay Area continuing into early Monday,
particularly across the North Bay. A cooling trend is forecast to
continue into early next week, with near normal temperatures
expected by Monday. Tuesday night into Wednesday morning looks
more likely to bring another offshore wind event with no
precipitation in the forecast.

&&

.DISCUSSION...as of 08:36 AM PDT Sunday...The high wind event and
fire weather threat has transpired so far as forecast. Winds
ramped up overnight with the highest winds at elevated areas of
the North Bay including: Healdsburg Hills North 93 mph, Mt. St.
Helena West 82 mph, Mt. Hood 75 mph with areas in the valleys
seeing gusts 30-40 mph. Over night two fires started in Contra
Costa county and one southeast of Santa Rosa. While reports appear
that those were smaller, the main attention remains on the
Kincade Fire in North Sonoma County which continues to burn with
minimal containment. Winds have slowly started to wane but, make
no mistake, are forecast to remain strong through the day as
relative humidity reduces as the sun comes up. There will be
another ramp up in wind gusts around 8pm today and into early
Monday morning. Winds should begin to calm after sunrise on Monday
and be more at ease by lunchtime. The Red Flag Warning and High
Wind Warnings and Advisories remain in effect with expirations
tomorrow at 11am on Monday.

Temperatures will be seasonably mild today and continue the
cooling trend through the week for the Bay Area. A week stratus
deck has developed off the coast of Southern Monterey County and
into the southern Salinas Valley, reducing visibility at the
Salinas airport but should dissipate by the afternoon.

Winds will calm on Monday and into Tuesday morning with no rain
expected in the short or long term forecasts. However, models
continue to bring the next upper level trough moves southward
setting up another offshore wind event event. Models showing it
getting stronger, though for now it does not appear to be as
strong as the current event, nor for a similar long duration.

&&

.PREV DISCUSSION...As of 3:33 AM PDT Sunday...Satellite night fog
product is showing rapid expansion of the Kincade Fire in northern
Sonoma County over the past several hours with additional dark
pixels showing up with every one minute image update. Latest
automated weather observations indicating wind gusts over 70 MPH
at several gauges in the higher terrain in Sonoma County, with a
couple gauges now reporting sustained winds over 50 mph with gusts
over 80 mph. Latest satellite imagery also shows the heat
signature very close to the town of Healdsburg. There is a new
heat signature now apparent near Bethel Island in eastern Contra
Costa County. Relative humidity values are plummeting as well,
with readings in the lower teens. These very strong winds will
persist through about mid morning, then taper off slightly, but
are still forecast to remain gusty throughout the day. Winds are
expected to ramp up again tonight briefly in the North Bay before
decreasing Monday morning.

A wind advisory remains in effect for most areas of the San
Francisco Bay Area while a high wind warning is in effect for the
North Bay mountains. In addition, a red flag warning is in effect
through 11am Monday morning. Please see the SFONPWMTR (wind) and
SFORFWMTR (red flag) products and the fire weather discussion
below for additional details.

All focus is on the developing situation in the North Bay, and
meanwhile a 1500 foot marine layer has developed from about the
Monterey Bay south with stratus clouds extending through the
entirety of the Salinas Valley. Seasonably cooler temperatures are
expected districtwide today and through the week.

Medium range model guidance continues to indicate another offshore
wind event developing late Tuesday into Wednesday. Although not
expected to be as strong as the current one, any increase in
winds across active wildfires will only exacerbate the situation.
Unfortunately, no rain in sight throughout the extended progs.

&&

.AVIATION...as of 10:55 AM PDT Sunday...For 18z tafs. VFR
conditions to prevail aside from occasional MVFR conditions due to
smoke from the Kincade Fire. Other impacts will be gusty NE flow
creating low level wind shear, except for Monterey and Salinas.
Winds will finally ease on Monday.

Vicinity of KSFO...VFR. Gusty N to NE winds will ebb and flow at
times through tonight before decreasing on Monday. Winds may
briefly get close to Airport Weather Warning, but conf is too low
to issue at this time. LLWS will also be a concerns with gusty
winds at 1500-2000 feet.

SFO Bridge Approach...Similar to KSFO. Will have to watch
slantwise vis with possible smoke impacts.

Monterey Bay Terminals...forecasting VFR at the terminals through
tomorrow. Some smoke may impact Monterey and Salinas at times.

&&

.FIRE WEATHER...As of 11:05 AM PDT Sunday...Morning conference
calls and coordination with agency partners have completed. No
change with current Red Flag Warnings and will still be valid
through Monday morning. Critical fire weather conditions continue
to impact the region with gusts still reaching over 70-80 MPH
across the peaks of the North Bay. Winds are also gusty on lower
elevations/valleys in the 30-40 mph range, including the Delta.
New fire near Vallejo behind enhanced by the gusty Delta winds.
Winds may briefly ease this early this afternoon then ramp back up
again this evening and overnight. Don`t want to downplay the winds
even if they dip a little in wind speed they`ll still be
critical. Regardless of the winds relative humidity critically dry
through out.

Regarding offshore flow event number three - confidence continue
to increase with another offshore flow event Tuesday into
Wednesday. Latest thinking is this event will be more like last
week. Will let current round of Red Flag Warnings expire before
issuing any new Fire Weather Watch for event number three.



&&

.MARINE...as of 10:44 AM PDT Sunday...Gusty offshore winds will
continue to create gale force gusts and hazardous conditions along
the immediate coast north of Pigeon Point and north of the Bay
Bridge. Winds are weaker elsewhere, but still causing hazardous
conditions with small craft advisories. These winds will generate
steep fresh swell. Additionally, larger  northwest swell will
continue through much of Sunday before  gradually subsiding. A
longer period northwest swell will then  arrive late tonight into
Monday morning.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
     .Tday...Red Flag Warning...CAZ505>507-509>512
             Wind Advisory...CAZ006-505-506-508>512
             High Wind Warning...CAZ507
             SCA...Pigeon Pt to Pt Pinos 0-10 nm
             SCA...Pt Arena to Pigeon Pt 10-60 nm
             SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm
             GLW...SF Bay until 3 PM
             GLW...Pt Arena to Pt Reyes 0-10 nm until 3 PM
             GLW...Pt Reyes to Pigeon Pt 0-10 nm until 3 PM
             SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm from 3 PM


&&

$$

PUBLIC FORECAST: Sims
AVIATION: MM
MARINE: MM
FIRE WEATHER: MM

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