614
FXUS66 KMTR 050026
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
426 PM PST Wed Dec 4 2024

...New AVIATION, MARINE...

.SYNOPSIS...
Issued at 139 AM PST Wed Dec 4 2024

Warm and dry conditions continue to prevail. Long range forecast
bring cooler and wetter conditions toward the middle of December.

&&

.SHORT TERM...
Issued at 151 PM PST Wed Dec 4 2024
(This evening through Thursday)

Near term, wall to wall sunshine blankets the Bay Area this
afternoon thanks to high pressure overhead. Curious looking
longwave pattern as low pressure mains over the Desert SW, low
pressure approaching the PacNW, and the Bay Area sandwiched in
between. Satellite imagery does show a quasi-marine layer as low
stratus continues to hug the Big Sur coast, which is similar to
yesterday.

Tonight through Thursday...for the most part quiet weather
continues with only localized weather impacts. A few high clouds
will approach from the NW as a system lurks off the coast. Given
the relatively light winds again tonight with mostly clear skies
patchy dense fog will impact the North Bay valleys again. Would
not be surprised if dense fog snuck into the East Bay through the
delta from the Central Valley. Expecting similar sensible weather
for Thursday with above normal temps and sunshine.

&&

.LONG TERM...
Issued at 233 PM PST Wed Dec 4 2024
(Thursday night through next Tuesday)

Not much change for Thursday night through Friday either. We
finally start to see a shift in the upper level blocking pattern
heading into the weekend. The system lurking off the PacNW coast
is able to ride across the top of the persistent upper ridge and
flatten it. The tail end of this system does drag across our
coastal waters and far NorCal. Latest guidance continues to show a
low possibility of precip (15-30%) over the waters and north of
the Bay Area, but most of the forecast area remains dry.
Additionally, still looking breezy to gusty over the waters this
weekend with the passing system. The large scale pattern
ultimately shows high pressure building aloft again and the upper
low moving into the Great Basin/N Plains. In fact, this pattern
shift over the weekend does result in some bursts of offshore
flow, but fortunately earlier rainfall has helped to mitigate fire
concerns.

Dry and cool early next week and through the middle of the
weekend. If the long range plays out we`ll have to take a look to
see if any frost/freeze products will be needed.

If you`re looking for precip in the long range there is good news.
Longer range ensemble guidance continues to increase confidence
on precip returning mid month. Definitely much higher conf on
precip, but low confi on impacts/timing. Keep watching....

&&

.AVIATION...
(00Z TAFS)
Issued at 419 PM PST Wed Dec 4 2024

VFR is expected to prevail through the forecast period, however
KSTS will see patchy fog develop overnight, dropping visibility in
the hours surrounding sunrise Thursday morning. Winds remain light
and variable, with southeast drainage winds affecting KSNS and
KMRY Thursday morning.

Vicinity of SFO...VFR through the TAF period, with weak offshore
flow becoming weak onshore after sunset tonight. Surface winds
will remain light and variable through the overnight and much of
Thursday morning, becoming westerly Thursday afternoon.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR is expected to prevail through the
forecast period with southeasterly drainage winds developing
overnight and persisting through Thursday morning.

&&

.MARINE...
(Tonight through next Tuesday)
Issued at 419 PM PST Wed Dec 4 2024

Expect light winds with longer period northwest swell along with
and wave heights between 3 to 7 feet continue through late week.
Winds look to strengthen and seas begin to build late this weekend
and continuing into next week.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.
&&

$$

SHORT TERM...MM
LONG TERM....MM
AVIATION...JM
MARINE...Murdock

Visit us at www.weather.gov/sanfrancisco

Follow us on Facebook, Twitter, and YouTube at:
www.facebook.com/nwsbayarea
www.twitter.com/nwsbayarea
www.youtube.com/nwsbayarea