956
FXUS66 KMTR 110821
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
121 AM PDT Wed Sep 11 2024

...New SYNOPSIS, SHORT TERM, LONG TERM...

.SYNOPSIS...
Issued at 120 AM PDT Wed Sep 11 2024

An upper level trough moving into the Pacific Northwest today will
bring breezy winds to the region that will continue into Thursday.
Slightly warmer for Friday, near seasonal averages. Then a second
trough will begin to impact the region bringing chances of
precipitation at times through next week.

&&

.SHORT TERM...
(Today and tonight)
Issued at 120 AM PDT Wed Sep 11 2024

A deep upper level trough is currently off of the Pacific Northwest
coast and is progressing southeastward and will move into the
Pacific Northwest by this evening. This will result in breezy
onshore winds late this morning and through the evening hours.
Widespread gusts of 30 mph are expected with gusts of 50+ mph
especially in the gaps, passes, and other favorable spots, namely
the Altamont Pass and the Salinas Valley. However, these speeds fall
short of needing a Wind Advisory but conditions will be monitored
closely.

A reminder from the previous forecaster...

Actions to take:

-Store or secure loose items such as patio furniture, sports
equipment, trampolines, and trash cans.

-Use caution when driving, especially high-profile vehicles.

-Have a plan in case of a power outage.

While the overall fire threat is on a downward trend due to lower
temperatures and higher relative humidities, fuels still remain
critically dry with large fires possible. Therefore, any fire that
starts will have no problem spreading and the strong winds will only
make matters worse. As always, it is imperative to remain vigilant
when it comes to exercising fire safety.

Actions to take:

-Properly discard cigarettes.

-Keep vehicles off of dry grass.

-Avoid activities with open flames or sparks.

-Avoid power equipment that creates sparks.

-Obey burn bans.

Tonight, winds diminish late this evening as the trough axis moves
inland and high pressure builds off of the West Coast. Expecting
northwest flow to remain breezy over the ocean with less widespread
cloud cover overnight. Any clouds will favor the northwest facing
terrain as a result.

&&

.LONG TERM...
(Thursday through Tuesday)
Issued at 120 AM PDT Wed Sep 11 2024

As the aforementioned trough shifts further inland, weak offshore
flow may develop over the Interior North Bay Mountains and East Bay
Hills on Thursday and into Friday morning. However, strong winds
that would reach Red Flag criteria are not expected at this time. A
small amplitude ridge will move in on Friday, bringing temperatures
to near seasonal averages.

Another trough will approach from the north on Saturday and cool
temperatures once again aloft. By Sunday and Monday, there remain
chances for precipitation across the region that will continue at
times through next week. There remains uncertainty with model
divergence in the extended forecast period and therefore there is
lower confidence in the details. However, the confidence is high
that troughing over the region will keep conditions cool for the
next 7-10 days at least. Stay tuned...

&&

.AVIATION...
(06Z TAFS)
Issued at 1104 PM PDT Tue Sep 10 2024

IFR-MVFR CIGs expected overnight with stratus currently moving
onshore across portions of the Bay Area and Central Coast. Patchy
stratus is expected to impact STS and APC within the next few hours
before becoming more widespread later tonight. Stratus is expected
to mix out mid to late tomorrow morning with northwest winds
becoming increasingly gusty by the early afternoon/evening as an
upper level low pressure system moves inland. Winds are expected to
gust between 20 to 25 knots with locally higher gusts up to 35 knots
expected at SFO and OAK.

Vicinity of SFO...MVFR CIGs are expected to continue overnight with
stratus cover dissipating around 15Z. Some potential continues for
IFR CIGs to develop overnight but this scenario remains lower
confidence due to a moderately deep marine layer around 2000 feet.
Moderate northwest winds around 10-15 knots continue overnight with
stronger, gustier winds between 25 to 35 knots returning early
tomorrow afternoon through the evening before moderate winds around
15 knots return overnight.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...MVFR-IFR CIGs to persist overnight with
moderate confidence in VFR conditions at least temporarily returning
to SNS during the afternoon/evening. CIGs are currently expected to
stay on the MVFR-IFR border but will continue to monitor the TAFs
and adjust as needed. Gusty northwest winds are expected to develop
late tomorrow morning and continue into the evening with sustained
winds around 15 knots and gusting up to 25 knots.

&&

.MARINE...
(Tonight through next Monday)
Issued at 1104 PM PDT Tue Sep 10 2024

Breezy winds continue to spread across the waters through the
night. Expect widespread moderate and gusty north to northwest
winds and rough waves across the coastal waters for Wednesday. A
gale watch has been issued for possible gale force gusts across
the Monterey Bay and inner coastal waters extending from Pigeon
Point to Point Pinos Wednesday morning into Wednesday afternoon.
Unsettled conditions are expected to continue through the end of
the week, but winds reduce in the late weekend.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 3 PM this afternoon to 3 AM PDT
     Thursday for SF Bay N of Bay Bridge.

     Small Craft Advisory from 9 AM this morning to 3 PM PDT this
     afternoon for Mry Bay-Pigeon Pt to Pt Pinos 0-10 nm.

     Gale Warning from 3 PM this afternoon to 9 PM PDT this evening
     for Mry Bay-Pigeon Pt to Pt Pinos 0-10 nm.

     Small Craft Advisory until 9 PM PDT Thursday for Pigeon Pt to Pt
     Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm.

     Small Craft Advisory until 9 AM PDT Thursday for Pt Reyes to
     Pigeon Pt 0-10 nm.

     Small Craft Advisory until 9 AM PDT this morning for Pt Pinos to
     Pt Piedras Blancas 0-10 nm.

     Gale Warning from 9 AM this morning to 9 PM PDT this evening for
     Pt Pinos to Pt Piedras Blancas 0-10 nm.

     Small Craft Advisory until 3 PM PDT this afternoon for Pt Arena
     to Pt Reyes 10-60 NM.

     Small Craft Advisory from 3 AM to 9 PM PDT Thursday for Pt Arena
     to Pt Reyes 10-60 NM.

&&

$$

SHORT TERM...RGass/Sarment
LONG TERM....RGass
AVIATION...Canepa
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