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
(12Z TAFS)
Issued at 459 AM PDT Wed Sep 11 2024

Mix of MVFR, LIFR, and VFR conditions this morning. The incoming upper level low pressure system is disrupting the marine layer and causing stratus to dissipate earlier than previously expected. Low to moderate confidence that OAK, SFO, SJC, and LVK will stay VFR through the remainder of the morning. Patchy MVFR-IFR CIGs are expected to redevelop at APC before VFR conditions return late morning. VFR conditions will persist for most sites through the afternoon/evening before stratus and MVFR CIGs return late this evening. Gusty west to northwest winds are on track to develop by early this afternoon and continue through the evening. Sustained winds will generally be between 15 to 20 knots at most airports with gusts between 20-25 knots. Locally higher gusts between 25-35 knots are expected at SFO and OAK.

Vicinity of SFO...Stratus is dissipating earlier than previously anticipated with low to moderate confidence that SFO will stay clear of CIGs through the remainder of the morning. Gusty west winds remain on track for SFO and OAK this afternoon with winds strengthening by late morning and continuing through the evening.
Guidance indicates sustained winds will be between 20-25 knots with gusts up to 35 knots. Winds are expected to weaken to 10-15 knots overnight. Some uncertainty remains on timing of stratus return tonight. Stratus is currently expected to return closer to 08Z but ensemble guidance suggests it could return closer to 05Z.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Patchy MVFR CIGs are expected to persist through the late morning. Current satellite observations show stratus clearing slightly slower in the Monterey Bay Region than observed in the rest of the Bay Area. However, given the overall early clearing trend, confidence is low to moderate that CIGs will clear earlier than currently forecast. Will continue to monitor satellite observations and adjust the TAFs as needed. VFR conditions are expected to return by mid to late this morning with stratus returning early this evening around 00-01Z. Gusty west to northwest winds remain on track with sustained winds between 10-15 knots and gusts up to 25 knots expected.



MARINE
(Today through Monday)
Issued at 459 AM PDT Wed Sep 11 2024

Widespread gusty north to northwest winds and rough seas continue over the coastal waters. Significant wave heights will gradually build to 8 to 10 feet by late Thursday. Gale warnings have been issued across the inner coastal waters from Pigeon Point to Point Piedras Blancas and for the Monterey Bay beginning Wednesday morning and continuing through Wednesday afternoon. Near gale force gusts to the occasional gale force gust are possible within the San Francisco Bay and across the inner coastal waters from Point Reyes to Pigeon Point. Unsettled conditions are expected to continue through the end of the week, but winds and wave heights reduce by 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.