FXUS66 KMTR 151522
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
822 AM PDT Thu Oct 15 2026

...New UPDATE...

.KEY MESSAGES...
Updated at 1149 PM PDT Wed Oct 14 2026

 - Above normal temperatures continue into the weekend before a
   cooling trend begins Sunday into next week

 - Near critical fire weather conditions due to moderate flow and
   very dry conditions across the higher elevations Thursday and
   Friday

 - Potential for light rain and breezy onshore winds early to mid
   next week

&&

.UPDATE...
Issued at 821 AM PDT Thu Oct 15 2026

No update to the forecast necessary this morning. A Fire Weather 
Watch was issued overnight for the North Bay interior mountains 
where very dry and windy conditions tonight through Friday morning 
will promote rapid spread of any fire ignitions. Winds at the 
highest spots are already sustained at 30+ MPH with little to no 
overnight relative humidity recovery last night. RH values this 
morning are generally in the 20-30% range, and expected to be in the 
teens by later today. The decision on whether to upgrade to a Red 
Flag Warning will be made this afternoon with the scheduled forecast 
update. There are pockets of moderate HeatRisk this afternoon with 
the warming temperatures, mainly in the North Bay and East Bay. More 
widespread HeatRisk is in store for Friday, including many coastal 
areas as offshore flow continues to work against the marine layer.

&&

.SHORT TERM...
Issued at 1149 PM PDT Wed Oct 14 2026
(Tonight through Friday)

Near critical fire weather conditions continue across the higher 
elevations, particularly the North Bay Interior Mountains, through 
Friday. A positively tilted upper level ridge remains over Oregon 
and Northern/Central California while a cut-off low lingers over 
Southern California. This setup promotes light to moderate offshore 
winds across the region with the potential for more moderate to 
gusty offshore winds across the higher elevations. Model guidance 
keeps gusts across the elevated terrain peaking between 20 to 30 mph 
with locally stronger gusts possible across the highest peaks (e.g. 
Mt. St. Helena). The GFS and HRRR are both in agreement that the SFO-
WMC gradient will peak around -9 mb Thursday morning and -10 mb 
Thursday night into Friday. The NAM continues to be an outlier and 
suggests the gradient could peak around -14 mb but looking closer 
into their forecast wind gusts still keeps gusts in a similar, but 
slightly stronger range, of 25 to 35 mph. Very dry conditions are 
expected across the higher elevations during both the daytime and 
overnight hours. Much of the region will see daytime RH in the 10s 
to 20s with poor to very poor overnight recoveries with the worst 
recoveries across the higher elevations. Given the very dry 
conditions and potential for offshore winds, any spark has the 
potential to start a fire. Remember, one less spark one less 
wildfire.

Warmer temperatures continue Thursday and Friday with highs in the 
80s to low 90s on Thursday and upper 80s to 90s on Friday. Patchy 
Moderate HeatRisk is expected on Thursday but becomes more 
widespread across urban areas on Friday. If you are outdoors during 
peak heating, make sure you are drinking plenty of water and taking 
frequent breaks in the shade. The marine layer remains mixed out 
through the short term due to the presence of the ridge so expect 

&&

.LONG TERM...
Issued at 1149 PM PDT Wed Oct 14 2026
(Friday night through next Wednesday)

Offshore winds decrease by Friday afternoon/evening as upper level 
ridging weakens and broad troughing returns to the region. High 
temperatures Saturday will still be warm in the 80s to low 90s but 
cooler temperatures return Sunday into next week. By Sunday, broad 
troughing returns to the region with temperatures cooling into the 
70s to low 80s. Fall weather returns in force next week as we get 
our first potential rainmaker of the season. This low pressure 
system looks to originate from the Gulf of Alaska and will bring 
much cooler, moister air into the region as the surface low weakens 
and moves into California next week. Highs will be seasonal to below 
normal in the 60s to low 70s across the interior and upper 50s to
low 60s along the coast. Rain chances increase Tuesday through 
late week with wetting rains (>0.10") likely across the Central 
Coast and potentially Santa Cruz County/the South Bay. Light rain 
is possible across the rest of the Bay Area but does not look to 
meet wetting rain criteria at this time. Guidance is showing a low
(<10%) chance of thunderstorms next week so that will be 
something to keep an eye on as this event gets closer in time. &&

.AVIATION...
(06Z TAFS)
Issued at 959 PM PDT Wed Oct 14 2026

Generally VFR conditions prevail through the TAF period, with some 
high resolution models depicting patchy coastal stratus developing 
tonight. Low confidence in HAF getting fog and low stratus. If it 
does happen, the most likely period for development would be 08-11Z 
before offshore winds mix out the lower layers. Light winds persist 
overnight, before a moderate offshore push in the interior Thursday 
morning, balanced by a gentle onshore flow developing in the 
afternoon.

Vicinity of SFO... VFR at the terminal through the TAF period. Light 
winds overnight will turn offshore Thursday morning before moderate 
northwest flow resumes in the afternoon.

SFO Bridge Approach... Similar to SFO. 

Monterey Bay Terminals... VFR through the TAF period. Light to 
gentle offshore winds persist overnight into Thursday morning before 
the moderate northwest flow resumes afternoon.

&&

.AVIATION...
(06Z TAFS)
Issued at 959 PM PDT Wed Oct 14 2026

Generally VFR conditions prevail through the TAF period, with some 
high resolution models depicting patchy coastal stratus developing 
tonight. Low confidence in HAF getting fog and low stratus. If it 
does happen, the most likely period for development would be 08-11Z 
before offshore winds mix out the lower layers. Light winds persist 
overnight, before a moderate offshore push in the interior Thursday 
morning, balanced by a gentle onshore flow developing in the 
afternoon.

Vicinity of SFO... VFR at the terminal through the TAF period. Light 
winds overnight will turn offshore Thursday morning before moderate 
northwest flow resumes in the afternoon.

SFO Bridge Approach... Similar to SFO. 

Monterey Bay Terminals... VFR through the TAF period. Light to 
gentle offshore winds persist overnight into Thursday morning before 
the moderate northwest flow resumes afternoon.

&&

.MARINE...
(Today through Tuesday)
Issued at 243 AM PDT Thu Oct 15 2026

Moderate seas continue across the outer waters, while the inner
waters see slight to moderate seas through Friday. During this
time frame, gentle to fresh northerly breezes continue. Moderate
to fresh northerly winds return for the weekend, which will be
accompanied with rough seas.

&&

.FIRE WEATHER...
Issued at 547 AM PDT Thu Oct 15 2026

A Fire Weather Watch was issued for the North Bay Interior
Mountains and will go into effect later this evening and run
through Friday morning. This is due to moderate offshore winds 
very dry with very poor overnight humidity recoveries only 
reaching 14 to 24 percent. Rapid fire spread is possible given the
combination of gusty northerly winds and very dry overnight 
conditions.

Elsewhere in the Bay Area, elevated to near critical fire weather
conditions are expected for the higher elevations late tonight 
through Friday morning. Dry conditions, poor overnight RH 
recovery, combined with the breezy winds, warmer weather, and 
available fuels leads to the elevated to near critical fire 
weather conditions. 

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Fire Weather Watch from this evening through Friday morning for 
     CAZ504.

PZ...None.
&&

$$

SHORT TERM...Kennedy
LONG TERM....Kennedy
AVIATION...KR
MARINE...KR

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Prepared by Boulder-Creek.com Weather at: Thu Oct 15 08:30:04 PDT 2026