FXUS66 KMTR 151252
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
552 AM PDT Thu Oct 15 2026
...New AVIATION, FIRE WEATHER...
.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
&&
.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...
(12Z TAFS)
Issued at 547 AM PDT Thu Oct 15 2026
Satellite imagery shows mainly clear skies across the region. There
are a few ribbons of stratus along the North Bay coastline, while
the patch that was near the San Francisco Peninsula is falling
apart. Look for VFR conditions at the terminals through the TAF
cycle and offshore winds this morning and yet again tonight.
Vicinity of SFO...Onshore flow is expected for a few more hours
which will be followed by a stint of weak offshore winds. By the
early afternoon, onshore winds of 10-15kt return and then decrease
after sunset. Offshore winds are expected Thursday morning. VFR
conditions are expected during the TAF cycle.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...Offshore winds are expected for through the
morning with onshore winds by late morning or early afternoon.
Onshore flow should continue through the evening, before another
round of offshore winds returns late evening and into early Friday
morning. VFR conditions will prevail.
&&
.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 06:30:03 PDT 2026
From the National Weather Service
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