FXUS66 KMTR 130726
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
1226 AM PDT Thu Aug 13 2026
...New SHORT TERM, LONG TERM, FIRE WEATHER...
.KEY MESSAGES...
Updated at 1225 AM PDT Thu Aug 13 2026
- Near-critical fire weather conditions through Thursday early morning
across Monterey and San Benito Counties due to high based
thunderstorms
- Up to a 15% chance for elevated rain showers/thunderstorms
through Thursday early morning across the Central Coast
- Cooling trend through Friday will bring well below normal
temperatures, gradual warming trend through the weekend and
into next week
&&
.SHORT TERM...
Issued at 1225 AM PDT Thu Aug 13 2026
(Today and tonight)
The upper-level low remains off Point Conception and will continue
to bring up to a 15% chance for elevated rain showers/thunderstorms
through early Thursday morning across the Central Coast as it moves
inland. This will bring near-critical fire weather conditions
through Thursday early morning across Monterey and San Benito
Counties. Erratic/gusty outflow winds up to 40 mph can be expected
with any elevated rain showers/thunderstorms. The main concern is
lightning which will pose the risk for new fire starts and has the
potential to hinder operations on the Timber Fire. Smoke from the
Timber Fire will continue to be transported into the Central Coast
via light southwesterly winds. Smoke will get trapped under the
inversion at night/in the morning, making the appearance and smell
worse. The proximity to the low will allow for a relatively deeper
marine layer across the Central Coast (2,000 feet) than the Bay Area
(1,800 feet). Sensible weather wise, the cooling and moistening
trend will continue through Friday with temperatures well below
normal.
&&
.LONG TERM...
Issued at 1225 AM PDT Thu Aug 13 2026
(Friday through Wednesday)
Friday will see the coolest conditions of the week with well below
normal temperatures and a deep marine layer as upper-level troughing
persists across the West Coast. By the weekend, upper-level ridging
will build in to the Desert Southwest and an upper-level low will
develop well off the West Coast. This will lead to cooler conditions
with a deeper marine layer in the Bay Area and hotter conditions
with a more compressed marine layer for the Central Coast.
Temperatures will remain below normal with the higher terrain
moderating to near normal with the help of warming 850 mb
temperatures.
&&
.AVIATION...
(06Z TAFS)
Issued at 919 PM PDT Wed Aug 12 2026
Currently VFR for majority of terminals with KHAF and Monterey Bay
sites in MVFR/IFR. Deeper marine layer (1800ft to 2000ft) and
stronger onshore flow will result in more widespread stratus
intrusion while an offshore eddy will continue to complicate
timing of MVFR/IFR ceilings for the Bay Area, especially KSFO. A
quasi- stationary upper level low and associated trough at our
latitude will produce gusty onshore flow at times through the TAF
period.
Vicinity of SFO...Gusty onshore flow will persist through much of
the TAF period with a better inland push overnight than we've seen
the past week. However, as a mentioned above, an offshore eddy
will continue to complicate timing and coverage of MVFR/IFR
ceilings, especially at KSFO.
SFO Bridge Approach...Expect MVFR/IFR ceilings in vicinity of KSFO
even if not measured at the terminal.
Monterey Bay Terminals...Quasi-stationary upper level low will
eventually produce and maintain IFR/LIFR ceilings overnight
through at least late morning, and possibly into the afternoon
especially at KMRY. A slight chance, but low confidence of KMRY
remaining socked in through the forecast period.
&&
.MARINE...
(Tonight through next Tuesday)
Issued at 919 PM PDT Wed Aug 12 2026
Fresh to strong northwest winds with isolated gale force gusts
will ease by early Thursday morning, with rough seas becoming
moderate by Thursday evening. Long period southerly swell will
gradually increase Thursday reaching 16 to 18 seconds (possibly
higher at times) by Friday and continuing through the remainder of
the weekend. Visibility may decrease due to haze and smoke nearby
the Big Sur coastline due to the Timber fire.
&&
.FIRE WEATHER...
Issued at 1225 AM PDT Thu Aug 13 2026
Near-critical fire weather conditions through Thursday early morning
across Monterey and San Benito Counties due to high based
thunderstorms. The greatest chance was Wednesday afternoon; however,
with the upper-level low still off Point Conception, there remains
up to a 15% chance for another round through early Thursday morning.
Erratic/gusty outflow winds up to 40 mph can be expected with any
elevated rain showers/thunderstorms. Lightning will pose the risk
for new fire starts and has the potential to hinder operations on
the Timber Fire in Big Sur. The areas of most concern will be in the
higher terrain above the marine layer (2,000 feet), namely the Santa
Lucia Mountains and Gabilan Range. Poor minimum daytime relative
humidity around 30% is expected with nocturnal drying bringing
little-to-no recovery overnight.
Sarment
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Coastal Flood Advisory until 2 AM PDT early this morning for
CAZ006-506-508-529-530.
PZ...Small Craft Advisory until 3 PM PDT this afternoon for Pt Arena
to Pt Reyes 10-60 NM.
&&
$$
SHORT TERM...Sarment
LONG TERM....Sarment
AVIATION...JM
MARINE...JM
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Prepared by Boulder-Creek.com Weather at: Thu Aug 13 02:30:02 PDT 2026
From the National Weather Service
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