610
FXUS66 KMTR 062034
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
134 PM PDT Sun Jul 6 2025

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

.KEY MESSAGES...
Updated at 129 PM PDT Sun Jul 6 2025

 - Moderate HeatRisk returns to portions of the Interior Bay Area
   and Central Coast Wednesday through next weekend.

 - Localized elevated fire weather conditions for the Bay Area and
   Central Coast Wednesday through next weekend.

 - Slight risk (20%-40%) of extreme heat for far interior portions
   of the Bay Area and Central Coast July 12th-14th.

&&

.SHORT TERM...
Issued at 129 PM PDT Sun Jul 6 2025
(This evening through Monday)

An upper-level cutoff low off the Northern California Coast will be
the defining feature of the short term forecast. Sensible weather
will feature seasonably cool conditions and onshore winds with gusts
up to 35 mph through gaps and passes, across ridgelines, and down
the Salinas Valley. The marine layer is currently being observed at
1,800 feet on the Fort Ord profiler and will continue to deepen to
3,000 feet by Tuesday. This, in addition to the stratus presentation
currently, means that it will have no problem penetrating farther
inland tonight and continuing that trend tomorrow night. There is
also a slight (15%) chance for drizzle along the coast and over the
waters due to the lifting mechanism in place. Southerly transport
winds may (you guessed it) transport smoke in from the Madre Fire
that is burning in San Luis Obispo through Tuesday.

&&

.LONG TERM...
Issued at 129 PM PDT Sun Jul 6 2025
(Monday night through next Saturday)

The pattern begins to change Wednesday as the upper-level cutoff low
becomes an open wave and gets nudged eastward by building broad high
pressure. This will kickoff the warming and drying trend with the
return of moderate HeatRisk and localized elevated fire weather
conditions. Fortunately, several rounds of upper-level shortwave
trough energy will help keep the ridge in check, not allowing the
axis or peak to enter our area. Global ensemble clusters are in
agreement with heights rising through Thursday with the ridge
showing signs of weakening, albeit slightly, Friday. This will
translate to Thursday being the warmest day of the week with
temperatures topping out at 10 degrees above normal with Friday
being slightly cooler. Global ensemble clusters diverge Saturday
with 51% in favor of heights rebuilding and 49% in favor of heights
falling, suggesting uncertainty in the forecast. The propagation
of what happens will be integral in the extended forecast as the
Climate Prediction Center (CPC) has highlighted the far interior
portions of the Bay Area and Central Coast with a slight (20%-40%)
chance of extreme heat July 12th-14th, thus it is intuitive to
believe that if the ridge has more time to build that we could be
dealing with hotter conditions and subsequently greater impacts
than what are currently being forecast. In terms of elevated fire
weather conditions, high pressure and the accompanying subsidence
aloft will compress the marine layer to 1,000 feet Wednesday
resulting in little inland intrusion and poor to moderate relative
humidity recovery above it. Additionally, light offshore flow is
expected in the higher terrain during the morning hours of
Wednesday and Thursday. Please exercise fire and heat safety,
especially coming off of a cool June.

&&

.AVIATION...
(18Z TAFS)
Issued at 1048 AM PDT Sun Jul 6 2025

IFR to MVFR stratus persist at coastal sites with sky conditions
either scattering out or clearing completely across the interior.
Moderate confidence for IFR to MVFR conditions to linger at the
coast throughout the remainder of the day, yet cannot rule out a few
hours of low clouds scattering out this afternoon. Onshore winds
increase this afternoon before diminishing after sunset. Moderate to
high confidence for an early return late tonight of stratus filling
into the coastal valleys and lowering early Monday morning. Low
clouds that do develop by Monday morning will likely scatter out
and/or clear by Monday afternoon, with the exception of coastal
locations.

Vicinity of SFO...VFR. Onshore winds increase this afternoon before
gradually easing after sunset. High confidence for MVFR ceilings to
return late tonight and potentially lowering to IFR at times early
Monday morning. Stratus is forecast to scatter out between 16Z-18Z
Monday morning.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...IFR at MRY, VFR at SNS. Moderate
confidence for IFR/MVFR ceilings to linger throughout much of the
day at MRY while sky conditions have scattered out at SNS. Onshore
winds will increase this afternoon before easing after sunset.
High confidence for IFR/MVFR ceilings to return this evening and
lower to LIFR at times early Monday morning.

&&

.MARINE...
(Today through Friday)
Issued at 1048 AM PDT Sun Jul 6 2025

Fresh northwesterly breezes will continue today for the outer
waters and coastal jet regions of Point Reyes and Point Sur. Winds
gradually begin to slack Monday with moderate to fresh breezes
forecast through Wednesday with a surface low positioned over the
outer waters. Northwesterly winds increase and significant wave
heights build beginning late in the week.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
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...RGass
MARINE...RGass

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