FXUS66 KMTR 091857
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco Bay Area
Issued by National Weather Service Eureka CA
1157 AM PDT Thu Jul 9 2026
.New AVIATION...
&&
.KEY MESSAGES...
Updated at 425 AM PDT Thu Jul 9 2026
- Warmer temperatures continues through the weekend
- Long period southwest swell causes an increased risk of sneaker
waves and strong rip currents through Friday
- Coastal Flood Advisory for up to 1.7 feet of inundation above
ground level is possible in low-lying areas near shorelines and
tidal waterways
- Potential for thunderstorms and elevated fire weather concerns
late this weekend into early next week
&&
.SHORT TERM...
Issued at 1244 AM PDT Thu Jul 9 2026
(Today and tonight)
Onshore winds are ushering stratus inland. 2.8 mb ACV-SFO and 3.0
mb SFO-SAC pressure gradients support northwest to west winds.
The 500 mb high pressure system centered over southern California
and northern Mexico will remain nearly stationary over the next
24 hours. Surface warming will mix out much of the stratus today
by late morning and afternoon. Daytime highs today will be in the
60s coastside, 60s/70s bayside to the 80s/90s inland.
Stratus returns tonight. Lows will be in the 50s except lower to mid
60s at higher elevations tonight.
&&
.LONG TERM...
Issued at 1244 AM PDT Thu Jul 9 2026
(Friday through Wednesday)
Global model guidance is consistent showing the 500 mb high
pressure system beginning to move northeastward Friday through
early next week. Daytime highs will be coolest along the coast
with 60s, 60s/70s bayside and in the 80s/90s inland to the lower
100s far inland mainly over the southern interior. Night-time lows
will cool to the 50s/60s.
Southerly winds aloft on the periphery of the high will transport
mid-level sub-tropical/tropical moisture to our forecast area
beginning Saturday night and Sunday and lasting through Tuesday
night. We'll continue to monitor the potential for a temporary
increase in mid level instability. At the earliest onset of
moisture arriving, recent 00z guidance from the NAM and RRFS are
mixed, the NAM shows pockets of instability to our southwest late
Saturday night to early Sunday, while the RRFS does not show any
mucape. 00z GFS continues to show essentially no mucape except
occasional pockets of mid-level mucape. We'll continue to monitor
the higher resolution models with each subsequent model run(s). A
possible limiting factor for convection over our forecast area is
500 mb height ridging is forecast to extend west from the eastward
departing 500 mb high center. If this occurs, broad anticyclonic
flow will be present, however can't completely discount embedded
thermal trough(s) within the broad anticyclonic flow given the
height field; summer weather systems can be a complex mix in the
various layers of the troposphere. There's currently good agreement
in this westward extending 500 mb ridge scenario in the ECMWF and
GFS, a good sign for less convective potential. At this time the
potential for convection is a low confidence forecast because of
the varied output seen so far. Please stay tuned to the latest
updates.
&&
.AVIATION...
(18Z TAFS) Issued at 1155 AM PDT Thu Jul 9 2026
W-NW flow brought stratus overnight but the vast majority has
since mixed out leaving VFR for all terminals except MRY and HAF.
The W-NW flow will likely be stronger today as the pressure
gradient tightens over the coastal waters resulting in wind
speeds higher than yesterday at most terminals. Stratus will
return overnight as the onshore flow persists with IFR to LIFR
conditions likely at most terminals into Friday morning.
Vicinity of SFO...Skies have cleared as SFO and VFR should persist
through the remainder of the day. W-NW winds gusting over 20 mph
can be expected this afternoon. MVFR or IFR ceilings will return
once again soon after sunset.
SFO Bridge Approach...Skies will remain clear today with a return
of MVFR/IFR ceilings overnight.
Monterey Bay Terminals...LIFR ceilings continue at MRY with an
eddy spinning over the bay pushing stratus toward the coast.
There is a 50/50 chance of a short window of VFR by mid-
afternoon, then IFR/LIFR returns after sunset through the
remainder of the forecast period. SNS has cleared and will see
several hours of VFR today followed by a return of IFR ceilings in
the evening.
&&
.MARINE...
(Today through Tuesday)
Issued at 425 AM PDT Thu Jul 9 2026
Fresh to strong northwest winds continue, increasing to near gale
force heading into the weekend. Wind driven rough seas (9-11 ft)
will persist into the weekend along with a long period southerly
swell.
&&
.FIRE WEATHER...
Issued at 425 AM PDT Thu Jul 9 2026
Warmer and drier conditions continue into this weekend. This
increases fire weather concerns slightly as fuels are forecast to
rapidly dry across the interior. Fire weather concerns further
increase late this weekend into early next week as a surge of
monsoonal moisture from the Gulf of California brings the
potential for high based convection to the region. If
thunderstorms are able to develop, dry lightning and gusty,
erratic outflow winds would be the main hazards. The current
pattern looks conducive for thunderstorms to develop but this may
change as the event gets closer in time. The main forecast concern
is the lack of instability across our region which may prevent
convection from developing. Given the combination of the potential
for dry lightning and rapidly drying fuels, it is important to
stay up to date on the forecast as it evolves.
&&
.BEACHES...
Issued at 425 AM PDT Thu Jul 9 2026
A Beach Hazards Statement remains in effect for Pacific coast
beaches through Friday afternoon. Long period southwesterly swell
will create an increased risk of sneaker waves and strong rip
currents, as well as breaking waves up to 10 feet. This will be
especially true for south and southwest facing beaches with
moderate to steep slopes along the North Bay, San Francisco
Peninsula, and Santa Cruz coasts. Sneaker waves can sweep across
the shoreline without warning, pulling people into the sea from
rocks, jetties and beaches. Dangerous swimming and surfing
conditions and localized beach erosion can be expected. Stay off
of jetties, piers, rocks, and other waterside infrastructure.
Remain out of the water to avoid hazardous surf and NEVER turn
your back on the ocean. Monitor local weather, surf and tide
forecasts at www.weather.gov/mtr.
A Coastal Flood Advisory is in effect for minor high tide
flooding through Thursday July 16th. The combination of a
perigean spring tide (lunar perigee on 7/13 and new moon on 7/14)
enhanced by 3-6 inches of additional water from thermal expansion
and accumulated sea level rise since the tidal datum was
established (1983-2001) will bring high tides up to 1.7 feet above
normal. This will lead to minor flooding of parking lots, parks
and roads with isolated closures expected. For context, in June we
reached 2.0 feet above normal.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement through Friday afternoon for CAZ006-505-
509-529-530.
Coastal Flood Advisory from 4 PM this afternoon to 4 AM PDT
Thursday for CAZ006-506-508.
Coastal Flood Advisory from 8 PM Saturday to 4 AM PDT Wednesday
for CAZ505-509-529-530.
PZ...Small Craft Advisory until 3 PM PDT Sunday for Pt Arena to Pt
Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM.
Small Craft Advisory until 3 AM PDT Friday for Pt Reyes to
Pigeon Pt 0-10 nm.
Small Craft Advisory until 9 PM PDT this evening for Pigeon Pt
to Pt Pinos 0-10 nm.
Small Craft Advisory until 3 AM PDT Saturday for Pigeon Pt to Pt
Pinos 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm.
&&
$$
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Prepared by Boulder-Creek.com Weather at: Thu Jul 9 12:30:04 PDT 2026
From the National Weather Service
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