FXUS66 KMTR 082337
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
437 PM PDT Tue Sep 8 2026
...New AVIATION, MARINE...
.KEY MESSAGES...
Updated at 218 PM PDT Tue Sep 8 2026
- Warming and drying trend will bring widespread moderate to
major HeatRisk through Thursday
- Cooler temperatures, closer to normal, Friday into the weekend
&&
.SHORT TERM...
Issued at 218 PM PDT Tue Sep 8 2026
(This evening through Wednesday night)
Temperature's early this afternoon are running 5-10 degrees warmer
than they were at this time 24hrs for most locations across our
area, including the coastal communities. A weak fetch of offshore
flow aloft with a weaker unorganized signal at the surface is still
holding back the marine layer influence from penetrating farther
inland. Decided to start the Heat Advisory this afternoon instead of
Wednesday morning due to warmer than normal temperatures overnight
beginning tonight along with the warmer than normal daytime
temperatures. With a shallow, unorganized marine layer persisting
through tonight and Wednesday, decided to increase temperatures
slightly for Wednesday to lineup more with current trends. Along
with a lack of a well organized marine layer, PWATs are expected to
gradually increase between now and Wednesday afternoon. As noted in
the previous forecast, we'll approach values that come close to
daily climatological records for this time of year. Although, some
high cloud cover is expected, we're not expecting enough to
significantly impact daytime max temperatures. That added moisture
will make for higher RH values with the warmer temperatures, making
for a muggy day and more heat related health impacts.
Please remember these tips to help mitigate impacts from heat exposure:
-Suspend unnecessary outdoor activities during the extreme heat, but
if you must be outdoors, take frequent breaks in the shade or AC
and drink cool water.
-Know the signs and symptoms of Heat Exhaustion vs. Heat Stroke!
Heat Stroke can be deadly if not treated immediately by a medical
professional. Call 911 if you suspect someone is suffering from Heat
Stroke.
-Wear a life jacket, swim near a lifeguard, and check conditions
before entering the water if going to a river or ocean to cool off.
Rivers and the ocean are extremely cold, and Cold Water Shock can
turn into paralysis and drowning if you are not careful.
-Use a cool and damp towel on your body if you do not have AC and
are feeling hot. Or, take a cool shower or bath.
-Do not leave kids or pets in a parked car.
-Ensure pets and livestock have access to shade and water.
&&
.LONG TERM...
Issued at 218 PM PDT Tue Sep 8 2026
(Thursday through next Monday)
The pattern change from high heat to cooler will highlight the
challenge going in to the long term forecast. Confidence is high
that the pattern change will occur and we'll see a notable cool
down. However, there may be some room in the forecast for the end
of the weekend into the beginning of next week for temperatures to
be higher than currently forecast depending on how progressive an
upper level system across the Great Basin moves inland and
suppresses the top of the ridge currently producing the warm
temperatures.
&&
.AVIATION...
(00Z TAFS)
Issued at 431 PM PDT Tue Sep 8 2026
VFR across the board. STronger onshore flow will bring some breezy
conditions this evening and again tomorrow afternoon/evening.
Vicinity of SFO...VFR with a few high clouds. Gusty onshore flow
tomorrow with gusts up to 20 kt.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...VFR...watching some low clouds/fog
develop in Monterey Bay and moving toward the peninsula. Low conf
on impacts to MRY,but a 20-30 pct chc of low clouds impacting SNS
overnight. Conf is not high enough to include them for SNS at this
time, but will monitor for 06z package.
&&
.MARINE...
(Tonight through next Sunday)
Issued at 431 PM PDT Tue Sep 8 2026
Gentle to moderate northwesterly breezes will prevail through
Wednesday, increasing to become fresh to strong Thursday afternoon
into the weekend. Slight to moderate seas will prevail, building
to become rough in the outer waters Friday into Saturday.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Heat Advisory until 10 PM PDT Thursday for CAZ006-502>506-
508>510-512>518-528>530.
Coastal Flood Advisory from 8 PM this evening to 1 AM PDT
Thursday for CAZ006-506-508-529-530.
PZ...None.
&&
$$
SHORT TERM...JM
LONG TERM....JM
AVIATION...MM
MARINE...Sarment
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Prepared by Boulder-Creek.com Weather at: Tue Sep 8 18:30:03 PDT 2026
From the National Weather Service
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