FXUS66 KMTR 080655
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
1155 PM PDT Wed Oct 7 2026
...New SHORT TERM, LONG TERM...
.KEY MESSAGES...
Updated at 1259 PM PDT Wed Oct 7 2026
- Hot inland temperatures continue Thursday
- Sharp cool-down this weekend and early next week
- Coastal flooding during high tides and large swell this
weekend
- Light rain possible early next week
&&
.SHORT TERM...
Issued at 1155 PM PDT Wed Oct 7 2026
(Tonight through Sunday)
Strong 500 mb high pressure ridging bringing inland areas hot
and dry weather will continue into Thursday. Well above early
October normal temperatures occurred again today, though none of
the long term stations set any new record highs today. The Heat
Advisory (WMO header WWUS76) for inland areas continues through
10 pm PDT Thursday. And a reminder there is a Coastal Flood
Advisory (WHUS36) for anomalous high tides with up to 1.2 feet of
inundation above ground level in low-lying areas.
As mentioned it'll be hot again inland Thursday while cooler
temperatures will prevail along the immediate coastline within a
compressed marine layer. NBM forecast highs were nudged downward
slightly for much of the immediate coastline for Thursday. Global
models continue to indicate a major pattern shift will take place
over the western states beginning later tomorrow through Friday.
A weak 500 mb low ~ 900 miles to our west will progress toward our
forecast area allowing part of the aforementioned 500 mb high
pressure ridge to slip westward (retrogressing) far to our west.
Separate strengthening 500 mb troughing will take place over the
Pacific Northwest; long wave troughing will begin to replace long
wave ridging over the west. Mid-latitude amplification and winds
will move the 500 mb trough southward, decidedly shifting the pattern
south and east including the near term weak 500 mb low just out
ahead of it and the rest of the 500 mb ridge. This pattern shift
will bring in much cooler air from the surface up through 500 mb
across the forecast area through the weekend.
Winds will become gusty over the coastal waters and gap winds will
increase as well during the weekend, both Saturday and perhaps Sunday
with gusts possibly nearing wind advisory level in the usual wind
favored gaps across the San Francisco Peninsula and the East Bay.
&&
.LONG TERM...
Issued at 1155 PM PDT Wed Oct 7 2026
(Sunday night through next Wednesday)
Winds over land diminish later Sunday. There may be some residual
moisture the cold core low will tap producing a few showers over
the southern forecast area later Sunday and Monday. Otherwise dry
and much cooler weather is forecast later Monday, Tuesday and
Wednesday. Daytime highs and lows will shift to below normal.
Daytime highs will generally be in the 60s coast to the 70s
inland. Night-time and morning lows will mostly be in the 40s
except around 50 at the coast and as cold as the 30s far inland
valleys.
&&
.AVIATION...
(06Z TAFS)
Issued at 949 PM PDT Wed Oct 7 2026
Stratus is filling in along the coast with ceilings and
visibilities dropping at HAF. The forecast remains more
complicated for MRY and SNS where stratus is filling in much more
slowly than originally anticipated within the Monterey Bay. The
Monterey Buoy shows an air temperature of 59 degrees and a sea
surface temperature of 65 degrees - indicating a good upwards
transport of warm moist air and increasing likelihood of fog
development. Thus, did not want to nix the mention of fog for
MRY/SNS but did push it back by a few hours. Conditions are
expected to improve by late morning but a deepening marine layer
Thursday night into Friday should allow for an earlier stratus
return along the coast (closer to 00Z than 06Z). Similar to last
night, satellite shows some tendrils of stratus extending into the
North Bay/San Francisco Bay areas but confidence is low that
stratus will impact interior airports. Otherwise, moderate onshore
winds continue during the afternoon and evening with lighter,
variable to offshore winds continue overnight.
Vicinity of SFO...VFR. Satellite shows some low level stratus on
the other side of the San Bruno Gap but confidence is low that it
will reach the airport at this time. If stratus does reach SFO it
is likely to be temporary in nature and not persist through the
entire night. Breezy onshore winds expected during the afternoon
and evening before winds weaken overnight.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...As mentioned above, stratus is slowly
filtering into the Monterey Bay towards MRY and SNS. LIFR to IFR
conditions are expected overnight as fog/low level stratus
arrives. Confidence is slightly higher in fog development at MRY
than SNS where most models have backed off of fog development
tonight. Conditions look to improve by late morning before an
early return of stratus tomorrow evening thanks to a deepening
marine layer (approx. depth of 1000 ft). Moderate onshore winds
continue during the day before winds weaken overnight.
&&
.MARINE...
(Tonight through next Tuesday)
Issued at 949 PM PDT Wed Oct 7 2026
A moderate to fresh northwesterly breeze and moderate seas
continues through Thursday. A deep upper level trough will arrive
Friday into the weekend and bring a return of strong to gale
force northerly winds, rough to very rough seas, and wave heights
between 10 to 15 feet. Conditions will be hazardous for small
craft with small craft advisories to be issued for this event. The
sea state will be very active as long period southerly swell and
very long period westerly swell arrive this weekend into next
week. Expect longer than normal lulls in between wave groups due
to the long periods of the incoming swell groups.
&&
.FIRE WEATHER...
Issued at 410 AM PDT Wed Oct 7 2026
Hot and dry conditions will lead to elevated fire weather conditions
across the higher terrain through Thursday. Temperatures 10 to 20
degrees above normal and poor minimum relative humidity will
continue away from the compressed marine layer at the coast. The
higher terrain will experience active thermal belting, little-to-no
recovery with nocturnal drying across the highest peaks, and thus
prolonged burn periods. Winds remain the limiting factor, with
diurnal winds prevailing except for light northerly/offshore flow
overnight across the higher terrain. ERC values will rise to near
records during the hot and dry conditions. A pattern change Friday
into the weekend will bring cooler, moister, and windier
conditions.
Sarment
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Coastal Flood Advisory from 9 AM Friday to 3 PM PDT Tuesday for
CAZ006-508-529-530.
Heat Advisory until 10 PM PDT Thursday for CAZ503-504-506-508-
510-512>518.
Coastal Flood Advisory until 4 PM PDT Wednesday for CAZ506.
PZ...Small Craft Advisory from 3 AM to 3 PM PDT Friday for Pt Arena
to Pt Reyes 10-60 NM.
&&
$$
SHORT TERM...Canepa
LONG TERM....Canepa
AVIATION...Kennedy
MARINE...Kennedy
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Prepared by Boulder-Creek.com Weather at: Thu Oct 8 02:30:03 PDT 2026
From the National Weather Service
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