FXUS66 KMTR 191142
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
442 AM PDT Tue May 19 2026
...New AVIATION, MARINE...
.KEY MESSAGES...
Updated at 1026 PM PDT Mon May 18 2026
- Diurnally driven winds, with onshore winds during the afternoon
and early evening.
- Above normal temperatures continue through midweek with seasonal
temperatures returning late week
&&
.SHORT TERM...
Issued at 1026 PM PDT Mon May 18 2026
(Tonight through Tuesday)
The forecast appears to be on track, with broad upper level
troughing holding over much of the western U.S. while high pressure
builds over the eastern Pacific. The good news, is that our breezy
offshore winds have eased substantially leaving us with fairly calm
weather in return. Tonight, skies will remain clear and temperatures
will generally fall into the 50s for the valleys, perhaps upper 40s
for some coastal sites and the southern Salinas Valley. At higher
elevations, a thermal belt will exist as temperatures fall into the
mid 50s to low 60s and may still have some northerly winds. For
those in the valleys, winds will generally be light and variable.
Tomorrow, another warm day will be on tap. The question will be, how
do the temperatures pan out? Offshore flow won't be as prevalent,
which means there could be less of a downsloping / warming of the
air affect. But, that upper level high slowly creeps towards us and
the marine layer is essentially negligible. Opted to blend a bit of
the observations from Monday to the NBM giving us a similar
forecast, to what occurred yesterday. The interior Bay Area valleys
should make it into the 80s, perhaps near 90 degrees, while coastal
communities experience a tighter gradient of highs in the 60s to low
70s. The San Francisco Peninsula should be similar, with the Pacific
side having temps range from the mid 60s to low 70s, while the Bay
side ranges from the upper 70s to mid 80s. And finally the Central
Coast, interior locations rise into the mid 70s to mid 80s, while
coastal communities vary from the mid 60s to the low 80s.
&&
.LONG TERM...
Issued at 1026 PM PDT Mon May 18 2026
(Tuesday night through next Monday)
No major changes to the extended forecast. Upper level troughing
looks to keep hold over the western US through at least Wednesday,
with that Pacific high slowly peeking into northern CA. This should
bring a return of onshore flow to the region and eventually the
marine layer. Warm weather looks to linger through at least
Wednesday, with Thursday potentially seeing a slight change in
temperatures if the marine layer develops. Guidance for Thursday
caps it at 500ft at best, with the marine layer getting to 1000ft by
Friday. The marine layer appears to better establish itself Friday
night into Saturday, likely getting to around 1000ft again. Will
need to keep an eye on this as it will affect how temperatures pan
&&
.AVIATION...
(12Z TAFS)
Issued at 436 AM PDT Tue May 19 2026
VFR through the forecast period. There is a 15-25% chc of seeing
MVFR CIGs by the very end of the TAF period. Not high enough
confidence to include in TAF just yet. Breezy onshore flow
expected again this afternoon.
Vicinity of SFO...VFR. Light NE flow expected this AM then switch
onshore this afternoon with gust up to 20 kt.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...VFR. Hedging toward the 20-25% for some
CIGs developing by 12Z Wednesday.
&&
.MARINE...
(Today through Sunday)
Issued at 436 AM PDT Tue May 19 2026
The overall sea state continues to improve with decreasing winds
and seas. Fresh northerly breezes will persist over the outer
waters north of Pigeon Point leading to hazardous conditions
through at least Wednesday night.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 9 AM PDT this morning for Pigeon Pt
to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm-Pt Reyes
to Pigeon Pt 0-10 nm.
Small Craft Advisory until 9 PM PDT Wednesday for Pt Arena to Pt
Reyes 10-60 NM.
&&
$$
SHORT TERM...KR
LONG TERM....KR
AVIATION...MM
MARINE...MM
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Prepared by Boulder-Creek.com Weather at: Tue May 19 06:30:03 PDT 2026
From the National Weather Service
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