FXUS66 KMTR 162359
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
459 PM PDT Thu Apr 16 2026
...New AVIATION, MARINE...
.KEY MESSAGES...
Updated at 112 PM PDT Thu Apr 16 2026
- Periods of gusty offshore winds, especially at higher
elevations, continue through early Friday morning
- Seasonably warm temperatures expected Friday and Saturday
- Cooler temperatures and beneficial rain Sunday into early next
week
&&
.SHORT TERM...
Issued at 112 PM PDT Thu Apr 16 2026
(This evening through Friday)
Gusty offshore winds continue across the higher terrain through late
Friday morning as a deep upper level trough pushes into the Northern
Rockies. The strongest gusts are expected across the Vaca Range and
the Mayacamas Range in Sonoma and Napa Counties respectfully. Winds
shifted offshore (north to northeast) early this morning with Mt.
St. Helena reporting a peak gust of 58 mph at 9:30AM this morning.
Outside of the highest peaks (including Mt. St. Helena), gusts are
expected to peak between 35 to 45 mph with locally stronger gusts
across the highest peaks/ridgelines. Winds ease slightly this
afternoon/evening before restrengthening tonight into Friday
morning. By late Friday morning, winds will diminish across the
higher elevations as the deep upper level trough progresses eastward
and ridging builds over the West Coast. Very dry daytime conditions
continue across the interior today and tomorrow due to the moderate
offshore winds. Overnight humidity recoveries will be good along the
coast but poor across the interior higher terrain (where gusty
winds continue throughout the night). Fire concerns remain minimal
thanks to the recent wetting rains and the upcoming wetting rains
next week.
Seasonal high temperatures in the 60s to low 70s continue across the
interior while highs in the 50s to 60s prevail along the coast.
Friday morning continues to look chilly as clear skies overnight
will lead to increased radiational cooling. Much of the region will
see low temperatures in the 40s on Friday while portions of the
eastern Santa Clara Hills and the interior Central Coast drop into
the 30s. Residents in the vicinity of Parkfield and Bradley
(Monterey County) will see temperatures drop into the low 30s. By
the afternoon, chilly temperatures will be a distant memory with
highs rising back into the low to mid 70s across the interior and
50s to 60s along the coast. This slight warming trend will continue
into Saturday as upper level ridging rebuilds over the West Coast.
&&
.LONG TERM...
Issued at 112 PM PDT Thu Apr 16 2026
(Friday night through next Wednesday)
Seasonably warm temperatures continue into Saturday as upper level
ridging builds. Interior highs will peak in the mid to upper 70s
with coastal areas staying in the 60s. Temperatures start to cool
Sunday as the ridge progresses east with seasonal temperatures in
the 60s to low 70s expected across most of the region. Seasonably
warm temperatures continue for one more day across the interior
Central Coast where highs linger in the mid to upper 70s. As the
ridge exits, a deep upper level trough will push into the West Coast
with an associated weak surface low and cold front. Model guidance
is still split as to when the trough will arrive. The GFS favors a
slower arrival (more so Monday-Tuesday) whereas the ECMWF favors a
slightly faster arrival late Sunday into Monday. In terms of
ensemble cluster guidance, three of the five clusters support a
stronger low that lingers offshore of California Sunday through
Tuesday. The other two clusters support a more progressive low that
moves inland faster. If the cut-off low lingers offshore, rather
than progressing inland, that may allow the storm to overperform
slightly and see higher amounts of rain across the region.
Thunderstorms are also possible Monday and Tuesday afternoons with
around a 10-20% chance of thunderstorms on Tuesday. Guidance shows a
few hundred joules of MUCAPE with decent lift and moisture from the
low. Models are showing early potential for a NCFR to develop on
Tuesday which will be interesting to see how it evolves as this
system gets closer in time. Rainfall totals from this event are
still beneficial with around 1.5-2.5" expected across the North Bay,
1-2" across the coastal mountain ranges, and 0.5-1.0" across the
lower elevations. Locally gusty onshore winds are expected Monday
into Tuesday along the coast and across the higher elevations but
winds are forecast to stay below Wind Advisory criteria.
Temperatures drop into the 60s across the region starting Monday and
remain there through midweek while morning lows remain in the 40s to
low 50s.
&&
.AVIATION...
(00Z TAFS)
Issued at 450 PM PDT Thu Apr 16 2026
VFR through the the TAF period thanks to dry low levels and an
offshore flow. The offshore flow comes with a price, LLWS. Left
LLWS in for STS/OAK/APC. Removed LLWS for SFO/LVK as both of those
sites are marginal. LLWS threat ends early Friday with onshore
flow returning at the surface.
Vicinity of SFO...VFR. Onshore gusts 25-30KT then switching to NE
around 06Z with decreasing winds. Onshore flow returns Friday
afternoon after 18Z.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...VFR. Offshore flow will kick in overnight
and last through Friday AM. NW flow returns tomorrow afternoon.
&&
.MARINE...
(Tonight through next Tuesday)
Issued at 450 PM PDT Thu Apr 16 2026
Building high pressure to the north will keep moderate to strong
breezes over the coastal waters through at least this evening.
Locally stronger gale force winds will occur north of Point Reyes
over the outer waters. The stronger winds will result in hazardous
conditions with rough seas. Winds will ease back to moderate
northwest breezes Friday through Saturday, allowing seas to
gradually subside.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 9 PM PDT this evening for Mry Bay-
Pigeon Pt to Pt Pinos 0-10 nm-Pt Arena to Pt Reyes 0-10 nm-
Pt Reyes to Pigeon Pt 0-10 nm.
Small Craft Advisory until 3 AM PDT Friday for Pigeon Pt to Pt
Pinos 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm.
Gale Warning until 9 PM PDT this evening for Pt Arena to Pt
Reyes 10-60 NM.
&&
$$
SHORT TERM...Kennedy
LONG TERM....Kennedy
AVIATION...MM
MARINE...MM
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Prepared by Boulder-Creek.com Weather at: Thu Apr 16 18:30:03 PDT 2026
From the National Weather Service
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