Bethel Island California Weather Forecast Discussion

120
FXUS66 KMTR 091757
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
1057 AM PDT Thu Oct 9 2025
...New AVIATION...
.KEY MESSAGES...
Updated at 151 AM PDT Thu Oct 9 2025
- Increasing clouds and cool with areas of drizzle
- Light rain chances increase Friday through Saturday morning for
the North Bay
- Confidence increasing for widespread wetting rain the first half
of next week
&&
.UPDATE...
Issued at 852 AM PDT Thu Oct 9 2025
Radar returns are showing a narrow boundary with light showers
extending from Marin and southern Sonoma Counties through the
inner waters off the San Mateo Peninsula and into the outer
waters off the Central Coast. The weather grids have been updated
to convert drizzle to rain through the rest of the day with some
increases in the forecast rain totals across the North Bay,
although the rainfall accumulations are still expected to be
relatively light with only the mountain peaks seeing totals
slightly over a tenth of an inch. Otherwise, the forecast remains
unchanged.
DialH
&&
.SHORT TERM...
Issued at 151 AM PDT Thu Oct 9 2025
(Today and tonight)
A surface trough extending from NorCal south to offshore of the
Central Coast will linger along the coastline today as the first of
several upper level shortwave troughs ejects east from the base of
the upper closed low to our north. Light rain and/or drizzle is
expected to persist across the North Bay most of today into tonight,
while coastal locations from the Bay Area south down to the Big Sur
will see periods of drizzle through most of the morning into the
early afternoon. As the upper low off the Pacific Northwest coast
deepens and slowly pushes onshore tonight into tomorrow a cold front
will drop temperatures in the North Bay into the mid-40s by early
Friday morning, with 50s most other locations, except for higher
elevation areas of the Central Coast that will also drop into the
40s.
&&
.LONG TERM...
Issued at 151 AM PDT Thu Oct 9 2025
(Friday through Wednesday)
Light rain chances linger across the North Bay Friday and begin to
taper off by early Saturday morning behind a second cold front that
won`t impact day time highs much, with temperatures rebounding under
sunny skies and a drier airmass Saturday afternoon. Upper level
shortwave ridging Saturday will result in a pleasant day area wide
under mostly sunny skies. Sunday will be similar to Saturday while
the upper level pattern shifts to zonal flow across the region. By
Monday the next rainmaker starts deepening to our north. Consensus
is improving with increasing confidence of multiple rounds of
wetting rain area wide from late Monday through Wednesday.
&&
.AVIATION...
(18Z TAFS)
Issued at 1045 AM PDT Thu Oct 9 2025
Generally VFR at terminals this morning, but pockets of MVFR are
passing through as well. MVFR and precip is most likely over the
North Bay as a weak boundary is stalled in that area through this
afternoon. Convective temps will be met leading to some strato-cu
this afternoon, which will briefing a SCT-BKN deck for portions
of the Bay Area. Despite some clouds heights should be VFR.
ANother system will approach late tonight and more so on Friday
bring some clouds/precip back to the North Bay toward the end of
the TAF pd. Overall conf is medium.
Vicinity of SFO...VFR with a few cu popping. Cigs will be in the
4-5k ft range. Lower cigs and VCSH still west of the San Bruno Gap
and over coastal waters.
SFO Bridge Approach...Same as SFO. Cig at the wrong place wrong
time could impact visuals occasionally in the afternoon.
Monterey Bay Terminals...VFR, but monitoring some cu popping to
the SW moving north. Cigs heights still look in the VFR range.
&&
.MARINE...
(Today through Tuesday)
Issued at 852 AM PDT Thu Oct 9 2025
Light precipitation is expected over the coastal waters,
especially south of Point Reyes. Light to locally moderate winds
will be shifting through tonight. Light rains build into the
waters through friday and exit into that night. Northwesterly
winds arrive Saturday and increase to a strong breeze that night,
building rough seas by Sunday. Disturbed conditions with periods
of rain and gusty winds are expected across the waters early next
week.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.
&&
$$
SHORT TERM...JM
LONG TERM....JM
AVIATION...MM
MARINE...MM
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NWS MTR Office Area Forecast Discussion