FXUS66 KMTR 220505
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
1005 PM PDT Tue Apr 21 2026
...New SHORT TERM, LONG TERM, AVIATION, MARINE...
.KEY MESSAGES...
Updated at 1004 PM PDT Tue Apr 21 2026
- Cool conditions Wednesday with lingering showers through the
morning
- Seasonal temperatures and dry conditions arrive Thursday
- Monitoring potential rain and drizzle this weekend into the
early part of next week
&&
.SHORT TERM...
Issued at 1004 PM PDT Tue Apr 21 2026
(Tonight through Thursday)
It was a pretty active day on Tuesday with quite a bit of lightning
reported across the Bay Area and Central Coast, and a funnel cloud
reported near Fremont. The chances for convection have basically
shut down as with the lack of solar heating, and while lingering
isolated showers are possible through the rest of the morning, not
expecting convection to be an issue through Wednesday. Beyond the
lingering showers, skies will be generally clearing Wednesday
morning with mostly sunny conditions and a gentle onshore breeze
developing by the afternoon hours. Low temperatures this morning
range from the upper 30s to the middle 40s in the inland valleys, to
the upper 40s and lower 50s near the coast and the Bays. High
temperatures on Wednesday are close to the upper 50s to the middle
60s in the lower elevations, with a slight warming gradient towards
the inland valleys, and the upper 40s to middle 50s at the higher
elevations.
&&
.LONG TERM...
Issued at 1004 PM PDT Tue Apr 21 2026
(Thursday night through next Tuesday)
Temperatures will warm slightly for Thursday and Friday as a barely
noticeable ridge sets up over the region, with highs in the lower
elevations range from the lower 60s to lower 70s, close to or
slightly below the seasonal averages. Into the weekend, another
trough will come into the region and cause temperatures to dip
again, introducing slight chances for light rain and drizzle that
are expected to continue through the middle of next week. The latest
CPC outlook leans towards precipitation totals above the seasonal
averages heading into the first week of May, with the note that this
late into the spring, the daily seasonal average rainfall at
downtown San Francisco falls around two or three hundredths of an
inch.
&&
.AVIATION...
(06Z TAFS)
Issued at 1004 PM PDT Tue Apr 21 2026
Mid to high level clouds are expected through the night and into
Wednesday, with spotty and inconsistent low clouds possible. Showers
will linger into the night, but chances will continue to decrease
until the early morning where another wave of showers moves
along/adjacent to the low pressure center. As these morning showers
move through, expect multiple shifts in winds specifically around
the SF Bay. Rain rates will lead to modest reductions in
visibilities from this wave of rain. These showers exit into the
afternoon as moderate westerly winds build and skies begin to clear.
Winds weaken into Wednesday night, becoming light and variable in
the inland areas, while sites near the ocean see more northerly
winds.
Vicinity of SFO...Spotty, non-impactful showers are beginning to
dissipate. Mid-level clouds linger across the area into the night
with west winds turning more southwest as the low center arrives.
Shower activity returns as the low center focuses over the SF Bay
into Wednesday morning, and the winds will become shifty and
variable. Showers exit into early afternoon as winds turn southwest,
then west-northwest for the late afternoon. Winds will ease into
Wednesday night and turn northwest.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...Despite the unsettled weather, KMRY and
KSNS should mainly expect VFR conditions this TAF period with a
brief period of MVFR conditions brought on by passing rain showers.
The rain Wednesday morning should remain light and will cause CIGs
to lower. After the last shower passes through however, the cloud
bases will begin to lift. The onset of the rain is an estimation,
therefore there is a possibility it may begin slightly earlier or
later. This will be updated as needed.
&&
.MARINE...
(Tonight through next Monday)
Issued at 1004 PM PDT Tue Apr 21 2026
Light pop-up showers are moving through the waters, but offer
little impacts. Additional showers will be possible into Wednesday
morning but these chances erode into that afternoon. As the
weather breaks on Wednesday, winds will shift to a moderate NW
breeze, before increasing to a fresh breeze on Thursday. Winds and
seas ease into the weekend.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 3 AM to 3 PM PDT Thursday for Pt Arena
to Pt Reyes 10-60 NM.
&&
$$
SHORT TERM...DialH
LONG TERM....DialH
AVIATION...Murdock/AN
MARINE...Murdock
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Prepared by Boulder-Creek.com Weather at: Wed Apr 22 00:30:02 PDT 2026
From the National Weather Service
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