FXUS66 KMTR 231124
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
324 AM PST Mon Feb 23 2026
...New AVIATION, MARINE...
.KEY MESSAGES...
Updated at 116 AM PST Mon Feb 23 2026
- Above normal temperatures and dry conditions today
- Widespread rainfall returns tonight into Tuesday
- Warming and drying trend kicks off Wednesday
&&
.SHORT TERM...
Issued at 116 AM PST Mon Feb 23 2026
(Today and tonight)
Surface high pressure will dominate most of today's weather with
above normal temperatures and dry conditions prevailing. The only
caveat to the dry conditions would be if an isolated rain shower
skirts the North Bay. Nonetheless, no adverse impacts are expected
from these rain showers.
&&
.LONG TERM...
Issued at 116 AM PST Mon Feb 23 2026
(Tuesday through Sunday)
A developing gale force low pressure system off the Northern
California Coast will pull in moisture from the tropics as it heads
toward the Washington/Canada border. ECMWF and GEFS ensemble mean
IVT forecast peaks in excess of 500 kg/ms Tuesday morning, quickly
decreasing as the moisture plume sinks south, with PWAT values
forecast to break the daily maximum record. Even with rich moisture
content, poor dynamics are expected to yield generally beneficial
rainfall, especially south of the Golden Gate Bridge. Light to
moderate rainfall is expected with low probabilities (10%) of
exceeding 0.50"/hour which even then is exclusive to the North Bay.
Ponding and slick roadways can still be expected. Any flooding will
likely be more of a product of infrastructure (clogged storm drains,
etc.) rather than the rain itself. No mainstem river flooding is
expected. The pattern and the location of the low leads to high
confidence that the North Bay will receive the highest rainfall
totals as they will be under the influence of pre-frontal rain
showers before the cold front progresses through. As such, minor
flooding in low-lying, poor drainage, and urban areas will be
possible and if rain rates get high enough, shallow landslides will
be possible. The source region of the moisture (off to our
southwest) will result in the highest rainfall totals in southwest
facing terrain with the help of orographic lift. Lee side valleys
will get rain shadowed. Global ensemble clusters are in agreement
that surface high pressure in Baja California will quickly rebuild
after Wednesday morning's cold frontal passage. A warming and drying
trend will result, with temperatures climbing to 10 degrees above
normal by Friday. Uncertainty arises this weekend in the evolution
of the troughing over the Eastern Pacific Ocean. The official
forecast advertises a slight cooling trend with the passing of a
system to the north of us.
&&
.AVIATION...
(12Z TAFS)
Issued at 324 AM PST Mon Feb 23 2026
Generally VFR throughout the region with some MVFR-IFR ceilings
within the North Bay and the immediate coast, as isolated to
scattered showers pass by. An onshore push of wind will develop this
afternoon and evening, although wind speeds remain light to gentle.
Overnight, some MVFR-IFR ceilings could develop at the North Bay and
the immediate coast as widespread rainfall approaches the region.
Timing for the rainfall is in question as some high resolution
models are showing a later approach than the current TAFs reflect.
Vicinity of SFO... VFR with mid- to high level clouds through the
day. Winds remain generally light through the day, before a gentle
southerly push begins late in the evening. At OAK, moderate
confidence for some stronger south winds on Tuesday morning. Rain
and the possibility of MVFR ceilings arrives tonight, with low to
moderate confidence on the timing of the rainfall.
SFO Bridge Approach... Similar to SFO.
Monterey Bay Terminals... VFR expected through the day with light
drainage flow turning to the northwest this afternoon and evening.
High resolution models show some passing showers and potential MVFR
ceilings passing through right at the end of the 24-hour TAF period,
but confidence is low in timing and impacts.
&&
.MARINE...
(Today through Saturday)
Issued at 324 AM PST Mon Feb 23 2026
Southerly winds and seas are diminishing across the coastal
waters today except across the far northwestern waters. Rain
chances continue across the northern waters then spread farther
south Monday night through Tuesday night. Winds and seas increase
tonight into Tuesday then ease by Wednesday. Dry weather prevails
late this week.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 9 PM this evening to 3 PM PST Tuesday
for Pt Arena to Pt Reyes 0-10 nm.
Small Craft Advisory from 3 AM to 3 PM PST Tuesday for Pt Reyes
to Pigeon Pt 0-10 nm.
Small Craft Advisory until 3 PM PST Tuesday for Pt Arena to Pt
Reyes 10-60 NM.
&&
$$
SHORT TERM...Sarment
LONG TERM....Sarment
AVIATION...DialH
MARINE...DialH
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Prepared by Boulder-Creek.com Weather at: Mon Feb 23 04:30:03 PST 2026
From the National Weather Service
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