FXUS66 KMTR 091900
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
1100 AM PST Mon Feb 9 2026
...New SHORT TERM, LONG TERM...
.KEY MESSAGES...
Updated at 1057 AM PST Mon Feb 9 2026
- Widespread rain chances start Tuesday and linger through early
Thursday, which 75% chances of at least 1.50" in the Santa
Lucias
- General thunderstorm potential Tuesday afternoon through early
Wednesday brining chances for isolated thunder, gusty winds,
small hail, and brief heavier rain
- Strengthening south winds Tuesday into early Wednesday could
produce gusts up to 40 mph in the high terrain of the central
coast, peaking late Tuesday
- A break in rain chances late Thursday into Friday, then rain
chances return Saturday and linger through early next week
&&
.SHORT TERM...
Issued at 1057 AM PST Mon Feb 9 2026
(This afternoon through Tuesday Night)
Mid to high level clouds are exist over much of the state today as
the storm track under goes a shift. Near the surface a cold front
existed the central coast of CA early this morning and ushered in
cooler air, with 24 hour temperature trends generally around 2 to 8
degrees cooler than yesterday. Light north winds behind the weak
boundary have been able to succumb to local influences with terrain
and coastal interactions, however a few higher elevation
observations do show north to northeast winds with occasional gusts
up to 15 to 20 mph (Santa Cruz Mts, Diablo Range, and some
East/North Bay Mts).
Current satellite places an upper trough and surface cyclone around
600 miles off the coast of northern CA today. This upper trough will
dig southeast and strengthen as the surface cyclone meets a
stationary boundary located to the southeast. This places the
location of these features around 300 miles off the coast of central
CA tonight into Tuesday morning. The upper wave will become a closed
low as these surface features phase and more moisture gets thrown in
the mix. The upper closed low continues to deepen Tuesday as it
rotates from positive to a more neutral tilt. This will also sling
the deepening surface cyclone to the northeast as reaches ~1001 mb
to 1005mb. Strong winds wrapping around these features will be
reflected all the way down to the surface.. with a 925mb to 850mb
jet of 35 to 45kts that moves over the central coast Tuesday
afternoon into Tuesday night. The track doesn't quite align for
stronger southeast winds down the Salinas Valley, and initial
gradients from KSNS-KPRB remain around 1.6 to 2.2mb which points
to lower confidence in winds trending stronger up the Salinas
Valley as we get closer. The higher terrain is a different story
with the stronger winds aloft. 12Z HREF probabilities 75% chances
of at least 35 to 45 mph gusts in the higher terrain of the Santa
Lucias and Diablo Range... with 25% chances for 45 to 55 mph.
Winds will begin to strengthen midday Tuesday, but peak in these
areas later Tuesday evening and night.
A little after winds start to strengthen (Tuesday afternoon and
evening) the upper closed low and surface cyclone will eventually
land just right off the coast. Through the afternoon upper heights
will trend down and increase mid-level lapse rates, as well as a
quick window of isentropic ascent should move in with ample moisture
(PWATs increasing to ~0.8"). Some lighter rain and clouds could be
realized Tuesday afternoon as things approach. As lapse rates
increase, instability will also increase. Rain will eventually
become more widespread Tuesday evening with embedded showers and
storms. Wind shear does exist, and will generally have more of a
speed shear component.. however local terrain and coastal influences
will very likely generate enhanced directional shear. Cooler air
aloft, will help with ice forming and therefore lightning/small hail
potential exists with some storms. Gusty winds and a few water
spouts are not out of the question either. Locally heavier rainfall
with storms will be seen too, however storms will be moving and the
low will be wiggling around Tuesday night... leading to low
confidence in training or stalling issues of storms.
&&
.LONG TERM...
Issued at 1057 AM PST Mon Feb 9 2026
(Wednesday through next Sunday)
Wednesday morning, another piece of energy will rotate along the
west side of the upper closed low... which will keep it centered
over central CA through early Thursday. Although the features linger
over the CWA, they will weaken starting Wednesday morning. Clouds
and light to occasionally moderate rain at times will be seen
Wednesday into early Thursday. Wind will gradually weaken Wednesday
morning, with the stronger gusts likely remaining confident to the
central coast (more details in short term section).
As the upper troughing exits to the south, upper ridging will build
in for later Thursday and into Friday. A break in rain chances will
be seen, with more sunny skies and temperatures slightly warming.
Chances for a quick return to a wet pattern continue to increase.
Starting Sunday, an upper trough will start to dig southward along
the state returning beneficial rain and cooler temperatures. Weaker
surface features look to accompany this system, resulting in higher
confidence in light to moderate rain... beneficial rain. The upper
trough continues to dig south and amplify into early next week,
which should continue wet and cool conditions over the CWA.
&&
.AVIATION...
(18Z TAFS)
Issued at 944 AM PST Mon Feb 9 2026
We'll have plenty of mid/upper clouds streaming overhead this
period, which means minimal concerns about fog for tonight into
Tuesday morning. Right now, there is a surface low located at
about 33N, 135W out in the Pacific that will push NE toward the
central CA coast Tuesday evening. As this low approaches the CA
coast, a band of rain will move onshore. However, based on the 12z
HREF, this rain looks to hold off in central CA until after 18z
Tuesday, so it's only SFO and OAK that have a rain mention with
this TAF set, with all other terminals getting in on the -RA
action with the 00z TAF set.
Vicinity of SFO...-RA will be pushing in Tuesday afternoon.
20z-23z currently looks like the window for -RA onset. With the
rain will also come the potential MVFR cigs, though RAP forecast
soundings don't really show MVFR cigs moving in until just after
Wednesday 00z, so kept cigs VFR for now, though did drop the vis
to MVFR with the precip. Another issue for SFO will be wind
directions. With the surface low approaching from the southwest,
we'll have a pressure gradient that will support southeast winds
that will have the potential to put the field into a southeast
configuration Tuesday afternoon and evening. Besides MVFR cigs,
just lurking beyond the end of this period will be the threat for
some TS Tuesday evening as well.
SFO Bridge Approach...No issues expected with visual approaches
until rain begins moving into the Bay area Tuesday afternoon.
Monterey Bay Terminals...As the low approaches from the southwest
and southerly 925mb winds begin to approach the CA coast, RAP
soundings do hint at the potential for some stratus coming in off
the Pacific between roughly 12z and 16z. For now, added that SCT
cloud group at 12z to cover this threat at MRY. It doesn't not
look to be an issue for SNS.
&&
.MARINE...
(Today through Saturday)
Issued at 241 AM PST Mon Feb 9 2026
Fresh to strong northwest breezes prevail across the coastal
waters today. A low pressure system will then approach from the
west bringing rain to the coastal waters and bays Tuesday through
Wednesday. Gale force gusts are possible on Tuesday in the waters
south of the Golden Gate depending on the strength and track of
the low. Rain chances return next weekend.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 9 AM Tuesday to 3 AM PST Wednesday for
Mry Bay-Pigeon Pt to Pt Pinos 0-10 nm.
Small Craft Advisory until 9 PM PST this evening for Pt Pinos to
Pt Piedras Blancas 0-10 nm.
Gale Watch from Tuesday morning through Wednesday morning for Pt
Pinos to Pt Piedras Blancas 0-10 nm.
Small Craft Advisory until 3 AM PST Tuesday for Pt Arena to Pt
Reyes 10-60 NM.
Small Craft Advisory from 9 PM Tuesday to 9 AM PST Wednesday for
Pt Arena to Pt Reyes 10-60 NM.
Small Craft Advisory until 3 PM PST this afternoon for Pigeon Pt
to Pt Pinos 10-60 NM.
Small Craft Advisory from 3 PM Tuesday to 9 AM PST Wednesday for
Pigeon Pt to Pt Pinos 10-60 NM.
&&
$$
SHORT TERM...KR
LONG TERM....KR
AVIATION...BFG
MARINE...DialH
Visit us at www.weather.gov/sanfrancisco
Follow us on Facebook, X, and YouTube at:
www.facebook.com/nwsbayarea
x.com/nwsbayarea
www.youtube.com/nwsbayarea
Prepared by Boulder-Creek.com Weather at: Mon Feb 9 14:30:03 PST 2026
From the National Weather Service
|