778
FXUS66 KMTR 170832
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1232 AM PST Mon Nov 17 2025

...New SHORT TERM, LONG TERM...

.KEY MESSAGES...
Updated at 1218 AM PST Mon Nov 17 2025

 - A strong cold front is moving through early Monday morning,
   bringing heavy rain, strong winds, and a small chance for
   waterspouts.

 - Scattered showers will gradually decrease through Monday before
   drier weather returns Tuesday.

 - Next system brings more beneficial type rain late Wednesday
   through Thursday.

&&

.SHORT TERM...
Issued at 1218 AM PST Mon Nov 17 2025
(Today and tonight)

Full scale warning operations on the watchfloor as the cold front
comes ashore. Several cells over the coastal waters have
displayed rotational velocity of 30kts, indicating a legitimate
waterspout potential. Fortunately the trend has been for these
cells to lose structure as they come ashore, but we can`t rule out
our classic landfalling waterspouts causing some damage along the
coast from San Mateo to Monterey County over the next several
hours. While narrow and fast moving, the main band of rain has
been intense, with a weather spotter in Marin reporting over six
tenths of an inch in less than an hour. These high rain rates
could cause some land slides, especially after the recent wet
weather. This threat is highest over the Pickett Burn Scar, where
a flash flood warning is in effect. Winds have been gusting to
gale force and quickly diminishing after the frontal boundary
passes. In the post frontal environment the rain will transition
to lighter scattered showers and persist through the day on a
decreasing trend before drier weather moves in overnight.

&&

.LONG TERM...
Issued at 1218 AM PST Mon Nov 17 2025
(Tuesday through Sunday)

In the wake of todays exiting system to the south we`ll see
progressive, high amplitude ridging move across central California
Tuesday and Wednesday resulting in drier conditions while
temperatures remain cooler than normal. Tuesday will be mostly sunny
area wide, with gradually increasing cloud cover on Wednesday. The
remainder of the extended forecast lacks consensus for the timing
and evolution of what appears to be a similar type storm system that
we saw overnight and today. Rain chances begin to increase across
the North Bay Wednesday evening, spreading across our whole area
during the day Thursday, and exiting to the south by early Friday
morning. Rainfall totals and winds will not be as strong as we`ve
seen the last 24hrs, however the saturated soils may bring more
risks for land/rock slides. Very high surf looks likely late
Thursday and Friday. Next weekend looks mostly dry attm, with a
signal for another upper level low bringing increasing rain
chances early next week.

&&

.AVIATION...
(06Z TAFS)
Issued at 915 PM PST Sun Nov 16 2025

Currently a mixed bag of MVFR-VFR at the terminals with the cold
front beginning to move ashore. Rain showers will increase in
coverage and intensity as it does so with a couple/few hours of
moderate to heavy rainfall expected at each terminal
tonight/tomorrow morning. Southerly winds will continue to
strengthen and become gusty ahead of and during the cold frontal
passage. Behind the cold front rain showers will remain possible
and winds will slowly veer to become onshore. MVFR conditions will
generally prevail through the TAF period with further reductions
possible in the heaviest rain. There`s also a chance for
thunderstorms with this system, but confidence is not high enough
in timing and/or location to include in the TAFs at this time.

Vicinity of SFO...Currently VFR with southerly flow. Light rain
showers will give way to moderate rainfall in the next couple of
hours. The heaviest rainfall will be only a few hours long with post-
frontal rain showers possible through the morning. Southerly winds
will continue to increase up to and through the cold frontal
passage, slowly veering to become westerly behind it. There`s a
general chance for thunderstorms in the area, but confidence is not
high enough to include in the TAF.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Currently VFR with easterly flow at MRY and
VFR with drainage flow at SNS. Light rain showers will give way to
moderate rainfall in the next few hours. Southerly winds will
increase ahead of and through the cold frontal passage, slowly
veering to become westerly behind it. There`s a general chance for
thunderstorms in the area, but confidence is not high enough to
include in the TAF.

&&

.MARINE...
(Tonight through next Saturday)
Issued at 942 PM PST Sun Nov 16 2025

Widespread hazardous marine conditions will prevail through
tomorrow night. Moderate to heavy rainfall is expected through
mid-morning with rain showers expected through the afternoon.
Embedded thunderstorms will be possible, especially during the
cold frontal passage tonight and into tomorrow morning. Southerly
winds will increase to become strong and gusty ahead of and
through the cold frontal passage with isolated gale force gusts
possible. Strong northwesterly winds will develop behind the cold
front, slowly beginning to diminish Tuesday. Seas will build
tonight to become very rough for the inner waters and outer
waters, slowly beginning to abate by Tuesday.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 9 PM PST this evening for Mry Bay-
     Pigeon Pt to Pt Pinos 0-10 nm-Pt Arena to Pt Reyes 0-10 nm-
     Pt Pinos to Pt Piedras Blancas 0-10 nm-Pt Reyes to Pigeon
     Pt 0-10 nm-SF Bay N of Bay Bridge.

     Small Craft Advisory until 3 AM PST Wednesday for Pt Arena to Pt
     Reyes 10-60 NM.

     Small Craft Advisory until 3 PM PST Tuesday for Pigeon Pt to Pt
     Pinos 10-60 NM.

&&

$$

SHORT TERM...Flynn
LONG TERM....Merchant
AVIATION...Sarment
MARINE...Sarment

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