111
FXUS66 KMTR 140521
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
921 PM PST Thu Nov 13 2025

...New AVIATION, MARINE...

.KEY MESSAGES...
Updated at 131 PM PST Thu Nov 13 2025

-Impactful storm system to continue through tonight

-Active weather pattern continues through next week

-Hazardous beach conditions persist

&&

.UPDATE...
Issued at 747 PM PST Thu Nov 13 2025

No changes to the forecast this evening as scattered showers are
being observed. Some of the 0Z hi-res models show some drier
weather overnight, but most keep showers lingering until the wee
morning hours. Some of the HREF members favor drier weather on
Friday, keeping chances south of San Francisco and over the
Central Coast. NBM highlights this area keeping PoP at about
25-40%.

&&

.SHORT TERM...
Issued at 131 PM PST Thu Nov 13 2025
(This evening through Friday Night)

Widespread rain showers continue to stream in ahead of a potent
upper low this afternoon. As far as wind headlines, we`ll maintain a
Wind Advisory for gusts near/above 45 mph across the Central
Coast. The Point Sur VWP continues to sample 0-1 km flow of at or
above 50 knots and this is generally in line with short-term
model guidance that advertises around 45-50 knots around 925mb.
Surface observations across this region also still indicate gusts
of 45 mph across interior San Benito, with gusts near or just
under 60 mph in a few spots along the Big Sur Coastline.

We`ll continue to see our band of showers persist through the
afternoon and into the early evening hours as forcing for ascent
continues across our area. Taking a look at some of the SPC MesoA
products, there still remains a small sliver of instability
across the extreme eastern portions of the Santa Clara Hills and
San Benito County, as well as far southern portions of Monterey
County. The overall trend, however, is diminishing, likely due to
the widespread rainfall that is flattening out mid/upper level
lapse rates. With 40 to 50 meter height falls and mid-level CAA,
there still seems to be a reasonable chance for thunder, at least
across the aforementioned geographic regions, but even this
potential is dwindling. Deep layer shear does remain plentiful,
but with the instability waning, the likelihood of organized
convective modes is on the decline. Still, we`ll monitor for any
transient low-topped organized convective modes.

For the rest of this afternoon and into the evening, our best
rain chances (and thus flood risk) will shift southward. The time-
lagged HRRR ensemble seems to align well with radar/satellite
presentations and in fact some of the precip-object tracking
items indicate that over the next 2-4 hours, the corridor of
heaviest rainfall will shift to the southern Big Sur Coastline.
This aligns well with short term NWP as the nose of the strongest
flow at 925mb will be focused here.

Upper troughing remains in place through the day on Friday. With no
real moisture being scoured out, we`ll maintain opportunities for
rainshowers. Not too atypical of these broadly forced scenarios,
there are a variety of solutions, all which have reasonable
outcomes (boom or bust). This results in a lower-confidence PoP
forecast. What I can say with confidence is that many if not most
areas will continue to have at least a 50 to 60 percent chance for
measurable rainfall given that we`ll still have broad ascent with
a moist regime (though PWATs will decrease). While it won`t
necessarily rain continuously through the day at all locales,
intermittent isolated to scattered precipitation will continue and
this is supported by hi-resolution model guidance.

Rain amounts this afternoon and into Friday night are anticipated
to average around 0.20-0.75" across the Bay Area to around 1"
across the Central Coast. Higher terrain such as the Santa Cruz
Mountains, the Diablo, Santa Lucia, and Gabilan Ranges could
average between 1-2" with isolated +3.5" (Santa Lucia) amounts.
This may support largely nuisance flooding across these areas.

&&

.LONG TERM...
Issued at 131 PM PST Thu Nov 13 2025
(Saturday through next Wednesday)

Confidence in a quasi-active weather pattern remains low to
moderate as the current upper trough is expected to detach from
the main flow and become a meandering upper low across the region.
As the parent low jogs eastward through the Central Valley, low
level 850-925mb theta-e advection will support ascent atop a
cool/moist airmass. Blended guidance seems very reasonable a PoP
gradient from near 10% or less across the North Bay to near 80%
across far southern Monterey and San Benito County.

By the end of the weekend into early next week, a broad upper
trough should kick our current low to the east. This next trough
is highly amplified and with the mid/upper level speed maxima
upstream of the main trough axis, there`s a chance that timing
could change. Cluster analysis indicates a wide array of
solutions with some scenarios advertising a swifter movement of
this feature to the east, while others delay the movement of the
trough. At any rate, large scale ascent support PoPs through just
about the entire outlook period. At this time rainfall amounts
Sunday afternoon and into Tuesday appear to be largely under 1.5",
however, we`ll fine-tune this forecast as we venture through the
weekend.

&&

.AVIATION...
(06Z TAFS)
Issued at 921 PM PST Thu Nov 13 2025

Isolated to scattered showers linger for the next few hours with
generally VFR with mid-level clouds and MVFR conditions prevailing,
barring HAF where IFR-LIFR stratus has formed. High-resolution
models are not picking up on the stratus and fog potential
overnight, but given the recent rainfall and potential radiational
cooling behind the stream of mid- to high-level clouds, will
continue with a moderate confidence for MVFR-IFR stratus development
overnight. Going for a more pessimistic 20-21Z clearing time for
most terminals on Friday, although this is a lower confidence
forecast. Winds will be light to gentle across the region on Friday
with a significant southerly component to the winds.

Vicinity of SFO... MVFR conditions through the night with isolated
showers possible through the next few hours. Stratus clears late
Friday morning through early afternoon. Light to gentle south
breezes prevail through the TAF period.

SFO Bridge Approach... Similar to SFO.

Monterey Bay Terminals... MVFR stratus expected to develop overnight
after the more scattered showers pass. Light drainage flow overnight
before gentle onshore winds resume Friday afternoon.

&&

.MARINE...
(Tonight through next Wednesday)
Issued at 921 PM PST Thu Nov 13 2025

Rough seas for the inner waters and very rough seas for the outer
waters continue through Friday, creating hazardous conditions for
small craft. Seas abate to become moderate by Saturday through
the weekend. Southerly winds will continue to abate into the
weekend with moderate to fresh breezes expected Friday night.
Chances for rain return to the southern waters on Saturday and
spread northward on Sunday through Monday.

&&

.BEACHES...
Issued at 124 AM PST Thu Nov 13 2025

A Beach Hazards Statement is in effect from this afternoon through
Friday evening. Long period westerly swell will result in an increased
risk for sneaker waves and rip currents. Breaking waves of 13 to 18
feet with the highest waves up to 23 feet in favored locations are
expected. Sneaker waves can unexpectedly run significantly farther
up the beach than normal, including over rocks and jetties. Rip
currents are typically more frequent and stronger in the vicinity
of jetties, inlets, and piers.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement through Friday evening for CAZ006-505-
     509-529-530.

PZ...Small Craft Advisory until 3 PM PST Friday for Pigeon Pt to Pt
     Pinos 0-10 nm-Pt Arena to Pt Reyes 0-10 nm.

     Small Craft Advisory until 9 AM PST Friday for Pt Reyes to
     Pigeon Pt 0-10 nm.

     Small Craft Advisory until 9 PM PST Friday for Pigeon Pt to Pt
     Pinos 10-60 NM-Pt Arena to Pt Reyes 10-60 NM-Pt Pinos to Pt
     Piedras Blancas 0-10 nm.

&&

$$

SHORT TERM...Bain
LONG TERM....Bain
AVIATION...DialH
MARINE...DialH

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