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NWS Technical
Weather Discussion |
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FXUS66 KMTR 152027
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
1227 PM PST Sun Nov 15 2026
...New SHORT TERM, LONG TERM...
.KEY MESSAGES...
Updated at 1225 PM PST Sun Nov 15 2026
- Rain arrives today through Monday
- High surf conditions through Tuesday morning
- Impactful system arriving Wednesday through Thursday
&&
.SHORT TERM...
Issued at 1225 PM PST Sun Nov 15 2026
(This evening through Monday night)
Light to occasionally moderate rain continues over the North Bay
as the cold front moves through the region. More steady rain is
forecast to move into the Bay Area around 1 PM, the Santa Cruz
Mountains and the South Bay around 5 PM, and then the north
Central Coast beginning between 7 PM and 9 PM and beyond into
Monday morning. In wake of the frontal passage, post-frontal rain
showers are forecast to persist through Monday afternoon if not
the rest of the evening. Rainfall from this even will largely be
beneficial, yet cannot rule out minor nuisance flooding in low-
lying and poor drainage areas.
Southerly winds are increasing ahead of this front, yet are
forecast to be weaker than Friday's system. Thus, expecting gusts
of 25 to 35 mph along the coast and through the favored gaps and
passes. Meanwhile, gusts up to 45 are forecast in the higher
terrain of the Bay Area. Winds have already becoming northwesterly
in areas of Marin and Sonoma county in wake of the frontal
passage.
A mix of sun and clouds are in the forecast for Monday afternoon,
yet isolated to scattered rain showers will still likely persist
over much of the region into Monday night.
&&
.LONG TERM...
Issued at 1225 PM PST Sun Nov 15 2026
(Tuesday through next Saturday)
From the previous forecaster: "A lull in the rainfall arrives
Monday night into Tuesday, with highs remaining cool across the
region. Cold temperature products (Frost Advisories and/or Cold
Weather Advisories) are possible for Tuesday morning, as lows in
the inland valleys drop into the middle 30s to lower 40s, which
could bring dangerous conditions to people living outdoors and
sensitive plants, especially when combined with the recent
rainfall making the body feel cooler.
Another system comes into the region beginning late Tuesday and
continuing into Wednesday, Thursday, and potentially early Friday.
This system is looking to be more impactful than the previous
two. On one hand, the associated low pressure system is expected
to slow down as it approaches California. The frontal rain band
would thus move slower as well, allowing for more rainfall to
accumulate at any particular location. On the other hand, as the
low comes into the state, it brings with it a strong jet at the
500 mb level that's aimed at the northern half of California.
Model guidance suggests that the jet could bring winds of 60 to 70
knots aloft as it comes across the SF Bay Area and Central Coast.
This would support wind gusts of 30 to 40 mph at the valley
floors and raise the possibility of Wind Advisories for the
coastal, Bayshore, and higher elevation regions. In addition, with
prior rainfall from the systems that came before the midweek
system arrives, flooding concerns will increase as soils saturate
and creeks and streams reach bankfull. This is in addition to a
model trend of remarkably higher rainfall totals across the region
from this system compared to the one we saw last Friday and the
one that's expected to arrive today. Although there's still time
for the final rain total to fluctuate, the current forecast
suggests 2 to 3 inches of rain across much of the Bay Area and
Central Coast while the coastal ranges see 3 to 5 inches of rain.
As a final note, the chance for thunderstorms has also continued
to increase and probabilities reach as high as 20-30% during
Wednesday and Thursday. The synoptic setup would favor convective
activity with a cold core low right over or very close to the Bay
Area and Central Coast, robust moisture flow, and the combination
of frontal and terrain-driven lift."
The WPC has added a Slight Risk (at least 15%) of Excessive
Rainfall from 4 AM Wednesday through 4 AM Thursday and a Marginal
Risk (at least 5%) from 4 AM Thursday through 4 AM Friday for much
of the region. This is highlighting the greater potential to see
flooding concerns. An active weather pattern is expected to
persist through the end of the month as the 8-14 CPC's Outlook
shows that precipitation is forecast to lean above average.
&&
.AVIATION...
(18Z TAFS)
Issued at 936 AM PST Sun Nov 15 2026
A mix of MVFR to VFR conditions as a cold front approaches from
the N. Since the 12Z TAFs slowed down onset timing of rain at
most terminals with transition to VCSH or -SHRA early Monday.
Vicinity of SFO...MVFR to VFR CIGs through this afternoon with
rain onset 20-22Z. Gradual improvement by Monday AM rush. VFR
Monday afternoon.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...VFR for most of the day with precip
arriving after 04-06Z. Enhanced SE flow for SNS through the period
as the front approaches.
&&
.MARINE...
(Today through Friday)
Issued at 849 AM PST Sun Nov 15 2026
Another cold front will move through the coastal waters bringing
unsettled weather with scattered light rain showers. Northwesterly
moderate to fresh winds develop behind the front this evening.
Very hazardous marine conditions and high northwest seas persist
through early Tuesday morning, with significant wave heights
between 15 to 20 feet. Seas subside slightly on Tuesday before
building again by Wednesday. This coincides with when a strong low
pressure system moves into the coastal waters resulting in
widespread rain, near gale to gale force winds, and potential for
thunderstorms.
&&
.BEACHES...
Issued at 1230 AM PST Sun Nov 15 2026
A High Surf Advisory is in effect now through Tuesday morning.
Long period swells 12 to 16 feet high at 14 to 16 seconds are
still coming through the coastal waters. Through the Advisory
period, breaking waves of 20-25 feet are expected with occasional
sets of 25-35 feet likely at favored breakpoints, including
Mavericks Beach. These waves are less energetic than the ones we
saw on Saturday, which ended up flooding portions of Pacifica and
damaging Capitola Pier, but remain hazardous to potential
swimmers, could still knock unaware people into the water, and
continue to feed an increased risk of rip currents. The risk of
drowning remains high. Do not go in the water, avoid climbing on
the rocks or leaning over seawalls, and never turn your back on
the ocean.
DialH
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...High Surf Advisory until 4 AM PST Tuesday for CAZ006-505-509-529-
530.
PZ...Small Craft Advisory until 3 PM PST this afternoon for SF Bay N
of Bay Bridge.
Small Craft Advisory until 7 PM PST Monday for Mry Bay.
Small Craft Advisory until 4 AM PST Tuesday for Pigeon Pt to Pt
Pinos 0-10 nm-Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt
Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM-Pt Pinos to Pt
Piedras Blancas 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm.
&&
$$
SHORT TERM...RGass
LONG TERM....DialH/RGass
AVIATION...MM
MARINE...MM
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Prepared by Boulder-Creek.com Weather at: Sun Nov 15 14:30:03 PST 2026
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From the National Weather
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Revised:
29 Mar 2008 09:53 -0800 GMT
(Pacific) |
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