FXUS66 KMTR 090943
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
143 AM PST Tue Dec 9 2025
...New SHORT TERM, LONG TERM, BEACHES...
.KEY MESSAGES...
Updated at 132 AM PST Tue Dec 9 2025
- Tule fog and stratus will clear this afternoon
- Quiet weather with warmer temperatures through Friday
- Light rain possible next week
&&
.SHORT TERM...
Issued at 132 AM PST Tue Dec 9 2025
(Today and tonight)
Another round of morning clouds and patchy fog across the Bay Area.
The coverage is less than yesterday and these clouds will clear in
the afternoon as temperature climbs a few degrees warmer than recent
days. The prolonged ridging pattern continues with the amplitude
notching up over the next few days. The Eastern Pacific high now
extends a ridge across northern California, and there is even a
somewhat uncommon cut off high way up at 250 mb directly over the
Bay Area. This is the jet stream altitude where the average wind
speed this time of year is around 60 knots. We'll be lucky to break
10 knots on the 12Z sounding. This vertically stacked dome of high
pressure is leading to widespread subsidence, calm winds, stagnant
surface air, and warmer than normal temperatures.
&&
.LONG TERM...
Issued at 132 AM PST Tue Dec 9 2025
(Wednesday through Monday)
While the ridge has been the main scapegoat for the ongoing Tule
Fog, the increasing ridge intensity will compress this cool moist
layer closer to the surface and limit it's horizontal spread to the
Central Valley and colder interior valleys across the Bay Area. Air
quality may also suffer as a result. The 850 mb temperature will
climb to around 17C by Wednesday, and park there until Friday.
That's around 10C warmer than normal, close to the average for June.
Surface temperatures will respond and warm up to 10F above normal,
pushing some clear areas of the Bay Area and Central Coast to the
mid 70s. This heat will peak on Thursday with noticeable cooling by
the weekend. Despite the warm afternoons, the dry atmosphere (PW 0.3-
0.5") and long December nights will still bring morning temperatures
into the 40s. The ridge axis will finally move through this weekend,
allowing the pattern to become more zonal. This opens the door for
some rain next week. While zonal flow doesn't support strong storms
or atmospheric rivers, it looks likely that we'll at least end the
dry streak sometime next week, possibly as early as Monday.
&&
.AVIATION...
(06Z TAFS)
Issued at 948 PM PST Mon Dec 8 2025
Low clouds and fog have reformed in the North Bay and interior East
Bay. SFO and SJC see CIGs arrive in the late night with some slight
reductions in visibilities. Winds stay mostly light to moderate
through the TAF period, with wind directions determined by more
localized affects. Cloud cover and fog will be slow to erode into
Wednesday afternoon, but conditions look to improve into the late
afternoon. However, the North and East Bay will continue to struggle
with low clouds and fog, causing some doubt for clearing at APC. As
cloud cover erodes, pockets of haze will affect much of the region.
Winds reduce again into Wednesday evening with fog and low cloud
looking again to reform in the North Bay and interior East Bay.
Vicinity of SFO...VFR lasts into the late night. Winds become
lighter into the night with scattered low clouds building into the
area, along with some slight reduction in visibilities. IFR level
CIGs fill into the late night with some weak easterly winds. Cloud
cover thins into the afternoon, but winds stay light and turn
slightly more northerly. These wind look to become light and variable
into the late evening.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...VFR through the TAF period. Winds stay
light for MRY through the TAF period, while SNS sees moderate
westnorthwest rebuild into Wednesday afternoon. These winds become
light and variable into that night.
&&
.MARINE...
(Tonight through next Sunday)
Issued at 948 PM PST Mon Dec 8 2025
North and northwest flow continues with moderate to fresh winds
continuing south of Point Sur. Winds increase to a strong breeze
Tuesday into mid week across the outer waters. A new, long period
northwesterly swell is expected by midday Wednesday,lasting into
the early weekend.
&&
.BEACHES...
Issued at 132 AM PST Tue Dec 9 2025
Long period swell will impact the coast Wednesday - Friday. This
energy brings strong rip currents, an increased risk for sneaker
waves, and large breaking waves. NW swell around 8 feet with a 15
second period will translate to breaking waves up to 15-20 feet.
These conditions may warrant a Beach Hazards Statement, particularly
with the warm weather likely luring more people to the Beach.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 9 PM PST this evening for Pt Pinos to
Pt Piedras Blancas 0-10 nm.
&&
$$
SHORT TERM...Flynn
LONG TERM....Flynn
AVIATION...Murdock
MARINE...Murdock
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Prepared by Boulder-Creek.com Weather at: Tue Dec 9 02:30:02 PST 2025
From the National Weather Service
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