National Weather Service - Area Forecast Discussion

FXUS66 KMTR 110807

Area Forecast Discussion
National Weather Service San Francisco CA
1207 AM PST Mon Dec 11 2023


Issued at 1206 AM PST Mon Dec 11 2023

Look for quiet weather this week with mild days and cool night. A
pattern change takes hold by early next week with a return to wet
and unsettled conditions.


(Today and tonight)
Issued at 1206 AM PST Mon Dec 11 2023

An upper level ridge initially across the region will flatten in
response to a shortwave trough progressing from the Pacific
Northwest into the Great Basin. This pattern change will bring a
more onshore wind component for this afternoon and evening while
increasing boundary layer moisture across coastal portions of the
area. Expect a return of coastal stratus and patchy fog this evening
into Tuesday morning along with warmer overnight coastal and bayside
temperatures. Highs this afternoon with top out mostly in the 60s,
with overnight lows mainly in the upper 30s and 40s. Some of the
colder inland portions of the Central Coast may see readings briefly
dip into the mid or lower 30s towards sunrise.


(Tuesday through Sunday)
Issued at 1206 AM PST Mon Dec 11 2023

The aforementioned shortwave will obtain sufficiently short
wavelength to close off over the Desert Southwest by late week as
transient ridging builds over California. Meanwhile a closed upper
low will approach the region from the eastern Pacific by late week.

An active and unsettled pattern still appears to evolve by early
next week. Model solutions have been rather provocative with a
robust basin-spanning Pacific jet and decent subtropical moisture
tap in play. Rain chances should enter the picture by Saturday and
persist into next week, with an Atmospheric River type setup
potentially in play. Exact details such as timing, rain amounts, and
intensity will be fine tuned in the days ahead. This will be an
evolving forecast so be sure to keep up with changes.


(06Z TAFS)
Issued at 922 PM PST Sun Dec 10 2023

Currently seeing VFR at all terminals. Most terminals will retain
this status through a majority of the TAF period with the
possibility of MVFR to IFR ceilings coming in at the end of the 24-
hour TAF period at 06Z Tuesday. Confidence is not yet high enough to
include definitive ceilings in any TAFs. There are still signals for
STS to see something similar to what they saw last night in terms of
low fog and low visibility; however, the passage of high clouds from
a shortwave may hinder that opportunity, thus not giving high enough
confidence to include in the TAF.

Vicinity of SFO... Currently VFR with calm winds and high clouds.
VFR will persist through most of the TAF period with chances for an
MVFR ceiling in the 08Z-18Z Tuesday time range. Winds will remain
breezy and onshore throughout the TAF period with northwesterly
winds giving way to westerly winds by 22Z tomorrow afternoon.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Currently VFR at both MRY and SNS. Both
terminals have a chance of ceilings at the end of the TAF period at
06Z Tuesday, IFR for MRY and MVFR for SNS; however, confidence is
not yet high enough to include in the TAFs definitively. Winds will
turn offshore and remain light overnight before returning to breezy
onshore flow tomorrow.


(Today through Saturday)
Issued at 1206 AM PST Mon Dec 11 2023

Quiet pattern over the next several days with high pressure
dominating. Gusty winds build over the southern waters early this
week as an upper level low deepens into the Great Basin. Slight
chance of showers over the waters late Monday into Tuesday
morning. Winds diminish into the later half of the week as high
pressure builds once again. New storm system approaches next


PZ...Small Craft Advisory until 3 AM PST Tuesday for Pt Pinos to Pt
     Piedras Blancas 0-10 nm.




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NWS MTR Office Area Forecast Discussion