975
FXUS66 KMTR 140940
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
140 AM PST Tue Jan 14 2025

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

.SYNOPSIS...
Issued at 1224 AM PST Tue Jan 14 2025

Mostly clear skies will continue through the week. High
temperatures will be in the 50s and 60s, with cold mornings in
the 30s and 40s.

&&

.SHORT TERM...
(Today and tonight)
Issued at 1224 AM PST Tue Jan 14 2025

The nocturnal cooling is behaving more predictably tonight with
the weaker offshore winds. Scattered to broken high clouds are
streaming across the cwa, which will take the edge off the
cooling. Many inland areas are already in the mid to upper 30s,
but many coastal areas have some light downslope winds keeping
them in the mid to upper 40s. The 500 mb pattern is stabilizing as
an elongated ridge over northern California and a vertically
stacked, cut-off low roughly 500 miles west of Baja. This is
supporting geostrophic NE winds through the depth of the
atmosphere. At the surface, the gradient between a 1037 mb high
over NE Nevada and a 1027 mb low near Vallejo is supporting
moderate offshore winds across higher terrain, weak offshore flow
at the coast, and mostly calm winds in the valleys. The wind
speed will gradually decrease as this gradient relaxes through the
day. Otherwise, it`s another day of comfortable afternoon
temperatures and ample sunshine.

&&

.LONG TERM...
(Wednesday through Monday)
Issued at 1224 AM PST Tue Jan 14 2025

The Baja cyclone has lost any upper-level divergence provided
from the jet stream, and it will slowly begin to fill while
meandering around the subtropical East Pacific. By the end of the
week, this system will finally be absorbed back into the
westerlies and kicked inland. There is very high certainty that
the next pattern in line is another omega block with a high
amplitude ridge off the coast and a deep, cold trough over the
central US. What does that mean for the long term forecast? It`s
pretty boring locally. Mostly clear skies, cold mornings, gentle
winds, and no chance of rain. Next week looks pretty similar at
this point, perhaps a bit colder. This prolonged dry spell is
unusual in January. There is a good chance we end the month in the
top 5 or 10 driest on record. Take this with a grain of salt, but
there is some agreement between the extended global models that
the dry anomaly will last until mid-February. That`s not to say
we won`t get any rain, just that it looks to stay drier than
normal.

&&

.AVIATION...
(06Z TAFS)
Issued at 911 PM PST Mon Jan 13 2025

High confidence of VFR through the TAF period. Light and variable
winds overnight into Tuesday morning. Some light onshore flow
develops on Tuesday afternoon at the immediate coast, with offshore
flow continuing in the interior.

Vicinity of SFO... VFR through the TAF period. Breezy north-
northwest flow is expected to continue into the early morning hours.
Winds become light on Tuesday morning before breezy onshore flow
resumes in the afternoon.

SFO Bridge Approach... Similar to SFO.

Monterey Bay Terminals... VFR with valley drainage winds overnight.
Winds shift onshore late Tuesday morning, remaining light to
breezy.

&&

.MARINE...
(Tonight through next Sunday)
Issued at 911 PM PST Mon Jan 13 2025

Generally weak winds will persist through much of the week as high
pressure remains over the region. Wave heights will also remain
relatively low, generally between 4 and 7 feet. Northwest winds
will build as well as wave heights late in the week and into the
upcoming weekend.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Frost Advisory until 9 AM PST this morning for CAZ504-506-510-
     512>518-528>530.

PZ...None.
&&

$$

SHORT TERM...Flynn
LONG TERM....Flynn
AVIATION...DialH
MARINE...DialH

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