000
FXUS66 KMTR 261750
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
950 AM PST Mon Feb 26 2024

...New AVIATION, MARINE...

.SYNOPSIS...
Issued at 1145 PM PST Sun Feb 25 2024

Look for scattered showers today followed by colder temperatures
tonight following a cold frontal passage. A dry period will resume
midweek before unsettled weather returns. Moderate rain, breezy
winds, and even some high elevation snow are possible by next
weekend.

&&

.UPDATE...
Issued at 716 AM PST Mon Feb 26 2024

Happy Monday everyone! We`re on track to get some light showers
today as the surface cold front, currently moving through NorCal,
progresses southward. In addition, a weak area of low pressure
continues to spin offshore from the Central Coast, resulting in
light radar returns over the coastal waters. As this front moves
into the region, rain chances will increase but accumulations
will remain light with only a few hundredths of an inch expected
across the area once all is said and done. The forecast remains on
track and no updates are needed at this time.

&&

.SHORT TERM...
(Monday and Monday Night)
Issued at 1145 PM PST Sun Feb 25 2024

An upper trough will progress from the Pacific Northwest towards the
central Great Basin as low pressure aloft locates offshore from
SoCal. A cold front attendant to the upper trough will progress
through the Bay Area today before dissipating along the Central
Coast this evening. Scattered showers will accompany the front, with
the greatest coverage over the Central Coast. The overall moisture
available to work with is rather meager, so rain amounts aren`t
looking overly impressive. In fact, storm total amounts over the Bay
Area are now generally under 0.05", with 0.1" possible for portions
of Monterey and San Benito Counties. Given the more convective
nature of the showers can`t rule out a locally higher total here or
there, but overall expecting minimum rain impacts from this system.
Expect breezy northwest winds behind the frontal passage this
afternoon and evening with gusts to around 25 mph along the coast.
Colder air arrives behind the front tonight with temperatures
dipping into the 30s and lower 40s. Portions of the North Bay
interior Valleys and Mountains have a moderate to high probability
(35-70 percent) of reaching 36 degrees or colder, and therefore
considering both cold temperatures and societal impacts a Frost
Advisory was issued for these areas for late tonight into Tuesday
morning. This may be a borderline situation for some valley
locations it will likely dip to near/below 36 at least in pockets
towards morning. Portions of the East Bay may also approach Frost
Advisory thresholds, but confidence and probabilities here are a
bit lower outside of the higher terrain.

&&

.LONG TERM...
(Tuesday through Sunday)
Issued at 1145 PM PST Sun Feb 25 2024

High pressure will bring dry conditions, northerly winds, and cooler
temperatures for Tuesday and Wednesday. Lows Wednesday morning will
remain chilly, with 30s away from the immediate coast and bays.

Conditions look rather unsettled for late week into the weekend as a
stronger storm system slowly migrates from the Gulf of Alaska
towards the West Coast. Breezy winds and hazardous marine conditions
will exist, along with periods of moderate rainfall. Storm total
amounts are holding steady from the previous forecast, with rain
spread out among several days. Global model ensemble members still
suggest total amounts around 1-2" for the lower elevations from
Thursday through Sunday, with higher totals in the coastal ranges.
Friday and Saturday remain the target period for when the heaviest
rain amounts are expected. This is colder system and snow levels
will lower this weekend. Some ridgetop snow accumulations are
possible, with the greatest potential for this over the Santa
Lucias and perhaps portions of the Diablo range.

&&

.AVIATION...
(18Z TAFS)
Issued at 938 AM PST Mon Feb 26 2024

Mix of VFR and MVFR conditions (with localized IFR at KSTS). Two
weak features are dictating the weather today - a cold front
approaching from Northern California and a low offshore the
Central Coast. These resulting in patchy MVFR cigs across the Bay
Area and VCSH further south, affecting SJC and Monterey Bay
terminals. However, rain is very light and currently with not
much reaching the ground. As we head into the afternoon with the
front getting closer, there`s a better chance that showers south
of the Bay Area will reach the ground and MVFR conditions will
ensue. After the front passes, breezy NW winds will prevail and
cigs will start to lift. Skies clear out tonight and winds
diminish.

Vicinity of SFO...Breezy SE winds currently expected to shift more
SW as a weak cold front from the north approaches. MVFR cigs will
be intermittent through the late morning with a better chance of
more persistent MVFR cigs between 20z-23z. After the FROPA late
this afternoon, cigs will scatter out and winds will shift NW and
become breezy around 10-15 knots.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Currently VFR with high-based showers
approaching the Monterey Peninsula. MVFR conditions and -SHRA will
become more likely after 22z. Winds become westerly this afternoon
and evening. Cigs scatter and winds diminish tonight.


&&

.MARINE...
(Today through Saturday)
Issued at 938 AM PST Mon Feb 26 2024

Light rain showers are expected to impact predominantly the
southern waters through the day today, with rain chances
diminishing into the night. Winds are increasing and will become
fresh to strong out of the north as a cold front approaches.
These winds will create hazardous conditions for small craft
through early Wednesday morning. Northwesterly swell continues to
move through the waters with a period of about 14-16 seconds.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Frost Advisory from 2 AM to 9 AM PST Tuesday for CAZ503-504-506.

PZ...Small Craft Advisory from 3 PM this afternoon to 3 AM PST
     Wednesday for Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt
     Reyes 10-60 NM.

     Small Craft Advisory from 3 PM this afternoon to 3 AM PST
     Tuesday for Pt Reyes to Pigeon Pt 0-10 nm.

     Small Craft Advisory from 9 PM this evening to 3 AM PST Tuesday
     for Pigeon Pt to Pt Pinos 0-10 nm.

     Small Craft Advisory from 3 PM to 9 PM PST Tuesday for Pigeon Pt
     to Pt Pinos 0-10 nm.

     Small Craft Advisory from 9 PM this evening to 3 AM PST
     Wednesday for Pt Pinos to Pt Piedras Blancas 0-10 nm.

     Small Craft Advisory from 9 PM this evening to 9 AM PST
     Wednesday for Pigeon Pt to Pt Pinos 10-60 NM.

&&

$$

SHORT TERM...SPM
LONG TERM....SPM
AVIATION...McCorkle
MARINE...Flynn

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NWS MTR Office Area Forecast Discussion