FXUS66 KMTR 310558

Area Forecast Discussion
National Weather Service San Francisco Bay Area
958 PM PST Mon Jan 30 2023

.SYNOPSIS...Frost and freezing temperatures are likely away from
the coast and are even possible for some coastal areas through mid
week. Warming by late week with rain chances returning.

...Frost and Freezing Temperatures Many Areas Tonight...

.DISCUSSION...as of 09:18 PM PST Monday...Tonight and into
Tuesday morning looks to offer the coldest temperatures of the
forecast. Frost Advisories and Freeze Warnings last into the mid
morning with widespread lows in the 30s and a few more interior
areas falling into the 20s. Temperatures will stay on the cool
side through the day with highs peaking in the mid to upper 50s.
Temperatures will begin to trend slightly warmer in the next few
days, but these gains will only be modest.


.PREV DISCUSSION...as of 12:04 PM PST Monday...

This Evening through Wednesday:

Upper ridging will build into the region as surface high pressure
centers over the central Great Basin. This will set up a north to
northeast wind pattern this evening with breezy conditions in the
North Bay hills. A consensus of the high resolution model guidance
then suggests these winds should weaken between 12-15Z (4-7 AM). So
while the breeze should keep things somewhat mixed during the first
portion of the night do expect winds to settle a bit heading towards
morning. This setup once again implies some complexity to the
temperature forecast and to which areas will fall, and how fast.
Before getting into the details let`s first state that it will be
cold. Lows for most places will drop into the 30s, with 20s for the
coldest interior valleys. So these readings will be hazardous to
unsheltered individuals, pets, and sensitive plants. Most areas
(outside of the warmest places immediately adjacent to the coast and
bays) will see frost potential (below 35 degrees) with a freeze
expected for some. Right now the highest confidence in seeing more
widespread freezing temperatures is across San Benito County, within
the Santa Clara hills, across the Santa Lucia range, and across far
southern Monterey County. However freezing temperatures are also
expected within wind sheltered locations (primarily inland) across
the Monterey and San Francisco Bay areas, and within the Santa Cruz
Mountains. Frost/freeze products are out to cover the temperature
threat in a broad sense but do be aware given our complex terrain
that results may vary locally with some spots dipping to freezing
while others remain just a bit above. The key message is to check on
people and pets, and cover or bring sensitive vegetation indoors.

For tomorrow high pressure will dominate at the surface and aloft
with quiet weather. High temperatures will warm a few degrees from
Monday with low elevation highs generally in the upper 50s to around
60. The higher terrain will remain chilly with highs in the 40s.
Look for a repeat on Wednesday with a frosty night followed by
afternoon warming. Winds do appear a little lighter so lows
Wednesday morning could even be a few degrees colder in the
sheltered valley locations. So another night to protect people,
pets, plants and pipes from the cold.

Friday through Sunday:

A progressive upper flow pattern will prevail with the storm track
focusing a bit to our north. However we`ll remain close enough for
some rain chances, with the greatest potential across the North Bay.
The first system should move through on Thursday night into Friday
bringing modest rain amounts to the region. Portions of the Sonoma
Hills and Santa Cruz Mountains may receive over 0.5 inches of rain
with much lighter totals elsewhere. This system will quickly depart
with another arriving on Saturday night into Sunday. This system
also looks to bring modest amounts with the greater totals across
the North Bay. Temperatures appear seasonal into early next week.


.AVIATION...as of 09:58 PM PST Monday...For the 06Z TAFs. VFR
through the TAF period. Building high pressure is resulting in
clear skies area-wide. Winds are light to calm. Another burst of
NE winds aloft tonight could bring some stronger gusts to North
Bay terminals and possible LLWS. Winds gusts of 35 kt are being
observed at 1600 ft in interior Sonoma County, but winds remain
light in the valleys. Other areas will continue to experience
light offshore flow.

Vicinity of KSFO...VFR. Light and variable winds currently. Moderate
confidence in winds staying AOB 10 kt tonight, with an offshore
component. Clear skies continue through the period.

KSFO Bridge Approach...Similar to KSFO.

Monterey Bay...VFR. Winds light and offshore. SE drainage winds
overnight tonight into Tuesday morning. NW winds develop Tuesday
afternoon. Clear skies prevailing.


.MARINE...as of 08:35 PM PST Monday...Moderate to fresh southerly
winds tonight, strongest in the southern outer waters. Lighter
winds Tuesday, except for some strong offshore winds along the San
Mateo coast. Winds remain relatively light through mid week,
increasing again and becoming southerly on Thursday. Seas
gradually diminish Tuesday into Wednesday, with a new
northwesterly swell along with a storm system arriving Thursday.


.BEACHES...A long period northwest swell is spreading through the
coastal waters tonight and will bring increased risk of sneaker
waves and strong rip currents along the coast, especially for
northwest facing beaches, beginning Tuesday morning through
Tuesday evening. Don`t be fooled by an ocean that looks calm.
There can be 30 minutes of small waves before a sneaker wave
strikes. Stay well back from the water`s edge and never turn your
back to the ocean. Fisherman should avoid fishing from rocks or


     .Tngt...Frost Advisory...CAZ502>504-508-512-528>530
             Freeze Warning...CAZ506-510-513>518
             SCA...Pt Reyes to Pigeon Pt 0-10 nm
             SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm until 3 AM



MARINE: Lorber

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NWS MTR Office Area Forecast Discussion