608
FXUS66 KMTR 241645
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
845 AM PST Fri Jan 24 2025

...New UPDATE, MARINE...

.SYNOPSIS...
Issued at 130 AM PST Fri Jan 24 2025

A downward trend in temperatures begins today, as a cold air mass
brings light rain to the Central Coast tonight and through the
weekend. Chilly temperatures persist into the early part of next
week, with the next chance for rain coming towards the latter part
of next week.

&&

.UPDATE...
Issued at 844 AM PST Fri Jan 24 2025

Temperatures this morning bottomed out in the 20s in the interior
portion of Monterey and San Bentio counties and into the low-to-mid
30s across the East Bay and North Bay valleys. Otherwise,
temperatures are on the warming trend this morning and will peak
this afternoon in the low-to-mid 60s across the Bay Area and to near
70 degrees for interior portions of Monterey and San Bentio
counties. The forecast for this morning remains on track with no
updates anticipated at this time.

&&

.SHORT TERM...
(Today and tonight)
Issued at 130 AM PST Fri Jan 24 2025

Satellite imagery shows decks of stratus just off the coast of the
North Bay, with a band of mid- to upper level clouds expected to
move southwards through the day, heralding a change in the weather
pattern. A positively tilted trough will develop from a trough in
the Canadian Prairies, eroding the ridge that has given us fair
weather over the last few days. As the trough axis approaches
California, it reinforces a surface level low moving southwards
across the state, and coastal drizzle is possible tonight.

Temperatures this morning range from the middle to upper 30s in the
interior valleys to the lower to middle 40s closer to the coast. A
Frost Advisory remains in effect for the southern Salinas Valley,
where the coldest locations could see lows dip below freezing, until
9 AM. Daytime highs will reach the middle to upper 60s in the inland
valleys, and the upper 50s to lower 60s along the coast. Frost
products may need to be issued in the North Bay and southern Salinas
valleys for the upcoming night, as low temperatures in those regions
reach the middle 30s tonight.

&&

.LONG TERM...
(Saturday through Thursday)
Issued at 130 AM PST Fri Jan 24 2025

The strengthening low pressure system will bring light rain to the
Central Coast beginning on Saturday morning, continuing throughout
the weekend. Rainfall totals are expected to be rather modest, with
totals around a tenth to a quarter of an inch in the Monterey Bay,
the Gilroy-Hollister area, and the northern Salinas Valley, and
isolated totals of up to an half an inch in the Santa Lucias and the
interior mountains. Across the Bay Area, rainfall chances are
limited to a few hundredths of an inch along the coast and in the
higher elevations, while strong offshore winds in the North Bay will
prevent rain in the area. With 850 mb temperatures (around 1500
feet) dropping to the freezing point, the higher peaks of the
Central Coast and eastern Santa Clara Hills could see snow on Sunday
morning, with totals reaching 2-3 inches at the favored peaks.

Speaking of the winds, with gusts of up to 40-50 mph in the higher
elevations, a Wind Advisory is in effect for the North Bay interior
mountains Friday night into Sunday morning. The East Bay hills could
also see some gusty winds with gusts around 25-30 mph through the
weekend. Finally, there`s a low chance for convective activity (up
to 10% probability) across the Central Coast late Saturday into late
Sunday. The cold upper level low will promote steep low level lapse
rates, but dry air aloft will limit the chances of lift.

Dry weather should return Monday and stick around through at least
the mid-week as ridging returns to the region. Highs during this
period will hover in the middle 50s to the lower 60s across the
lower elevations, near or slightly below the seasonal averages. Lows
from Monday through Wednesday morning drop to the lower to middle
30s in the inland valleys, around 5 to 10 degrees below seasonal
averages, and even near the coast lows hover around 40, resulting in
a strand of chilly temperatures across the region. The NBM is
starting to pick up on a chance for rain to return towards the
latter part of next week, but rainfall amounts and timing depend on
the prognosis of an incoming trough and how quickly it erodes the
ridging. CPC outlooks show a signal for rainfall totals near or
slightly above seasonal averages for the first week of February.

&&

.AVIATION...
(12Z TAFS)
Issued at 345 AM PST Fri Jan 24 2025

VFR conditions with light winds through this afternoon as low cigs
lurk offshore. Mid-high level clouds will increase from the north
as the day progresses. Low cigs will be possible tonight with some
fog...cigs most likely around Monterey Bay into Sat AM and fog
most likely for KSTS Sat AM.

Vicinity of SFO...VFR and light winds. Onshore flow by this
afternoon with winds up to 10 kt.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR. Cigs with MVFR to poss IFR
conditions develop 03-06Z Saturday.

&&

.MARINE...
(Today through Wednesday)
Issued at 844 AM PST Fri Jan 24 2025

Northerly winds will increase over the coastal waters today as a
cold front moves through. The strongest winds will be this
afternoon through Saturday morning north of Point Reyes over the
outer waters. Expect rough to very rough seas today through Sunday
before wave heights begin to abate and winds weaken Monday.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory from 10 PM this evening to 10 AM PST Sunday for
     CAZ504.

PZ...Small Craft Advisory from 3 PM this afternoon to 9 AM PST
     Saturday for Pt Arena to Pt Reyes 0-10 nm.

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

     Small Craft Advisory until 3 PM PST this afternoon for Pt Arena
     to Pt Reyes 10-60 NM.

     Gale Warning from 3 PM this afternoon to 9 AM PST Saturday for
     Pt Arena to Pt Reyes 10-60 NM.

     Small Craft Advisory from 3 PM this afternoon to 3 PM PST
     Saturday for Pigeon Pt to Pt Pinos 10-60 NM.

&&

$$

SHORT TERM...DialH
LONG TERM....DialH
AVIATION...MM
MARINE...Canepa
UPDATE...RGass

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