201
FXUS66 KMTR 181716
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1016 AM PDT Tue Mar 18 2025

...New AVIATION, MARINE...

.SYNOPSIS...
Issued at 151 AM PDT Tue Mar 18 2025

Lingering showers continue in the higher elevations of the Central
Coast, expected to diminish overnight. Chilly morning temperatures
will settle in for the next couple of days, with Frost Advisories
issued for the North bay and Central Coast interior. Light rain is
expected for the Bay Area on Wednesday, with temperatures turning
mild towards the latter part of the week.

&&

.UPDATE...
Issued at 808 AM PDT Tue Mar 18 2025

Will allow the Frost Advisory for this morning expire at 9 AM PDT as
temperatures will continue on a warming trend through the afternoon.
Temperatures this afternoon will warm into the mid 50s to lower 60s
across the region with mostly clear sky conditions. The forecast
remains on track for the remainder of the day with no updates needed
at this time.

RGass

&&

.SHORT TERM...
(Today and tonight)
Issued at 151 AM PDT Tue Mar 18 2025

Radar imagery is showing some lingering showers across the northern
Santa Lucia range, the byproduct of bay effect processes where
moisture from Monterey Bay interacts with the higher terrain to
enhance the shower activity, and across the higher elevations of San
Benito and interior Monterey Counties. The shower activity is
relatively light, with only a few hundredths of an inch of
additional rainfall totals, and is expected to diminish over the
rest of the night. The rest of the region varies from mostly clear
skies over the North Bay, into generally higher elevation stratus in
the Bay Area and down into the Central Coast. This stratus is
expected to continue diminishing through the night, mixed out by
breezy winds aloft. Thus, temperatures are expected to dip through
sunrise. A Frost Advisory is in effect this morning through 9 AM in
the North Bay interior, the southern Salinas Valley, the Santa Lucia
range, and the mountains of San Benito and interior Monterey
counties. Temperatures in these areas reach into the lower to middle
30s, Elsewhere, lows this morning range from the middle 30s to the
lower 40s in the inland valleys, and the lower to middle 40s along
the coast.

Clear skies and light winds are expected today with a shortwave
ridge passing through the region. Highs range from the lower to
middle 60s in the inland valleys, the upper 50s to the lower 60s
near the bays, the lower to middle 50s along the Pacific Coast, and
the upper 40s to middle 50s in the higher elevations.

&&

.LONG TERM...
(Wednesday through Monday)
Issued at 151 AM PDT Tue Mar 18 2025

Chilly morning temperatures are expected to continue into Wednesday,
with temperatures around the same as those expected this morning. A
new Frost Advisory has been issued for Wednesday morning from 2 AM
to 9 AM for the North Bay interior and the interior Central Coast.
Light rain arrives in the Bay Area later on Wednesday, the fringes
of a system that will bring impactful rain and snow to the Pacific
Northwest and northern California. Across our region, beneficial
impacts are expected. Rain totals have trended downwards over the
last few model runs, with 0.2-0.3" expected in the Sonoma coastal
ranges and the Mayacamas, 0.05-0.15" in the North Bay valleys, up to
0.1" in the Bay Area and the Santa Cruz mountains, and virtually
nothing in the Central Coast. Further rain systems are expected
through the end of the week up north, but any impacts to the region
are limited to transitory drizzle across the northern fringes of
Sonoma and Napa counties.

A gradual warming trend is expected through the week as an upper
level ridge builds over the western United States. Temperatures will
generally tick up on Wednesday with the inland valleys reaching
highs in the middle to upper 60s, except in the North Bay where the
fringe influence from the storm system will cause temperatures to
dip a couple degrees, with the valleys reaching the upper 50s.
Temperatures in the North bay recover the next day, and by the
weekend, most of the forecast region will see temperatures near or
slightly above the seasonal average, with temperatures reaching the
lower to middle 70s in the inland valleys and the lower to middle
60s along the coast. Temperatures early next week will be even
warmer, and the current forecast calls for the inland valleys to
reach (do we dare say it?) the 80s next Monday and Tuesday.

&&

.AVIATION...
(18Z TAFS)
Issued at 1016 AM PDT Tue Mar 18 2025

Mostly clear skies across the region. Expect VFR through the TAF
period for all terminals. There is a chance for MVFR conditions near
KHAF for haze, but confidence is low. Onshore winds will build this
afternoon to breezy, but will diminish to light this evening.

Vicinity of SFO...VFR through the TAF period. Winds build to W/NW
breezy winds, but will decrease to light overnight.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR through the TAF period with light to
moderate winds. Winds will turn to S/SE overnight. There is a slight
chance for low ceilings developing overnight but confidence is low.

&&

.MARINE...
(Today through Sunday)
Issued at 1016 AM PDT Tue Mar 18 2025

Northerly winds continue to subside to a moderate to gentle breeze
into the afternoon. A cold front bring renewed chances for
rainfall, rough seas and a strong southerly breeze Wednesday into
Thursday. Moderate seas return Friday into the weekend.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Frost Advisory from 2 AM to 9 AM PDT Wednesday for CAZ504-506-
     516>518.

PZ...Small Craft Advisory from 3 AM to 9 AM PDT Thursday for Pt Arena
     to Pt Reyes 0-10 nm.

     Small Craft Advisory until 9 PM PDT this evening for Pt Pinos to
     Pt Piedras Blancas 0-10 nm.

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

     Small Craft Advisory from 9 PM Wednesday to 9 AM PDT Thursday
     for Pt Arena to Pt Reyes 10-60 NM.

&&

$$

SHORT TERM...DialH
LONG TERM....DialH
AVIATION...SO
MARINE...SO

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