471
FXUS66 KMTR 180406
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
906 PM PDT Mon Mar 17 2025

...New UPDATE, MARINE...

.SYNOPSIS...
Issued at 132 PM PDT Mon Mar 17 2025

Post-frontal showers and thunderstorms possible through the day
before tapering off by tonight. Light rain is expected in the Bay
Area on Wednesday and Wednesday night, mostly focused on the North
Bay. A gradual warming trend is then expected over the weekend with
temperatures above normal by next Monday.

&&

.UPDATE...
Issued at 855 PM PDT Mon Mar 17 2025

Forecast remains on track tonight with ongoing light scattered
showers moving southeast across the interior East Bay, South Bay
and Central Coast. Gusty winds will continue into the overnight as
the upper level low that moved onshore earlier this afternoon,
moves into the San Joaquin Valley overnight. Winds will ease by
sunrise, allowing for enhanced radiational cooling. A Frosty
Advisory is in place for portions of the North Bay, Monterey and
San Benito County.

&&

.SHORT TERM...
(This evening through Tuesday)
Issued at 132 PM PDT Mon Mar 17 2025

Isolated to scattered rain showers are moving over the region early
this afternoon. We also have a 15-20% chance of thunderstorms this
afternoon as the atmosphere becomes more unstable with cooling
temperatures aloft and MUCAPE values are forecast to rise to above
250 J/kg. Greatest potential being over the East Bay and North Bay
regions. Any heavier shower or thunderstorms will be capable of
producing small hail, locally heavy downpours, and strong gusty
winds.

As conditions begin to dry overnight and winds ease, temperatures
will drop into the low-to-mid 30s in the North Bay Valleys, the
southern Salinas Valley, the Santa Lucia Range, and the mountains of
San Benito and interior Monterey counties. Thus, a Frost Advisory
has been issued from 2 AM to 9 AM Tuesday for the aforementioned
areas. These cold temperatures will lead to the risk of hypothermia
for vulnerable populations, including children, the elderly, and
people without adequate heating.

Tuesday is forecast to be dry with afternoon temperatures reaching
into the mid 50s to low 60s under mostly sunny skies.

&&

.LONG TERM...
(Tuesday night through next Sunday)
Issued at 132 PM PDT Mon Mar 17 2025

Another cold morning is in store for Wednesday as temperatures once
again drop into the low-to-mid 30s for interior portions of the
region with Frost Advisories likely needed.

Our next chance of precipitation will be on Wednesday and Wednesday
night as another frontal system impacts the region. Rainfall amounts
and chances of precipitation continue to see a lowering trend. It is
now looking like the highest totals will be across the North Bay
with the coastal ranges and higher peaks across Napa and Sonoma
County picking up around 0.33" with 0.05-0.25" in the valleys of the
North Bay. South of the Golden Gate, we are expecting to see up to
0.05" with little to no rainfall across the Central Coast.

A ridge of high pressure will begin to build over the eastern
Pacific late week. As the system moves closer to the coast
temperatures will be on the rise to near seasonal averages. By
Monday and Tuesday, temperatures look to be up to 10 degrees above
average as the ridge aloft builds over the region. Overnight
temperatures will also be on the rise, lessening the need for Frost
Advisories.

&&

.AVIATION...
(00Z TAFS)
Issued at 455 PM PDT Mon Mar 17 2025

A cold core 500 mb low pressure area with scattered showers is
moving eastward across the Bay Area late this afternoon. VFR-MVFR
conditions will continue through mid evening with decreasing cloud
cover tonight. With the loss of daytime surface heating, showers will
gradually end after sunset. VFR is forecast Tuesday.

Vicinity of SFO...VFR-MVFR with showers and gusty west to northwest
wind to 35 knots to mid to late evening. Otherwise northwest wind 10
to 20 knots tonight and Tuesday. VFR is forecast Tuesday.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR-MVFR with showers and gusty west to
northwest winds to 30-35 knots to mid to late evening. Otherwise
northwest wind 10 to 15 knots tonight and Tuesday. VFR is forecast
Tuesday.

&&

.MARINE...
(Tonight through next Sunday)
Issued at 855 PM PDT Mon Mar 17 2025

Widespread hazardous conditions continue tonight with strong
northwesterly winds with gale force gusts and rough seas.
Isolated to scattered rain showers will come to an end tonight.
Another system will bring renewed chances for rainfall, rough seas
and a strong southerly breeze Wednesday into Thursday.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Frost Advisory from 2 AM to 9 AM PDT Tuesday for CAZ506-516>518.

PZ...Small Craft Advisory until 3 AM PDT Tuesday for Mry Bay-SF Bay N
     of Bay Bridge.

     Small Craft Advisory until 9 AM PDT Tuesday for Pigeon Pt to Pt
     Pinos 0-10 nm-Pt Arena to Pt Reyes 0-10 nm-Pt Reyes to
     Pigeon Pt 0-10 nm.

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

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

&&

$$

SHORT TERM...RGass
LONG TERM....RGass
AVIATION...Canepa
MARINE...Canepa

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