985
FXUS66 KMTR 162039
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
139 PM PDT Fri May 16 2025

...New SYNOPSIS, SHORT TERM, LONG TERM...

.SYNOPSIS...
Issued at 137 PM PDT Fri May 16 2025

Breezy to windy conditions and cooler temperatures on tap for the
weekend as a potent system enters the Great Basin. A warming and
drying trend is expected through the upcoming week as high
pressure builds into the Pacific Northwest and northern
California.

&&

.SHORT TERM...
(This evening through Saturday)
Issued at 137 PM PDT Fri May 16 2025

Mostly clear sky conditions have returned to the region this
afternoon. Afternoon temperatures will be within a few degrees (-5
to +5) of seasonal averages. However, passing high clouds
continue over the region. Low clouds are likely to return tonight
and into Saturday morning, and push further inland, as we have
abundant low level moisture.

Coastal drizzle will also be possible Saturday morning as the
marine layer deepens overnight. Low clouds spreading further
inland, the deepening of the marine layer, and an approaching
trough of low pressure will result in a slight cool down for
Saturday afternoon. Maximum forecast high temperatures will range
from the mid 50`s to mid 60`s on northwest facing coastal
locations to upper 60`s to mid 70`s across the interior.
Northwesterly winds are expected by Saturday afternoon with gusts
25-35 mph in lower elevations across the region with stronger
gusts up to 45 mph in the higher elevations and just along the
North Bay coast.

&&

.LONG TERM...
(Saturday night through next Thursday)
Issued at 137 PM PDT Fri May 16 2025

Winds ease slightly Saturday night into Sunday morning, with the
exception of the higher elevations. Breezy and gusty winds will
persist on Sunday afternoon with similar values mentioned above,
maybe a tad bit stronger. The aforementioned upper level trough
will dig into the Great Basin through Sunday before ejecting
further to the east. This will result in northerly, potentially
offshore winds in the higher elevations and typically windy gaps
and passes of Napa, Contra Costa, Alameda, and Santa Clara
counties Sunday night into Monday. This will lead to elevated fire
weather conditions as humidity values will be in the 40-50% range
Sunday night and as low as 15% on Monday afternoon (again in the
higher elevations).

High pressure will begin to build into the Pacific Northwest and
northern California in wake of the exiting trough with the warmest
day currently anticipated to be Wednesday. Temperatures Wednesday
afternoon look to be 5-15 degrees above seasonal averages with
mid 60`s to mid 70`s for coastal areas, mid 70`s to lower 80s
across the bayshore, and mid 80`s to lower 90`s across the
interior. More of a zonal flow is expected by late next week with
the likely return of a shallow marine layer and more seasonal
temperatures.

&&

.AVIATION...
(18Z TAFS)
Issued at 1055 AM PDT Fri May 16 2025

It`s VFR except for a lingering patch of stratus over the Monterey
Bay. VFR prevailing today with VFR extending into the evening,
otherwise increasing coastal stratus and patchy fog /IFR-MVFR/
tonight and Saturday morning with patchy light coastal drizzle
possible. Gusty northwest winds aloft resulting in low level wind
shear over KSTS Airport 12z-17z Saturday morning.

Vicinity of SFO...VFR. Light northeast wind until early afternoon
then shifting to westerly and increasing with gusts near 30 knots
during the afternoon and evening. Gusty westerly wind tonight and
Saturday.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...MVFR-VFR improving to VFR by early afternoon
under diurnal surface warming and mixing winds. MVFR due to coastal
stratus developing tonight, a few patches of light drizzle are possible
as well. MVFR Saturday morning. Onshore winds 5 to 15 knots, strongest
during the afternoon and early evening.

&&

.MARINE...
(Today through Wednesday)
Issued at 1045 AM PDT Fri May 16 2025

Gusty to strong northwest winds will continue over the coastal
waters today through the weekend, including much of early to mid
next week. Hazardous marine conditions with rough to very rough
seas will continue through Tuesday night.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 3 PM PDT Saturday for Mry Bay-SF Bay
     N of Bay Bridge.

     Gale Warning until 3 PM PDT Saturday for Pt Arena to Pt Reyes 0-
     10 nm-Pt Arena to Pt Reyes 10-60 NM-Pt Reyes to Pigeon Pt 0-
     10 nm.

     Small Craft Advisory until 3 PM PDT Saturday for Pigeon Pt to Pt
     Pinos 0-10 nm-Pt Pinos to Pt Piedras Blancas 0-10 nm.

     Gale Warning until 3 AM PDT Saturday for Pigeon Pt to Pt Pinos
     10-60 NM.

&&

$$

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

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