860
FXUS66 KMTR 162334
AFDMTR

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

...New AVIATION...

.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...
(00Z TAFS)
Issued at 423 PM PDT Fri May 16 2025

VFR is expected to persist through much of the evening, until
coastal stratus and patchy fog produce /IFR- MVFR/ cigs, primarily
after midnight. Gusty northwest winds aloft will result in periods
of low level wind shear at KSTS Airport 12z-17z Saturday morning.

Vicinity of SFO...VFR is expected to persist through much of the
evening with /IFR- MVFR/ cigs set to settle in after midnight.
Gusty westerly winds will produce wind gusts at or exceeding 35
knots at times this evening, with an Airport Weather Warning in
place until 9 PM tonight. Similarly gusty winds are expected to
develop Saturday afternoon and evening.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...MVFR due to coastal stratus developing
tonight, a few patches of light drizzle are possible as well. Cigs
may break at times until late in the overnight, when MVFR
cigs are expected to persist through the day and evening hours
with the development of steady onshore winds from 10 to 20 knots,
strongest from Saturday afternoon into the evening hours.


&&

.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-Pigeon
     Pt to Pt Pinos 0-10 nm-Pt Pinos to Pt Piedras Blancas 0-10
     nm-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.

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

&&

$$

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

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