761
FXUS66 KMTR 202015
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
115 PM PDT Fri Jun 20 2025

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

.SYNOPSIS...
Issued at 1257 PM PDT Fri Jun 20 2025

Seasonably cool temperatures through this weekend with windy
conditions. Elevated fire weather concerns continue into Sunday
morning as gusty winds combine with dry conditions. Return to
normal temps and quiet conditions by early next week.

&&

.SHORT TERM...
(This evening through Saturday)
Issued at 1257 PM PDT Fri Jun 20 2025

Mostly clear skies across the region today a gusty NW winds ramp
up. Current winds gusting in the 25-35 mph range across some of
the more wind-prone gaps and passes. Most notably up to about 40
mph at Altamont. Winds are expected to remain gusty through
tonight as a deep upper low digs into the Great Basin. Due to the
positioning of the low and juxtaposition of the upper level jet,
winds will largely remain onshore through the event, which is a
bit of a silver lining, keeping the marine layer moisture present
below about 2000 feet. For areas above the marine layer, very dry
afternoon RH and limited overnight recovery will present an
elevated fire weather threat thanks to dry grasses and shrubbery.

&&

.LONG TERM...
(Saturday night through next Thursday)
Issued at 1257 PM PDT Fri Jun 20 2025

The peak of the winds looks to be Saturday during the early
morning hours, but gusty conditions will linger through into
Sunday morning. Towards the end of the event Monday morning,
there is a small chance that the winds make a turn towards a more
offshore direction, but by the time the surface pressure gradient
supports this, much of the upper level support from the system
will have moved on. Therefore, we aren`t expecting any offshore
wind component Monday morning to have much more than a very minor
impact as of this forecast issuance. For the rest of the period, a
more "normal" pattern is restore as a ridge builds over our region
and subtle troughing to the north subdues any substantial
warming. Thus, we return to seasonable temperatures and relatively
quiet conditions next week.

&&

.AVIATION...
(18Z TAFS)
Issued at 1028 AM PDT Fri Jun 20 2025

Patches of stratus near HAF and Monterey Bay will mix out through
the afternoon. Strong and gusty northwest winds will continue
through the TAF period, especially along the immediate coast and
through the San Bruno Gap. Some LLWS is possible across the North
Bay tonight through Saturday morning as surface winds decouple from
flow aloft. Low confidence of stratus development along the
immediate coast late tonight through Saturday morning.

Vicinity of SFO... VFR through the TAF period. Strong northwesterly
gusts of 40 to 45 kt are expected through late tonight, with gusts
around 20 to 30 knots continuing through the TAF period. Monitoring
possibility of gusts exceeding 35 knots on Saturday afternoon;
confidence is too low to include in the TAF but some high resolution
model guidance is pointing to development of strong gusts.

SFO Bridge Approach... Similar to SFO.

Monterey Bay Terminals... MVFR stratus mixing out to VFR within the
next couple of hours. Breezy northwest winds gusting to 25 knots
will develop this afternoon and into the evening. A low confidence
for MVFR-IFR ceilings at MRY tonight, driven mainly by high
resolution models expecting development on the northern edge of the
Santa Lucias. Otherwise, VFR at the terminals through the end of the
TAF period.

&&

.MARINE...
(Today through Wednesday)
Issued at 1028 AM PDT Fri Jun 20 2025

Widespread hazardous marine conditions continue through the
weekend with strong northwesterly breezes, gale force gusts, and
rough to very rough seas. Fresh to strong northwesterly breezes
and moderate to rough seas are expected through the middle of
next week.

&&

.FIRE WEATHER...
Issued at 323 AM PDT Fri Jun 20 2025

Elevated fire weather conditions continue today across the
interior becoming more widespread on Saturday, with RH values
around 30% expected across the interior of the East Bay south
through the Gabilan Range, along with the Santa Lucia mountains
this afternoon. Gusty winds above the marine layer and elevated
interior locations will once again be around 25 to 40 mph with
less coverage today than Thursday. Brief periods of critical fire
weather conditions are possible with daytime relative humidities
of 15 to 25% in the interior. However, continuing marine layer
influence, especially during the night, and the fact that winds
remain onshore, mean that widespread critical fire conditions do
not develop across the district. Gusty winds begin to subside
somewhat on Saturday, but the upper level pattern will lead to
more northerly winds developing across the region. As with
Thursday`s fire weather threat, widespread critical fire weather
conditions are not expected within the district, although the fire
weather threat will increase once again for areas closer to the
Central Valley. The fire weather threat will continue to diminish
Sunday into the early part of next week with the gusty winds
further relaxing, although humidity values in the interior will be
slow to rise.

&&

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

     Gale Warning until 9 PM PDT this evening for Pigeon Pt to Pt
     Pinos 0-10 nm-Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt
     Reyes 10-60 NM.

     Gale Warning until 3 AM PDT Saturday for Pt Reyes to Pigeon Pt 0-
     10 nm.

     Gale Warning until 3 AM PDT Sunday for Pigeon Pt to Pt Pinos 10-
     60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm.

&&

$$

SHORT TERM...Behringer
LONG TERM....Behringer
AVIATION...DialH
MARINE...DialH

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