417
FXUS66 KMTR 191009
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
309 AM PDT Thu Jun 19 2025

...New SYNOPSIS, SHORT TERM, LONG TERM, MARINE, FIRE WEATHER...

.SYNOPSIS...
Issued at 305 AM PDT Thu Jun 19 2025

Cooling trend starts today and will continue into the weekend.
Elevated fire weather concerns across much of our interior today,
especially elevated grassy areas where gusty winds will combine with
dry conditions and increasing fuels. King tide coastal flooding
possible Sunday into the beginning of next week.

&&

.SHORT TERM...
(Today and tonight)
Issued at 305 AM PDT Thu Jun 19 2025

The first of several shortwave troughs will begin to transect our
area later this afternoon into tonight. Temperatures will be right
around normal today with breezy winds this morning out ahead of the
first weak cold front that pushes through our area this afternoon.
Winds increase behind the surface  becoming gusty later today and
tonight front especially at higher elevations inland and near the
surface along the coast. Wind gusts up to 50 MPH are possible above
2000ft across the East Bay hills during the overnight into early
Friday morning. A wind advisory is not expected attm.

&&

.LONG TERM...
(Friday through Wednesday)
Issued at 305 AM PDT Thu Jun 19 2025

Robust onshore flow Friday will result in the marine layer expanding
and penetrating farther inland as an upper low pushes inland across
the Pacific Northwest and a tightening pressure gradient continues
the gusty winds along the coast and elevated interior locations
through late Saturday into early Sunday. Fire weather concerns
abate for Friday into the weekend despite the gusty winds with
improved RH recovery. Still watching the upper level pattern for
Sunday into the beginning of next week, for the potential of a
stalled upper low/trough possibly leading to weak offshore flow
and increased fire weather concerns.

&&

.AVIATION...
(06Z TAFS)
Issued at 941 PM PDT Wed Jun 18 2025

850 mb cold air and dry air advection arriving on northwest winds
are helping to keep VFR going area-wide except it`s 5 miles /MVFR/
in haze/mist at KHAF. The ACV-SFO and UKI-STS pressure gradients
are 8.2 mb and 1.7 mb respectively while the onshore pressure
gradient is 3.5 mb. Nocturnal radiative cooling to space and lower
level cold air advection may combine to produce redevelopment of
coastal stratus later tonight to the predawn hours Thursday, though
by how much areal extent of development is a very challenging
forecast. It`s moderate to high confidence the Bay Area terminals
stay VFR tonight with exception of IFR in stratus and mist/fog
developing at KHAF tonight and Thursday morning and it may be slow
for KHAF to mix out Thursday. Otherwise for the north Central
Coast it`s a moderate to high confidence VFR forecast for early to
mid evening then it`s a low to moderate confidence IFR forecast
mid to late evening and overnight. VFR inland Thursday, along the
immediate coastline patchy stratus /IFR-MVFR/ may linger.

Vicinity of SFO...VFR. Gusty west wind to 30 knots gradually
subsiding tonight. Gusty west wind near 30 knots Thursday and
Thursday evening. Stratus /MVFR/ returning Thursday evening and
night.

SFO Bridge Approach...Similar to SFO with VFR.

Monterey Bay Terminals...VFR conditions extending into late
evening, then nocturnal cooling and lower level cold air advection
favors redevelopment of stratus /IFR/ tonight and Thursday morning.
Tempo IFR forecast 04z-08z at KMRY and KSNS terminals then IFR
prevailing tonight/Thursday morning then mixing out to MVFR-VFR by
late Thursday morning or early afternoon. Stratus /MVFR-IFR/
returning Thursday evening and night.

&&

.MARINE...
(Today through Tuesday)
Issued at 305 AM PDT Thu Jun 19 2025

Hazardous conditions and widespread gale force winds over the
coastal waters continue into Friday as a dry cold front passage
occurs. Winds ease from gale force to near gale to strong late
Friday into Saturday which will persist into early next week.
Winds will be strongest across the outer waters and for the inner
coastal waters north of Point Reyes and south of Point Sur where
coastal jets are expected to develop. Significant wave heights
build to 10 to 12 feet across the coastal waters Thursday into the
weekend before abating early next week.

&&

.FIRE WEATHER...
Issued at 305 AM PDT Thu Jun 19 2025

Elevated fire weather concerns today with strong winds gusting at
25 to 40 mph and daytime relative humidities of 15 to 25%
developing across the interior, with the biggest threat coming in
the interior mountains of the North Bay, the interior East Bay,
the eastern Santa Clara Hills, and the Gabilan Range in interior
Monterey and San Benito Counties. Fuels have been curing across
the interior, especially across the finer fuels of grass and
brush, and there`s already been several notable grass fires across
the interior portions of the region. However, the fact that winds
will remain onshore and temperatures will cool will keep fire
weather conditions below critical levels into the weekend.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 1 PM this afternoon to 3 AM PDT Friday
     for Mry Bay-SF Bay N of Bay Bridge.

     Gale Warning until 9 AM PDT Friday for Pt Arena to Pt Reyes 0-10
     nm-Pt Arena to Pt Reyes 10-60 NM.

     Small Craft Advisory until 9 AM PDT this morning for Pt Reyes to
     Pigeon Pt 0-10 nm.

     Gale Warning from 9 AM this morning to 9 AM PDT Friday for Pt
     Reyes to Pigeon Pt 0-10 nm.

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

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

&&

$$

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

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