327
FXUS66 KMTR 191201
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
501 AM PDT Thu Jun 19 2025
...New AVIATION...
.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...
(12Z TAFS)
Issued at 501 AM PDT Thu Jun 19 2025
Patchy stratus is currently impacting HAF, MRY, and SNS with low
confidence that it will spread inland. The Fort Ord profiler shows
the marine layer at a depth of around 1000 ft with much drier air
above that height. Stratus looks to clear along the coast by mid to
late morning with more widespread stratus expected tonight. High
resolution guidance (HRRR) is leaning on the more optimistic side
and keeps stratus from going far inland whereas NAM/NBM/LAMP
guidance are more pessimistic/have stratus moving farther inland.
The marine layer is set to deepen to around 2000 ft tonight which
should help push moist air farther inland and allow for increased
stratus development. Currently leaning towards stratus reaching HAF,
SFO, OAK, MRY, and SNS again tonight but confidence is lowest for
SFO and OAK. Otherwise, gusty west to northwest winds develop this
morning and continue through the end of the TAF period. Winds will
be strongest in the afternoon/evening hours with gusts up to 35
knots possible. While winds do ease overnight, they will still be on
the breezier side with sustained winds between 10 to 15 knots and
gusts to around 20 knots possible overnight.
Vicinity of SFO...VFR becoming MVFR late tonight. Confidence is low
to moderate on return of stratus tonight with high resolution
guidance indicating potential for SFO to remain VFR overnight.
Current thinking is that a slightly deeper marine layer will allow
CIGs to fill in over the SF Bay and reach SFO with MVFR CIGs to
develop. Strong west to northwest winds are expected through much of
the TAF period with gusts to around 34 knots expected this afternoon
and evening. Winds look to ease overnight but still remain gusty (25
to 30 knots) overnight.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...IFR to MVFR conditions persist through mid
to late morning before becoming VFR through this evening. Stratus is
set to return around 03Z tonight at MRY and SNS with a slightly
deeper marine layer to keep CIGs MVFR. Gusty winds develop this
afternoon with gusts to around 25 knots expected at both MRY and
SNS. Winds ease somewhat overnight but will still remain breezy with
sustained winds around 15 knots and the occasional gust to around 20
knots.
&&
.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...Kennedy
MARINE...Kennedy
Visit us at www.weather.gov/sanfrancisco
Follow us on Facebook, X, and YouTube at:
www.facebook.com/nwsbayarea
x.com/nwsbayarea
www.youtube.com/nwsbayarea