FXUS66 KMTR 091836
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
1136 AM PDT Tue Jun 9 2026
...New AVIATION, MARINE...
.KEY MESSAGES...
Updated at 1208 AM PDT Tue Jun 9 2026
- Chance for coastal drizzle continues through the morning hours
- Warmer and drier conditions expected Wednesday through Saturday
- Moderate risk of heat-related illnesses for interior locations
on Wednesday and Thursday
- Elevated to near critical fire weather conditions in the
interior Bay Area late Wednesday through Thursday
&&
.SHORT TERM...
Issued at 1208 AM PDT Tue Jun 9 2026
(Today and tonight)
Light showers are moving through the Bay Area as an incoming cold
front drags some moisture through the region. These showers have
overperformed a little, and we've gotten reports of a few hundredths
of an inch of rain as far south as the Santa Cruz Mountains. With
continuing bands of precipitation moving through, have added a
chance for coastal and foothill drizzle across the Bay Area and
Santa Cruz County through the night, but accumulations are still
light and won't top a tenth of an inch across most of the Bay Area.
Today will mark the beginnings of a pattern change as an upper level
trough over the Pacific Northwest starts to shift eastwards and
allow a building ridge to come in from the Pacific. Today's highs
will be seasonable to cool, but they will be slightly warmer than
yesterday's with highs in the middle 70s to middle 80s throughout
the inland valleys, up to the upper 80s and near 90 in the warmest
spots of southern Monterey County, the upper 60s to middle 70s near
the bays, and the upper 50s to middle 60s along the Pacific coast.
&&
.LONG TERM...
Issued at 1208 AM PDT Tue Jun 9 2026
(Wednesday through Monday)
The pattern change will continue through Wednesday and Thursday as
the ridge extends into the West Coast while the trough dips a little
south of due east to create an inside slider-like setup, allowing
for a dramatic warming of temperatures for the middle and latter
parts of the week. In addition, strong northerly gusts and low
humidities late on Wednesday into Thursday could result in elevated
to near-critical fire weather conditions across the North Bay
interior mountains, the Diablo range across the interior East Bay,
and the eastern Santa Clara County mountains. For more information
on the expected conditions, see the FIRE WEATHER section.
Hot temperatures on Wednesday and Thursday will contribute to
Moderate HeatRisk across the inland regions, as high temperatures
reach the 90s into the triple digits across the inland valleys,
while temperatures reach the 80s to lower 90s close to the bays and
the 60s to the middle 70s at the Pacific Coast. This corresponds to
a moderate risk of heat-related illnesses, especially for people
sensitive to heat including children, the elderly, pregnant women,
people with chronic health conditions, and people who work or live
outside without adequate cooling or shelter. People spending time
outdoors should take frequent breaks in the shade and drink plenty
of water.
The ridging pattern will persist Friday into the upcoming weekend
with the ridge axis further developing into the northeast Pacific
off British Columbia and the Alaskan panhandle, and the current
forecast depicts a gradual cooling trend during that time persisting
into the early part of next week. Confidence remains low regarding
the time that a marine layer redevelops, but model output hints that
the marine layer stratus could return as soon as Saturday or Sunday.
Conversely, without any major large-scale forcing to move the
general ridging pattern away, temperatures could continue to trend
warmer for Friday and the following weekend. The extended range
outlook has around a 50-50 chance that temperatures remain above the
seasonal average heading into the third week of June.
&&
.AVIATION...
(18Z TAFS)
Issued at 1133 AM PDT Tue Jun 9 2026
Lingering MVFR ceilings are making their way out of the region by
this afternoon. Widespread VFR conditions are also expected to
prevail by the afternoon through the TAF period. W to NW winds
increase to a moderate breeze (10-15kts) with a few terminals
experiencing ~20kt gusts. Winds begin to ease by sunset and continue
to diminish overnight.
Vicinity of SFO...VFR through the TAF period. High confidence that
westerly winds will increase by the early afternoon with some
embedded gusts above 20kts. Winds are expected to diminish overnight
and increase back to moderate breezes by Wednesday early afternoon.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...The remaining low-level clouds are
currently mixing out as onshore winds increase by the early
afternoon. NW winds are expected to begin to ease by sunset and
remain light overnight. Low confidence on an MVFR ceiling this
evening given how dry the atmosphere is (and will continue to be)
in this post-frontal environment. VFR all the way!
&&
.MARINE...
(Today through Sunday)
Issued at 1133 AM PDT Tue Jun 9 2026
Fresh to moderate northwest breezes will build seas today
resulting in hazardous conditions for small craft across the
waters through Thursday afternoon. Gale force gusts will spread
across the northern waters Wednesday night into early Thursday.
Wind and seas begin to ease by Thursday evening and are expected
to stay light through the weekend.
&&
.FIRE WEATHER...
Issued at 1208 AM PDT Tue Jun 9 2026
Hot temperatures, gusty north winds, and low humidities across the
North Bay interior mountains into the Diablo Range will raise the
fire weather threats late on Wednesday into Thursday, with a
particular emphasis on the interior mountains of Napa County.
Although the strongest winds will remain within the Sacramento
Valley, gusts of 25 to 35 mph are expected to spread into Napa
County and the Diablo Range south through Santa Clara County, with
stronger gusts of 40-50 mph possible along the Vaca Mountains along
Napa County's eastern edge. Meanwhile, daytime humidity retention
will be very poor with relative humidity values as low as 10-15%,
while overnight recoveries are likewise poor as RH values top out at
20-30%. Thus, fuels are expected to dry rapidly, leading to the
elevated fire weather concerns. Also important to note that even
with the drizzle and light rain coming through the region, wetting
rains (rain totals above 0.1") are not expected, limiting any relief
that will be realized for the midweek period. Elsewhere across the
district, conditions remain hot and dry, but we're not expecting
winds to be as strong as they are across the interior North Bay.
We are continuing to monitor the potential for fire weather products
to be issued for the interior mountains of the North, East, and
South Bays for Wednesday and Thursday. At present, conditions are
right on the edge of critical fire weather criteria, but the
confidence isn't there at this point to pull the trigger on any
warnings. The day shift will reevaluate the fire weather forecast
for Wednesday and Thursday and in collaboration with neighboring
offices, will be in a better position to determine the extent of
necessary products. Regardless of whether any products are issued
across the interior, elevated to near critical fire weather
conditions are still forecast and care must be taken to avoid
starting a fire that could spread rapidly. Remember, one less
spark, one less wildfire.
DialH
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Red Flag Warning from 11 PM Wednesday to 9 AM PDT Thursday for
CAZ504-515.
PZ...Small Craft Advisory until 9 PM PDT this evening for Mry Bay-Pt
Arena to Pt Reyes 10-60 NM.
Small Craft Advisory from 9 AM to 9 PM PDT Wednesday for Mry Bay.
Small Craft Advisory until 9 AM PDT Wednesday for Pt Arena to Pt
Reyes 0-10 nm.
Gale Warning from 9 AM Wednesday to 3 AM PDT Thursday for Pt
Arena to Pt Reyes 0-10 nm.
Small Craft Advisory until 9 PM PDT Wednesday for Pigeon Pt to
Pt Pinos 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm.
Small Craft Advisory until 3 AM PDT Thursday for Pt Pinos to Pt
Piedras Blancas 0-10 nm.
Gale Warning from 9 PM this evening to 3 AM PDT Thursday for Pt
Arena to Pt Reyes 10-60 NM.
Small Craft Advisory until 3 PM PDT Thursday for Pigeon Pt to Pt
Pinos 10-60 NM.
&&
$$
SHORT TERM...DialH
LONG TERM....DialH
AVIATION...Navarrete
MARINE...CW
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Prepared by Boulder-Creek.com Weather at: Tue Jun 9 12:30:02 PDT 2026
From the National Weather Service
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