FXUS66 KMTR 081857
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
1157 AM PDT Mon Jun 8 2026
...New AVIATION...
.KEY MESSAGES...
Updated at 1201 AM PDT Mon Jun 8 2026
- Cooler temperatures persist through Tuesday
- Chance for coastal drizzle this evening into early Tuesday
- Warmer and drier conditions return mid to late week with
moderate risk of heat-related illnesses in the interior
- Elevated fire weather concerns in the interior North Bay late
Wednesday and Thursday
&&
.SHORT TERM...
Issued at 1201 AM PDT Mon Jun 8 2026
(Today and tonight)
High level clouds are streaming over the Bay Area and Central Coast
as a trough continues to impact the West Coast. The latest reports
from the Bodega Bay profiler suggest a marine layer around 1000-1500
feet has developed, but owing to the incoming high clouds inhibiting
radiative cooling, not sure if we will see much of a stratus deck
tonight.
Cooler temperatures will persist today as an upper level low
reinforces the troughing pattern, with high temperatures reaching
the 70s across the inland valleys, perhaps the lower to middle 80s
in the warmest spots, the middle 60s to the lower 70s near the SF
Bay and the Santa Cruz coastal plain, and the middle 50s to lower
60s along the Pacific coast and southern Monterey Bay. Once again,
breezy and gusty onshore pattern winds will develop this afternoon
and evening with wind gusts reaching 20 to 30 mph along the coast,
through gaps and passes, and at the ridgelines, with favored
locations in the Salinas Valley and the Altamont Pass seeing gusts
of 35 to 40 mph.
This evening into the early morning of Tuesday, some coastal drizzle
might develop across the northern reaches of Sonoma County as a weak
cold front makes its way through the state, but elsewhere in the
region, rain chances have backed off. Rainfall amounts will range
from a tenth of an inch in favored locations in coastal Sonoma
County, to a trace across other parts of the coastal Bay Area, to
nonexistent pretty much everywhere else.
&&
.LONG TERM...
Issued at 1201 AM PDT Mon Jun 8 2026
(Tuesday through Sunday)
Tuesday will see a slight warming trend as the trough begins to make
its way eastward, as the inland valleys sees highs rising into the
middle 70s to middle 80s. Afterwards, temperatures will rise
dramatically on Wednesday with the departing trough allowing a
strong ridge to develop in the eastern Pacific and spread its
influence into the West Coast. The current forecast for the inland
valleys places high temperatures into the middle 80s to middle 90s
with particularly warm areas in the North and East Bays and interior
Central Coast reaching the triple digits. There's still some caution
to be noted with the warmest temperatures. The previous forecaster
noted that ensemble model runs were showing a wide range of possible
highs for Wednesday and Thursday. This is still somewhat true,
particularly on Thursday and especially beyond. Drilling into a
specific example, the current forecast for the Livermore area
suggests high temperatures in the middle to upper 90s for Wednesday
through Friday. NBM model statistics reveal that the spread between
the 25th and 75th percentile high temperature forecasts for
Livermore is around 5 degrees, while the spread for the 10th and
90th percentile highs hovers around 8 to 9 degrees. In other words,
if you look at the range of possible high temperatures for Thursday,
when the current high temperature forecast is 99, there's a 50%
chance that when the Livermore region reports its high temperature
for Thursday, it falls between 96 and 101 degrees, and there's an
80% chance that the high falls between 94 and 103 degrees. All of
this to say, don't be surprised if the forecast highs continue to
fluctuate as the models come into better agreement. Hot temperatures
will continue into Friday, but will start to dip as the inland highs
reach the upper 80s to middle 90s. Beyond that, the spread in the
forecast becomes even wider still, and ensemble model cluster
analysis suggests that the conditions will depend critically on if,
and how, the ridge interacts with potential downstream trough
development.
The hot temperatures across the middle and later portions of the
week will contribute to Moderate HeatRisk across the inland regions.
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. In addition, the hot temperatures
combined with gusty north winds and low humidities will contribute
to fire weather concerns across the interior North Bay mountains
late on Wednesday into Thursday. More information will be available
in the FIRE WEATHER section. Remember, one less spark, one less
wildfire.
&&
.AVIATION...
(18Z TAFS)
Issued at 1155 AM PDT Mon Jun 8 2026
VFR through the afternoon as high level clouds begin to move across
the region as the low pressure system to our northwest moves
onshore. MVFR ceilings begin to fill in at terminals beginning as
early as 5pm PDT today and will be widespread by sunset. Moderate
westerly winds (10+ kts) prevail through the afternoon and early
evening with embedded gusts in excess of 20kts. Medium to high
confidence that most terminals will develop IFR ceilings overnight,
except for LVK and SJC where it will remain MVFR through Tuesday
morning. Winds ease overnight and may become variable at times at
some sites, but will predominantly come from the west unless
otherwise stated in TAF. North Bay and coastal terminals have a 20-
30% chance of experiencing some drizzle (up to 0.01 inches) this
evening through the overnight hours from the approaching upper-level
trough, though confidence is currently too low to include in the TAF.
Vicinity of SFO...VFR and strong gusts prevail through the day into
the evening. MVFR ceilings will settle over the Bay around 5pm as
westerly winds begin to ease. Ceilings will become borderline IFR-
MVFR around sunset time and eventually get pushed to IFR through the
overnight hours. Conditions improve back to VFR by late Tuesday
morning due to mixing. High confidence in forecast.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...VFR through the afternoon as westerly winds
increase to moderate breezes (10-15kts). Winds diminish slightly
early evening (~5pm PDT) with developing MVFR ceilings that
eventually become IFR through the overnight hours. Expecting
conditions to transition back to VFR by Tuesday morning.
&&
.MARINE...
(Today through Saturday)
Issued at 413 AM PDT Mon Jun 8 2026
Winds and seas will continue to ease today through late tonight.
Overnight into early Tuesday morning fresh to moderate
northwesterly wind and seas will begin to build again, with
hazardous conditions for small craft developing by mid-morning
across both the outer and inner waters. Gale force wind gusts are
possible by early Wednesday morning over the outer waters.
&&
.FIRE WEATHER...
Issued at 1201 AM PDT Mon Jun 8 2026
Hot temperatures, gusty north winds, and low humidities across the
North Bay interior mountains 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, with stronger gusts of 40-50
mph possible along the Vaca Mountains along the 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. It's a little too early to put out fire weather
products at this stage, but this will be re-evaluated today and
Tuesday as the dry conditions approach. 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.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 9 AM Tuesday to 3 AM PDT Wednesday for
Mry Bay-Pigeon Pt to Pt Pinos 0-10 nm-Pigeon Pt to Pt Pinos
10-60 NM-Pt Arena to Pt Reyes 0-10 nm-Pt Arena to Pt Reyes
10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm-Pt Reyes to
Pigeon Pt 0-10 nm.
Small Craft Advisory until 3 PM PDT this afternoon for Pigeon Pt
to Pt Pinos 0-10 nm-Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena
to Pt Reyes 0-10 nm-Pt Arena to Pt Reyes 10-60 NM-Pt Reyes
to Pigeon Pt 0-10 nm.
Small Craft Advisory until 1 PM PDT this afternoon for Pt Pinos
to Pt Piedras Blancas 0-10 nm.
Gale Warning until 9 PM PDT this evening for Pt Pinos to Pt
Piedras Blancas 0-10 nm.
&&
$$
SHORT TERM...DialH
LONG TERM....DialH
AVIATION...Navarrete
MARINE...JM
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Prepared by Boulder-Creek.com Weather at: Mon Jun 8 14:30:03 PDT 2026
From the National Weather Service
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