FXUS66 KMTR 110032
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
532 PM PDT Wed Jun 10 2026
...New AVIATION, MARINE...
.KEY MESSAGES...
Issued at 100 PM PDT Wed Jun 10 2026
- Hot and dry through Saturday with a moderate risk of heat-
related illnesses for interior locations Thursday and Friday.
- Critical fire weather threat for the interior North Bay and the
East Bay Mountains late tonight into Thursday morning with
critically dry conditions persisting into Thursday afternoon.
- Increased risk of sneaker waves and strong rip currents along
south and southwest facing beaches through the weekend.
- Minor coastal flooding due to higher than normal high tides
anticipated across coastal regions of the San Francisco Bay
area this weekend.
&&
.SHORT TERM...
Issued at 100 PM PDT Wed Jun 10 2026
(This afternoon through Thursday)
Our well advertised warm up is in full swing today with afternoon
temperatures already climbing into the 70s and 90s. With clear
skies and a dry airmass interior valley regions will experience
mid to upper 90 degree heat this afternoon.
Tonight, more impactful weather is anticipated to take shape as a
diffuse trough swings through Big Sky Country into the northern
high plains. In the wake of this feature, 3 hour 5-7 mb surface
pressure rises across the Great Basin will tighten the low level
height/surface pressure gradient between building high pressure
and the coastal trough. Subsequently the wind field is anticipated
to respond with the latest NWP remaining consistent with a 30-40
knot 925mb jet extending from the northern Sac Valley down into
the delta. Lower elevations/valleys will likely see the planetary
boundary layer decouple from the free atmosphere and as a result,
I'm not anticipating overly gusty winds in the population centers.
For locations at elevation (above 1500 feet), boundary layer
decoupling is unlikely and this will be two fold. Firstly,
temperatures will remain elevated and overnight humidity recovery
will be poor (RH values likely not climbing above 40%). Secondly,
the aforementioned momentum at 925mb will be transfered down to
the surface (again at elevations at or above 1500 feet). This
should translate to frequent gusts above 30 to 35 mph. Cross-
sections from the 2km SJSU/PG&E WRF advertise tightly packed
isentropes or lines of potential temperature downwind of higher
terrain features such as Mt. Saint Helena. This implies a
potential for mountain wave type activity as well as a greater
threat for wind gusts in excess of 60 mph. Fuels intelligence
reveals that grasses (more of the 1 and 10 hour or fine fuels) are
largely cured and with the combination of the forecast winds and
RH, a critical fire weather threat is anticipated to materialize.
A Red Flag Warning is in effect to capture the most likely time
period for these conditions described above from 11pm tonight into
9am Thursday across the North Bay Interior Mountains and East Bay
Hills. Individuals should obey any fire restrictions/burn bans,
extinguish any camp fires, secure tow chains trailers/RVs, and
NEVER toss cigarette butts out the window. Remember, one less
spark, one less wildfire. While winds will abate after sunrise
Thursday, RH will remain critically dry, especially interior
portions of the Bay Area and Central Coast. While winds remain
below threshold, it's important for people to remain vigilant and
avoid activities that could spark a wildfire.
The burst of offshore winds will keep the marine layer at bay (no
pun intended) and result in a dry airmass. Both will promote a
sharp diurnal temperature curve. With sunny skies and virtually
non-existent onshore flow (except maybe at the immediate
coastline). Thursday high temperatures are anticipated to soar 15
to 25 degrees above normal with widespread mid to upper 90s. Some
locations may even exceed the century mark, especially across far
interior valleys of the North Bay, East Bay, and South Bay. A
handful of our climate sites may also flirt with or exceed daily
record highs for June 11th. With the probability of moderate
HeatRisk at or above 95% for these locales, a Heat Advisory is in
effect for Thursday (and parts of the area on Friday). Heat of
this caliber affects most individuals sensitive to heat,
especially those without effective cooling and/or adequate
hydration. Some impacts can be expected to health systems and in
heat-sensitive industries. Be sure to hydrate with plenty of water
and check on those vulnerable groups that are sensitive to heat
(elderly and young). Never leave pets or children unattended in
vehicles! Do your best to limit strenuous outdoor activity during
peak heating. If headed to the coast, be sure to be mindful of the
increased risk for sneaker waves and rip currents! More details
in the beaches section below.
&&
.LONG TERM...
Issued at 100 PM PDT Wed Jun 10 2026
(Thursday night through next
Tuesday)
Thursday Night - Friday morning lows may cool some, with the
exception being across some of the higher terrain where the
thermal belt may remain somewhat active. Offshore winds are not
expected to be quite as stout, however.
Uncertainty in the MaxT forecast persist on Friday. With the upper
trough responsible for driving the offshore winds moving farther
east, the low level height/pressure gradient should ease. In fact,
a very diffuse front/trough will approach from the north and try
to encourage some onshore flow. The diffuse nature of this
boundary, however, means that the wind field may not be overly
impressive. While some high-resoultion NWP does indicate onshore
flow, magnitudes are on the lighter side with speeds of 5 to 10
knots, though terrain enhancements may result in some accelerations
across the coastal range. I would anticipate a more structured
sea-breeze push on Friday afternoon and areas across the North Bay
may experience a very weak frontal passage. Farther east and
south, however, very little in the way of onshore flow may
transpire. Probability of Moderate HeatRisk remains at or above
80% for interior sections of the East Bay and South Bay and as a
result, we've extended the Heat Advisory for an additional day
(Friday here). I wouldn't discount the need for at least continued
heat messaging into the weekend, however, more diurnal
offshore/onshore flow is anticipated which may give more areas
relief from the heat. Afternoon conditions will likely remain very
pleasant and as noted above, be mindful if headed to the beach as
the sneaker wave threat will continue. In addition, higher than
normal high tides (1 to 1.5 feet above normal) are advertised
through June 15th. As a result, extension of the Coastal Flood
Advisory is probable in subsequent shifts.
Morning fog/drizzle may need to be added as we get a little
closer to the weekend. Ridging is expected across the Pacific
Northwest into British Columbia through next week. There's some
degree of broad troughing that is advertised in the ensemble
means. Given the orientation of this upper trough (positively
titled), we cannot discount a few more burst of offshore winds.
Deterministic NBM guidance does appear to support this with a
warming trend advertised for next week.
&&
.AVIATION...
(00Z TAFS)
Issued at 531 PM PDT Wed Jun 10 2026
VFR through the TAF period with the exception of HAF which will see
reductions in visibilities from haze. Moderate to breezy surface
winds reduce into the evening and become light across overnight.
Winds aloft over the North Bay, East Bay, and the SF Bay terminals
will remain stronger and northerly, causing concerns for LLWS. Winds
aloft look to weaken into the mid morning, reducing wind shear
concerns. Winds will stay lighter through the rest of the morning,
but become moderate to breezy for Thursday afternoon. Wind
directions will not be as uniform across the area for Thursday, with
much of the wind directions caused by localized effects.
Vicinity of SFO...VFR through the TAF period. Winds reduce into the
night with some LLWS expected in the late night as winds around
2000ft AGL will be northerly and around 35 kts through the mid
morning before reducing. Winds will be lighter and variable for the
rest of the morning and into the afternoon before more moderate
northwest winds build. These winds will last into the night before
becoming light and variable again.
SFO Bridge Approach...Similar to SFO, but with weaker winds aloft.
Monterey Bay Terminals...VFR through the TAF period. Expect winds to
reduce into the evening and become light into the night. In the late
night and through the rest of the morning, winds look to be mostly
variable. Expect west to northwest winds to build by the late
morning and into Thursday afternoon.
&&
.MARINE...
(Tonight through next Tuesday)
Issued at 531 PM PDT Wed Jun 10 2026
Strong to near gale force NW winds will gradually decrease to a
moderate NW breeze by Friday morning, and shift to a gentle
southerly breeze this weekend. Rough seas will steadily diminish
through early next week as the winds ease.
&&
.FIRE WEATHER...
Issued at 100 PM PDT Wed Jun 10 2026
Increasing northerly 20 foot winds of 10 to 20 mph with gusts to
45 mph are forecast late tonight into Thursday morning. With
energy release components trending above the 85th percentile and
overnight humidity recovery anticipated to be below 40 percent,
a critical fire weather threat is expected to unfold. The threat
will be greatest across the North Bay Interior Mountains and East
Bay Hills. Pending ignitions, extreme fire behavior and/or spread
is likely during the overnight hours into Thursday morning. Winds
will subside after 9am Thursday, however, afternoon humidity
values in the teens to near single digits are forecast across
interior regions. Minimal shading will help to cure fuels further
in the afternoon and while wind speeds are largely anticipated to
fall below 10 mph, fire spread will remain a possibility,
particularly in areas with the favorable alignment of weather,
fuels, and topography.
&&
.BEACHES...
Issued at 100 PM PDT Wed Jun 10 2026
Long period swell will continue, likely during the weekend,
especially for south and southwest facing beaches. Hazardous beach
conditions are advertised, specifically for moderate to steeply
sloped beaches along the Pacific Coast of the North Bay, San
Mateo, Santa Cruz counties. Be sure check beach conditions before
you head out. Sneaker waves will run up the beach much farther
than other waves, potentially catching beachgoers by surprise and
resulting in people being swept into the water. Rip currents are
strong enough to pull the strongest swimmers away from shore. Swim
near a lifeguard if possible. Stay back from the beach, and away
from jetties, piers, beachside rocks, and other infrastructure
near the water. Never turn your back to the ocean!
&&
.CLIMATE...
Issued at 1235 AM PDT Wed Jun 10 2026
The following are the record highs for June 11th.
Station Record Highs June 11th
Santa Rosa 100 in 2019
San Rafael 97 in 1985
Napa 102 in 2019
Livermore 105 in 1985
San Francisco 92 in 2019, 1877
SFO Airport 98 in 2019
Redwood City 102 in 2019
Oakland Museum 99 in 2019
Half Moon Bay 85 in 2019
San Jose 99 in 2019
Monterey Airport 92 in 2019
Salinas Airport 104 in 2019
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Coastal Flood Advisory from 7 PM Thursday to 7 PM PDT Friday for
CAZ006-508.
Heat Advisory from noon to 11 PM PDT Thursday for CAZ503-504-506-
508.
Red Flag Warning from 11 PM this evening to 9 AM PDT Thursday
for CAZ504-515.
Beach Hazards Statement through Thursday evening for CAZ505-509-
529.
Coastal Flood Advisory until 7 PM PDT Friday for CAZ506.
Heat Advisory from noon Thursday to 7 PM PDT Friday for CAZ510-
513>515.
PZ...Gale Warning until 9 PM PDT this evening for Pt Arena to Pt
Reyes 0-10 nm.
Small Craft Advisory until 9 PM PDT this evening 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 until 9 PM 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...Bain
LONG TERM....Bain
AVIATION...Murdock
MARINE...Flynn
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Prepared by Boulder-Creek.com Weather at: Wed Jun 10 18:30:02 PDT 2026
From the National Weather Service
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