535
FXUS66 KMTR 101736
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1036 AM PDT Wed Jul 10 2024

...New AVIATION...

.SYNOPSIS...
Issued at 334 AM PDT Wed Jul 10 2024

Last peak of the heat wave starts today and lasts through
Friday. Cool down through the weekend with near normal temps by the
start of next week.

&&

.UPDATE...
Issued at 822 AM PDT Wed Jul 10 2024

Widespread stratus continues to impact the region this morning with
low clouds spreading inland into most interior valleys. This is all
thanks to a marine layer of around 1,500-1,8000 feet in depth at
this hour. However, as we move through this warm up, it should
compress to around 1,000 feet later tonight and into tomorrow. These
low clouds impacting the region should mix out and retreat to the
coast by this afternoon giving way to the much anticipated warm up.
Coastal areas are expected to remain in the 60`s and 70`s while the
interior reaches as high as 100-105 degrees. The ongoing forecast
remains on track with no updates anticipated this morning.

&&

.SHORT TERM...
(Today and tonight)
Issued at 334 AM PDT Wed Jul 10 2024

Deep marine layer this morning promoting abundant stratus
and even some drizzle (on this forecasters drive into work last
night). However, the marine layer compresses through today as the
ridge is reinforced over the West. Heat Advisories and Excessive
Heat Warnings go into effect today for inland areas and the Bay
shoreline. Moderate HeatRisk across most areas in the heat
highlights, and isolated areas of major HeatRisk, most notable in
the inland East Bay and Santa Clara county.

&&

.LONG TERM...
(Thursday through Tuesday)
Issued at 334 AM PDT Wed Jul 10 2024

Thursday is expected to mark the peak of these next three
days of heat. The aforementioned areas of moderate and major
HeatRisk remain with isolated areas of extreme noted in the major
risk areas. Not notably different day-to-day in terms of overall
risk since some lower elevation areas will see some cooling
overnight, and we are pretty confidently dealing with only three
days with a sufficient cool down afterwards. However, the magnitude
of the temperatures will still be problematic for those sensitive to
heat and those recreating or working outdoors. Continue to use
caution and practice heat safety into this weekend. By the weekend,
temperatures start their decline as the ridge migrates to the NW and
a deep upper low digs into the Gulf of Alaska. This should set up a
reliable onshore flow pattern which would bring us cooler air and
some better moisture return from the seabreeze. Temperatures are
expected to be closer to seasonal normals by the start of next week.
As of this morning, heat highlights still look good to keep as
is...expiring Friday night.

&&

.AVIATION...
(18Z TAFS)
Issued at 1035 AM PDT Wed Jul 10 2024

Inland IFR-LIFR stratus continues to mix out and should retreat to
the immediate coastal region later this morning or early afternoon.
Breezy onshore flow resumes this afternoon with gusts around 15-20
knots at the terminals. Tonight into Thursday evening there is
considerable uncertainty in the stratus extent. The greatest
confidence for inland stratus lies in the Monterey Bay region into
the Salinas Valley. Some models continue to show stratus intruding
into the SF Bay Area and North Bay valleys, but more recent model
runs keep the regions scattered to clear. Confidence in stratus
ranges from low to moderate across the greater SF Bay Area, with a
particularly lower confidence in the North Bay. Have kept the
existing stratus forecasts for tonight in the TAFs, but subsequent
updates may elect to remove those lines as confidence in a
particular solution increases.

Vicinity of SFO... Stratus over the terminal has mixed out and VFR
conditions continue at least into the evening hours. Northwest winds
gusting to 25 knots will develop later this afternoon and continue
into the evening. Low to moderate confidence for IFR-MVFR stratus
tonight into Thursday morning, subsequent TAF updates might remove
the mention of stratus ceilings as confidence improves.

SFO Bridge Approach... Stratus could continue to impact the approach
for an hour or so after the terminal clears. Otherwise similar to
SFO.

Monterey Bay Terminals... Stratus is continuing to retreat to the
coastal areas and MRY should clear to VFR in the next couple of
hours. Breezy onshore winds develop this afternoon and last through
the evening. Moderate to high confidence that IFR-LIFR stratus
returns to the terminals overnight.

&&

.MARINE...
(Today through Monday)
Issued at 822 AM PDT Wed Jul 10 2024

Northwest winds continue with fresh to strong gusts becoming more
widespread over the coastal waters, particularly over the
northern outer coastal waters, this morning through the weekend.
Occasional gusts near gale force may be possible over the far
northern outer waters Thursday into Friday. Beginning later today,
significant wave heights will build to between 10 to 12 ft, on
average, over the outer coastal waters. Portions of the northern
outer coastal waters will see wave heights peak between 12 to 14
feet during the late week. Significant wave heights, sustained
wind speeds, and wind gusts begin to subside over the weekend.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Heat Advisory until 8 PM PDT Friday for CAZ502-503-506-508-512-
     516-528.

     Excessive Heat Warning until 8 PM PDT Friday for CAZ504-510-
     513>515.

     Excessive Heat Warning until 8 PM PDT Friday for CAZ517-518.

PZ...Small Craft Advisory from 3 PM this afternoon to 9 PM PDT this
     evening for Pt Arena to Pt Reyes 0-10 nm.

     Small Craft Advisory until 9 PM PDT Thursday for Pt Arena to Pt
     Reyes 10-60 NM.

     Small Craft Advisory until 3 AM PDT Thursday for Pigeon Pt to Pt
     Pinos 10-60 NM.

&&

$$

SHORT TERM...Behringer
LONG TERM....Behringer
AVIATION...DialH
MARINE...DialH

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