831
FXUS66 KMTR 111210
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
510 AM PDT Thu Jul 11 2024

...New AVIATION, MARINE...

.SYNOPSIS...
Issued at 138 AM PDT Thu Jul 11 2024

Last stint of heat peaks today with gradual cooling into the
weekend. Heat highlights remain in effect through Friday evening.
Near normal temps by early next week. Otherwise fairly quiet
weather through the forecast period.

&&

.SHORT TERM...
(Today and tonight)
Issued at 138 AM PDT Thu Jul 11 2024

Decent stratus coverage this morning with the marine layer still
about 1,000 feet deep per Fort Ord profiler. Some compression has
occurred from yesterday afternoon as 500 mb heights rise and
large scale subsidence dominates. Further compressional warming is
set to take place today increasing high temps by a few degrees
over yesterday. Moderate to major HeatRisk in place for inland and
high elevation locations, and urban areas away from the immediate
coastline. Temperatures look to peak today as a bit of a remnant
low traverses up the California coast this evening, bringing in a
little bit of mid-level moisture into the weekend.

Remember these heat safety tips:

* Stay hydrated and drink plenty of fluids.
* Wear lightweight, light-colored clothing.
* Reduce time spent outdoors or stay in the shade.
* Never leave people or pets unattended in vehicles.
* Use sunscreen if going to the coast or the pool.

&&

.LONG TERM...
(Friday through Wednesday)
Issued at 138 AM PDT Thu Jul 11 2024

The aforementioned remnant low begins to influence our area by
Friday, where we will likely see some degree of mid-to-high level
cloudiness, especially over southern portions of the area. This
will aid in bringing afternoon highs down a bit, in addition to
the low deepening the marine layer and the ridge axis migrating
eastward. This will still be a gradual cool down, so temps will
still be well above normal on Friday with moderate HeatRisk across
areas where advisories or warnings are in place. High temps
continue their gradual decline into the weekend, so the Heat
Advisory and Excessive Heat Warning will be left as is, expiring
Friday evening. By the start of next week and through the rest of
the forecast period, temperatures look to be right around seasonal
normals. The larger scale pattern advertised by ensemble guidance
would promote tranquil summer weather from this weekend beyond.

&&

.AVIATION...
(12Z TAFS)
Issued at 510 AM PDT Thu Jul 11 2024

VFR everywhere except MRY and SNS where LIFR conditions continue.
Visibilities will continue to temporarily decrease at MRY and SNS
through the mid morning with visibilities down to 1SM possible. Low
to moderate confidence that lowered visibilities and LIFR CIGs will
develop in the early to mid morning at STS. Ensemble guidance is
leaning towards only few to scattered clouds at STS. However,
increasing RH at STS and observed LIFR conditions downstream of STS
at the Petaluma airport serves to increase confidence in IFR to LIFR
conditions developing close to sunrise at STS. Similar to last
night, stratus continues to look less widespread tonight with
stratus currently only expected to return at MRY and SNS. Light,
onshore flow strengthens and becomes more moderate during the
afternoon before becoming light and variable again overnight.

Vicinity of SFO...VFR through the TAF period. Satellite shows some
stratus moving through the Golden Gate into the SF Bay but
confidence remains low that it will reach SFO or OAK. Guidance
support FEW to SCT cloud development at SFO through the late
morning. Clear skies will return by late morning and continue
through the evening. Some potential for stratus to return tonight
but confidence remains low at this time given a shallower marine
layer and lack of model consensus. Northwest winds continue with
moderate, gusty winds returning during the afternoon before
weakening overnight.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...LIFR conditions continue through the late
morning. Observations at MRY and SNS have shown visibilities
temporarily decreasing to 1 to 1 1/2 SM before returning to
unlimited visibilities. Tempos are in place from 12-16Z with
temporary decreases in visibility down to 1SM expected to continue
through the late morning. Stratus coverage is will diminish by 18-
19Z with ensemble guidance suggesting stratus returning by 02-04Z.
Variable, light winds continue through the late morning with
moderate onshore flow from the northwest returning during the
afternoon.

&&

.MARINE...
(Today through Tuesday)
Issued at 510 AM PDT Thu Jul 11 2024

Widespread, gusty fresh to strong winds and elevated significant
wave heights continue over the northern outer coastal waters.
Occasional high end near gale force gusts are possible over the
far northern outer waters through late Friday evening. Significant
wave heights between 10 to 12 ft continue over the outer coastal
waters with peak wave heights between 12 to 14 ft expected over
the far northern outer coastal waters. Significant wave heights,
sustained winds, and wind gusts begin to subside below small craft
advisory criteria by the late weekend.

&&

.CLIMATE...
Issued at 342 PM PDT Wed Jul 10 2024

Record high temperatures at the long term climate stations for
July 11.

Station          July 11th record high

Santa Rosa       113 in 1913
Kentfield        112 in 1913
Napa             106 in 1961, 1913
Livermore        111 in 1961
San Francisco     92 in 1983
SFO Airport       93 in 1983
Redwood City     104 in 1961, 1959
Half Moon Bay     74 in 1959
Oakland downtown  98 in 1983
San Jose         103 in 1913
Salinas Airport   87 in 1934
King City        107 in 1983

&&

.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>515-517-518.

PZ...Small Craft Advisory until 3 AM PDT Saturday for Pt Arena to Pt
     Reyes 10-60 NM.

&&

$$

SHORT TERM...Behringer
LONG TERM....Behringer
AVIATION...Kennedy
MARINE...Kennedy

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