919
FXUS66 KMTR 081807
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1107 AM PDT Mon Jul 8 2024

...New AVIATION...

.SYNOPSIS...
Issued at 111 AM PDT Mon Jul 8 2024

Day 7 of the inland heat wave. There will be a decent cooling
trend through Tuesday before temperatures increase again Wed-Fri.
More substantial cooling is on the way this weekend.

&&

.UPDATE...
Issued at 911 AM PDT Mon Jul 8 2024

Marine layer of around 1,200-1,500 feet in depth has resulted in
widespread low clouds and/or fog well inland across the Salinas
Valley, North Bay vallies, and locally inland into the East Bay
vallies this morning. Expecting conditions to mix out by afternoon
with these clouds retreating to the coast. All that said, no updates
are anticipated this morning as the forecast remains on track. For
more information, see previous forecast discussion below.

&&

.SHORT TERM...
(Today and tonight)
Issued at 111 AM PDT Mon Jul 8 2024

Inland temperatures were roughly 5-15 degrees cooler on Sunday,
compared to the peak of the heat wave on Saturday. As the ridge
continues to slide east, temperatures will continue to decrease.
Monday will be another 5 degrees cooler than Sunday was. This is
welcome relief and the HeatRisk product has moved out of the major
and extreme categories we saw for much of the last week, into
minor and moderate for Mon-Tue. As such, we have decided to
downgrade many of the Excessive Heat Warnings to Heat Advisories.
That`s the good news. The bad news is we extended many of the new
heat advisories through Friday. More information in the long term
section.

&&

.LONG TERM...
(Tuesday through Sunday)
Issued at 111 AM PDT Mon Jul 8 2024

The much anticipated cool-down will continue through Tuesday,
with inland max temperatures staying in the low to mid 90s. The
forecast gets a little more uncertain starting Wednesday. The
strong ridge will gradually flatten out as the jet stream
transitions from a very stable meridional block to more zonal
flow. While the ridge leaving is certainly a good thing to help
end this heat wave, the new pattern with higher pressure inland
could support offshore winds later in the week. Most guidance
agrees the current cooling trend will reverse, and Wednesday-
Thursday will be roughly 10 degrees warmer than Tuesday for
inland areas. This brings inland areas back to Moderate/Major
HeatRisk for the second half of the work week. Fortunately there
is a more substantial cool-down arriving next weekend, and we may
even see temperatures get close to normal by the middle of next
week. There is still a lot of model disagreement beyond the
weekend. The GFS continues cooler while ECMWF stays steady. Either
way, this week will be cooler than last week, and next week will
be cooler than this week. It`s just that after all that cooling,
we may still be above normal.

&&

.AVIATION...
(18Z TAFS)
Issued at 1107 AM PDT Mon Jul 8 2024

Coastal stratus and fog /LIFR-IFR/ moving inland on onshore breezes
tonight and Tuesday morning, otherwise VFR.

Vicinity of SFO...VFR, increasing west wind gusting to near 25 knots
this afternoon and evening. West wind easing tonight, otherwise IFR
due to stratus forecast 06z-17z tonight and Tuesday.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Coastal stratus and fog /LIFR-IFR/ moving
inland this evening and overnight, stratus and fog mixing out by late
Tuesday morning, otherwise VFR. West to northwest winds 5 to 15 knots.

&&

.MARINE...
(Today through Saturday)
Issued at 911 AM PDT Mon Jul 8 2024

Northwest winds persisting through the week. Widespread fresh to
strong northwest winds return across the coastal waters by
Wednesday and continue through Friday. Significant wave heights
will build to 10-14 feet across the outer waters beginning
Wednesday.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Heat Advisory until 8 PM PDT Friday for CAZ502>504-506-510-
     512>516-528.

     Heat Advisory from 11 AM Wednesday to 8 PM PDT Friday for CAZ508.

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

PZ...None.
&&

$$

SHORT TERM...Flynn
LONG TERM....Flynn
AVIATION...Canepa
MARINE...Canepa

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