045
FXUS66 KMTR 111744
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1044 AM PDT Sun Aug 11 2024

...New AVIATION, MARINE...

.SYNOPSIS...
Issued at 115 AM PDT Sun Aug 11 2024

Notable cooling begins today, with temperatures at or below seasonal
averages through the rest of the week.

&&

.SHORT TERM...
(Today and tonight)
Issued at 115 AM PDT Sun Aug 11 2024

Mid- to high-level clouds are streaming over the region, keeping
winds somewhat breezy and disrupting the formation of marine layer
stratus away from the immediate coast. This morning`s lows remain in
the 50s to low 60s in the valleys, and up to the mid 70s in the
thermal belts. A significant cooling trend is set to begin as an
upper level trough forms over the West Coast, with forecast highs
across the inland regions dropping by up to 5 to 10 degrees from
yesterday`s highs, resulting in highs in the mid 70s to the low 90s,
except in the warmest spots in interior Monterey and San Benito
counties where highs could reach values near 100. Along the Pacific
coast, highs will remain in the mid 50s to mid 60s.

Breezy onshore winds will develop this afternoon and evening with
wind gusts up to 25 to 30 miles per hour through the gaps, passes,
and northwest-southeast oriented valleys. Combined with low
humidities above the thermal belts, the last two days have seen some
stations above the marine layer influence reaching red flag
criteria. Overnight humidity recoveries remain poor over the thermal
belt; otherwise fire weather conditions will improve with cooler and
more moist air moving in.

&&

.LONG TERM...
(Monday through Saturday)
Issued at 115 AM PDT Sun Aug 11 2024

Upper level troughs will be the theme of the upcoming week, and by
mid-week, inland highs should bottom out in the mid 70s to upper
80s. The coastal regions remain relatively stable in the mid 50s to
the mid 60s. CPC outlooks continue to show a lean towards
temperatures at or below seasonal averages into the first week of
September.

Model cross-sections are noting a wedge of elevated dry air coming
in on Monday and Tuesday, which could cause elevated fire weather
concerns in elevations above 2000 feet. While onshore winds should
prevent widespread critical fire weather, breezy and gusty winds at
elevation could result in some locations seeing conditions reach red
flag criteria.

&&

.AVIATION...
(18Z TAFS)
Issued at 1043 AM PDT Sun Aug 11 2024

Stratus has receded from most airports with stratus expected to
persist slightly (1-2 hours) longer at OAK and MRY. Winds generally
stay out of the northwest and strengthen to 12-15 knots during the
day before weakening again overnight. Locally stronger gusts up to
25 knots are expected to SFO during the afternoon/evening. IFR to
LIFR CIGs and pockets of decreased visibility are expected to
develop overnight with moderate to high confidence in stratus
reaching all airports with the exception of LVK and SJC. For LVK and
SJC, low to moderate confidence that stratus will reach SJC with a
later arrival time between 10-12Z possible. The NBM and GLAMP
suggests stratus will temporarily reach LVK between 12-16Z but
confidence remains low.

Vicinity of SFO...CIGs have cleared from the vicinity of SFO with
few to scattered low level clouds expected to persist through the
remainder of the morning. Northwest winds strengthen during the
afternoon/evening with gusts up to 25 knots possible. Moderate to
high confidence that stratus and IFR CIGs will return during the
late evening with decent model consensus between NBM, NAMnest, and
RAP but the HRRR does suggest some potential for a later stratus
return closer to 09/10Z.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...IFR CIGs and decreased visibility are
expected to clear at MRY within the next 1-2 hours with VFR to
persist afterwards through the evening at both MRY and SNS. Moderate
northwest winds continue through the afternoon/evening before
lighter winds return overnight. Stratus returns early this evening
with IFR-LIFR CIGs expected overnight and pockets of decreased
visibility at MRY and SNS. Moderate confidence that CIGs will stay
IFR at SNS but ensemble guidance indicates some potential that LIFR
CIGs may develop.

&&

.MARINE...
(Today through Friday)
Issued at 1043 AM PDT Sun Aug 11 2024

Fresh northwest winds will continue over the coastal waters
through  the middle of next week, afterwards increasing to become
strong.  Significant wave heights between 6 to 8 feet are expected
through  the remainder of the weekend. Coastal jets look to
develop along the  Big Sur coastline and along the coastline
extending from Point  Arena to Point Reyes during the early work
week. Moderate  northwest swell and light southerly swell continue
to move through the waters over the next few days.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 3 AM PDT Tuesday for Pt Arena to Pt
     Reyes 0-10 nm.

     Small Craft Advisory until 3 AM PDT Monday for Pigeon Pt to Pt
     Pinos 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm.

     Small Craft Advisory from 9 AM Monday to 3 AM PDT Tuesday for Pt
     Pinos to Pt Piedras Blancas 0-10 nm.

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

     Small Craft Advisory from 9 PM Monday to 3 AM PDT Tuesday for Pt
     Arena to Pt Reyes 10-60 NM.

&&

$$

SHORT TERM...DialH
LONG TERM....DialH
AVIATION...Kennedy
MARINE...Kennedy

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