333
FXUS66 KMTR 202044
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
144 PM PDT Fri Sep 20 2024

...New SYNOPSIS, SHORT TERM, LONG TERM...

.SYNOPSIS...
Issued at 143 PM PDT Fri Sep 20 2024

Warming trend continues through the weekend into early next week,
with moderate HeatRisk possible inland Monday and Tuesday.

&&

.SHORT TERM...
(This evening through Saturday)
Issued at 143 PM PDT Fri Sep 20 2024

A warming trend was expected to start today as an upper level low
moves off to the east, but you wouldn`t know it from the 24 hour
temperature trends, which have not shown much warming from the same
time yesterday, and if anything, have ran up to five degrees cooler
across the valleys. The extensive stratus deck this morning and the
continuing onshore flow may have kept things cooler than what was
earlier forecast. Have bumped today`s high temperatures across the
inland valleys down to account for this. The current forecast calls
for high temperatures today to rise into the upper 70s to the lower
80s across the inland valleys, around the mid 60s to the mid 70s
along the Bayshore, and into the upper 50s to mid 60s along the
Pacific coast. Some more warming is expected tomorrow with the
warmest inland regions scraping into the low 90s.

Stratus has retreated back to the coastal regions and the Monterey
Bay region, where the clouds are expected to persist through the day
before the stratus extends inland this evening and overnight.

&&

.LONG TERM...
(Saturday night through next Thursday)
Issued at 143 PM PDT Fri Sep 20 2024

The fringes of an upper level ridge will impact the state through
the weekend into early next week, with the main impact being a
warming trend across the region. By the early part of next week,
high temperatures should peak into the mid to upper 90s across the
inland valleys and the upper 60s to the mid 70s across the Pacific
coast. Model ensemble clusters continue to show poor consensus on
the upper level pattern towards the rest of the next week. However,
CPC outlooks suggest a lean towards temperatures above seasonal
averages and precipitation below seasonal averages into the first
several days of October.

&&

.AVIATION...
(18Z TAFS)
Issued at 1057 AM PDT Fri Sep 20 2024

Mix of IFR and MVFR CIGs expected to gradually clear by late
morning. Stratus has started to recede from inland locations (LVK,
SJC, SFO) with all sites across the Bay Area to clear by 19-20Z.
Across the Central Coast, a healthy feed of stratus from Monterey
Bay may keep ceilings around longer with clearing tentatively
anticipated to occur around 20Z. Stratus will return again tonight
but is not expected to be quite as widespread. Confidence is low to
moderate that stratus will reach LVK and SJC overnight with current
thinking that clouds will be predominantly scattered and any lower
ceilings that do form will only be temporary in nature. Elsewhere,
stratus is expected to return slightly later tonight with most Bay
Area sites seeing returns between 06-10Z. Light, locally variable
winds continue through the remainder of the morning before more
moderate generally west to northwest winds return during the
afternoon.

Vicinity of SFO...VFR to persist through the afternoon/evening
before MVFR CIGs return overnight. CIGs look to stay on the MVFR-IFR
border but the NBM and GLAMP are in agreement that CIGs should stay
MVFR. Stratus is expected to return later tonight around 10Z
compared to around ~09Z yesterday. Light northwest winds are
expected to strengthen by early this afternoon with moderate west to
northwest winds persisting through the remainder of the day.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...A healthy feed of stratus continues to move
into SNS and MRY which is pushing back the timing of clearing.
Moderate confidence that stratus will clear around 20-21Z for at
least a few hours this afternoon. The main uncertainty revolves
around how long stratus will continue feeding in from the Monterey
Bay and if a scenario similar to yesterday, where clearing did not
really happen, will occur. Assuming stratus does clear, an early
return around 00-01Z is expected at both MRY and SNS with MVFR-IFR
CIGs persisting through the rest of the TAF period. Moderate
northwest winds persist during the day before weakening overnight.

&&

.MARINE...
(Today through Wednesday)
Issued at 912 AM PDT Fri Sep 20 2024

Moderate northwesterly winds continuing through Monday, then
decrease to become gentle towards Tuesday. Seas will continue to
build through the weekend, with wave heights up to 13 feet in the
far northern outer waters as large, and shorter period
northwesterly swell continues to move into the waters. Seas begin
to abate Tuesday through the end of the forecast period.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 9 PM PDT Saturday for Pt Arena to Pt
     Reyes 10-60 NM.

&&

$$

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

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