946
FXUS66 KMTR 252318
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
418 PM PDT Wed Sep 25 2024

...New AVIATION, MARINE...

.SYNOPSIS...
Issued at 104 PM PDT Wed Sep 25 2024

Mild weather today under a deep marine layer. Warming trend begins
tomorrow, much warmer by Friday. High temps near or above average
persist into next week.

&&

.SHORT TERM...
(This evening through Thursday)
Issued at 104 PM PDT Wed Sep 25 2024

Quick check of current temps shows about 15-30 degrees cooler than
24 hours ago, depending on where you are. All thanks to a deep
marine layer and robust onshore flow in response to a passing
upper level trough in the Pacific Northwest. This pattern evolves
rather quickly back to a ridge setup with effects beginning
Thursday. High temps start to trend upwards Thursday as the marine
layer becomes compressed and cloud cover clears sooner in the day,
compared to today. Temperatures Thursday look to be about seasonal
normals. Some high clouds may end up in the picture this evening
for locations in the North Bay, making for a nice sunset if you`re
inland or above the stratus.

&&

.LONG TERM...
(Thursday night through next Tuesday)
Issued at 104 PM PDT Wed Sep 25 2024

Friday is expected to be the warmest day headed into the weekend
with highs ranging 5-15 degrees above normal. There`s a short
window of a weak offshore gradient that will likely set up in the
morning, eroding most of the marine layer and causing temps to
increase rapidly. By the afternoon, the gradient will reverse and
breezy onshore flow will ensue. Therefore, there is more
uncertainty than normal with the highs on Friday based on the
timing of the wind reversal. A progressive Gulf of Alaska trough
pattern remains through the weekend with another upper level
disturbance heading into the PNW Saturday and Sunday. This will
aid in flattening the ridge influence, bringing high temps back
down towards normal. However, the roller coaster ride continues
with a ridge influence building back in through early next week,
resulting in another warming trend. Ensemble guidance shows fairly
reasonable agreement in this pattern, so confidence is high that
we will see above average temperatures at least through the middle
of next week.

&&

.AVIATION...
(00Z TAFS)
Issued at 416 PM PDT Wed Sep 25 2024

Currently VFR at all terminals with the exception of the Monterey
Bay terminals of MRY and SNS. High confidence in all terminals
developing MVFR ceilings overnight. A deep marine layer currently
measured at 2,500 feet will aid in MVFR ceilings, VFR visibilities,
and drizzle along the immediate coast. Widespread VFR will prevail
by tomorrow afternoon.

Vicinity of SFO...Currently VFR with westerly flow. High confidence
in the terminal developing an MVFR ceiling tonight with VFR
prevailing by late-morning Thursday. Winds will prevail out of the
west through the TAF period with the exception of brief, light
offshore flow tomorrow during the late morning/early afternoon
timeframe before the sea breeze kicks in.

SFO Bridge Approach...Low clouds will filter in late this
evening and linger through 19Z.

Monterey Bay Terminals...Currently MVFR with westerly flow at MRY
and MVFR with northwesterly flow at SNS with VFR prevailing at both
terminals by tomorrow afternoon. Westerly winds will veer to become
northerly overnight for MRY before backing to become westerly with
SNS prevailing out of the west/northwest through the TAF period.

&&

.MARINE...
(Tonight through next Monday)
Issued at 416 PM PDT Wed Sep 25 2024

Light to gentle northwesterly breezes continue through the
evening, strengthening to become moderate to fresh Thursday
through the weekend, and causing rough seas to develop in the
outer waters.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 3 AM Thursday to 9 AM PDT Friday for
     Pt Arena to Pt Reyes 10-60 NM.

     Small Craft Advisory from 3 PM Thursday to 9 AM PDT Friday for
     Pigeon Pt to Pt Pinos 10-60 NM.

&&

$$

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

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