637
FXUS66 KMTR 051148
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
448 AM PDT Thu Jun 5 2025

...New AVIATION, MARINE...

.SYNOPSIS...
Issued at 252 AM PDT Thu Jun 5 2025

Fair weather continues over the next several days with cloudy
mornings and clear afternoons. Temperatures around seasonal
normals with a slight warming trend over the weekend.

&&

.SHORT TERM...
Issued at 252 AM PDT Thu Jun 5 2025
(Today and tonight)

Key Messages
-Marine layer persists

Overnight satellite fog product once again reveals a solid marine
layer blanketing the coast and inland valleys. A comparison to 24
hours ago also shows better stratus coverage this morning as well.
This makes sense given the deeper marine layer with a depth of
close to 1700-2000 feet per profilers. The deeper marine layer is
likely due to passing upper level shortwave with a slight dip in
500mb heights. Otherwise, overall sensible weather for today and
tonight will be similar to Wednesday. Morning marine layer, which
includes low clouds, fog, drizzle, will gradually roll back to
the coast. Just like Wednesday, coastal areas will not completely
clear given lingering onshore flow. Given the deep push clearing
of inland areas will be a slightly later than yesterday.
Regardless still expecting inland sunshine. Temperatures today
will be seasonably cool with the coast upper 50s and 60s and
interior 70s to near 90. Onshore flow is forecast to peak around
4mb, which will result in breezy to gusty winds again this
afternoon/evening for the coast and any inland valley/gap/pass.
For tonight, marine layer will rush back inland with low clouds,
fog, and drizzle

&&

.LONG TERM...
Issued at 333 AM PDT Thu Jun 5 2025
(Friday through Wednesday)

Key Messages
-Gradual warming trend over the weekend into Tuesday

Heading into Friday we`ll see a shift in the upper level longwave
pattern. A very amplified and wavy jet rides the ridge into the
PacNW before taking a 180 and digging SW into California. The
digging jet will help facilitate the development of a cut-low
over the Bay Area Friday. This low will gradually retrograde or
meander off the CA coast heading into the weekend. As the low
meanders ridging develops inland. While ridging will bring a
warmer weather Friday through Tuesday the nearby upper low will
keep some variation of a marine layer intact. As such, we`ll see a
larger temp spread from the coast to inland areas. Warmest inland
areas will reach the 90s and take a run at 100 degrees Monday and
Tuesday. A cooling trend looks to develop by the middle of next
week with broader troughing developing aloft.

One fly in the ointment will be the pesky upper low developing
over the region with a slight easterly flow aloft. Not all models
show it, but a few of them do hint that the upper low will pull
some moisture in from the east. Additionally, a few of the
convectively hot models (NAM) even generate some MUCAPE over the
N Bay this weekend. Not mentioning any convection at this time and
not even a non-zero chance, but wanted to at least mention it.

&&

.AVIATION...
(12Z TAFS)
Issued at 430 AM PDT Thu Jun 5 2025

Marine layer stratus has returned to the majority of the
terminals overnight and will persist through the morning. The
pattern is fairly similar to yesterday with afternoon clearing
and a return of IFR-MVFR stratus overnight. Winds have begun to
shift to a southerly breeze as the coastal trough drifts
offshore. Several terminals will keep a southerly breeze through
the day while others will see a wind shift to NW as the sea
breeze kicks in this afternoon.

Vicinity of SFO...The donut hole of clear skies over SFO was
present again early this morning, though the walls are starting
to close in. Once they do, MVFR stratus will likely be observed
through the mid morning. Clear skies and a moderate sea breeze are
expected through the afternoon before stratus returns tonight.
While it`s likely the winds will shift today, it`s not a
guarantee, and the timing of a potential shift is still a little
uncertain.

SFO Bridge Approach...MVFR stratus is already impacting the
approach, despite the delayed arrival at the terminal.

Monterey Bay Terminals...High confidence in IFR-MVFR stratus
through mid morning before a few hours of clearing in the middle
of the day. By late afternoon the marine layer stratus will
likely start to rebuild across both MRY and SNS and remain through
the night. The wind direction at MRY will be tricky today, with a
southerly component possible through the day. Wind at SNS will
likely reamin NW through the TAF period due to more straight
forward terrain blocking and funneling.

&&

.MARINE...
(Today through Tuesday)
Issued at 430 AM PDT Thu Jun 5 2025

A moderate to strong northerly breeze is diminishing in the outer
waters while strong southerly winds persists through the day
along the coast and in the northern San Francisco Bay. The
pressure gradient will relax over the next 36 hours, causing winds
to diminish and allowing seas to subside. Mostly favorable
conditions will persist through the weekend with a long period SW
swell arriving early next week.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 9 PM PDT this evening for Pt Reyes to
     Pigeon Pt 0-10 nm-SF Bay N of Bay Bridge.

     Small Craft Advisory until 3 PM PDT this afternoon for Pt Arena
     to Pt Reyes 10-60 NM.

&&

$$

SHORT TERM...MM
LONG TERM....MM
AVIATION...Flynn
MARINE...Flynn

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