740
FXUS66 KMTR 200211
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
711 PM PDT Thu Sep 19 2024

...New UPDATE...

.SYNOPSIS...
Issued at 130 PM PDT Thu Sep 19 2024

There remains a chance for showers and thunderstorms across the
interior Central Coast through this evening. A warming trend is on
tap by this weekend and into early next week with temperatures
rebounding to near or slightly above seasonal averages.

&&

.UPDATE...
Issued at 800 PM PDT Thu Sep 19 2024

The KMUX radar still remains active picking up lingering showers
over Southern Monterey/San Benito counties this evening. Most of
the activity occurred during the pre-dawn hours into early this
morning as far as thunderstorms go. Since then, there`s been a
gradual decline since then. Latest analysis from NUCAPS and KVBG
soundings show some instability aloft with some inhibition near
the lingering shower activity. However, further analysis from
radar/MRMS data reveals not a lot of vertical depth or ice
through any convective column leading to no lightning production.
All that being said, a few showers to the east of San Benito may
produce a strike or two this evening, but not much more than that.
The storm motion with these convective showers has been slow
leading to wetting rains across some parts of Monterey county.
Lockwood has recorded 0.28" and a station near Greenfield measured
0.42". Not bad for September.

On the flip side...while the instability inland is aloft a much
more stable regime persists at the coast with a marine layer near
1500 feet. This marine layer will deepen slightly and move inland
overnight night.

No update needed this evening, but we`ll be monitoring the nearby
precip/convection.

MM

&&

.SHORT TERM...
(This evening through Friday)
Issued at 130 PM PDT Thu Sep 19 2024

The upper level low that brought rain showers and thunderstorms to
the interior Central Coast this morning remains south of the
Monterey Bay region. As it moves onshore, there will be a chance of
additional convection this afternoon over the aforementioned region
as the air mass aloft is marginally unstable. The warmest conditions
this afternoon will be across the North Bay and East Bay with
interior areas warming into the low 80`s with 60`s and 70`s as you
move closer to the coast.

The marine layer is projected to deepen tonight bringing low clouds
locally inland to the coastal adjacent valleys. The upper level
trough will push further inland Friday, yet its effects will still
linger with temperatures remaining below seasonal averages. Tomorrow
expecting more widespread 80`s across the interior with the
potential for a few spots to reach 90 degrees such as Lake
Berryessa. Elsewhere, 60`s and 70`s near the coast and San Francisco
Bay Shoreline.

&&

.LONG TERM...
(Friday night through next Wednesday)
Issued at 130 PM PDT Thu Sep 19 2024

Warming will continue into Saturday and moreso on Sunday as a ridge
of high pressure builds over the eastern Pacific. HeatRisk increase
by Monday and Tuesday with moderate risk across the interior. During
this time, evening clouds will spread into the coastal adjacent
valleys through early morning and then retreat back to the coast by
the afternoon.

&&

.AVIATION...
(00Z TAFS)
Issued at 421 PM PDT Thu Sep 19 2024

Currently VFR everywhere except the Monterey Bay terminals of MRY
and SNS which are enveloped in MVFR ceilings. The blanket of stratus
off the coast will filter inland, impacting all terminals tonight in
the form of ceilings. Rain shower activity will continue to diminish
through the night as the low pressure system finally moves out of
the area. Widespread VFR expected by tomorrow afternoon.

Vicinity of SFO...Currently VFR with northwesterly flow. High
confidence in a low-end MVFR ceiling impacting the terminal from
this evening through tomorrow morning.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Currently MVFR with westerly flow at MRY
and MVFR with northwesterly flow at SNS with high confidence in both
terminals further deteriorating to IFR early this evening. Earlier
thunderstorm activity has transitioned into rain shower activity
south of the terminals. Winds will prevail out of the west through
the TAF period. VFR will prevail by tomorrow afternoon.

&&

.MARINE...
(Tonight through next Tuesday)
Issued at 421 PM PDT Thu Sep 19 2024

Moderate northwesterly winds continue over the majority of the
coastal waters. Across the far northern outer waters, rough seas
return and northwesterly winds continue to strengthen. Winds and
seas will then remain elevated through the weekend but begin to
ease early next week.

&&

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

&&

$$

SHORT TERM...RGass
LONG TERM....RGass
AVIATION...Sarment
MARINE...Kennedy

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