730
FXUS66 KMTR 100332
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
732 PM PST Sat Nov 9 2024

...New UPDATE, MARINE...

.SYNOPSIS...
Issued at 1253 AM PST Sat Nov 9 2024

Active pattern continues with a shift towards cooler temps and
increased moisture. Decent rain chances across the region by early
next week, and potentially later in the week as well.

&&

.UPDATE...
Issued at 730 PM PST Sat Nov 9 2024

Relatively quiet weather day around the Bay Area and Central
Coast. Mostly sunny skies today with highs reaching the upper 50s
to mid 60s along the coast and mid 60s to mid 70s inland, which is
close to seasonal averages.

The bigger story for the evening is that KMUX radar has been
switched precip mode. The next rainmaker is lurking off the coast.
A few radar echoes are now showing up over the outer coastal
waters. These echoes will inch their way toward the coast, but
best chance for precip still remain over the coastal waters
tonight. That being said, the lowest levels of the boundary layer
will continue to moisten allowing for some drizzle over the North
Bay and coastal spots tonight into Sunday. As for actual steadier
rain...we`ll need to watch for a re-enforcing cold front farther
upstream. This second front will need a push from an upper level
jet pushing through the Gulf of Alaska. As noted below, the second
push will occur Sunday night and early Monday with steadier
precip.

No update for this evening needed.

Did take a peak at longer range ensemble guidance and CPC 6-10
day and 8-14 day outlooks, which show a wet and active pattern
ahead.

&&

.SHORT TERM...
(This evening through Sunday)
Issued at 109 PM PST Sat Nov 9 2024

Cloud cover continues to build ahead of the next rain maker arriving
in the late weekend. But between now and then, calm weather
continues. Expect partly cloudy skies to turn mostly cloudy this
afternoon with still relatively dry conditions. Overnight, expect
building coastal fog along with pockets of drizzle as the warm
sector ahead of the next cold front builds into the area. Sunday
will have lingering pockets of drizzle and mostly cloudy conditions
with the front arriving from the north that night.

&&

.LONG TERM...
(Sunday night through next Friday)
Issued at 109 PM PST Sat Nov 9 2024

The forecasting team discussed the potential of the cold front
slowing as it begins to interact with the California coast, which is
common for these systems. As such, some polishing was added to the
time of arrival of the initial rains, but otherwise the forecast
remains on track. Rain chances arrive Sunday night and spread
southward into Monday with the main band of the cold front passing
over the SF Bay 10 am to possibly noon on Monday. This line of rain
will offer the more moderate rain rates, and breezier winds. The
front move southeast through the rest of the afternoon, and only
light showers linger into Monday night.

Cold and dry air moves into the area behind the front leading to
Tuesday and Wednesday mornings having some concerns for interior
lows dipping into the 30s. Otherwise, mostly calm conditions are
expected in the mid week.

Models and blends are struggling with the time of arrival of the
next rain system, but do agree that the one-two-punch will of a cold
front and parent low passing through the Bay Area will lead to
prolonged chances for rain. As of the current forecast: the pre-
frontal drizzle arrives Wednesday evening, then the front that
night, followed by lingering showers through Thursday, and then rain
from the low pressure circulating through the region late Thursday
and lasting through much of the weekend. While rain chances look
strong, rainfall rates and amounts don`t look to be of much of
concern with overall rain totals below an inch for the rainiest
spots over the Wed-Saturday period and much lower the areas farther
south.

In the long-long term, the conveyor belt of rain systems looks to
continue with models hinting at another cold front arriving just as
the previous low pressure exits on the 17th. Model agreement is
fairly impressive considering how far out this is in the current
run, but much can still change between now and then. Be sure to keep
checking in!

&&

.AVIATION...
(00Z TAFS)
Issued at 332 PM PST Sat Nov 9 2024

VFR through early Sunday morning as low stratus builds at the
immediate coast. Some model output showing stratus intrusion into
the SF Bay region, but expecting conditions to remain quite dry and
as a result have kept SFO and OAK TAFs at VFR. Light to marginally
breezy onshore winds continue through the evening, with light
offshore flow overnight and Sunday morning before the onshore flow
returns in the afternoon.

Vicinity of SFO... VFR through Sunday morning, with a low confidence
for IFR-LIFR ceilings in the early morning hours. Generally light
winds through the TAF period, flowing onshore during the afternoon
and evening.

SFO Bridge Approach... Similar to SFO.

Monterey Bay Terminals... VFR through early Sunday morning with IFR-
LIFR conditions through the late morning hours. Light to breezy
onshore flow through the evening with light offshore flow overnight.

&&

.MARINE...
(Tonight through next Friday)
Issued at 705 PM PST Sat Nov 9 2024

A cold front approaches and moves across the coastal waters and
bays on Veterans Day. The front will result in a band of light
rain, then a wind shift over to drier northwesterly winds.
Another frontal system with rain approaches the Bay Area during
the middle of next week. Wave heights also gradually build
through the middle of the upcoming week.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.
&&

$$

SHORT TERM...Murdock
LONG TERM....Murdock
AVIATION...DialH
MARINE...DialH

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