Point Reyes Station, California Weather Forecast Discussion

707
FXUS66 KMTR 190509
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
1009 PM PDT Thu Sep 18 2025
...New AVIATION, MARINE...
.KEY MESSAGES...
Updated at 304 AM PDT Thu Sep 18 2025
- Showers with isolated thunderstorms today into Friday
- Cooler temperatures today and Friday, with a weekend warm up
- Rainfall chances increase again for the beginning of next week
&&
.UPDATE...
Issued at 815 PM PDT Thu Sep 18 2025
No major changes needed this evening. A slight eastward jog of the
system introduced mid-level dry air that essentially squashed most
of our thunderstorm activity across the Bay Area and Central
Coast. We will continue to see isolated showers through the
overnight hours, but most locations should be dry by the morning
and through the rest of Friday. Places that did actually perform
would be portions of interior southern Monterey county and the
southern Diablo Range, which picked up around 0.25" as of writing,
and Napa and Sonoma counties, which saw some decent thunderstorms
this evening. The real winners of this event are outside of our
area in the interior mountains of SoCal, where many locations
picked up 1-2".
Behringer
&&
.SHORT TERM...
Issued at 209 PM PDT Thu Sep 18 2025
(This evening through Friday)
The richer and juicier tropical air has finally arrived into the
Central Coast and continues to push northward this afternoon.
ACARs soundings out of SJC show the influx of upper level
moisture. However, its impact isn`t panning out as advertised on
some of the guidance the last few days. We`ve mentioned how low
confidence and how nuanced the forecast would be and that is still
the case even as events unfold. Showers and thunderstorms have
been most prolific for our area over the ocean and that was well
advertised. Where the forecast is suffering is over land. Rainfall
amounts over the land have been slashed from previous forecast as
the focus for most precip this afternoon through Friday is either
over the ocean or east of the forecast area. Rainfall amounts are
still forecast to be highest over the Central Coast, but for the
Bay Area not expecting much with only a few hundredths to a tenth.
So what`s happening? We have a few things at play. For one, the
moisture continues to surge north, but ACARS still indicate a
rather robust dry layer still hanging around. While the radar
shows echoes over land they`re evaporating before reaching the
ground. This will ultimately change later this afternoon and this
evening as the column becomes more saturated. Starting to see this
trend with a few gages finally showing a few tips in
Monterey/Carmel and East Bay Hills. Second, a weak surface low has
remained west of Monterey Bay and continues to drift northward.
This explains the better convection over the ocean. Third, the
Mario left over circulation is trending eastward focusing the
forcing to the Central Valley. Fourth, the northward movement of
the initial moisture was slightly delayed. As such, it`s now
battling the approaching upper level trough seen on water vapor
to the northwest. The upper trough may also be helping to push the
Mario circulation eastward as well.
All that being, still expecting some showers and isolated
thunderstorms across portions of the Central Coast and Bay Area
through Friday. The convective threat has decreased, but cannot
rule out an isolated rumble or two. Will still feel muggy given
the higher dew points and tropical nature. Would not be surprise
to near record moisture on the Oakland sounding this evening.
&&
.LONG TERM...
Issued at 239 PM PDT Thu Sep 18 2025
(Friday night through next Wednesday)
Friday night into Saturday is looking much drier than previous
forecast. There may be one or two lingering showers early Friday
due to wrap around moisture with the departing circulation.
Over the weekend the approaching upper trough deepens enough at
500 to eventually become cut-off. The upper low meanders off the
coast before moving to SoCal early next week. As the trough/and
low move through there is a sliver of upper level moisture/lift
Saturday into Sunday. Maybe some cu building on the hills.
Forecast is dry for now as precip seems more likely over the
Sierra and mt ranges north of here.
Early next week gets interesting once again as the upper low that
meandered to SoCal pulls in some higher PWAT air and moves
northward to the forecast area. This feature will bring rain
chances, possibly thunderstorms, back to the forecast area
Tuesday/Wednesday.
&&
.AVIATION...
(06Z TAFS)
Issued at 1009 PM PDT Thu Sep 18 2025
Shower activity is largely decreasing across the Bay Area and
Central Coast with only a few scattered showers remaining. Isolated
showers will continue overnight but confidence is low that showers
will directly impact any airports. Thunderstorm chances have
diminished with confidence low that any additional thunderstorms
will develop in our CWA. Low to moderate confidence on stratus
return along the coast and across interior areas. Starting to see
some MVFR-IFR CIGs along the coastline - impacting HAF, MRY, SNS -
with satellite showing some stratus moving into the SF Bay. The
intrusion of stratus into the SF Bay has increased confidence that
OAK will at least temporarily see stratus overnight as early as 09Z.
Conditions will improve by mid to late morning with CIGs potentially
taking longer to clear along the Monterey Bay Peninsula than along
the SF Bay/SF Peninsula.
Vicinity of SFO...VFR. Low chance of isolated showers continues
overnight but confidence is low that a shower will directly impact
the airport. There is some potential for MVFR CIGs to impact SFO
after 09Z but confidence is low that that will occur. If stratus
starts to fill in across the SF Bay then there will be a higher
chance for stratus to impact SFO and the bridge approach. Any
stratus that does develop will clear by late morning with a low
possibility that stratus will return again late tomorrow night.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...Isolated showers continue across the
southern portions of the Central Coast with low confidence that
additional showers/thunderstorms will impact MRY/SNS. MVFR-IFR CIGs
overnight with clearing by late morning/early afternoon. CIGs are
expected to become IFR at both sites overnight but not currently
anticipating LIFR CIGs or fog to develop. Stratus looks to come back
tomorrow evening for MRY with a slightly later return at SNS after
06Z.
&&
.MARINE...
(Tonight through next Wednesday)
Issued at 1009 PM PDT Thu Sep 18 2025
Locally fresh to strong gusts continue through early Friday across
the far northern outer waters. Winds are decreasing across the
coastal waters with gentle to moderate winds prevailing through
the  weekend. Isolated showers are possible through early Friday
before  dry weather returns over the weekend. Unsettled weather
returns next Tuesday and Wednesday with another round of isolated
showers and thunderstorms possible.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 9 AM PDT Friday for Pt Arena to Pt
     Reyes 10-60 NM.
&&
$$
SHORT TERM...MM
LONG TERM....MM
AVIATION...Kennedy
MARINE...Kennedy
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NWS MTR Office Area Forecast Discussion