Seaside, California Weather Forecast Discussion

949
FXUS66 KMTR 030428
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
928 PM PDT Thu Oct 2 2025
...New AVIATION...
.KEY MESSAGES...
Updated at 120 PM PDT Thu Oct 2 2025
- A slight chance for thunderstorms across the North Bay and
   Central Coast this afternoon and evening
- Gusty onshore winds develop on Friday
- Gradual warming trend begins this weekend with moderate offshore
   winds, especially in the higher elevations
&&
.UPDATE...
Issued at 858 PM PDT Thu Oct 2 2025
The surface cold front has passed through Monterey and San Benito
Counties and is currently located over Southern California. The bulk
of the convective showers are located to our southeast, over the
Central Valley, ahead of the cold front. That isn`t to say we don`t
have a chance for any additional showers in our CWA tonight. The
limiting factor will be how fast dry air advects into the Bay Area
as the upper level trough axis progresses inland. The 00Z (5PM) OAK
sounding reported a PWAT value around 1.0 inches with aircraft
soundings taken around 7/730PM showing PWAT values of 0.9 inches at
SFO and OAK. KMUX shows showers just off of the North Bay coastline
and a few more isolated showers developing off of the San Mateo
Peninsula. This will bring another round of light rain to the North
Bay and portions of the San Mateo Peninsula tonight. However, mid-
level water vapor satellite data shows a much drier airmass
approaching the Bay Area and Central Coast behind these showers. The
arrival of this drier airmass will greatly reduce the chances for
any additional shower development overnight across the South Bay and
Central Coast. Enough mid-level moisture will linger over the North
Bay tonight to support a 25-40% probability of precipitation
overnight.
Guidance shows some potential for isolated showers Friday
afternoon as the trough exits to our east and briefly brings some
moist mid-level air over the Bay Area and Central Coast again. These
showers would be very isolated in nature with any associated
precipitation only amounting to a few hundredths of an inch.
&&
.SHORT TERM...
Issued at 120 PM PDT Thu Oct 2 2025
(This evening through tonight)
Showers remain confined to interior areas of San Bentio County as of
this writing. By this afternoon and evening there will be chances
for rain showers and isolated thunderstorms across the North Bay and
Central Coast with potential for rain showers elsewhere across the
Bay Area. This is as MUCAPE values reach up to 500 J/kg across the
Central Coast this afternoon and North Bay this evening and into
early Friday morning. The CAMs (Convection-Allowing Models) also
show indications of this.
Temperatures this afternoon are forecast to range from the mid 60s
near the coast to mid 70s across the warmer interior locations.
Tonight, temperatures will cool into the upper 40s across the
interior Central Coast and North Bay valleys with 50s elsewhere.
&&
.LONG TERM...
Issued at 1254 AM PDT Thu Oct 2 2025
(Friday through Wednesday)
The strong upper level low will move through the state through
Friday, with drier conditions across the region with the moisture
having moved off to our south. A strong pressure gradient over the
Bay Area and Central Coast will enhance northwesterly winds
across the region, with wind gusts reaching 25 to 35 mph at the
immediate coast, within the Salinas Valley, and through favored
gaps and passes across the region. Wind Advisories may prove
necessary if confidence in more widespread gusty winds increases.
Temperatures will be around the same as today for the Bay Area
with a drop expected in the Central Coast, with the southern
Monterey Bay region and northern Salinas Valley seeing highs in
the lower to middle 60s, while the warmest locations in southern
Monterey County reach highs in the lower to middle 70s.
The weekend features a warmup as the upper level low moves off
into the Great Basin. High temperatures range from the middle 70s
to the lower 80s in the inland valleys, the lower to middle 70s
close to the Bays, and the middle to upper 60s along the Pacific
coast. A surface high will develop in the northern Rockies,
setting up the possibility for moderate offshore flow Saturday
through Monday. These would usually raise fire weather concerns,
but the antecedent rainfall and the limited strength of the
offshore flow will mitigate the risk. The latest update of the
PGE-WRF model shows the SFO-WMC gradient reaching -2 to -6 mb,
which will cause some offshore flow, but keep it from being strong
enough to warrant any critical fire weather threats.
Beyond Monday, upper level troughing is expected to persist over
the western United States, at least through the middle part of
next week. CPC outlooks lean towards temperatures and
precipitation totals near the seasonal average into the middle
part of October.
&&
.AVIATION...
(06Z TAFS)
Issued at 928 PM PDT Thu Oct 2 2025
VFR-MVFR except IFR in showers and perhaps fog, including possibly
a few downpours tonight and Friday morning. Recent global and
mesoscale model forecasts are not showing much precipitation,
however the potential is there for additional wet weather tonight
and Friday morning. Lengthening night-time hours i.e. lengthening
potential for night- time radiative cooling and a largely water
vapor rich air mass will favor fog, including dense fog development.
Nocturnal radiative cooling to space above cloud tops will favor
strengthening instability/showers, which may include isolated
lightning. Will closely monitor radar and satellite through the
evening, amending TAFs as needed.
Vicinity of SFO...VFR. Shower activity west of the SF Peninsula
will be monitored for potential additional development due to an
aligning and eventual arrival of a 700 mb to 500 mb thermal trough.
Will continue to amend SFO TAF as needed based on any changes seen
e.g. on radar, satellite and upstream and nearby surface observations.
The presently water vapor rich air mass lingering tonight to the
time of max nocturnal cooling nearest daybreak Friday may present
forecast difficulties with respect to areal coverage of low clouds
and/or fog. Drier conditions arrive Friday improving the chance of
VFR during the day.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...VFR, however post sunset cooling and the
arrival of a 700 mb to 500 mb thermal trough tonight will likely
bring a combination of lowering cloud ceilings and surface
visibilities /IFR/ in addition to temporary mixing winds associated
with passing showers and/or downpours. Similarly to the Bay Area,
the presently water vapor rich air mass lingering tonight to the
time of max nocturnal cooling nearest daybreak Friday may present
forecast difficulties with respect to areal coverage of low clouds
and/or fog. Drier conditions arrive Friday improving the chance of
VFR during the day.
&&
.MARINE...
(Tonight through next Wednesday)
Issued at 858 PM PDT Thu Oct 2 2025
An upper level trough of low pressure will move eastward over the
coastal waters and bays resulting in scattered showers, including
a few downpours tonight and Friday morning. Winds increase tonight
through Friday, causing widespread hazardous conditions for small
craft. These winds will support rough wind waves up to 10 feet
through the weekend. Winds and seas ease into the next work week.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 9 AM Friday to 3 AM PDT Saturday for
     Mry Bay-Pigeon Pt to Pt Pinos 0-10 nm-Pt Arena to Pt Reyes
     10-60 NM.
Small Craft Advisory from 3 AM Friday to 3 AM PDT Saturday for
     Pigeon Pt to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm-
     Pt Pinos to Pt Piedras Blancas 0-10 nm-Pt Reyes to Pigeon
     Pt 0-10 nm.
&&
$$
SHORT TERM...RGass
LONG TERM....DialH
AVIATION...Canepa
MARINE...Canepa
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NWS MTR Office Area Forecast Discussion