Strawberry Point, California Weather Forecast Discussion

987
FXUS66 KMTR 280041
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
541 PM PDT Sat Sep 27 2025
...New AVIATION...
.KEY MESSAGES...
Updated at 209 PM PDT Sat Sep 27 2025
- Rain and thunderstorm chances return Monday
- Rain lingers through Wednesday
&&
.SHORT TERM...
Issued at 209 PM PDT Sat Sep 27 2025
(This evening through Sunday)
We have a southerly surge underway with low stratus along the
Pacific Coast and even continuing to push inland through the Golden
Gate Gap and Monterey Bay - as such, I don`t think the sun will be
seen along the Pacific Coast today. The cooling and moistening trend
will continue through the weekend due to an approaching upper-level
longwave trough. This aforementioned feature will allow for the
marine layer to deepen and perhaps even provide enough lift to
squeeze out some drizzle along the coast and orographically enhanced
locations. Temperatures will be near to slightly below normal today
with widespread well below normal temperatures by tomorrow.
&&
.LONG TERM...
Issued at 209 PM PDT Sat Sep 27 2025
(Monday through next Friday)
The first of two systems will approach the region on Monday. Warm
sector (light, stratiform) rain is expected Monday morning ahead of
the cold front that will bring relatively intense rainfall and the
chance for thunderstorms Monday afternoon into Monday evening. The
moisture is sourced from the subtropics with the GEFS and ECMWF
Ensemble IVT Forecast ensemble mean showing it peaking around 350
kg/ms Monday afternoon and dropping below 250 kg/ms by Monday night.
Thunderstorm chances remain, but have decreased. The essential
ingredients for a thunderstorm are lift, instability, and moisture.
The lifting mechanisms and moisture have already been discussed, but
the instability is looking more and more like it will be the
limiting factor. Lapse rates have decreased to become stable and
MUCAPE has trended down to 100-150 J/kg and even this was difficult
to find as coverage has shrunk. Post-frontal rain showers are to be
expected on Tuesday between system one and two. System two will get
it`s moisture from Typhoon Neoguri in the Northwestern Pacific Ocean
as it overtops a subtropical ridge in the Central Pacific Ocean and
feeds into a developing gale force low pressure system off the
Washington Coast. There is uncertainty in the exact timing of this
second system, but as with the first system, the timing has been
pushed back. It is now looking like the arrival time of this second
system will be early Wednesday morning. This system is expected to
have even less favorable ingredients for thunderstorms. As is
typical with Gulf of Alaska systems, there will be a stark northwest
to southeast rainfall gradient. When all is said and done, the North
Bay can expect to see up to 1.25" with the Interior Central Coast
becoming less likely to receive any rainfall. We will continue to
monitor the potential for any stalling/stationary nature of these
systems. Fortunately, right now rainfall rates and totals are not
worrisome. It is also worth noting that as the track has shifted
farther north, rainfall totals have decreased.
&&
.AVIATION...
(00Z TAFS)
Issued at 541 PM PDT Sat Sep 27 2025
The SBA-SFO and SMX-SFO pressure gradients are 1.6 mb and 2.1 mb
respectively, while the SFO-SAC pressure gradient is 2.5 mb, these
are stronger than the ACV-SFO pressure gradient 0.7 mb. The surface
pressure gradients are resulting in a mix of southerly and onshore
winds, combining with deepening marine layer stratus, fog and a few
areas of light drizzle/sprinkles in the coastal mountains. The NAM
and HREF show an increase in stratus /IFR-MVFR/ tonight and Sunday.
90-100% probability of IFR in the HREF suggests increasing drizzle
potential in the coastal mountains, some of which may also reach
into the North Bay tonight and Sunday morning.
Vicinity of SFO...VFR-MVFR. Southwest wind 15 to 22 knots until 04z
this evening, wind decreasing to 10 knots tonight and Sunday morning
with a few gusts to 20 knots Sunday afternoon and early evening.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...VFR this evening, then IFR-MVFR in stratus
tonight and Sunday morning. Patchy drizzle possible tonight and
Sunday. Southerly winds along the coast are resulting in a mix of
variable and southwesterly wind at KMRY while it`s northwesterly
at KSNS. Post sunset stabilizing of the initial land/sea temperature
differences and pressure gradients will result in a decrease in
winds tonight and Sunday morning. Winds generally becoming light
and variable tonight and Sunday morning then onshore Sunday
afternoon and early evening.
&&
.MARINE...
(Tonight through next Thursday)
Issued at 209 PM PDT Sat Sep 27 2025
Strong southwesterly gusts will persist over the San Pablo Bay,
Suisun Bay, the West Delta and the San Francisco Bay north of the
Bay Bridge through this evening. Gentle to moderate southerly
breezes will allow for seas to subside into early Sunday morning.
An approaching upper level trough and surface cold front will
bring rain, isolated embedded thunderstorms, and building seas to
the coastal waters Monday into early Tuesday. A second system will
arrive Tuesday into Wednesday and continue rain chances across
the coastal waters.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 9 PM PDT this evening for SF Bay N of
     Bay Bridge.
&&
$$
SHORT TERM...Sarment
LONG TERM....Sarment
AVIATION...Canepa
MARINE...RGass
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NWS MTR Office Area Forecast Discussion