Letterman Army Medical Cente, California Weather Forecast Discussion

441
FXUS66 KMTR 050326
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
826 PM PDT Sat Oct 4 2025
...New UPDATE, MARINE...
.KEY MESSAGES...
Updated at 124 PM PDT Sat Oct 4 2025
- Warmer and drier conditions through midweek, with moderate
   offshore wind expected through Tuesday in the higher elevations
- Next chance for rain late next week, yet lowering confidence in
   amount of rainfall
&&
.UPDATE...
Issued at 822 PM PDT Sat Oct 4 2025
Satellite imagery shows patches of stratus on the western side of
San Francisco and the San Mateo Peninsula, and the southern half
of the Monterey Bay region, as profilers at Bodega Bay and Point
Sur show attempts to redevelop the marine layer at around 1000
feet. Offshore flow persists across the interior mountains, with
an uptick in wind speeds expected tomorrow, although recent rains
and mild temperatures will mitigate the fire weather risk. The
forecast generally remains on track with no changes necessary.
DialH
&&
.SHORT TERM...
Issued at 124 PM PDT Sat Oct 4 2025
(This evening through Sunday)
The mid/upper level low pressure is currently over Utah/Wyoming and
will become absorbed into the long wave pattern over the next 12-24
hours. Meanwhile, building high pressure over the eastern Pacific
will support moderate north-northwesterly winds along the coast and
in the Salinas Valley this afternoon. However, north-northeasterly
(offshore) winds prevails in the higher elevations, strongest across
the North Bay region.
The marine layer is projected to become suppressed to around 1,000
feet in depth overnight. This would allow for stratus to return to
coastal areas and into some of the adjacent valleys. Offshore winds
will once again increase overnight and into tomorrow morning before
easing a bit by Sunday afternoon. Overnight temperatures will
generally remain in the 50s.
Any low clouds that do develop will dissipate by late Sunday
morning. Sunday is looking like it will be another warm day, warming
up a few degrees from our forecast maximum temperatures Saturday
afternoon. Thus, afternoon temperatures on Sunday will be in the
upper 60s to lower 70s near the coast to lower 80s inland under
mostly sunny skies.
&&
.LONG TERM...
Issued at 124 PM PDT Sat Oct 4 2025
(Sunday night through next Friday)
A cut-off low will develop within the upper level trough over the
Bay Area on Monday and the gradually shift to the southwest. This
will likely result in increasing offshore winds from late Sunday
night into Monday morning across the higher elevations in the North
Bay. Wind gusts will likely be between 35 and 45 (potentially
stronger) in places such as Mount Saint Helena in the North Bay and
Mount Diablo in the East Bay. While the minimum humidity will drop
below 30% across the North Bay Interior Mountains and East Bay
Hills, the mild temperatures, and higher than normal fuel moisture
will limit fire weather concerns. The warmest day of the week is
currently forecast to be on Tuesday as the interior warms into the
lower to upper 80s, upper 70s to lower 80s around the Bayshore, and
mid 60s to mid 70s elsewhere.
Temperatures begin to cool Wednesday through Friday as an upper
level trough approaches the West Coast. Thus, unsettled weather is
expected to return by Friday and into the upcoming weekend. However,
the ensembles are trending less with the amount of rainfall expected
during this timeframe. There is less than at 15% chance of receiving
more than 0.50" of rain across the North Bay. Regardless,
temperatures are likely to cool to below seasonal averages late in
the week and into the upcoming weekend. As we remain 6-7 days out in
time, be sure to remain up-to-date with the latest forecast
information.
&&
.AVIATION...
(00Z TAFS)
Issued at 517 PM PDT Sat Oct 4 2025
VFR except coastal low clouds /MVFR-IFR/ and patchy valley fog
/IFR-LIFR/ developing tonight and Sunday morning. West to northwest
winds 5 to 15 knots decreasing and becoming light offshore winds
tonight and Sunday except locally onshore Sunday afternoon.
Vicinity of SFO...VFR. West wind diminishing to 5 to 10 knots
tonight then light northeast-east Sunday.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...Visible satellite imagery shows low clouds
developing over the Monterey Peninsula. VFR-MVFR then IFR ceilings
developing tonight and Sunday morning. West to northwest winds 5 to
10 knots, becoming light southeast tonight and Sunday morning. Winds
becoming west to northwest 5 to 10 knots mainly Sunday afternoon.
&&
.MARINE...
(Tonight through next Friday)
Issued at 822 PM PDT Sat Oct 4 2025
Fresh breezes continue across the waters, with a few gale force
gusts for the offshore waters north of Pigeon Point. Winds will
gradually subside through the weekend. This will translate to
steep and rough seas up to 10 feet resulting in hazardous boating
conditions. Winds continue to ease into next week with light winds
persisting across the waters through the work week.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 3 AM PDT Sunday for Pigeon Pt to Pt
     Pinos 0-10 nm-Pt Arena to Pt Reyes 0-10 nm-Pt Pinos to Pt
     Piedras Blancas 0-10 nm.
Small Craft Advisory until 3 PM PDT Sunday for Pt Arena to Pt
     Reyes 10-60 NM.
Small Craft Advisory until 9 AM PDT Sunday for Pigeon Pt to Pt
     Pinos 10-60 NM.
&&
$$
SHORT TERM...RGass
LONG TERM....RGass
AVIATION...Canepa
MARINE...Canepa
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NWS MTR Office Area Forecast Discussion