Pacheco, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

031
FXUS66 KMTR 252335
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
435 PM PDT Fri Jul 25 2025

...New AVIATION, MARINE...

.KEY MESSAGES...
Updated at 1211 AM PDT Fri Jul 25 2025

 - Cool weather continues through Saturday

 - Temperatures return closer to normal starting Sunday

&&

.SHORT TERM...
Issued at 108 PM PDT Fri Jul 25 2025
(This evening through Saturday)

Low clouds are scattering out and/or dissipating across much of the
region this afternoon. However, temperatures this afternoon will
remain 5-15 degrees F below seasonal averages as a cut-off low
remains over the San Francisco Bay Area. With PWAT values just above
1.00" and MUCAPE values between 100-250 J/kg, there is around 5%
chance of high based convection across the far northern portions of
the North Bay this evening into early Saturday morning.

Expecting an early return of stratus into the coastal valleys again
overnight with a good likelihood for coastal drizzle and drizzle in
the favored upslope regions across the area. These low clouds are
then forecast to dissipate across much of the region as we head into
Saturday afternoon with similar temperatures as today.

&&

.LONG TERM...
Issued at 1211 AM PDT Fri Jul 25 2025
(Saturday night through Thursday)

The long wave pattern is mounting a rescue mission for the cut-off
low this weekend. By Sunday an approaching trough over the East
Pacific will gradually re-absorb the low. The pattern change might
not be obvious at the surface as the trough will then linger near
the coast, providing a similar cooling effect as the cut-off low.
At the same time high pressure will build over the desert SW,
bringing triple digit heat to our friends in southern Arizona.
The battle between these two features will cause temperatures to
rise Sunday, but still remain slightly below seasonal normals. The
loss of the cut-off low will cause the marine layer to thin a bit,
but don`t expect to see a sunrise anytime soon. This new pattern
looks very stable, with temperatures remaining near or just below
seasonal normal through next week. That`s still warmer than it`s
been, however.

So will a summer heat wave ever hit? There is some indication in
the ECMWF ensemble mean that the SW US high and subtropical high
over the central pacific will merge over northern California
sometime around August 6. The GEFS mean shows similar timing.
We`re talking nearly 2 weeks out, so take this with a grain of
salt. In fact we had similar indications a month ago about July.
Not only did that heat wave not happen, July 2025 may end up in
the coldest 10% of Julys on record.

&&

.AVIATION...
(00Z TAFS)
Issued at 435 PM PDT Fri Jul 25 2025

Coastal MVFR-IFR stratus persists along patches on the coast, coming
inland near Point Reyes, through the Golden Gate immediately north
of SFO, across the western half of the San Mateo Peninsula, and into
the southern Monterey Bay region. Stratus will redevelop inland this
evening and overnight, with the stratus retreating to the immediate
coast through Saturday morning. Low to medium probability that
stratus lingers through the Golden Gate and impacts SFO and OAK
through Saturday. Breezy onshore flow continues through the evening
hours, diminishing overnight before returning Saturday afternoon.

Vicinity of SFO... MVFR-IFR stratus hovers just to the north of the
terminal and will return to the terminal area imminently. Stratus
continues into Saturday, with low confidence in the clearing time
and a distinct possibility that stratus will clear just to the north
of the terminal. Probabilities that stratus lingers through Saturday
hover around 30-40% at this time. Stratus returns to the terminal
Saturday afternoon or evening. Breezy west flow continues through
the evening hours, diminishing overnight before resuming Saturday
afternoon.

SFO Bridge Approach... Similar to SFO.

Monterey Bay Terminals... Stratus has arrived at MRY and is expected
to return to SNS within the next couple of hours. Generally IFR
ceilings are expected with some LIFR possible at the coast. Stratus
clears through Saturday afternoon at SNS, with moderate confidence
for clearing at MRY sometime in the afternoon. Breezy onshore flow
persists through the evening with the winds diminishing overnight,
before the onshore winds return Saturday afternoon.

&&

.MARINE...
(Tonight through next Wednesday)
Issued at 435 PM PDT Fri Jul 25 2025

A moderate northwest breeze and moderate seas prevail through
Tuesday. Low clouds with drizzle can be expected through Saturday.

&&

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

$$

SHORT TERM...RGass
LONG TERM....Flynn
AVIATION...DialH
MARINE...DialH

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