Alamo, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

748
FXUS66 KMTR 070605
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1105 PM PDT Mon Apr 6 2026

...New SHORT TERM, LONG TERM...

.KEY MESSAGES...
Updated at 1104 PM PDT Mon Apr 6 2026

 - Above normal temperatures and dry conditions through Wednesday

 - Unsettled weather returns Thursday with below normal
   temperatures and beneficial rainfall

 - Isolated to scattered thunderstorms Thursday and Friday

&&

.SHORT TERM...
Issued at 1104 PM PDT Mon Apr 6 2026
(Tonight through Wednesday night)

Upper-level shortwave ridging will dominate our weather through
Wednesday. This will result in above normal temperatures and dry
conditions. Fortunately, a decent marine layer of about 1,500 feet
is expected during this time which will keep conditions cooler at
the coast and the natural air conditioning on.

&&

.LONG TERM...
Issued at 1104 PM PDT Mon Apr 6 2026
(Thursday through next Monday)

A vertically stacked surface low in the Eastern Pacific Ocean near
37 N, -140 W will kickoff our pattern change. As it encroaches our
marine zones on Thursday, it`ll increase PWAT values to near the
90th percentile (0.79 inches for 12Z April 9th). The RRFS sounding
profile can be characterized by low CAPE, conditionally unstable
lapse rates, and low shear. As such, a slight (up to 15%) chance for
thunderstorms is being advertised for Thursday. Thunderstorm chances
increase Friday (15%-25%) as the surface low moves inland.
Thunderstorm impacts include lightning, locally heavy rainfall,
erratic/gusty winds, and small hail. There still remains uncertainty
in the exact location and timing of the cutoff low as this feature
is notoriously difficult to forecast due to their independence from
the Polar Jet Stream. As such, rainfall totals on Thursday and
Friday will be heavily dependent upon where rain
showers/thunderstorms develop. Upper-level longwave troughing
develops off the West Coast Saturday as an upstream trough digs
south and connects with the cutoff low with the help of a dip in the
Polar Jet Stream. As a result, widespread beneficial rainfall, below
normal temperatures, and strong onshore winds are expected Saturday
into Sunday with a cold frontal passage. Gusts up to 40 mph can be
expected in the higher terrain and through west-east oriented gaps
and passes. When all is said and done, rainfall on the order of
0.25"-0.75" inches is expected with locally higher totals of 1.00"-
1.50" inches in the coastal ranges.

&&

.AVIATION...
(06Z TAFS)
Issued at 955 PM PDT Mon Apr 6 2026

MVFR-IFR stratus has developed at the coast and moving inland with
impacts expected to persist through the night. Some lingering
moderate onshore winds will diminish through the next couple of
hours. The stratus deck retreats to the immediate coast on Tuesday
morning, with breezy onshore winds returning in the afternoon. Some
high resolution models suggest that HAF might scatter out sometime
on Tuesday afternoon, but this is a low confidence forecast and have
opted to keep the terminal socked in for now. Towards Tuesday night,
not seeing an impressive signal for inland stratus development with
winds staying breezier aloft into the end of the 24-hour TAF period,
with some model output persisting near SFO, OAK and the Monterey Bay
terminals. This might make for bumpy takeoffs and landings in the
interior terminals, although LLWS concerns remain below TAF criteria.

Vicinity of SFO... Lingering moderate westerly winds will diminish
through the next couple of hours. MVFR-IFR stratus persists through
the night and will dissipate Tuesday morning around 18-20Z, with
breezy west-northwest winds in the afternoon. Low confidence in
stratus returning Tuesday night with breezier winds persisting aloft.

SFO Bridge Approach... Similar to SFO.

Monterey Bay Terminals... MVFR-IFR ceilings persist through the
night and dissipate late Tuesday morning. Gentle northwest winds
overnight will increase and become moderate Tuesday afternoon. Lower
confidence for stratus development Tuesday night, but some model
output places stratus over the terminals before the end of the TAF
period.

&&

.MARINE...
(Tonight through next Sunday)
Issued at 955 PM PDT Mon Apr 6 2026

High pressure off the California coast will maintain light to
moderate breezes across the coastal waters through the week, with
localized fresh breezes off the Big Sur Coast through Tuesday.
Unsettled weather returns mid to late week, bringing light
showers, a slight chance of thunderstorms, and moderate seas.
Winds increase next weekend with a fresh breeze expected over
portions of the coastal waters.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 9 PM PDT Tuesday for Pt Pinos to Pt
     Piedras Blancas 0-10 nm.

&&

$$

SHORT TERM...Sarment
LONG TERM....Sarment
AVIATION...DialH
MARINE...DialH

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