FXUS66 KMTR 121841
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1141 AM PDT Sun Apr 12 2026

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

.KEY MESSAGES...
Updated at 1139 AM PDT Sun Apr 12 2026

 - Scattered rain showers with isolated thunderstorms will linger
   into midday on Monday

 - Gusty winds, especially at higher elevations Wednesday through
   Friday

 - A gradual warming and drying trend returns through the 
   remainder of extended forecast 

&&

.SHORT TERM...
Issued at 1139 AM PDT Sun Apr 12 2026
(This afternoon through Monday)

Scattered to numerous rain showers and isolated thunderstorms will 
remain possible throughout this evening. This is as the colder air 
mass aloft continues to provide enough instability in the post-
frontal environment. Now through early evening is when we have the 
greatest potential for convection as Surface Based CAPE remains 
between 200-700 J/kg across must of the region as a result of 
daytime heating. With the loss of daytime heating, the threat for 
thunderstorms will diminish and give way to mostly isolated to 
scattered rain showers, especially over the Pacific, Bay Area, and 
Central Coast. These rain showers may linger into midmorning on 
Monday as the mid/upper level low shift southward into southern 
California. 

Overnight temperatures will be chilly as winds diminish with mid-to-
upper 30s across the North Bay valleys and interior Central Coast 
(and higher elevations across the region). This may lead to frost 
formation the coldest, wind sheltered regions. However widespread 
frost is not likely. 

Monday will be up to 7 degrees F cooler than average (up to 20 
degrees F cooler in the higher elevations). Cloudy skies are 
anticpated to give way to mostly sunny skies by midday. However, 
fair weather cumulus will remain possible throughout the day over 
the higher terrain. 

&&

.LONG TERM...
Issued at 1139 AM PDT Sun Apr 12 2026
(Monday night through next Saturday)

Troughing will remain in place through Wednesday with temperatures 
warming slightly as high pressure nudges eastward over the eastern 
Pacific. By Wednesday, another mid/upper level through is forecast 
to drop down the British Columbia coast and into the Pacific 
Northwest. This will bring the potential for light rain to the North 
Bay with a 15-30% chance of precipitation by Wednesday afternoon and 
into Wednesday night. Little to no measurable rainfall is currently 
anticipated. Thus, we are not currently expecting any major impacts 
from this system as it slides into the Great Basin Thursday and into 
Friday. 

This will result in winds becoming offshore (northerly to 
northeasterly) across the North Bay Mountains and East Bay Hills 
Thursday afternoon and into Friday. Winds will also become offshore 
in other higher elevations across the Bay Area and Central Coast, 
however to a lesser extent. Again, fire weather concerns are not 
expected giving the decent wetting rainfall the region has 
experienced over the past several days. 

Forecast ensembles indicate a good probability of shortwave ridging 
building in across the eastern Pacific Friday and through the 
upcoming weekend. Thus, temperatures look to warm into the mid-to-
upper 60s near the coast and low-to-mid 70s across the interior.

&&

.AVIATION...
(18Z TAFS)
Issued at 1051 AM PDT Sun Apr 12 2026

Scattered showers/tstorms continue to traverse the region this 
morning. Flight CAT will vary greatly with the passing shower 
activity with VFR to MVFR/IFR temporarily. Current timing keeps 
SHRA through 20-23Z with gradual clearing this afternoon. Winds 
will remain breezy to gusty through this timeframe as well. Winds 
ease after 00Z this evening. Given the ample low level moisture 
there is a 10-20% chc for Monday AM fog for the N Bay Valleys. Not
high enough conf to include at this time

Vicinity of SFO...AWW for lightning through 3 PM. About 40-60% 
chc for the lightning with in 5 mi. Otherwise, periods wet 
runways, but thankfully more SW wind than SE. -SHRA will fade 
after 03Z with VFR developing.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...Scattered showers are making their way 
through the Monterey peninsula bringing a persistent low-level 
cloud deck and a few passing mid-level clouds. Rain showers should
clear out this afternoon by 2-3pm, but low clouds are expected to
linger for the remainder of the day. Onshore winds will remain 
breezy with a few embedded gusts until the evening. There is some 
potential for another round of light rain showers to return later 
tonight after sunset, though confidence is low(20%) at this time.

&&

.MARINE...
(Today through Friday)
Issued at 1051 AM PDT Sun Apr 12 2026

Rain showers and isolated thunderstorms will continue to move 
through the waters today with lingering showers possible into 
early Monday morning. Any stronger shower or thunderstorm would be
capable of producing strong and erratic winds. A moderate to 
fresh westerly breeze will prevail through the afternoon before 
veering to northwesterly tonight and diminishing. Winds continue 
to diminish and seas subside into the work week.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 3 PM PDT this afternoon for Mry Bay-
     Pt Arena to Pt Reyes 10-60 NM-Pt Reyes to Pigeon Pt 0-10 nm-
     SF Bay N of Bay Bridge.

     Small Craft Advisory until 9 PM PDT this evening for Pigeon Pt 
     to Pt Pinos 10-60 NM.

&&

$$

SHORT TERM...RGass
LONG TERM....RGass
AVIATION...MM/AN
MARINE...RGass

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Prepared by Boulder-Creek.com Weather at: Sun Apr 12 14:30:03 PDT 2026