FXUS66 KMTR 130459
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
959 PM PDT Sun Apr 12 2026

...New AVIATION, MARINE...

.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...
(06Z TAFS)
Issued at 959 PM PDT Sun Apr 12 2026

Isolated showers persist across the region through Monday morning 
with MVFR-VFR conditions possible within the showers. Otherwise, 
generally VFR through Monday afternoon. Light to gentle winds 
continue overnight with moderate onshore flow will developing in the 
afternoon. There is a low confidence (around 10-20% probability) of 
fog developing in the interior valleys tonight due to the recent 
rainfall. Confidence is too low to put this in the TAFs at this 
time. Monitoring the potential for MVFR-IFR stratus to develop 
Monday evening, potentially impacting immediate coastal and interior 
valley terminals.

Vicinity of SFO... Periodic shower activity continues through Monday 
morning, with generally VFR conditions expect when showers pass over 
the terminal. Light winds persist overnight before northwesterly 
flow develops Monday afternoon.

SFO Bridge Approach... Similar to SFO.

Monterey Bay Terminals... Isolated showers across the region through 
Monday morning, otherwise VFR through Monday afternoon. Light 
drainage flow continues overnight before moderate northwest winds 
develop for Monday afternoon. Monitoring the potential for IFR-MVFR 
stratus to develop along the northern edge of the Santa Lucia and 
Gabilan ranges on Monday evening, with potential side impacts to the 
terminals.

&&

.MARINE...
(Tonight through next Saturday)
Issued at 959 PM PDT Sun Apr 12 2026

Isolated showers persist into early Monday morning. Gentle
northwest winds are expected to prevail tonight through Monday
morning, increasing to a moderate to fresh breeze through
Wednesday and a strong breeze to near gale force by Thursday.
Moderate seas continue through Wednesday before rough seas arrive
on Thursday.

&&

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

$$

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

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Prepared by Boulder-Creek.com Weather at: Sun Apr 12 22:30:02 PDT 2026