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
From the National Weather Service
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