FXUS66 KMTR 130642
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
1142 PM PDT Sun Apr 12 2026
...New SHORT TERM, LONG TERM...
.KEY MESSAGES...
Updated at 1136 PM PDT Sun Apr 12 2026
- Slightly cooler to near normal temperatures through Thursday
- Periods of gusty winds, especially at higher elevations
Wednesday through Friday
- Warmer temperatures return Friday into the weekend
&&
.SHORT TERM...
Issued at 1136 PM PDT Sun Apr 12 2026
(Tonight through Tuesday)
The coverage in light shower activity continues to gradually shift
south late tonight into early Monday morning. Earlier this evening
the KOAK sounding reported a 23.0C temperature at H50 which is in
the 10th percentile for this time of the year. That cold core aloft
helped support continued light shower activity after sunset from the
SF peninsula south to Monterey Bay. The upper low will become more
unorganized as it moves farther inland, evolving into a positively
tilted upper trough extending from the Great Basin southwest into
SoCal today. Lingering offshore scattered light showers will
occasionally drift into the Big Sur coastline through mid-morning
today with maybe a trace to a few hundredths of rain. Mondays highs
at lower elevations will run around 5F-10F degrees below normal,
with higher elevations 10F-20F degrees below normal. Cooler than
normal temperatures persist tonight into early Tuesday, especially
farther inland with cooler than normal air aloft persisting much of
the work week.
&&
.LONG TERM...
Issued at 1136 PM PDT Sun Apr 12 2026
(Tuesday night through next Sunday)
A progressive shortwave pattern sets in Tuesday through Thursday
behind the exiting trough defining the term 'gradual warming' with
most locations seeing an increase of 1 or 2 degrees each day through
the middle of the week. A developing trough shifts south from the
Pacific Northwest on Wednesday. There is a slight chance for
rainfall across the North Bay Wednesday afternoon as the trough axis
pivots east and south, but any rainfall will be measured in
hundredths of inches with no impacts. Gusty winds will develop on the
backside of the exiting trough later Wednesday through Thursday
and into the early morning hours of Friday. However, updated
deterministic guidance has shifted the disturbance farther east
than this time last night with less of an 'inside slider' signal.
Winds will still be gusty at times especially at higher elevations
but impacts seem low. There is also a signal for the potential of
another round of rainfall toward the end of next weekend into the
beginning of next week.
&&
.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...JM
LONG TERM....JM
AVIATION...DialH
MARINE...DialH
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Prepared by Boulder-Creek.com Weather at: Mon Apr 13 00:30:02 PDT 2026
From the National Weather Service
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