FXUS66 KMTR 231159
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
459 AM PDT Mon Mar 23 2026
...New AVIATION, MARINE...
.KEY MESSAGES...
Updated at 1135 PM PDT Sun Mar 22 2026
- Slightly above normal to seasonal temperatures through the week
- Dry weather through 7 day outlook; potential for light rain
beginning of April
&&
.SHORT TERM...
Issued at 1135 PM PDT Sun Mar 22 2026
(Tonight through Tuesday)
Upper level ridging gradually rebuilds on Monday with above normal
temperatures continuing. High temperatures will be in the upper 70s
to low 80s across the interior with 60s to 70s along the coastline.
The warmest areas will be in the interior Central Coast where high
temperatures will reach the mid to upper 80s. High temperatures are
running 10-15 degrees above normal which is cooler than the 20-30
degrees above normal that we saw last week. One of the reasons for
this difference is that the upper level ridge is weaker with heights
peaking around 5850 meters over the Bay Area (compared to over 5900
meters we saw last week). The center of the ridge is located to our
south over the desert southwest. We can expect temperatures to cool
down overnight with morning lows on Monday and Tuesday in the upper
40s to mid 50s. Minor HeatRisk is forecast across the region through
the entire week which primarily impacts those who are extremely
sensitive to heat. Guidance is showing some potential for a shallow
500-750 ft marine layer developing tonight but confidence is on the
lower end given the rebuilding ridge.
&&
.LONG TERM...
Issued at 1135 PM PDT Sun Mar 22 2026
(Tuesday night through next Sunday)
Above normal temperatures continue through the Long Term forecast
with some potential for rain to return end of March/start of April.
Upper level ridging persists through at least Tuesday with highs in
the upper 70s to low 80s across the interior, 60s to 70s along the
coast, and upper 80s to low 90s across the interior Central Coast.
Heading into Wednesday, the forecast gets a little more
interesting. Both the Euro and the GFS show a cut-off upper level
low over the Pacific being reabsorbed into the large scale pattern
and moving through southern CA as a shortwave trough. This
displaces center of the upper level ridge further eastward
(vicinity of AZ/NM) and coincides with the passage of a weak
surface based cold front. Temperatures will drop 3-5 degrees
Wednesday and Thursday with highs largely in the mid to upper 70s
across the interior, 60s along the coast, and mid 80s across the
interior Central Coast. A look at the Precipitable Water forecast
shows PWAT values between 0.8-0.9" across the North Bay before the
front falls apart as it moves south of the Golden Gate. Don't go
getting to hopeful for rain just yet though. Models aren't showing
any rain associated with this frontal passage, but, it may be
enough moisture to generate some coastal drizzle. WRF guidance
shows a shallow marine layer redeveloping on Wednesday which may
increase coastal drizzle odds for the North Bay. Gusty winds
briefly return Wednesday as frontal passage occurs but the
windiest conditions largely stay over the marine environment and
the higher elevations. Upper level ridging makes an effort to
redevelop late week but, with the center of the ridge displaced
farther east, we are only looking at a temperature increase of 2-3
degrees Friday into the weekend.
For any rain fans out there, long range guidance shows a deep upper
level trough moving onshore at the end of March/beginning of April.
The current forecast shows precipitation chances increasing as early
as March 30th but this is likely to be pushed backwards in time.
Cluster guidance maintains ridging influence over the West Coast
through at least the 31st with troughing becoming more likely
starting April 1st. The clusters are not fully in agreement on this
scenario yet either with 3 out of 5 showing troughing, 1 showing
more zonal flow, and 1 showing ridging over the West Coast on April
1st. While there is uncertainty as to when precisely the trough will
arrive, models are in agreement that rain will in fact return at the
beginning of April. It is worth mentioning that nearly all the Euro
and GFS ensembles are picking up on light rain returning in the 4/1-
4/3 timeframe. Do the current ensemble rain amounts look impressive?
Not terribly. Most models are showing around 0.5" with only a
handful showing over 1" to 1.5" of precipitation. Still, it's better
than nothing especially as the rainy season is winding down. The CPC
maintains the potential for above normal precipitation across our
CWA through April 5th with a return to below normal precipitation
expected after that in the Weeks 3-4 outlook.
&&
.AVIATION...
(12Z TAFS)
Issued at 450 AM PDT Mon Mar 23 2026
Isolated patches of IFR conditions are currently impacting STS
and SNS, but impacts will fluctuate with any wind helping to clear
out the localized clouds and mist. In a few hours VFR conditions
will dominate all terminals for the rest of the day. Gentle winds
will become a moderate onshore breeze this afternoon. A shallow
marine layer has the potential to bring isolated impacts to
flight conditions Tuesday morning at the coastal terminals.
Vicinity of SFO...VFR conditions will almost certainly last
through the morning and there is a very good chance they prevail
through the TAF period. Winds will remain onshore and increase to
a moderate breeze in the afternoon before decreasing back to a
gentle breeze overnight.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...A very small patch of stratus moved
through MRY early this morning and is now parked over SNS. Due to
the thin and localized nature of these clouds, the impacts may be
transitory and/or temporary through the early morning hours before
VFR conditions take hold for the rest of the day.
&&
.MARINE...
(Today through Saturday)
Issued at 450 AM PDT Mon Mar 23 2026
A moderate NW breeze will prevail today before decreasing to
gentle Tuesday. Conditions will deteriorate through the day
Wednesday as a strong to near gale force northerly breeze
develops, building very rough seas of 12-17 feet across exposed
waters by Thursday morning.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 9 AM PDT this morning for Pigeon Pt
to Pt Pinos 10-60 NM-Pt Arena to Pt Reyes 0-10 nm-Pt Arena
to Pt Reyes 10-60 NM-Pt Pinos to Pt Piedras Blancas 0-10 nm-
Pt Reyes to Pigeon Pt 0-10 nm.
Small Craft Advisory from 3 PM to 9 PM PDT Tuesday for Pt Pinos
to Pt Piedras Blancas 0-10 nm.
&&
$$
SHORT TERM...Kennedy
LONG TERM....Kennedy
AVIATION...Flynn
MARINE...Flynn
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Prepared by Boulder-Creek.com Weather at: Mon Mar 23 10:30:03 PDT 2026
From the National Weather Service
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