FXUS66 KMTR 101924
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
1224 PM PDT Fri Apr 10 2026
...New SHORT TERM, LONG TERM, MARINE...
.KEY MESSAGES...
Updated at 1220 PM PDT Fri Apr 10 2026
- Rain and thunderstorms through the weekend
- Gradual warming and drying trend next week
&&
.SHORT TERM...
Issued at 1220 PM PDT Fri Apr 10 2026
(This evening through Saturday)
A mid/upper level low pressure system remains about 100 miles off of
the northern California coast. This feature has resulted in
widespread rain showers across our region the past 24 hours with the
North Bay picking up between 0.25"-1.25". Lesser amounts have been
reported south of the North Bay, but some coastal and mountain
locations have received up to 0.75". Overall, this has been greater
than originally forecasted. This band of rain showers continues to
shift inland and the threat for rain showers and thunderstorms will
persist throughout the afternoon and evening, especially as day time
heating increases surface based CAPE to between 500-1000 J/kg. Any
thunderstorm will be capable of producing lightning, locally heavy
rainfall, erratic/gusty winds, and small hail. Weak low-level wind
shear does not support a mention of rotation that would lead to
tornadoes and/or waterspouts through this evening. Rain showers and
a slight chance of thunderstorms will continue into the night, yet
chances for both trend downward overnight.
An approaching mid/upper level low is forecast to drop out of the
Gulf of Alaska on Saturday and move inland Sunday afternoon across
northern California. This is when we have all three ingredients for
thunderstorms: lift, instability, and moisture. Some of the higher
resolution and conviction-allowing models (CAMs) such as the RRFS
indicate the potential for a narrow cold-frontal rainband (NCFR) to
move across the Bay Area and Central Coast Saturday afternoon and
evening. This will be when we have the greatest potential for
rotating cells that may produce waterspouts and/or weak tornadoes.
In coordination with the Storm Prediction Center, we have been
upgraded to a Marginal Risk of severe thunderstorms on Saturday. The
greatest potential being the threat of wind exceeding 40 knots.
From previous forecaster: "Anglers should take special note of the
expected weather and have a plan to reach safe harbor quickly when
the weather turns. Even without thunderstorms, the marine conditions
will deteriorate through the day Saturday. If thunderstorms develop,
the associated wind gusts are capable of capsizing small vessels.
Fishing leads to more lightning deaths in the U.S. than any other
activity. When thunder roars, head indoors!"
&&
.LONG TERM...
Issued at 1220 PM PDT Fri Apr 10 2026
(Saturday night through next Thursday)
The rainfall amounts continue to trend higher today through Sunday
with 0.50"-0.75" in the southern Salinas Valley, 1"-2" across much
of the Bay Area and Central Coast, and up locally up to 4" in the
coastal ranges. However, this rainfall will be mostly beneficial
with no widespread river flooding anticipated. However, we can still
see ponding of water on roadways, minor urban and small stream
flooding, and flooding of poorly drained areas. This will be
especially so if any heavier showers and/or thunderstorms develop
and train over any one given area.
Post-frontal rain showers and isolated thunderstorm will continue
into Sunday as a colder air mass settles into the region. This is
when we may see snow fall across the higher peaks across the region,
however little to no snow accumulation is expected. Lingering rain
showers and isolated thunderstorms may persist into early Monday
morning before a warming and drying trend resumes by Monday
afternoon. Slightly below normal temperatures are expected Monday
afternoon before rebounding to near seasonal averages by Thursday
and Friday.
&&
.AVIATION...
(12Z TAFS)
Issued at 442 AM PDT Fri Apr 10 2026
A band of moderate to heavy showers is moving slowly eastward
over the forecast area. In addition to showers during the 12z
TAFs, there's a slight chance to chance of thunderstorms today.
Conditions are otherwise forecast VFR-MVFR.
Vicinity of SFO...VFR-MVFR. Showers with a convective potential
today, but will monitor radar and satellite before adding VCTS to
the TAF. Southeast wind 5 to 10 knots becoming south-southwest 10
to 15 knots in the afternoon
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...VFR-MVFR. Showers. Southeast to southwest
winds 5 to 12 knots.
&&
.MARINE...
(Tonight through next Wednesday)
Issued at 1220 PM PDT Fri Apr 10 2026
Isolated to scattered showers and a chance of thunderstorms
remain in the forecast today. The next round of precipitation
arrives late Saturday into Sunday, as the next weather system
arrives. Increasing winds are expected, with isolated gale force
gusts from Pigeon Point to Point Pinos. High pressure builds
behind the system with fresh northwest winds developing early next
week.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 9 AM to 9 PM PDT Saturday for Mry Bay-
Pigeon Pt to Pt Pinos 0-10 nm-Pt Pinos to Pt Piedras
Blancas 0-10 nm-Pt Reyes to Pigeon Pt 0-10 nm-SF Bay N of
Bay Bridge.
Small Craft Advisory from 9 AM to 3 PM PDT Saturday for Pt Arena
to Pt Reyes 0-10 nm.
Small Craft Advisory from 3 PM to 9 PM PDT Saturday for Pigeon
Pt to Pt Pinos 10-60 NM.
&&
$$
SHORT TERM...RGass/Sarment
LONG TERM....RGass
AVIATION...Canepa
MARINE...KR
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Prepared by Boulder-Creek.com Weather at: Fri Apr 10 12:30:03 PDT 2026
From the National Weather Service
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