FXUS66 KMTR 222108
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
208 PM PDT Wed Apr 22 2026
...New SHORT TERM, LONG TERM...
.KEY MESSAGES...
Updated at 1004 PM PDT Tue Apr 21 2026
- Cool conditions Wednesday with lingering showers through the
day
- Seasonal temperatures and dry conditions arrive Thursday
- Monitoring potential rain and drizzle this weekend into the
early part of next week
&&
.SHORT TERM...
Issued at 129 PM PDT Wed Apr 22 2026
(This afternoon through Thursday)
While not as active as 24 hours ago we still have KMUX is precip
mode. Current radar loop this afternoon still shows widely
scattered showers around the Bay Area and Central Coast.
Afternoon visible satellite shows popcorn city with an extensive
CU field blanketing the region. Why the showers? The main storm
system from yesterday has exited to the east. On the back side of
this system are trialing embedded vort maxes/shortwaves. Those
features in conjunction with lingering moisture, daytime heating,
and weak instability has led to the showers. That being said, not
enough lift or vertically developed storms to generate
thunderstorms.
This evening and tonight, once the sun sets expect shower activity
to quickly diminish and CU field thin. One potential impact
tonight will be some developing low stratus and fog. Clearing
skies and decreasing winds will allow for some fog development
over the inland valleys.
Thursday: Dry, warmer, and more sunshine due to weak upper level
ridging. Max temps will be in the 60s to mid 70s, which is closer
to seasonal averages.
&&
.LONG TERM...
Issued at 129 PM PDT Wed Apr 22 2026
(Thursday night through next Tuesday)
A few days ago the longer term forecast didn't look to interesting
from a weather impact standpoint, but a trend has emerged over the
last 24-36 hrs showing active weather will continue. First and
foremost it will not be as dynamic as the system that we just
had. However, a previously dry-ish weekend is now trending
"wetter". What's the trend? Subtle ridging aloft is now looking
more trough-y with an upper low over the region. The longwave
pattern keeps kicking the upper low from yesterday eastward. In
its wake subtle ridging is now being replaced by another upstream
trough. It now appears enough jet dynamics aloft emerge to shift
the broad upper trough to a more pronounced upper low late
Thursday into Friday. Heights begin to fall by Friday lowering
temps and ushering in more clouds. By Saturday morning an upper
low develops off the Central Coast. As such, light drizzle/light
rain will return. This set up will persist through early Sunday
with drizzle/light rain. Not expecting much accumulation, just
some wet ground, clouds, and cooler temps. Another upper low
develop early next week bring additional rain chances on Tuesday
into Wednesday. Again, not a big storm, just additional moisture.
&&
.AVIATION...
(18Z TAFS)
Issued at 1136 AM PDT Wed Apr 22 2026
The last band of rain is passing through the region, with drier air
working in behind it. VCSH and -SHRA are possible for the next
couple of hours for most sites, with precip turning off later this
afternoon. Satellite shows a mess of clouds, slowly breaking apart
leaving us with a smattering of MVFR cigs at terminals or they're
flirting with them. Clearing skies should continue and bring VFR by
the late afternoon and evening. The question for tonight will be do
clear skies and light wind lead to patchy fog. Most models say no,
but it will be something we need to monitor for the next few TAF
cycles.
Vicinity of SFO...The challenge for the next few hours will be the
east to southeast winds and when they'll shift to the southwest.
Most model guidance has not captured the current wind pattern at SFO
and around the region, with MOS guidance and the some NBM guidance
showing it occuring between 20-21Z. Winds should eventually become
onshore this afternoon before going light again overnight. Tomorrow
onshore winds pick up mid to late morning, with the with winds
increasing to around 15kt around or after 21Z.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...Showers will linger around the Monterey Bay
this afternoon with conditions drying out by the evening. VFR cigs
are generally expected through this period unless a stronger shower
moves through which could bring MVFR cigs.
&&
.MARINE...
(Today through Monday)
Issued at 1136 AM PDT Wed Apr 22 2026
Scattered light showers continue to drift to the southeast
through the southern waters this morning and will exit the region
this afternoon. A moderate northwest breeze will develop this
afternoon, then increase on Thursday to a fresh northwest breeze.
Wind and seas will begin to gradually subside on Friday,
continuing into the weekend.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 3 PM to 9 PM PDT Thursday for Pigeon
Pt to Pt Pinos 0-10 nm-Pt Arena to Pt Reyes 0-10 nm-Pt
Pinos to Pt Piedras Blancas 0-10 nm-Pt Reyes to Pigeon Pt 0-
10 nm.
Small Craft Advisory from 3 AM Thursday to 3 PM PDT Friday for
Pt Arena to Pt Reyes 10-60 NM.
Small Craft Advisory from 3 PM Thursday to 3 AM PDT Friday for
Pigeon Pt to Pt Pinos 10-60 NM.
&&
$$
SHORT TERM...MM
LONG TERM....MM
AVIATION...KR
MARINE...KR
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Prepared by Boulder-Creek.com Weather at: Wed Apr 22 14:30:02 PDT 2026
From the National Weather Service
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