FXUS66 KMTR 240404
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
904 PM PDT Thu Apr 23 2026

...New AVIATION, MARINE...

.KEY MESSAGES...
Updated at 1201 AM PDT Thu Apr 23 2026

 - Seasonal temperatures and dry conditions return today

 - Potential for rain/drizzle and slightly cooler temperatures 
   this weekend into early next week

 - Warming trend begins early to mid next week

&&

.SHORT TERM...
Issued at 126 PM PDT Thu Apr 23 2026
(This evening through Friday)

Radar is finally quiet this afternoon after a period of somewhat
active weather. Visible satellite shows mostly clear skies around
the region with a few pop up CU hugging the hills. Increased
insolation this afternoon has led to a warmer temperatures across
the board.

Stepping back and looking at the longwave pattern over EPAC and
CONUS reveals an interesting pattern. The EPAC is highly 
amplified with a solid ridge extending into E AK and W BC with a 
low off the CA coast with a rex block vibe. Farther east two 
pronounced upper lows spin, one north of MT and the other east of
Nova Scotia with a ridge smacked in between with an omega block 
vibe. In other words a little bit of a traffic jam in the upper 
atmosphere. That being said, we do see some minor movement on the 
small scale and closer to home. A weak embedded shortwave/fuzzy 
upper low off the CA coast is slowly moving eastward. As this 
feature moves eastward high clouds will increase over the region 
tonight and Friday. The higher clouds may limit fog production 
tonight, but some low stratus will be possible. Interestingly, 
some of the CAMs resolve some forecast 1KM radar reflectivity
tonight. Forecast is dry for Friday morning, but a few echoes may
appear on radar. Increased cloud cover will also lead to cooler 
temperatures on Friday with highs dropping below seasonal averages
again. 

&&

.LONG TERM...
Issued at 126 PM PDT Thu Apr 23 2026
(Friday night through next Wednesday)

A trend that emerged a few days ago is still on track for the
upcoming weekend, "wetter" and cooler. Broad troughiness remains
over region with re-enforcing upper lows. Another upper low is on
track to move over the region Friday night into Saturday and
subsequent vort maxes Saturday into Sunday. These features 
combined with the northern fringes of sub-tropical moisture 
pulses will lead to some drizzle/light rain showers Friday night 
through Sunday morning. Not expecting much in the way of 
accumulation, trace to a few hundredths. Areas most favored will 
be coastal mts with enhanced low level lift. Temperatures for the
upcoming weekend will be below seasonal averages with highs in 
the upper 50s and 60s.

By early next week 500mb heights begin to rebound with warming
850mb temps kicking off a gradual warming and drying trend. No
precip in the forecast Monday through Wednesday.

&&

.AVIATION...
(06Z TAFS)
Issued at 904 PM PDT Thu Apr 23 2026

Mid and high cloud layers including low clouds /VFR-MVFR/ will 
increase tonight and Friday. Diurnal mixing will help lift low 
cloud ceilings during late morning and afternoon Friday, but 
clouds may persist much of the day.

Vicinity of SFO...VFR-MVFR tonight and Friday. West wind easing
tonight to less than 10 knots, then increasing to 10 to 15 knots
Friday afternoon and evening.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR-MVFR tonight and Friday. West to
southwest winds 5 to 15 knots. 

&&

.MARINE...
(Tonight through next Wednesday)
Issued at 858 PM PDT Thu Apr 23 2026

Moderate northwest breezes continue then gradually ease later in
the weekend. Choppy seas at times will begin to subside Friday
and through the weekend. Light rain and drizzle return this
weekend.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 9 PM PDT this evening 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 until 9 AM PDT Friday for Pt Arena to Pt 
     Reyes 10-60 NM.

     Small Craft Advisory until 3 AM PDT Friday for Pigeon Pt to Pt 
     Pinos 10-60 NM.

&&

$$

SHORT TERM...MM
LONG TERM....MM
AVIATION...Canepa
MARINE...Canepa

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