Technical NOAA Weather Discussion

FXUS66 KMTR 280523
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1023 PM PDT Mon Apr 27 2026

...New AVIATION, MARINE...

.KEY MESSAGES...
Updated at 1055 AM PDT Mon Apr 27 2026

 - Warming and drying trend kicks off Tuesday, peaking Thursday
   and Friday

 - Cooler conditions return this weekend with a chance of rain

&&

.SHORT TERM...
Issued at 1055 AM PDT Mon Apr 27 2026
(This afternoon through tonight)

Isolated light rain showers are continuing with the help of remnant 
surface troughing across the Bay Area. Activity will wane this 
afternoon, giving way to a mix of sun and clouds and below normal 
temperatures. With remnant moisture, low clouds will return to 
bayshore and coastal locations tonight as the lower levels 
destabilize.

&&

.LONG TERM...
Issued at 1055 AM PDT Mon Apr 27 2026
(Tuesday through Sunday)

The upper-level troughing that brought us light rain over the 
weekend will pinch off a cutoff low as upper-level longwave ridging 
moves in from the Eastern Pacific Ocean. This will result in a 
warming and drying trend with temperatures rebounding to near to 
slightly above normal. The warmest day of the week will be on 
Thursday for the Bay Area and Friday for the Central Coast. The 
locations of the two features, ridge over the Pacific Northwest and 
low off the coast of Southern California, will support light 
offshore flow during the overnight hours. Subsidence aloft and 
offshore flow in the higher terrain will likely yield a shallow 
marine layer that will only impact coastal locations. Global 
ensemble clusters are in agreement that the ridge will get tamped 
down by an approaching upper-level trough as we approach the 
weekend. There is some uncertainty on how we get there, but by 
Sunday it is likely that there will be an upper-level low off the 
California Coast. While there's no measurable precipitation in the 
forecast right now, this will renew chances for rainfall as we head 
into next week.

&&

.AVIATION...
(06Z TAFS)
Issued at 1023 PM PDT Mon Apr 27 2026

Generally VFR conditions at present, with MVFR stratus expanding 
across the coastal valleys through the night. Stratus will dissipate 
Tuesday morning with gentle to moderate onshore pattern winds 
developing in the afternoon hours, with stratus beginning to develop 
on Tuesday evening, although the highest probabilities of stratus 
development at the terminals fall after the end of the 24-hour TAF 
period.

Vicinity of SFO... VFR with some low clouds for the next few hours, 
with MVFR stratus developing early Tuesday morning before 
dissipating later that morning. Moderate west-northwest winds will 
develop in the afternoon and evening hours before diminishing in the 
late evening. High resolution models depict stratus flowing across 
the Golden Gate late Tuesday evening, with low confidence of impacts 
to the terminal itself before the end of the TAF period. Greater 
confidence in earlier impacts at OAK.

SFO Bridge Approach... Similar to SFO.

Monterey Bay Terminals... MVFR ceilings will develop overnight 
before diminishing in the later hours of Tuesday morning. Gentle to 
moderate northwest winds Tuesday afternoon and evening, otherwise 
light drainage flow persists in the overnight and morning hours.

&&

.MARINE...
(Tonight through next Sunday)
Issued at 1023 PM PDT Mon Apr 27 2026

High pressure off the Pacific Northwest coast and low pressure
inland will maintain northwesterly flow over the coastal waters.
Moderate to fresh breezes will develop Tuesday as high pressure
strengthens. These stronger winds will build rough seas of 8-12
feet across exposed waters later in the week.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 3 PM Tuesday to 3 PM PDT Wednesday for 
     Pt Arena to Pt Reyes 10-60 NM.

&&

$$

SHORT TERM...Sarment
LONG TERM....Sarment
AVIATION...DialH
MARINE...MM

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Prepared by Boulder-Creek.com Weather at: Mon Apr 27 22:30:03 PDT 2026
From the National Weather Service