Technical NOAA Weather Discussion

FXUS66 KMTR 281119
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
419 AM PDT Tue Apr 28 2026

...New AVIATION, MARINE...

.KEY MESSAGES...
Updated at 1047 PM PDT Mon Apr 27 2026

 - Morning stratus and fog returns to the forecast!

 - Warming and drying trend continues into the late week for areas
   away from the coast.

 - Cooler conditions return this weekend with a chance of rain

&&

.SHORT TERM...
Issued at 1047 PM PDT Mon Apr 27 2026
(Tonight through Wednesday)

The evening still had a few areas of rain in the northernmost 
portions of Sonoma Co, but it looks like they have mostly 
diminished. Drizzle chances linger for some of the coast and 
mountaintops districtwide overnight, while the valleys see good 
chances for fog building in the  late night and lingering into the 
mid morning.

The steady warming trend continues for Tuesday with most areas 
getting close to average, though slightly below. Coastal areas will 
peak around 60 degrees while areas inland will see the upper 60s to 
mid 70s. Interior mountains will still be dealing with lingering 
moisture, so they'll still be on the cool side with some struggling 
to break 50 degrees in on the Big Sur Coast.

The warming comes from a building ridge to the north, but a cut off 
low to the south will prevent too much of a warm up, especially for 
the coastal areas. The low looks to offer just enough influence over 
the area that the marine layer stays intact through the week, and 
keep conditions breezy over the marine environment and immediate 
coast. This marine influence won't spread too far inland, so the 
more interior areas will see more of a steady warming until the 
pattern changes this weekend.

Wednesday sees high temperatures along the coast plateauing: still 
around 60 degrees. Areas inland will continue warming and get back 
above average with the more interior areas getting into the upper 
70s and a few spots breaking 80.

Overnight lows will also see a slight warming trend, with most areas 
seeing lows in the 50s by the mid week.

&&

.LONG TERM...
Issued at 1047 PM PDT Mon Apr 27 2026
(Wednesday night through next Monday)

The inland warming trend looks to peak on Friday with the 80s 
expected across the interior areas and maybe a few 90s in the 
southern Salinas Valley. This will be while the coast will continue 
to stick to the 60s under the influence of good coastal breezes, the 
marine layer, and nightly marine stratus. The areas slightly inland 
will be a mixed bag. Those that see the marine layer and stratus look 
to only warm into the mid 70s, while areas that will be just outside 
of the marine influence will lean closer to 80 degrees. It'll be the 
kind of day where you drive from Half Moon Bay to San Jose and 
experience around a 20 degree difference.

A trough and low approach the region into Friday night, increasing 
cloud cover and expanding the marine layer both in height and inland 
push. Models are going back to the solution hinted at a few nights 
ago, with this low causing another drizzle-fest with some scattered 
light rain. The timing of the best rain chances is still not firm 
across models, but for now it does look better for drizzle in the 
mid-weekend with measurable rain arriving Late Sunday and into the 
next work week. Welcome to May-Gray!

&&

.AVIATION...
(12Z TAFS)
Issued at 419 AM PDT Tue Apr 28 2026

Generally VFR conditions persist with some patches of MVFR stratus 
across the SF Bay Area and in the interior Central Coast. Confidence 
in widespread stratus development through dawn has diminished, with 
a passing trough potentially disrupting the marine layer. Stratus 
will dissipate after sunrise with gentle to moderate onshore pattern 
winds developing in the afternoon hours, with stratus beginning to 
develop on this evening, moderate confidence on timing and extent.

Vicinity of SFO... VFR at present with moderate confidence of MVFR 
stratus developing through dawn. 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 tonight, with moderate confidence of impacts to the 
terminal overnight into Wednesday morning. Greater confidence in 
stratus impacts at OAK.

SFO Bridge Approach... Lower confidence of stratus impacts 
tonight through Wednesday morning. Otherwise similar to SFO.

Monterey Bay Terminals... Low to moderate confidence of MVFR 
ceilings developing through dawn. Light drainage flow this morning 
will give way to gentle to moderate northwest winds this afternoon 
and evening, diminishing overnight. Stratus returns to MRY early 
this evening, with greater uncertainty about development at SNS 
before the end of the TAF period.

&&

.MARINE...
(Today through Sunday)
Issued at 419 AM PDT Tue Apr 28 2026

High pressure off the Pacific Northwest and low pressure inland
will maintain northwesterly flow over the coastal waters. Moderate
to fresh breezes will develop through the day and persist into
the weekend 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 this afternoon to 3 PM PDT 
     Wednesday for Pt Arena to Pt Reyes 10-60 NM.

&&

$$

SHORT TERM...Murdock
LONG TERM....Murdock
AVIATION...DialH
MARINE...DialH

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Prepared by Boulder-Creek.com Weather at: Tue Apr 28 04:30:03 PDT 2026
From the National Weather Service