FXUS66 KMTR 271112
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
412 AM PDT Mon Apr 27 2026
...New AVIATION, MARINE...
.KEY MESSAGES...
Updated at 1208 AM PDT Mon Apr 27 2026
- Light rain and pockets of drizzle possible today
- Warming and drying trend this week
- Disturbed weather returns next week
&&
.SHORT TERM...
Issued at 1208 AM PDT Mon Apr 27 2026
(Today and tonight)
The radar is showing some light returns over the marine environment
as well as on some of the higher peaks, indicating some lingering
light rains along with the drizzle along the coast.
Some of these chances will linger into the day for a few isolated
spots, particularly in higher elevations on the Big Sur Coast, the
North Bay Mountains, and the Santa Cruz Mountains. Rainfall totals
will be fairly light, with mostly traces to a few hundredths
expected. Cloud cover will be more on than off through the first
part of the day, but sunnier conditions are expected for the
afternoon, leading to slightly warmer conditions than previous days.
The onshore flow and lingering moisture will prevent too much of a
warm up, but this will be the start of our warming trend.
This warming trend will be less pronounced for the coast and areas
slightly inland as the marine layer rebuilds and becomes better-
defined into Monday night and early Tuesday. Marine stratus will
also keep things on the cooler side for the coast, but areas inland
will begin to see much warmer and sunnier conditions into the work
week.
&&
.LONG TERM...
Issued at 1208 AM PDT Mon Apr 27 2026
(Tuesday through Sunday)
The combination of a building ridge to the north and a cutoff low to
the south will set us up for an interesting gradient of temperatures
through the mid-week and into the weekend.
The pressure gradient caused by the low to the south looks to keep
the marine environment and the coast breezy, and will help keep the
marine layer intact. This will result in high on the immediate coast
to stay around 60 degrees through the week, and areas slightly
inland mostly staying in the 60s.
The more interior areas will not benefit from the marine influence,
leading to warming and drying more akin to a typical ridging
pattern. Wednesday will offer widespread highs in the 70s for areas
away from the coast, with a few isolated 80s. Conditions look to
continue to warm for the interior through Friday with more areas
breaking into the 80s and possibly the 90s in the southern Salinas
Valley.
Model agreement got much worse for the weekend than last night, and
the movement of highs and lows through the Pacific has not become
any less complicated across any of the main long-term models nor
ensemble clusters. There are hints toward a Rex-Block (high pressure
to the north, low pressure to the south) forming into the weekend,
but the positioning vary quiet a bit across models. In most cases, it
looks like the Bay Area and Central Coast will see some cooling due
to the low bing closer than the high pressure. It could also include
some light rain into the next work week, but confidence isn't great.
There are also some hints at the Rex-Block losing momentum and this
pattern arriving and exiting at a slower pace.
Be sure to keep checking back in to see if we start May with some
moisture.
&&
.AVIATION...
(12Z TAFS)
Issued at 412 AM PDT Mon Apr 27 2026
A mix of MVFR to VFR conditions across the region this morning will
lift starting in the late morning hours, with lingering chances of
isolated showers dissipating by the afternoon. Gentle to moderate
onshore pattern winds develop this afternoon and evening,
diminishing overnight as MVFR-low end VFR ceilings return to the
terminals.
Vicinity of SFO... Low end VFR ceilings will scatter out in the
afternoon hours with MVFR stratus returning in the overnight period.
Breezy west-northwest winds will develop this afternoon and evening
before diminishing overnight.
SFO Bridge Approach... Similar to SFO.
Monterey Bay Terminals... VFR conditions through the day with mid-
level cloud cover scattering out in the later morning. Breezy
northwest winds will develop this afternoon and evening with light
drainage winds overnight as MVFR ceilings return to the terminals.
&&
.MARINE...
(Today through Saturday)
Issued at 412 AM PDT Mon Apr 27 2026
Moderate west to northwest breezes persist through the middle of
the week, increasing to fresh to strong northwest breezes by
Thursday. These stronger winds will build rough seas of 8-12 feet
in exposed waters Wednesday through Friday.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 9 PM this evening to 3 AM 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: Mon Apr 27 08:30:03 PDT 2026
From the National Weather Service
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