San Martin, California 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

588
FXUS66 KMTR 061831
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1131 AM PDT Mon Apr 6 2026

...New AVIATION, MARINE...

.KEY MESSAGES...
Updated at 1139 PM PDT Sun Apr 5 2026

 - Cooler into the work week

 - Beneficial rain arrives in the mid week and lasts into the
   weekend

 - Slight chances for storms Thursday and Friday

&&

.SHORT TERM...
Issued at 1139 PM PDT Sun Apr 5 2026
(Tonight through Tuesday)

It was the warmest day of the week with highs mostly in the 80s and
a daily high temperature record broken at Livermore. Temperatures
look to steadily cool into the night with the dropping pressure
allowing the marine layer to rebuild. Low stratus has been slowly
building along the coast and spreading from the North to South since
sunset. Most coastal areas and some of the interior valleys look to
see low clouds and fog chances into the early morning through the
mid morning. Low temperatures will be slightly cooler tonight.

The increase in moisture from the rebuilding marine layer and better
onshore flow will make for a much cooler Monday. High temperatures
in most areas will be around 10 degrees cooler than Sunday
afternoon! The immediate coast looks to peak around 60 degrees while
the inland areas span the 60s and 70s. Only the far interior areas
look to break the 80 degree mark, but just barely.

The cooling trend will affect Monday night`s temperatures as well,
with lows falling back into the 40s for the more inland areas and
around 50 for the coastal areas.

&&

.LONG TERM...
Issued at 1139 PM PDT Sun Apr 5 2026
(Tuesday night through next Sunday)

High temperatures stay mostly the same for Tuesday and Wednesday as
onshore flow says fairly persistent and the marine continues to
deepen. Wednesday night does see a bit of warm up in a few areas as
the warm-sector ahead of the next low pressure system begins to
affect the area.

The evening model updates have slowed the arrival of the low
pressure and trough combo heading our way in the . The warmer air
ahead of it will foster some drizzle chances into Wednesday evening
along the coast and across the northern portions of the North Bay
counties. These chances become more widespread later into that
night. Measurable, but still very light, rain has mostly been pushed
back to the mid to late morning on Thursday for the Bay Area and
Central Coast. These chances for light showers look to be off and on
through Saturday morning, but there is still potential for the low
to slow and precip chances lingering into that night.

The mixing environment around the low will offer slight chances for
storms both Thursday afternoon and Friday afternoon. Friday shows
more widespread chances than Thursday, but it will be something for
forecasters to keep an eye on as the low can still change trajectory
and shift around these storm chances.

Even though the low pressure exits Saturday, cloud cover and onshore
flow look to last into the next work week. This will keep things on
the cool side into the end of the forecast period.

&&

.AVIATION...
(18Z TAFS)
Issued at 1129 AM PDT Mon Apr 6 2026

The marine layer made a triumphant return last night and will
remain the most important feature for aviation weather over the
next few days. The current marine layer depth is around 1500 feet,
deep enough to allow some impacts to make it all terminals with
the exception of Livermore. The stratus is gradually mixing out
this morning, with clear skies expected for all terminals away
from the immediate coast (sorry Half Moon Bay) through the
afternoon and early evening. There is very high confidence that
the marine layer stratus will return overnight.

Vicinity of SFO...While we feel confident that the marine layer
stratus will return overnight, the exact impact at SFO is less
certain. As we saw this morning, microscale eddies and downsloping
can create some clear patches at and around the terminal. If a cloud
deck does move over SFO, expect high IFR or low MVFR ceiling heights.

SFO Bridge Approach...VFR with clouds confined north of the terminal.

Monterey Bay Terminals...The marine layer is a little more shallow
at these terminals, which brought lower ceilings and and earlier
clearing time than the Bay Area. While the afternoon should be
clear, the stratus bank is hanging out just off the coast and there
is a chance for encroachment over MRY at any time. A similar trend
is expected tonight with IFR ceilings expected through mid Tuesday
morning at both MRY and SNS.

&&

.MARINE...
(Today through Saturday)
Issued at 1129 AM PDT Mon Apr 6 2026

High pressure off the California coast will maintain light to
moderate breezes across the coastal waters through the week.
Locally fresh breezes will develop along the Big Sur coast this
afternoon with the strongest wind near and south of Point Sur.
Unsettled weather returns mid to late week, bringing light
showers, a slight chance of thunderstorms, and moderate seas.
Winds increase next weekend with a fresh breeze expected over the
northern coastal waters.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 3 PM this afternoon to 9 PM PDT
     Tuesday for Pt Pinos to Pt Piedras Blancas 0-10 nm.

&&

$$

SHORT TERM...Murdock
LONG TERM....Murdock
AVIATION...Flynn
MARINE...Flynn

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