FXUS66 KMTR 012031
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
131 PM PDT Fri May 1 2026
...New SHORT TERM, LONG TERM...
.KEY MESSAGES...
Updated at 125 PM PDT Fri May 1 2026
- Overnight and morning stratus will persist as the marine layer
deepens through the weekend
- Cooler temperatures this weekend with a chance of drizzle
and/or light rain, mainly along the coast, into early next
week
- Warm and dry condition's return the middle of next week
&&
.SHORT TERM...
Issued at 125 PM PDT Fri May 1 2026
(This evening through Saturday)
We'll lose the influence of the upper ridging moving across our area
this afternoon by sunset, with a pattern shift to persistent
troughing through the weekend into the beginning of next week.
Stratus has mostly retreated back to the coastline with San
Francisco and SF Peninsula lagging a little behind early this
afternoon. Otherwise expect mostly sunny skies with a layer of thin
cirrus for the remainder of the day. As an upper low continues
tracking south offshore toward our latitude, we'll see the marine
layer continue to gradually increase through the weekend. Stratus
development tonight and its intrusion inland will be similar as what
we saw last night into this morning. With the slight increase in the
depth of the marine layer as well tonight, it should take a little
longer to mix out Saturday, into the early afternoon for adjacent
inland spots, and potentially linger most if not all day for
immediate coastal areas. There is a chance of drizzle along the
coast late tonight into Saturday morning with the best chances in
higher elevated coastal ranges.
&&
.LONG TERM...
Issued at 125 PM PDT Fri May 1 2026
(Saturday night through next Thursday)
The increased cloud clover inland and cooler temperatures will lead
to a more notable drop in inland high temperatures this weekend,
around 5 degrees from todays values on Saturday and another 5 on
Sunday, with little change for coastal areas under the continuous
influence of the marine layer. As the Rex Block begins to pivot
inland, so too will the offshore upper low, beginning to take a more
direct path inland on Sunday. The cooling trend will continue into
the beginning of next week. By Monday and Tuesday, high temperatures
will bottom out to between 5-10 degrees below normal as the system
tracks inland into the desert southwest. Unfortunately, this system
has continued to trend drier from already anemic moisture offered in
guidance earlier this week. As mentioned above, there will be
patches of drizzle at times mostly confined to the coast but with
no impacts. Wednesday appears to be the beginning of an extended
period of warm and dry weather under persistent ridging well
beyond the current forecast period.
&&
.AVIATION...
(18Z TAFS)
Issued at 1135 AM PDT Fri May 1 2026
Starting our May gray season off right with the coastal stratus deck
largely impacting our region this morning with MVFR conditions. Most
sites are expected to clear out shortly after 18Z today if they have
not already with some lingering low-level clouds. Widespread VFR
conditions are forecast by the early afternoon accompanied by breezy
winds and high clouds. HAF is an exception as they will continue to
experience IFR-MVFR cloud decks throughout the day and night. The
stratus deck will return to most sites on Saturday between 02-08Z
and persist until late Saturday morning.
Vicinity of SFO...IFR/MVFR CIGs currently at the Bay Area terminals
this morning with conditions forecast to improve to VFR around 20Z.
Winds increase out of the west-northwest this afternoon with gusts
up to 25 kt at SFO. Winds diminish in the evening with MVFR CIGs
returning by around 02Z-04Z Saturday with high confidence of them
prevailing through early Saturday morning. There is a 30%-45%
probability of CIGs lowering to IFR between 04Z-14Z Saturday, yet
confidence is not high enough to include in the current TAFs.
Expecting VFR conditions to return mid-to-late morning on Saturday
with onshore winds increasing once again.
SFO Bridge Approach...Similar to today, may see an earlier clearing
across the approach on Saturday morning. Otherwise, similar to SFO.
Monterey Bay Terminals...VFR conditions for SNS will settle in until
this evening when the stratus deck begins to move onshore. MRY will
remain MVFR through 20Z Friday, experience a brief clearing/VFR
period before transitioning back to MVFR by 01Z Saturday. Breezy
westerly winds will assist in this brief clearing period before
calming down by the evening. Both sites will be on the border
between MVFR-IFR again with moderate confidence of IFR CIGs to
trickle in late tonight into the overnight hours and will remain
until Saturday morning.
&&
.MARINE...
(Today through Wednesday)
Issued at 451 AM PDT Fri May 1 2026
A fresh to strong northwesterly breeze continues into Saturday
before winds diminish, becoming moderate to fresh, late Saturday
into Sunday. Moderate, wind driven, seas will build to 10 to 12
feet across the northern outer waters and 8 to 10 feet across the
rest of the waters today through Saturday afternoon. Seas subside
late Saturday into Sunday as winds continue to diminish next
week.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement from Saturday morning through Sunday
evening for CAZ006-505-509-529-530.
PZ...Small Craft Advisory until 9 AM PDT Saturday for Pt Arena to Pt
Reyes 0-10 nm.
Small Craft Advisory until 3 PM PDT Saturday for Pt Arena to Pt
Reyes 10-60 NM.
&&
$$
SHORT TERM...JM
LONG TERM....JM
AVIATION...Navarrete
MARINE...Kennedy
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Prepared by Boulder-Creek.com Weather at: Fri May 1 16:30:02 PDT 2026
From the National Weather Service
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