FXUS66 KMTR 022358
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
458 PM PDT Sat May 2 2026
...New AVIATION...
.KEY MESSAGES...
Updated at 1201 PM PDT Sat May 2 2026
- Cooler temperatures through the early part of next week with a
chance for drizzle and light rain, mainly along the coast
- Widespread stratus persists overnight and into the morning
through the weekend
- Warmer and drier conditions return for the middle of next week
&&
.SHORT TERM...
Issued at 1201 PM PDT Sat May 2 2026
(This evening through Sunday)
Satellite imagery showed widespread stratus across the region this
morning, in addition to high clouds streaming over the SF Bay Area,
gradually eroding across the interior regions into the afternoon
hours. This comes as a upper level low builds and strengthens off
the West Coast, allowing the marine layer to expand and reinforcing
the stratus development across the region. For today, there are some
indications that the stratus layer will continue to scatter out,
particularly in the inland valleys, but with the interaction with
the higher clouds complicating the heating profile, this isn't a
high confidence forecast. As it stands, high temperatures today
range from the lower to middle 70s in the interior valleys, around
80 in the southern Salinas Valley, and the upper 50s to middle 60s
along the Pacific coast and the Bays. Lower those interior
temperatures around 5-10 degrees if the stratus layer does not
scatter out today. For tonight, stratus clouds will return to the
inland regions, with temperatures dropping into the middle 40s to
middle 50s across most of the region, with some lower 40s possible
in the coldest regions of southern Monterey County.
Conditions will be similarly cool on Sunday as the upper level low
starts to edge into California, as high temperatures dip into the
middle 60s to lower 70s for the inland valleys, while remaining in
the upper 50s to middle 60s along the coast and the Bays.
A Beach Hazards Statement remains in effect through Sunday evening
due to long period northwesterly swell, an increasing risk of
sneaker waves and strong rip currents. See the BEACHES section for
more information.
&&
.LONG TERM...
Issued at 1201 PM PDT Sat May 2 2026
(Sunday night through next Friday)
The upper level low moves across California through Tuesday,
resulting in an extended period of cool temperatures, thick marine
layers, extensive stratus decks, and a slight chance for light rain
and drizzle across the region, but mainly at the coast and within
topographically favored locations. As the previous forecaster noted,
residual precipitable water from an extension of the jet stream far
to the north of Hawaii will move into the Bay Area, with model
output showing around 0.9-1" of precipitable water coming to the SF
Bay Area Monday night through Tuesday. This is above the 90th
percentile value for precipitable water for this time of year.
Rainfall totals for this period are generally paltry, with the
ensemble model spread at San Francisco International Airport
basically anywhere between a trace to near a tenth of an inch with a
couple of outlier ensemble members pouring down with up to a half of
an inch of rain by Tuesday night.
By Wednesday, the upper level low moves into the Great Basin and
southern Rockies with ridging building back behind it, leading to a
warming and drying trend in the region with highs rising to the 70s
and 80s inland.
&&
.AVIATION...
(00Z TAFS)
Issued at 446 PM PDT Sat May 2 2026
Had to make some late day AMDs to a few sites as MVFR CIGs linger
making it an all day event. May Gray has arrived. The final nail
are the high clouds streaming overhead limiting insolation for any
late clearing. That being said, a few sites may thin, but probably
not clear totally. MVFR to near IFR CIGs for tonight through the
Sunday AM rush. Late day clearing likely again for Sunday. Solid
onshore flow will persist through this evening and then ease
overnight before increasing again Sunday afternoon.
Vicinity of SFO...some pockets of blue knocking on SFO, but CAMs
show solid clouds feeding in through the gap. MVFR CIGs expected
to persist through 20Z Sunday.
SFO Bridge Approach...Less clouds through this evening, especially
near the bridge, but then clouds fill in overnight.
Monterey Bay Terminals...MVFR CIGs through Sunday.
&&
.MARINE...
(Today through Thursday)
Issued at 1044 AM PDT Sat May 2 2026
A fresh to strong NW breeze will continue across the northern
most outer waters through this afternoon, diminishing to moderate
to fresh afterwards. Seas subside this afternoon and into Sunday
as winds continue to diminish. Moderate seas and a gentle to
moderate NW breeze prevail Sunday into the early work week.
&&
.BEACHES...
Issued at 1201 PM PDT Sat May 2 2026
Long period northwest swell, with periods of 15 seconds or above, is
expected to arrive along the Pacific coast today. These long period
swells increase the risk of sneaker waves and rip currents,
particularly as the period between swell impulses results in lulls
of around 20 to 30 minutes before larger sets of waves arrive. Due
to the dangers, a Beach Hazards Statement for all Pacific coast
beaches comes into effect at 11 AM today and remains in effect until
11 PM Sunday night. Never turn your back to the ocean! Don't be
fooled by calmer seas; observe the waves for at least 20 minutes
before approaching the coast.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement through Sunday evening for CAZ006-505-
509-529-530.
PZ...None.
&&
$$
SHORT TERM...DialH
LONG TERM....DialH
AVIATION...MM
MARINE...RGass
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Prepared by Boulder-Creek.com Weather at: Sat May 2 20:30:05 PDT 2026
From the National Weather Service
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