FXUS66 KMTR 041824
AFDMTR

Area Forecast Discussion
National Weather Service San Francisco CA
1124 AM PDT Fri Sep 4 2026

...New SHORT TERM, LONG TERM...

.KEY MESSAGES...
Updated at 1122 AM PDT Fri Sep 4 2026

 - Hazardous conditions at Pacific Coast beaches Friday through
   Monday

 - Minor coastal flooding during high tide for bayshore locations
   along the San Pablo Bay Friday afternoon/evening

 - Below normal temperatures through the weekend, gradual warming
   and drying trend kicks off Monday

 - Remnant tropical moisture likely Tuesday through Thursday

&&

.SHORT TERM...
Issued at 1122 AM PDT Fri Sep 4 2026
(Friday through Monday)

The primary concern over the Labor Day holiday weekend is hazardous 
conditions at Pacific Coast beaches Friday through Monday. Two sets 
of long period southerly swell from distant Hurricane Karina and 
Hurricane Marie will result in an increased risk for sneaker waves 
and strong rip currents with breaking waves up to 10 feet. Remaining 
out of the water will not be enough, you will need to stay off of 
beaches, jetties, and rocks to avoid being swept into the ocean by a 
sneaker wave. Blue sky days are the most deadly at area beaches, 
don't further the narrative. Minor coastal flooding is expected 
during high tide for bayshore locations along the San Pablo Bay 
Friday afternoon/evening. Impacts can be expected primarily in 
bayside Marin County. Sensible weather wise, anomalously deep upper-
level troughing will maintain below normal temperatures and onshore 
flow through Sunday. The marine layer will likely be extremely 
nuanced, especially today into tomorrow, as it has to form from 
scratch after being mixed out by the front. Generally speaking, it 
should be on the deeper side with the associated lift. In the 
interim, ample low-level moisture and clear skies will make patchy 
fog possible in the mornings. Gradual warming and drying trend kicks 
off Monday as the low begins to fill and move east.

&&

.LONG TERM...
Issued at 1122 AM PDT Fri Sep 4 2026
(Tuesday through Thursday)

Upper-level ridging will nose in from the east on Tuesday, likely 
bringing the warmest day of the week with temperatures rebounding to 
near normal. A reinforcing trough is expected to dig well off the 
West Coast and pickup what will likely be Tropical Depression Marie 
Tuesday into Wednesday. This will turn the upper-level pattern into 
a conveyor belt of moisture with cyclonic flow to the west and anti-
cyclonic flow to the east. As we are dealing with two moving 
targets, the low and Marie, uncertainty is relatively high. It's 
important to note that Marie will not be making landfall in 
California, let alone will it be tropical by the time it gets here. 
We are simply going to get remnant moisture from it. The official 
forecast has widespread rainfall up to 0.25" with locally higher 
amounts up to 0.50" in the higher terrain. Right now, this looks 
like a beneficial event with limited instability.

&&

.AVIATION...
(18Z TAFS)
Issued at 1045 AM PDT Fri Sep 4 2026

VFR is expected to persist through the remainder of today and
tonight for a majority of the terminals. Monterey Bay sites may
see a return of MVFR/IFR ceilings in the hours after midnight but
confidence is low in the extent and timing of stratus
redevelopment while the marine layer attempts to reorganize this
weekend in the wake of the weak cold front passing east today.

Vicinity of SFO...VFR is expected to prevail with breezy diurnal
onshore flow that will ease after sunset. There is a chance of
MVFR ceilings around sunrise, more likely at KOAK if they develop,
otherwise VFR.

SFO Bridge Approach...Similar to SFO.

Monterey Bay Terminals...VFR through the remainder of today and
tonight with low confidence in timing and extent of MVFR/IFR
ceiling development after midnight into the early pre-dawn hours
Saturday. 

&&

.MARINE...
(Today through Wednesday)
Issued at 1045 AM PDT Fri Sep 4 2026

Gentle to moderate west/northwest breezes will persist through
the weekend into next week, when they become more widespread.
Occasionally strong gusts are possible across the San Pablo, San
Francisco Bay and Monterey Bays. Tropical activity will continue
to produce long period southerly swell through the weekend into
the beginning of next week.

&&

.BEACHES...
Issued at 1010 PM PDT Wed Sep 2 2026

A Beach Hazards Statement is in effect Friday-Monday as the swell 
from both Hurricane Marie and Hurricane Karina reaches the coast.
As these hurricane whip up the ocean, the waves travel over 1,000
miles in all directions, gradually flattening out to low 
amplitude, but long period swell. These waves aren't very 
intimidating if you're on a boat in the open ocean, but the long 
period allows them to push much farther up the beach. Long period 
swell always increases the chance for sneaker waves, but that's 
particularly true this weekend since there are 2 different sets of
southerly swell, and their energy will periodically combine. In
addition to sneaker waves, expect strong rip currents and 
breaking waves up to 10 ft. As this is a holiday weekend and the 
weather is otherwise pretty nice, the exposure to the risk is 
high. Avoid the water if you're not an expert swimmer. If caught 
in a rip current, swim parallel to shore until you stop feeling 
the pull. Even on the beach, be prepared for sneaker waves this 
weekend and never turn your back on the ocean.

&&

.MTR WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement through Monday evening for CAZ006-505-
     509-529-530.

     Coastal Flood Advisory from 4 PM this afternoon to 9 PM PDT this 
     evening for CAZ506.

PZ...Small Craft Advisory from 3 PM this afternoon to 9 PM PDT this 
     evening for Mry Bay.

&&

$$

SHORT TERM...Sarment
LONG TERM....Sarment
AVIATION...JM
MARINE...JM

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Prepared by Boulder-Creek.com Weather at: Fri Sep 4 14:30:03 PDT 2026