FXUS66 KMTR 010543
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
943 PM PST Sat Feb 28 2026
...New AVIATION...
.KEY MESSAGES...
Updated at 135 PM PST Sat Feb 28 2026
- Cooler Sunday with very light rain across the North Bay and
Pacific Coast
- Above normal temperatures with elevated winds and offshore
flow next week
- Potentially hazardous marine conditions next week
&&
.SHORT TERM 135 PM PST Sat Feb 28 2026
(This evening through Sunday)
Another pleasant day is in progress across the Bay Area and
Central Coast. Mostly sunny skies, outside of some building
mid/upper level clouds, has translated to temperatures largely in
the 60s to near 80 degrees. While weaker offshore flow has
resulted in 24 hour temperature departures are running 5 to 10
degrees lower at the coast. Cloud cover has hampered some warming
across the North Bay. Mostly sunny skies across East Bay, South
Bay, and Salinas Valley regions have allowed +7 to +10 degree 24
hour temperature departures. By mid to late afternoon, the sea-
breeze should kick in and knock temperatures down a a few degrees.
Winds may elevate briefly as well, with gusts in the 15 to 25 mph
range for 1 to maybe 2 hours. Thereafter, winds will abate with
gusts below 15 mph.
Our initial wave that resulted in thunderstorm activity across
our outer marine zones will continue to lift northward. In its'
wake, a secondary upper trough/low will swing eastward. Mid-level
height falls and large scale ascent should promote largely shower
type activity Sunday afternoon and evening.
&&
.LONG TERM...
Issued at 135 PM PST Sat Feb 28 2026
(Sunday night through next Friday)
MUCAPE needed for lightning appears that it'll remain confined to
extreme northern parts of the East Bay and a 20% chance for
thunderstorms seems reasonable. While PoPs average between
40%-60%, rain amounts are anticipated to remain largely under one-
tenth of an inch. Higher end amounts suggest that areas that would
approach one-tenth of an inch (or greater) are most probable
across the North Bay terrain (namely Coastal Ranges/Hills). PoPs,
while probably a little broad-brushed, extend as far south as the
Big Sur Coastline where RRFS output suggest the potential for a
few showers. Onshore flow should encourage orographic ascent
across the coastal ranges and there will be a potential for
drizzle along the Pacific Coast (and across some of the higher
terrain in the East Bay).
Rain chances fall down to near zero Monday afternoon with a
predominately rain-free forecast (outside of the mid-week time
frame). On Wednesday, an amplifying trough with an attendant front
will slice through the area. The latest guidance does paint a
20-30 PoP across the North Bay, however, there does remain some
spread in this portion of the forecast. Taking a look at the
multi-model ensemble clusters reveals that 75% of the guidance
offers a more northern track to this upper trough which would mean
a lower chance for rain across the North Bay. However, the
remaining quarter of the multi-model ensemble (including the
deterministic ECMWF) does offer a more southern trek for the mid-
week system. This would equate to a larger PoP footprint as far
south as the Golden Gate strait. For now, NBM PoPs seem reasonable
and I didn't make any deviations here and rain chances are limited
to the North Bay during this time. QPF during the mid- week
system is also anticipated to be predominately a few hundredths
of an inch.
The primary weather headline in the long term will be the
potential for increased northerly winds, particularly across the
higher terrain as well as across the marine environment. Overall,
the blended guidance seems to offer a reasonable wind gusts forecast
given where it is (over 72 hours out). As surface pressures rise
in the wake of the aforementioned trough/front, the MSLP gradient
between building high pressure and the surface coastal trough will
tighten. This is a common pattern that result in winds
overachieving, particularly across the complex terrain. As a
result, wind gusts across the mountain zones have been adjusted
upward closer to the higher end of the NBM envelope. It should be
noted, the position of the trough as discussed earlier, will
modulate just exactly how the winds manifest themselves across
the higher terrain. As noted before, any fire ignitions may pose
some growth potential in dead/dormant vegetation. The marine
environment, however, seems more likely to experience wind gusts
in excess of 30-35 knots. Similar to PoPs, the blended guidance
may have a broader than reality wind field, but hazardous marine
conditions do appear that they'll transpire. For more details, see
the marine section below.
&&
.AVIATION...
(06Z TAFS)
Issued at 920 PM PST Sat Feb 28 2026
Widespread VFR lasts into the night with high clouds continuing to
build. Expect winds to reduce into the night with MVFR/IFR CIGs
flowing through the area. Some of these CIGs will be inconsistent.
CIGs thin in the late morning and early afternoon on Sunday, with
lingering mid-level clouds. Expect more moderate winds to build into
Sunday afternoon. Light rain and drizzle affect the North Bay and
the immediate coast into Sunday evening. These chances for light
precip will be accompanied by IFR/MVFR CIGs, that look to become
widespread into Monday morning.
Vicinity of SFO...VFR lasts into the late night. Expect light to
moderate northwest winds into the night before winds turn more
westerly. Winds reduce slightly as MVFR CIGs fill around the SF Bay.
Moments of IFR CIGs look to affect the terminals in the early to mid
morning on Sunday. CIGs erode into the late morning. West winds
reduce early Sunday night a drizzle begins to affect the area with
IFR CIGs building later that night.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...VFR lasts through the late night. Winds
become light into the late night as MVFR/IFR CIGs begin to fill
around the bay. CIGs last through much of Sunday morning, but look
to lift and scatter into that afternoon. IFR CIGs arrive into Sunday
evening with drizzle later into the night around MRY.
&&
.MARINE...
(Tonight through next Friday)
Issued at 846 PM PST Sat Feb 28 2026
Moderate northwesterly swell lingers through Sunday with wave
heights and swell periods gradually decreasing. Chances for
showers and isolated thunderstorms return late Sunday into Monday
morning for the northern waters, which will bring rougher seas,
heavy rain, lightning, and erratic seas. Seas continue to abate
until about mid- week. Thereafter, conditions will deteriorate as
a series of stout strong systems usher in Gale Force wind gusts
and steep seas over 12 feet.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.
&&
$$
SHORT TERM...Bain
LONG TERM....Bain
AVIATION...Murdock
MARINE...KR
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Prepared by Boulder-Creek.com Weather at: Sun Mar 1 00:30:03 PST 2026
From the National Weather Service
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