FXUS66 KMTR 210433
AFDMTR
Area Forecast Discussion
National Weather Service San Francisco CA
933 PM PDT Wed May 20 2026
...New AVIATION...
.KEY MESSAGES...
Updated at 256 PM PDT Wed May 20 2026
- Diurnally driven winds, with onshore winds during the
afternoon and early evening.
- Warm and dry weather through Thursday leads to elevated fire
weather concerns for the interior Bay Area and Central Coast.
- Above normal temperatures continue through midweek with
seasonal temperatures returning by the upcoming weekend.
&&
.UPDATE...
Issued at 805 PM PDT Wed May 20 2026
Interesting developments along the coastal Bay Area this
afternoon, where an impulse of energy from the Pacific Northwest,
visible as a band of higher clouds descending into the North Bay,
and perhaps a coastal eddy were able to scour out the stratus deck
along the coast north of Santa Cruz. Will monitor the stratus
development overnight as the differing forces interact over the
region. Forecast remains on track.
DialH
&&
.SHORT TERM...
Issued at 256 PM PDT Wed May 20 2026
(This evening through Thursday)
A deeper marine layer, ~750 ft in depth, and stratus has resulted in
cooler conditions near the coast so far this afternoon. Temperatures
there are in the upper 50s to mid 60s. However, inland areas are
well on their way to the upper 80s to lower 90s. Breezy onshore
winds are likely to increase this afternoon and peak early in the
evening with gusts up to 30 mph before easing overnight. With low
clouds hovering near and along the coast, expecting a greater
potential for stratus to spread inland through the Golden Gate and
into the Salinas Valley tonight and into Thursday morning.
For Thursday afternoon, expecting little change compared to today
with mostly sunny sky conditions across the interior. The higher
elevations above 1000 feet will remain critically dry (10-20%) with
poor overnight (less than 30% in spots) humidity recoveries.
&&
.LONG TERM...
Issued at 256 PM PDT Wed May 20 2026
(Thursday night through next Tuesday)
Temperatures on Friday will heavily depend on how deep the marine
layer becomes as the Bay Area and Central Coast remains between the
high pressure to the west and troughing to the east. The stronger
the marine layer, the less time there is for daytime heating
(especially where the stratus hangs around for much of the day).
Temperatures gradually cool over the weekend as troughing develops
to the north.
Then, cooler and potentially unsettled weather returns for early
next week as the aforementioned trough drops southward across the
West Coast. As such, the 6-10 Day Temperature Outlook from the CPC
indicates temperatures leaning below average with the same outlook
for precipitation leaning above. Again, above average for this time
of year may bring either drizzle and/or very light rain to the
region as we go deeper into our "dry season". All that said, please
keep up to date with the latest forecast information over the next
few days.
&&
.AVIATION...
(06Z TAFS)
Issued at 926 PM PDT Wed May 20 2026
Currently a mixed bag of IFR-VFR at the terminals. Moderate to
high confidence on IFR conditions at HAF, MRY, and SNS with VFR
elsewhere tonight. Relatively lower confidence for HAF than the
Monterey Bay terminals as stratus has been wiped out north of the
Otter Eddy in Monterey Bay. If stratus does redevelop, it'll
likely be around 12Z. Diurnal winds will prevail.
Vicinity of SFO...Currently VFR with northwesterly flow. High
confidence in VFR and diurnal winds prevailing through the TAF
period. FEW/SCT IFR clouds will be possible on the north side of
the terminal if stratus sneaks through the Golden Gate Gap.
SFO Bridge Approach...The San Mateo Bridge Approach has a lower
probability of IFR conditions.
Monterey Bay Terminals...Currently VFR and calm at MRY and IFR
with northwesterly flow at SNS. Moderate to high confidence on
IFR conditions through the night; however, this Otter Eddy could
be a case where SNS continues to get fed IFR stratus while MRY
remains just on the periphery. VFR is expected by late morning
with IFR stratus sticking close to the coast during the day.
&&
.MARINE...
(Tonight through next Monday)
Issued at 441 PM PDT Wed May 20 2026
Hazardous conditions for small craft will continue through
Thursday for the northern outers due to rough seas and strong
northerly breezes. Elsewhere, moderate northwesterly breezes and
moderate seas will prevail. Conditions improve into the weekend
as seas and northwesterly breezes become moderate.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory until 3 AM PDT Friday for Pt Arena to Pt
Reyes 10-60 NM.
&&
$$
SHORT TERM...RGass
LONG TERM....RGass
AVIATION...Sarment
MARINE...Sarment
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Prepared by Boulder-Creek.com Weather at: Wed May 20 22:30:02 PDT 2026
From the National Weather Service
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