Sweeney, South Dakota Weather Forecast Discussion

965
FXUS63 KABR 280808
AFDABR
Area Forecast Discussion
National Weather Service Aberdeen SD
308 AM CDT Sun Sep 28 2025
.KEY MESSAGES...
- Abnormally warm temperatures (Highs in the mid to upper 80s, 15-
20 degrees above normal) will be in place through most of this
coming week.
- Dry and windy conditions will return for the end of the weekend
into the first half of next week. Gusts of 25 to 35 miles per hour
are expected both this afternoon and Monday afternoon.
&&
.SHORT TERM /TODAY THROUGH MONDAY AFTERNOON/...
Issued at 303 AM CDT Sun Sep 28 2025
The main forecast concern this morning are strengthening southerly
winds due to a tightening pressure gradient as a surface high
pressure center moves to the east. Still expecting broad coverage of
25 to 35 mile per hour gusts in the afternoon, but the forecast area
will stay well clear of reaching Wind Advisory criteria (sustained
of 30 mph, gusts to 45). This southerly wind will also advect
moisture into the region, increasing dew points 10+ degrees over
central and north central South Dakota over the course of the day
(from mid 40s to mid to upper 50s). This strong moisture advection
likely saves that area from needing a Red Flag Warning, as it keeps
minimum afternoon humidity up into the 30-40% range. Northeastern
South Dakota and west central Minnesota are a bit more borderline,
as that area will not see the same moisture advection, and dew
points will remain in the 40s. Minimum afternoon humidity is
forecast to remain above the Red Flag threshold of 25%, but
observations and trends will need to be watched this afternoon to
ensure that one will not be needed. Broad coverage of 20 to 30 mile
per hour gusts will return Monday, but humidity will again be just
high enough to where Red Flag conditions will likely not be a
concern.
Temperatures will be well above today and Monday due to the
persistence of the upper level ridge. Highs both today and Monday
will reach the mid to upper 80s, about 15 to 20 degrees above normal
for late September. The forecast highs will be about 5-10 degrees
short of record high temperatures, but record low temperature
records may be jeopardy. Particularly on Monday morning, lows will
be in the low 60s, which is where many of the records sit as well.
There are some CAMs showing a signal for some scattered light rain
showers Sunday night into Monday. Coverage is expected to be very
limited, and showers will be isolated in nature. Have added some
PoPs to the forecast, but are still less than 15 percent across the
board. Little to no measurable rainfall is anticipated with showers
that develop, due to the lower-levels staying quite dry.
&&
.LONG TERM /MONDAY EVENING THROUGH SATURDAY/...
Issued at 303 AM CDT Sun Sep 28 2025
Weak flow aloft under an upper ridge starts off the extended
portions of the forecast, with a plume of elevated monsoon moisture
having lifted up from the Desert Southwest overhead through the
course of the day Tuesday. Still looking at moist adiabatic profiles
above an elevated mixed layer, warm enough to cap the area from
surface based convection, but weakly unstable in the mid-levels so
cant rule out some mid-level showers/virga.  Deterministic GFS spits
out a 0.01 or two here and there, with GEFS plumes indicating about
the same though with a member or two up towards 0.1 inches though
according to NBM there is less than a 10% chance for that occurring.
The pattern remains mainly dry thusly, as we move through mid-week,
with a deepening western CONUS trough. Still not a lot of continuity
on the progression of this feature as we get into late week/next
weekend, and the cluster phase appears pretty scattershot in the
days 5-7 range (meaning low confidence forecast for the upper
pattern).
Most of the `weather` from Tuesday through Friday is in the low
levels anyway, with above normal temperatures, a touch of humidity
and winds. There is a persistent gradient across the area Tuesday
and for the eastern CWA through the day Wednesday, with a weak low
out west actually helping to lessen winds for western/central South
Dakota.  That trough decays quickly, and that strong south wind may
become re-invigorated late in the week. Not a great mix direction
and under a warm/neutral advection regime. Thus will stick with
deterministic NBM. As for fire weather conditions, with above normal
temperatures and persistent winds, NBM dewpoints generally remain
stuck  around 60F.  Despite continuing to see vegetation dry out,
that one linchpin means we`re expected to remain above criteria for
any Red Flag conditions.
&&
.AVIATION /06Z TAFS THROUGH 06Z SUNDAY/...
Issued at 1134 PM CDT Sat Sep 27 2025
Terminals KABR,KATY,KPIR,KMBG
Expect VFR conditions over the next 24 hours. Winds 30-35kts will
be just above the surface overnight into Sunday morning (while
near 25-30kts at ATY). Low level wind shear may be possible, and
we`ll continue to monitor the latest trends, but it has not been
included in the forecast at this time. Low level wind shear is
more likely at both PIR and MBG late Sunday night.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
SHORT TERM...BC
LONG TERM...07
AVIATION...06

NWS ABR Office Area Forecast Discussion