449
FXUS63 KABR 040513 AAC
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1213 AM CDT Sat Oct 4 2025

.KEY MESSAGES...

- Near record high temperatures will remain possible east of a
  line from Pierre to Ipswich on Saturday, where highs will be in
  the mid 80s to near 90 degrees.

- Windy conditions Saturday and Saturday night will be east of a
  line from Vivian to Aberdeen, where winds out of the south will
  gust 30 to 40 mph. On Sunday the winds will be switching out of
  the northwest, with gusts of 35 to 45 mph with locally higher
  gusts.

- A cold front will bring rain Saturday night through Sunday
  morning. There is a Marginal Risk, level 1 of 5, for severe
  storms Saturday night. Damaging winds will be the main concern.
  Heavy rain or hail will also be possible.

- There is a slight shift westwards with the highest rainfall
  potential. There is a 50 to 75% chance of rain in excess of 1"
  along and west of a line from Mobridge to Hayes.

- Localized frost is possible Monday morning, Tuesday morning,
  and Wednesday morning, mainly over portions of northern SD.

&&

.UPDATE...
Issued at 1212 AM CDT Sat Oct 4 2025

Updated discussion for the 06Z TAFs below.

UPDATE Issued at 806 PM CDT Fri Oct 3 2025

Red Flag warning was allowed to expire at 01Z as RH increases and
winds slowly subside. Otherwise, forecast remains on track
overnight with breezy/gusty southerly winds persisting especially
for eastern portions of the CWA. Localized gusts in the Sisseton
Hills region from 30 to 45 mph.

&&

.DISCUSSION...
Issued at 300 PM CDT Fri Oct 3 2025

Winds will remain the main story through Sunday, with gusty winds
not only during the daytime hours but at night as well. Fire weather
wise, the near-critical areas with less green component in grasses
is west of the Missouri River. Elsewhere there is green in the
ditches and other grasses, but any farm land is dry (soybeans/corn).
These crops would be the main carrier of any fire that may start
over the next few days. With the continued lowering/western shift in
the the overall precipitation amounts for Saturday night into Sunday
morning, winds and fire weather will continue to be the main
concerns.

Looking at the 19Z surface map, the main low was centered over
southeastern MT/southwestern NE/northwestern SD, with plenty of
clouds on the northern and western side of the low. Out ahead, winds
were out of the south gusting 25-45 mph (strongest just west of
Jones County). The lowest relative humidity values around 20-30
percent were over south central SD, with teens over southwestern SD.

This main surface low will shift across northern ND by 06Z Saturday,
with a cold front extending south-southwest over Corson County
through southwestern SD. Strong winds today out of the south will
only slowly weaken overnight, but remain elevated over the Prairie
Coteau of northeastern South Dakota, with gusts of 35 to 45 mph from
eastern Marshall County down through Summit and South Shore.
Relative humidity recoveries will be around 75 percent or higher,
except closer to 65 percent over the eastern slopes of the Prairie
Coteau.

A series of lows will slide northeast along the cold front as it
shifts over mainly central SD by 00Z Sunday. The surface low
overhead will continue to deepen as it moves over our north central
forecast area by 06Z and southeastern SD into northwestern MN by 12Z
Sunday. Expect windy conditions east of a line from Vivian to
Aberdeen Saturday and Saturday night, out of the south will gusts 30
to 40 mph. This is where lowest relative humidity values of 25 to 35
percent will reside.

A Downslope wind event is possible Saturday night over the
traditional locations from eastern Marshall through western/central
Roberts (Summit/Peever) and northeastern Codington to western Grant
through northern Deuel County. Winds between 800-900mb are 60-65kts
with mixing, with a localized mixed environment and gusts of 45-
50kts for a good portion of the night. A wind headline may be needed.

Rain is also expected Saturday night into Sunday morning, but the
higher amounts have again shifted to the west. A wetting rain of
0.10 inches or greater is expected northwest of a line from Pierre
to Aberdeen. The probability of 0.25" or more in that same area is
25% or greater. The probability of 1" or more is 45% or greater
northwest of a line from around Eagle Butte through Mobridge and
Herreid. Little to no rain is forecast over west central MN and east
central SD.

On Sunday the winds will be switching out of the northwest, with
gusts of 35 to 45 mph and locally higher gusts. While relative
humidity values will stay above 70 percent for most locations west
of the James River, they will be as low as 50 percent over portions
of west central MN and east central SD.

High pressure over southwestern Canada/MT on Sunday will build
across SD on Monday, ushering in drier air and much cooler air. Highs
Monday will be in the mid 50s to low 60s. Confidence remains high in
the temperature forecast through Monday, before the 25-75th
percentiles spread out a bit Monday night. Temperatures will
moderate back into the 70s for highs by the end of the work week. We
do still have the potential for frost each morning from Monday
morning, Tuesday morning, and Wednesday morning. The overall
coverage looks limited at this time, and focused over norther
portions of SD.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1212 AM CDT Sat Oct 4 2025

Terminals KABR,KATY,KPIR,KMBG

Low-level wind shear will continue to be a concern during the
overnight hours, with 40 to 50 knot south-southwest winds around
2000ft. Southerly surface winds will continue to be gusty through
much of the period for KABR/KATY, but KMBG/KPIR will start to see a
wind shift to the north as a frontal boundary moves east. Some
uncertainty to the exact timing of the wind shift, especially in the
KABR area, which may occur roughly around 00Z Sunday. -SHRA is also
forecast to affect portions of central SD Saturday night, along with
MVFR CIGs arriving right towards the end of the TAF period for KMBG.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&

$$

UPDATE...MMM
DISCUSSION...06
AVIATION...MMM