Gann Valley, South Dakota Weather Forecast Discussion

044
FXUS63 KABR 082335
AFDABR
Area Forecast Discussion
National Weather Service Aberdeen SD
635 PM CDT Mon Sep 8 2025
.KEY MESSAGES...
- Mainly elevated smoke will remain across the area into Tuesday.
Some of this smoke will near the surface with visibility reductions
possible mainly west of the Missouri River tonight.
- There is a 20% chance of showers and a few thunderstorms over
portions of northeastern South Dakota late this afternoon into  this
evening. Severe weather is not expected at this time.
&&
.UPDATE...
Issued at 620 PM CDT Mon Sep 8 2025
No major changes to the forecast this evening.
See below for the 00Z update to Aviation Discussion...
&&
.DISCUSSION...
Issued at 250 PM CDT Mon Sep 8 2025
A look at the current surface map showed a low pressure center
over western ND with a trough over much of the area. A milky sky was
observed due to wildfire smoke, with reductions in visibility
reported from AWOS/ASOS over far eastern MT and far western ND this
afternoon. The surface low will be stretched across central South
Dakota and western Minnesota this evening, before exiting across
southeastern South Dakota Tuesday afternoon.
Isolated showers have been common over Corson County and portions of
south central ND during the morning and early afternoon hours, with
the line extending northeast to storms near Bemidji, MN and southwest
to the Black Hills. The showers in our area have continued to
struggle, and remain limited in coverage and intensity. We`ll
continue to monitor the trends, as the boundary moves into an area
over eastern SD and western MN that is more unstable. Lapse rates
around the entire area will be around 8 C/km, shear is a bit more
limited, and CAPE values increase to around 2k J/kg (or higher with
the NAM).
The main concern will be around 00-04Z if the cap of
warmer air above the surface is able to be eroded. We`ll also be
looking for additional light shower and potential thunderstorm
development across central SD this evening that may shift to
northeastern SD by daybreak Tuesday. Low chances of precipitation
(generally less than 30%) remain in the forecast for these 2 areas
this evening and overnight into Tuesday morning.
Another elongated are of low pressure will organize to our west on
Wednesday, with the pressure gradient increasing over the Dakotas.
Winds Wednesday afternoon gust out of the southeast 25 to near 35
mph over central South Dakota. The surface low will finally edge east
and move across at least central/NE by 00Z Saturday. Expect 30-60%
chances of showers and storms over central SD Friday night to slowly
expand across the rest of the forecast area Saturday and Sunday.
While timing and placement of the surface low looks reasonable
through 06Z Saturday, enough variability begins to move in later
Saturday and Sunday to result in a lower confidence forecast. These
differences show up in the ensemble clusters for 500mb as well, with
the ridge that will be overhead Wednesday either hold on a bit
longer with a weaker trough sliding in from the west (as shown by
around 35% of solutions) to the ridge shifting east across MN and
the Upper Great Lakes (65% of solutions).
High temperatures through Friday will be in the 80s, with just a few
upper 70s across far northeastern SD and west central MN both
Tuesday and Wednesday. Lows will remain in the 50s to low 60s
through the upcoming weekend.
&&
.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/...
Issued at 620 PM CDT Mon Sep 8 2025
Terminals KABR,KATY,KPIR,KMBG
A cluster of storms northwest of Mobridge may come close enough to
the terminal to warrant the inclusion in this set of TAFs, and
may translate eastwards into the vicinity of the KABR terminal.
Otherwise, smoke, both at the surface and aloft, could impact the
KPIR/KMBG terminals, with ceilings up around 6kft and surface
visibilities at the high end of MVFR (5-6 miles) from the plume
of smoke that will traverse this area overnight into Tuesday.
&&
.ABR WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
&&
$$
UPDATE...07
DISCUSSION...06
AVIATION...07

NWS ABR Office Area Forecast Discussion