424
FXUS63 KABR 201739
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
1239 PM CDT Sun Sep 20 2026

.KEY MESSAGES...

- Light rain moves as far east as parts of the James and Big
  Sioux Valleys tonight. Rain tapers off from north to south on
  Monday. There will be a brief break on Tuesday before rain
  returns Tuesday night and continues off and on through the
  work week.

- Temperatures will remain near to slightly below seasonal
  averages through Tuesday before climbing above normal toward
  the middle of the week.

&&

.DISCUSSION...
Issued at 1237 PM CDT Sun Sep 20 2026

Easterly sfc flow is almost staving off movement of the rain past
the Missouri River this afternoon. There is a pocket of drier air at
the midlevels that is helping to hold the rain west river even with
ample llm in place. All of that effort will be for nought as the
upper low slowly makes its way east through South Dakota tonight. As
it sinks south and east Monday, the precip will exit with it.

Once again, the NBM is likely too high with its overnight lows given
the cloud cover and rain expected. All hi-res models keep lows in
the low to mid 50s (except in west central MN where some scattering
is possible), but did not blend toward them today in deference to
neighbors and because of the chance for scattered cloud cover in the
northeast. Expect clearing through the afternoon Monday from north
to south as the system exits.

Return flow winds shift back to the southeast and south on Tuesday
ushering in some warmer air. Skies should be mostly clear which will
also help push temperatures above average. That said, models have
shifted the upper level trends a bit for Tuesday moderating the
upper ridgeand leaving some remnant shortwave energy around which
could increase clouds, especially along the Coteau. There`s now also
a llj developing Tuesday night so can`t rule out a shower or two
early Wednesday. A 30 kt llj spreads over the region Wednesday
afternoon and increases Wednesday night. There is some shortwave
energy around, though it doesn`t align perfectly. But, the ample mid
level moisture should still allow for some showers and thunderstorms
to develop. A 700 mb low could help amplify the precip probs through
Friday night.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1237 PM CDT Sun Sep 20 2026

Terminals KABR,KATY,KPIR,KMBG

MVFR/IFR cigs will prevail with brief VFR breaks through Monday
morning. Rains progresses east tonight affecting KMBG and KPIR
with MVFR/IFR vsby at times before exiting from north to south
Monday morning.

&&

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

&&

$$

DISCUSSION...20
AVIATION...20