289
FXUS63 KABR 192329 AAA
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
629 PM CDT Wed Aug 19 2026

.KEY MESSAGES...

- Small chances (15-30%) for thundershowers late this afternoon
  through tonight across portions of the region. Severe storm
  chances are very low.

- Generally dry conditions Thursday through Saturday. Rain
  chances (20-40%) return to the forecast Saturday night, then
  on and off chances into early next week.

&&

.UPDATE...
Issued at 625 PM CDT Wed Aug 19 2026

See below for an aviation forecast discussion for the 00Z TAFs.

&&

.DISCUSSION...
Issued at 226 PM CDT Wed Aug 19 2026

A stationary front across western SD earlier this morning is
forecast to eventually make its way eastward across the CWA as a
weak warm front. South-southwest winds from 10 to 20 mph overnight
should prevent lows from dropping below 60 degrees for many areas.

On Thursday, a weak cold front will drop southeast through the area
with winds switching to the northwest. Ahead of this front, there
remains just a slight chance (20% or less) for a shower or
thunderstorm mainly over the northern CWA overnight. MUCAPE values
early this evening are generally around 750 J/KG or less, with
around 30 kts or so of effective shear. CAMs showing pretty sparse
coverage of showers/storms this evening, which can be seen nicely in
HREF ensemble paintball product. One thing to note for late this
afternoon, there are a couple CAMs trying to build up some shower
activity between the James and Missouri rivers, which currently is
uncapped with about 1000-1500 J/KG MLCAPE. Although, mid-level lapse
rates are rather weak. Will watch for any building cumulus fields in
this area over the next several hours and adjust PoPs if necessary.
For now, will add just some slight chances (15%) for that area.

On Thursday, winds will be from the northwest in the post-
frontal/trough air mass. Blended in only about 20-25% of the NBM90
for winds across the eastern CWA as it appears to be on the breezy
side with gusts around 20-25 kts. Surface high pressure then looks
to build into the region Friday night into Saturday, which should
keep conditions dry.

Chances for rainfall return to the forecast for the latter half of
the weekend. Southerly low-level flow at the surface up through
850mb develops across central SD, with moisture increasing as well.
Weak wave moving into the region with a surface trough may bring
increasing chances for showers/thunderstorms across the region
Saturday night into Sunday morning. Inherited PoPs generally feature
30-40% chances over central SD during said time frame.

&&

.AVIATION /00Z TAFS THROUGH 00Z FRIDAY/...
Issued at 625 PM CDT Wed Aug 19 2026

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are forecast through the TAF period. Had one
shower form over KMBG a little while ago. There could be a
couple more showers or weak thunderstorms, mainly at/near the
KMBG terminal between now and sundown. Probability is pretty
low. Will amend to add short-lived precipitation this evening as
needed.

&&

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

&&

$$

UPDATE...10
DISCUSSION...TMT
AVIATION...10