840
FXUS63 KABR 090525 AAB
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1225 AM CDT Wed Jul 9 2025

.KEY MESSAGES...

- Marginal/Slight risks for severe storms across the region
  Wednesday and Thursday. Hail up to 2 inches in diameter possible
  over central/north central SD on Wednesday (10% or greater
  probability within 25 miles of a point).

- Heat and humidity return Wednesday/Thursday (especially James
  River westward), with highs in the 90s and heat indices
  approaching 100 degrees on Wednesday over central SD.

&&

.UPDATE...
Issued at 1213 AM CDT Wed Jul 9 2025

Updated Aviation Discussion Below.

UPDATE Issued at 608 PM CDT Tue Jul 8 2025

The forecast remains on track this evening. No major changes are
planned.

&&

.DISCUSSION...
Issued at 324 PM CDT Tue Jul 8 2025

Surface high pressure is anchored over eastern SD this afternoon,
bringing mostly sunny skies and light winds to the region.
Overnight, this high shifts east and allows for south-southeast
return-flow winds to develop. There`s a weak low-level jet (25-
30kts) that develops late tonight into early Wednesday morning over
central/south central SD. MUCAPE values generally from 1000-2000
J/KG (HREF ensemble mean), but with minimal shear. CAMs/paintball
output show just a few blips of elevated convection over the
southern CWA, so added slight chance (20%) PoPs for this.

Otherwise, focus will then shift to Wednesday/Wednesday night with
increasing heat, and chances for storms once again. By 00Z Thursday,
850mb temps rise to around +20C across the James River valley, to as
warm as +28C across central SD. 90+ degrees looks probable from the
James River westward, with highs more into the mid/upper 90s over
central SD. Dewpoints will also be creeping up there into the
mid/upper 60s to around 70 degrees. Latest iteration of heat indices
brings values close to 100 over parts of central SD, but as of now
it seems too brief/marginal to issue a headline for heat (100+
degree heat indices), although something to monitor.

Will also be watching convection chances by late afternoon Wednesday
as CAMs/paintball output continue to target the west-river counties
of the CWA seeing initiation between 21-00Z along a frontal
boundary. With rich low-level moisture (60s dewpoints) streaming
northward into central SD, moderate/strong instability sets up by
late afternoon as MLCAPE values peak around or just above 3000 J/KG.
Shear is not overly strong, but models indicating perhaps 25-35kts.
Whatever coverage of storms that develop across central SD late
Wednesday afternoon/evening will push east-southeast across the CWA
into the nighttime hours, likely waning in severe intensity as it
does so. Looking at more potential for strong to severe storms
Thursday/Thursday night also, while we remain in an active weather
pattern across the Northern Plains.

Looking further ahead, GEPS/GEFS/ENS all in good agreement in
showing a cold front moving through the area on Friday, bringing
cooler temperatures to the region after widespread 80s/90s Wednesday
and Thursday. At 12Z Friday, all three camps of ensembles are in
generally good agreement in showing the cold front position just
exiting the CWA. 850mb temps on Friday off the Grand Ensemble range
from about +13C to +16C, several degrees cooler from the +20s C
expected Wednesday/Thursday. We may see a bit of a break in the
stormy pattern as well, with minimal chances for precip showing up
this weekend into Monday.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1213 AM CDT Wed Jul 9 2025

Terminals KABR,KATY,KPIR,KMBG

VFR conditions will continue into Wednesday afternoon. Winds are
expected to pick up and start gusting during the morning at KMBG and
during the afternoon at KABR and KPIR. There is a trough moving
through Wednesday evening that could cause thunderstorms near KABR,
KPIR, and KMBG. These storms have the potential for large hail and
severe strength wind gusts.

&&

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

$$

UPDATE...12
DISCUSSION...TMT
AVIATION...12