898
FXUS63 KABR 230539 AAC
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
1239 AM CDT Mon Jun 23 2025

.KEY MESSAGES...

- Severe storm threat has diminished across the area but showers
  and thunderstorms remain in the forecast through daybreak across
  parts of the region.

- Much cooler temperatures move in the first half of the week with
  several chances for showers and thunderstorms across the area
  Tuesday through Thursday. Marginal risk (level 1 of 5) for
  severe storms over southern SD Tuesday/Tuesday night.

&&

.UPDATE...
Issued at 1235 AM CDT Mon Jun 23 2025

The aviation discussion has been updated for the 06Z TAFS.

UPDATE Issued at 725 PM CDT Sun Jun 22 2025

Allowed the heat advisory to expire this evening. Temperatures and
heat indices are quickly falling behind the front this evening.

UPDATE Issued at 620 PM CDT Sun Jun 22 2025

The front is now east of I-29 this evening with the trailing low
center just east of Aberdeen. Will continue to monitor a few areas
for storms this evening, focusing for now on the storms moving
into SD out of central NE.

&&

.DISCUSSION...
Issued at 322 PM CDT Sun Jun 22 2025

Surface low is approaching the James River this afternoon and is
rather evident on obs/satellite. Surface frontal boundary also shows
up nicely on radar, so fairly east to track these features this
afternoon. Unstable air mass across the region, with MLCAPE values
around 2000-3000 J/KG. Still capped across a good portion of the
CWA, but may be eroding it along the frontal boundary as witnessed
by latest mesoscale analysis. Still a bit unclear on how convection
pans out in our CWA, with better potential for supercellular
activity across eastern ND into northern MN where a Tornado Watch is
currently in effect. Seeing post-frontal convection across central
ND, evident of increasing lift in that region. Once that area of
lift pushes eastward over the next couple hours, will see if any
convection can get going across the CWA. Otherwise, may have to wait
until later this evening/tonight with whatever emerges across
western NE and moves northeast across southern/southeast SD.

Heat Advisory remains in effect until 00Z this evening. Still seeing
hot and humid conditions along and east of the James River, with
many areas between 100 and 105 heat index. That said, with the way
the frontal boundary is moving across Brown county, heat indices may
cool below criteria earlier than the set expiration time, especially
northern and western parts of Brown.

Monday will be cooler and much less humid compared to the past few
days. In the post-frontal air mass, 850mb temps cool down to around
+8c to +12C across the CWA. Northwest breezes will also be felt,
with dewpoints only forecast to be in the 40s by afternoon for most
areas.

Southwest flow aloft continues into mid-week, with a northward
movement of a surface frontal boundary Tuesday into Tuesday night.
By Wednesday morning, GEFS/GEPS/ENS agree fairly well in showing the
frontal position along the SD/NE border, or just into southern SD.
With passing disturbances mid-week, shower and thunderstorm chances
(60-80%) are best Tuesday night into Wednesday morning. But, it
appears additional opportunities arise Wednesday night as well.
Parameters/setup do seem to support at least a marginal risk for
severe storms Tuesday night over southern SD, which seems to line up
with the current Day 3 outlook.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1235 AM CDT Mon Jun 23 2025

Terminals KABR,KATY,KPIR,KMBG

Post frontal showers and thunderstorms are moving northeast through
the region tonight. Thunderstorms will be near KPIR and KATY at
times tonight. There is also MVFR stratus. Expect both thunderstorms
and cigs to improve after 12z leaving VFR conditions and breezy west
to northwest winds through afternoon.

&&

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

$$

UPDATE...20
DISCUSSION...TMT
AVIATION...20/Vipond