245
FXUS63 KABR 020750
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
250 AM CDT Tue Jun 2 2026

.KEY MESSAGES...

- There is a Slight Risk (Level 2 of 5) for severe weather this
evening, mainly along and west of a line from Eureka to Murdo. There
is a Marginal Risk (Level 1 out of 5) for severe storms east of this
line through the James River Valley. Large hail of 1-2" in diameter
and wind gusts of 60 mph are the main threats. Tornadoes cannot be
ruled out, along with heavy rain that could lead to flash flooding.

- Another Slight Risk for severe weather is in place for storms
Wednesday afternoon and evening over northeastern and parts of
central and north central South Dakota. Large hail of 1-2" in
diameter and wind gusts of 60 mph are the main threats. Tornadoes
will also be a threat in the evening. Areas west of the Missouri
River are under a Marginal Risk.

- Thursday, yet another Slight Risk for severe weather is in effect
along and south of US Highway 12. Areas to the north of US Highway
12 are under a Marginal Risk. Large hail of 1-2" in diameter will be
the main threat, with wind gusts  of 60 mph and tornadoes possible
as secondary threats.

&&

.DISCUSSION...
Issued at 247 AM CDT Tue Jun 2 2026

Upper-level low continues to bring chances for showers, storms, and
severe weather to the Northern Plains this week, beginning this
evening. The focus for today`s severe weather potential is over
central and north central South Dakota (mainly along and west of the
Missouri River). There will be some chances for sub-severe showers
and storms earlier this afternoon and evening over parts of
northeastern South Dakota, but the main severe threat will arrive
around 01Z-03Z, moving in from the west. While the latest hi-res
ensemble guidance indicates that the best environment is off to the
west, there will still be plenty of CAPE and shear (~2000 J/kg and
30-40 knots respectively) to sustain storms as they move in. Hail is
the main threat, with the above ingredients as well as mid-level
lapse rates around 6.5-7 C/km all supportive of at least severe
hail, perhaps significant (2" in diameter) at times. Confidence on
the wind threat is a bit lower, with only some marginal DCAPE
(approaching 1000 J/kg) to play with as storms move in, and little
else favoring wind gusts beyond collapsing storms. Not very
enthusiastic about the tornado potential either at this point, as
the setup for such would be quite marginal. In particular, 3CAPE
appears to be somewhat limited, and 0-3km shear may struggle to
reach up to 30 knots at times. Still, can`t quite rule anything out
along the line of storms, especially if storms remain discrete
moving into the area. However, model guidance is trending more in
the direction of a line of storms by the time they enter the
Aberdeen CWA. Regardless of storm mode, if any tornadoes do develop,
the most likely location will be over north central South Dakota.

Wednesday`s severe threat times out more to the afternoon to evening
hours, with storms developing in the James River Valley and
continuing off to the east through the rest of the day. Once again
expecting hail to be the main threat, and conditions appear
favorable for significant hail development (2000-2500 J/kg of CAPE,
30-40 knots of shear, and mid-level lapse rates > 7 C/km) and
perhaps supercells as well. Severe wind gusts will be the secondary
threat, with northeastern South Dakota once again being the main
potential threat area. DCAPE over 1000 J/kg will be present, along
with near-surface lapse rates nearly dry adiabatic, supporting
easier mixing to the surface. Concern for tornadoes is a little bit
higher Wednesday than today, mainly later in the afternoon to the
early evening. It`s at that point at which low-level shear is
expected to increase above 20 knots and SRH up to around 150-200
m2/s2 over the area. Strong curvature in low-level hodographs also
indicate the potential threat.

Yet another outlook is in place Thursday evening, with the main
threat being over parts of central and north central South Dakota
west of the Missouri River. Strong CAPE will be present in that
area, and while early looks at shear profiles are a bit varied,
there is enough of a signal for 30-40+ knots of shear to be
confident in the severe hail threat, perhaps significant at times.
There is again some disagreement on the mid-level lapse rates, but
some pockets of up to 6-7 C/km will also be in place, favorable
conditions for hail growth. Less concerned about the wind threat at
this point, as model soundings do not appear favorable at this time.
However, can`t quite rule out a stray gust or two with some marginal
DCAPE over central South Dakota. There does appear to be an isolated
tornado threat late Thursday evening, based on favorable helicity,
strong low-level shear, and low-LCLs lining up. However, this threat
appears to be fairly localized, and at this time range guidance
struggles to find consensus on exactly where the tornado threat is
greatest. At this time, forecaster confidence in the potential
threat is greatest over central South Dakota, but there is still
plenty of time for this to shift and evolve with future forecasts.

A weak upper-level ridge builds overhead late Friday into Saturday,
temporarily cutting off precipitation chances for the weekend. This
break may not last long however, as ensemble confidence remains
fairly high on another upper-level trough developing over the
western CONUS by next week.

&&

.AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1233 AM CDT Tue Jun 2 2026

Terminals KABR,KATY,KPIR,KMBG

VFR conditions are currently forecast through the TAF period.
Shower and thunderstorm potential will increase across central
(KPIR) and north central (KMBG) South Dakota Tuesday afternoon
and evening, and some of the thunderstorms could be severe,
including large hail and damaging winds. For now, prob30 groups
have been introduced to the KPIR/KMBG TAFs.

&&

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

&&

$$

DISCUSSION...BC
AVIATION...10