922
FXUS63 KABR 280531
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
1231 AM CDT Sat Jun 28 2025

.KEY MESSAGES...

- SLIGHT RISK (2 of 5) again for Saturday, mainly east of a line
  from Aberdeen to Pierre, with a large hail and wind threat.

&&

.UPDATE...
Issued at 935 PM CDT Fri Jun 27 2025

The earlier severe-warned storms down along I-90 have since moved
off into FSD`s CWA. A second area of severe-warned storms has
moved into portions of central and north central South Dakota and
is expected to produce 58+mph wind gusts and there has been
rotation noted along the leading edge of this system, which has
garnered a couple of tornado warnings. Meanwhile, short
range/rapid update guidance is still suggesting thunderstorms up
in North Dakota, as well as additional redevelopment down here
over north central South Dakota, could move through northeast
South Dakota later after 07Z. No substantive changes are being
made to tonight`s forecast.

UPDATE Issued at 619 PM CDT Fri Jun 27 2025

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

&&

.DISCUSSION...
Issued at 259 PM CDT Fri Jun 27 2025

Initial round of what was supposed to be morning convection finally
dissipated this past hour. A flat cu field is developing across
Lyman and Jones county in the warm sector south of a weak warm front
stretching west to east near I-90. This front will push northward
this evening and is expected to be the focus point for the first
strong to severe round of storms after 22z. Any storms along the
front will be discrete cells with a lot of instability to work with.
Around 4000 J/kg MUCAPE, a 20 kt llj, lapse rates of 7 to 8, and 35
kts of shear will be enough to support supercells. There`s an STP of
1 to 2 on the RAP13, as well, right around Pierre, so expect all
threats to be possible with any storms tied to the warm front.

Farther north is more questionable initially. The nose of the theta-
e ridge is in south central ND. So, while supercells may form along
that and shift south into the moisture tongue, there`s not really a
forcing mechanism across northern SD. Lower LCL heights, an
increasing and expanding llj, and 30 kts of low level shear will
still be very supportive of supercell continuation from western
Brown county back to the Missouri River late in the evening between
3z and 6z.

The severe threat shifts east on Saturday as the sfc low pushes into
central SD. By 18z, a sfc trough will stretch northeast from I-90 to
Sisseton. Along with a shortwave trough in the evening to the
southwest, storms may form along the boundary.

Another concern today and tomorrow will be the potential for
additional flooding across northeast and east central SD as storms
move over already saturated soil and rivers/creeks at bankfull.
PWATS remain at 1 to 1.5.

An upper trough slides into the Dakotas late Sunday with cooler
temps and somewhat drier conditions under a sfc high. Can`t rule out
some instability showers on northwest flow, however, through Monday.
A building ridge on Tuesday will also usher in a drier mid level air
mass briefly before return flow reintroduces moisture on southerly
flow Tuesday evening.

&&

.AVIATION /06Z TAFS THROUGH 06Z SATURDAY/...
Issued at 1229 AM CDT Sat Jun 28 2025

Terminals KABR,KATY,KPIR,KMBG

Storms in south central North Dakota may migrate south-southeast
and clip the KABR terminal, while we have showers moving towards
the KATY terminal. Another round of storms is possible for the
KATY terminal again Saturday afternoon.

A low level jet overhead will also be responsible for LLWS this
morning.

&&

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

$$

UPDATE...10
DISCUSSION...20
AVIATION...07