473
FXUS63 KABR 070649
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
149 AM CDT Sun Jun 7 2026

.KEY MESSAGES...

- Strong winds will be out of the south to southeast, with gusts of
30 to 50 mph west of Interstate 29 this afternoon. Highest gusts
will be over portions of north central South Dakota, with locally
higher gusts possible.

- There is an Enhanced Risk, level 3/5, for scattered to numerous
severe storms over the western half of Corson County. There is a
Slight Risk, level 2/5, for scattered severe storms along and west
of the line from Eureka to Murdo. Main threats include large hail,
one to two inches in diameter, and wind gusts of 70+ mph. A tornado
or two cannot be ruled out or hail over 2 inches in diameter within
the Enhanced Risk. Heavy rain that could lead to flooding is also be
a concern.

- Highs will range in the upper 80s to the mid 90s again today,
warmest over central South Dakota. Brief cooldown for Monday before
high temperatures back in the 90s on Tuesday with the potential of a
few 100 degree readings.

&&

.DISCUSSION...
Issued at 142 AM CDT Sun Jun 7 2026

Winds will continue to be strong today, similar to yesterday. As of
06Z, a high is to our east (over southern Ontario) and low just to
our west (along eastern MT/WY and western Dakotas). We continue with
a tightened pressure gradient (~10-12mb across the state) with winds
currently between 10-20 mph sustained. By midday into the afternoon
Rap soundings indicate dry and steep low level lapse rates to about
750mb with the top of the mixed layer around 20-30kts at KABR/KATY
to 30-35kts over KMBG/KPIR. With daytime mixing, winds will increase
out of the south to southwest with gusts of 30 to potentially 50
mph. These gustier winds will extend a bit more eastward then
yesterday, mainly west of I29, with the highest gusts of 45-50mph
over north central SD. NBM Probability of wind gusts>45 mph is 45-
65% over Corson/Dewey and Leola Hills with NBM max gust potential of
50-55mph for this area. A Wind Advisory has been issued for counties
in north central SD from 17-01Z.

Return flow at 850mb with speeds between 20-30kts and temps will
once again range from ~18 to 25C at peak heating, which runs in the
94-99th percentile range at this height. Mixing with warm
southeasterly winds at the surface and highs will be similar to
yesterday ranging in the upper 80s to the mid 90s. Add in dewpoints
ranging in the 60s and it will feel quite sticky out there!

Our attention then turns this evening through late tonight. By 00Z,
the center of the deepening low is forecast to be over ~northwestern
ND/Canada with its cold front extending south and southwest through
western ND and SD. Aloft a strong shortwave will be over the
Northern Rockies within an overall long wave trough with a belt of
45-70kt winds along the southern and eastern side of the low mainly
over MT/ND, brushing northwestern SD. With this ongoing low level
moisture and synoptic setup, this sets the stage for showers and
thunderstorms to fire up once the cap breaks ahead of the front.
CAMs show this occurring over the western Dakotas/MT/WY late this
afternoon/evening as discrete cells turning more into a linear
fashion as it enters north central SD (Mainly Corson/Dewey who get
the brunt of it) through ND by ~00-02Z. Little bit uncertain on
exact storm mode at this time whether its more discrete, embedded
discrete cells turning linear, or all linear. Also low confidence on
the southern extent of this potential line as a few of the CAMS show
more of an extent into south central SD. This line (or lines) will
all track east/northeast through early Monday morning. Looking at
parameters, CAPE will range from 1000-2000j/kg with HREF max up to
3000j/kg this evening with values rapidly diminishing with sunset.
Bulk shear of 30k-40kts will be over far western Corson County this
evening with these values shifting a bit eastward over north central
SD through 06Z and to the James River by 12Z. Ongoing steep low
level lapse rates with mid level lapse rates between 7-8C/km over
central SD supports the threat of large hail if cells are still
discrete or embedded within the line at this time.

Only change to the Enhanced Risk is that Dewey County is out of
it and now in the slight therefore, there is an Enhanced Risk
(level 3/5) for the potential of scattered to numerous severe
storms over the western half of Corson County as max 2-5km
UH>75m2s2 per HREF indicates organized convection tracking
southwest to northeast over western SD/ND and possibly clipping
western Corson with the threat of supercells staying mainly to
our north and west, however, if cells are still discrete it is
not out of the question for a couple to clip Corson. Main threat
will be large hail of 1-2" in diameter mainly between 02-05Z
with SPC highlighting the tornado threat north and west of us.
Again if we can get a couple supercells over this enhanced area,
then a tornado or two could be possible as there is a bit of
low level SRH but 0-1km shear is very weak as RAP hodographs are
curved but small. Any supercell could also have the potential
of over 2" hail with these stronger lapse rates. Otherwise if
its linear coming into the CWA, wind gusts of 60-75+mph is
possible too as DCAPE will be above 1000j/kg. There is a Slight
Risk (Level 2/5) along and west of the line from Eureka to just
west of Murdo (to the enhanced risk). Main threat for this area
will be 1-2" diameter hail (any embedded discrete cells) and
wind gusts of 60-70+ mph as storm mode should be linear by this
time meaning more of a wind threat then anything. Especially
with the help with a LLJ of 30-40kts ahead of the cold front,
this could develop into more of an MCS as it tracks across the
Dakotas. Lastly, there is a Marginal Risk (level 1/5) along and
east of a line from Long Lake to Murdo to just west of I29. As
these storms track east of the slight risk, it will lose steam
and the better instability as CAMs show it breaking apart and
more of a messy line or blob of storms. However, hail up to
quarter and 60 mph winds cannot be ruled out. With PWAT being at
or above an inch, heavy rain is a threat with these storms that
could lead to flooding, especially for areas that have recieved
an abundance of rain last week.

By 12Z Monday, the fropa is forecast to be along the James River
with any ongoing convection occurring ahead and along the front
before the fropa exits the eastern CWA by late Monday evening.
There is a Marginal Risk (level 1/5) for ongoing severe storms
mainly for the James Valley. This unsettled weather pattern
continues as another low (and its shortwave) will track across
the Northern Plains Tuesday and Wednesday bringing the return of
showers and thunderstorms and the threat of severe weather. The
SPC has a 15% risk for the entire CWA Tuesday and James Valley
and eastward Wednesday.

Cooler air moves in behind the front Monday into Monday night but
that will be short lived as highs will jump right back into 90s to
as high as 102 over portions of south central SD. Add in dewpoints
in the upper 60s to the lower 70s and heat index could top out at or
over 100 degrees for some locations along the James River and south
central SD. A Heat Headline may possibly be needed closer to time.
Fast forward to the end of next week and weekend as the region will
be influenced by an upper level trough with winds west to northwest.
Highs are forecast to only range in the 70s to low 80s.

&&

.AVIATION /06Z TAFS THROUGH 06Z MONDAY/...
Issued at 1239 AM CDT Sun Jun 7 2026

Terminals KABR,KATY,KPIR,KMBG

Expect to see VFR conditions prevailing at all TAF sites through
most of this forecast cycle. Breezy southeast surface winds
will persist through the early morning but not enough to
preclude mention of low level wind shear (LLWS) at
KABR/KPIR/KMBG terminals. Gusty southeast winds between 25-35
kts are expected by mid to late morning through the end of the
day at all terminals. Increasing low level moisture advecting
into east central SD toward the end of the period could lead to
high end MVFR/low end VFR CIGs. A PROB30 group was added to the
KMBG forecast for -TSRA potential late in this TAF cycle.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Wind Advisory from noon CDT /11 AM MDT/ today to 8 PM CDT /7
    PM MDT/ this evening for SDZ003>005-009-010-015.
MN...None.

&&

$$

DISCUSSION...MMM
AVIATION...Vipond