209
FXUS63 KABR 061146 AAA
AFDABR

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
646 AM CDT Sat Jun 6 2026

.KEY MESSAGES...

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

- Thunderstorms return to the area Sunday evening through Sunday
night. There is a Slight Risk, level 2/5, for severe weather along
and west of a line from Eureka to Pierre. There is a Marginal Risk,
level 1/5, along and east of a line from Long Lake to Murdo. Main
threats include large hail (1"+ in diameter) and 60 mph wind gusts.
Heavy rain that could lead to flooding is also be a concern.

- Highs will range in the upper 80s to the mid 90s this weekend,
warmest over central South Dakota. This is about 10 to 15 degrees
above average for early June.

&&

.UPDATE...
Issued at 640 AM CDT Sat Jun 6 2026

The aviation discussion has been updated for the 12Z TAFS.

&&

.DISCUSSION...
Issued at 144 AM CDT Sat Jun 6 2026

Dry conditions expected through much of the weekend before chances
of precipitation move back in Sunday evening through Monday. Strong
winds are also expected along with above average temperatures. A
weak ridge aloft is centered over the Northern Plains into southern
Canada with zonal to slight northwest flow aloft under it. The ridge
will continue to amplify over the region before it starts to drift
eastward on Sunday as our next longwave trough moves in off the
Pacific and sets up over the western CONUS. Under this ridge, 850mb
winds will be out of the south to southeast with temps ranging from
18-24C this afternoon and again Sunday afternoon (94-99 percentile).
Add in daytime mixing with return flow at the surface and highs will
be in the mid 80s to the lower 90s this afternoon and upper 80s to
the mid/upper 90s on Sunday with temps about 2-5 degrees warmer for
any one location on Sunday. This is about 10-15 degrees above
average for this time of year. Dewpoints will range in the upper 50s
to the lower 60s today and lower to mid 60s Sunday, so this will add
a muggy feel to the air as well. Heat indices will stay below 100
(REFS probability less then 10%) so no Heat Headlines are expected
at this time. Heat Risk indicates Minor to Moderate Category this
weekend with Moderate Category meaning "affects those who are
sensitive to heat, especially those without cooling/hydration."

With high pressure over the eastern Dakotas into MN and low pressure
over MT, the pressure gradient will steepen this afternoon and
evening (~10mb difference across the CWA) with the steepest
gradients over central SD. NAM soundings show steep low level lapse
rates to about 700mb with the top of the mixing layer around 30kts
over central SD. So gusts at the surface are forecast between 30-50
mph, with the highest gusts over Corson/Dewey Counties. As
everything shifts a bit east for Sunday, gusts of 30 to 45+ mph are
forecast again with these windy conditions extending more eastward,
mainly west of I29, with the highest gusts again north central SD.
NBM Probability of wind gusts>45 mph is up to 85% over Corson and
northern Dewey this afternoon and 55-65% over this area along with
the higher elevations of the Leola Hills Sunday afternoon. NBM Max
Gusts show the potential of 40-55 mph over central SD this afternoon
and west of I29 Sunday afternoon, again highest gusts over north
central/Leola Hills. With collab from surrounding offices went ahead
and issued a Wind Advisory for Corson/Dewey Counties from 18Z this
afternoon through 05Z Sunday.

By Sunday evening, this low (and shortwave) that was over MT will
extend over the western Dakotas (center of low over northern ND)
with a warm front extending southeastward through north central
through southeastern SD and a cold front extending southward over
the western Dakotas as a surface trough lies vertically ahead of the
cold front. At the same time, a shortwave will be tracking
northeastward and over southeastern SD/NE/IA border by the evening.
Both of these systems will be the focus of showers and
thunderstorms. Storms will be moving in/developing mainly along and
west of the Mo River Sunday late afternoon/evening through Sunday
night with the cold front tracking east and along the James River by
12Z Monday. Shower and thunderstorms are also possible over east
central SD with the shortwave. Showers and thunderstorms chances
will continue along and ahead of the front (James Valley and
eastward) before the front exits our far eastern CWA by ~late Monday
afternoon/evening with cooler air moving in behind the front.
NAMNest is the only CAM to go out this far but does indicate broken
lines/clusters of storms moving in over central SD with most of this
convection west of the James River by 06Z Monday. We will have to
wait for more of the HiRes models to come in today. For Sunday
evening/night, REFS indicates CAPE between 1000-1500 j/kg, mid level
lapse rates of 7-8C/km, and bulk shear of 30-40kts (highest over
north central SD) and increasing behind the cold front as it track
east with ongoing moist low levels and warm temps. So with this, the
SPC has a Slight Risk, level 2/5, for severe weather along and west
of a line from Eureka to Pierre. There is a Marginal Risk, level
1/5, along and east of a line from Long Lake to Murdo. Main threats
include large hail (1"+ in diameter) and 60 mph wind gusts. Heavy
rain that could lead to flooding is also be a concern.

Another low will sweep across the Northern Plains, and shortwave
aloft, Tuesday through Thursday bringing the return of shower and
thunderstorms and the risk of severe weather both Tuesday and
Wednesday afternoon into the night. As of now the SPC has
highlighted a 15% chance of severe weather over portions of north
central SD Tuesday and mainly east of the James River on Wednesday.
As this is several days out, more details and specifics will be
nailed down in the upcoming days. With a break in the heat on
Monday, temps will rise back up into the 90s Tuesday/Wednesday with
a probability of 100 degrees is 35-55% over south central SD Tuesday
afternoon and 30-40% over southern Lyman/Buffalo Counties Wednesday
afternoon. Heat Risk category is Moderate over most of the CWA
Tuesday with Major over portions of east central SD Tuesday and
Wednesday meaning "affects anyone without cooling/hydration". Behind
the cold front much cooler air moves in with temps in the 70s and
80s for the end of the week.

&&

.AVIATION /12Z TAFS THROUGH 12Z SUNDAY/...
Issued at 640 AM CDT Sat Jun 6 2026

Terminals KABR,KATY,KPIR,KMBG

Outside of some brief shallow morning fog at KABR/KATY early
this morning, all terminals are expected to remain VFR for the
next 24 hours. MVFR vsbys are possible at KABR/KATY for the
first hour or two of this TAF set. Southeast winds will turn
gusty today, especially across central SD. KPIR/KMBG terminals
will see gusts of 25-35 kts from mid morning through the end of
the day. KABR/KATY sites will southeast winds gusting up to
15-25 kts late this morning through the afternoon.

&&

.ABR WATCHES/WARNINGS/ADVISORIES...
SD...Wind Advisory from noon today to 11 PM MDT this evening for
     SDZ003-015.
MN...None.

&&

$$

UPDATE...Vipond
DISCUSSION...MMM
AVIATION...Vipond