085
FXUS63 KABR 211816
AFDABR

Area Forecast Discussion
National Weather Service Aberdeen SD
116 PM CDT Sun Jun 21 2026

.KEY MESSAGES...

- Rain will continue over south central through east central SD
  this afternoon with the last of the rain moving out of south
  central SD late this evening. Additional amounts up to a half
  inch are possible.

- There is a Marginal Risk (level 1/5) for isolated severe
  storms Tuesday afternoon through the early evening along and
  east of a line from Britton to Doland. Main threats include
  wind gusts of 60 mph and quarter sized hail.

- Temperatures remain near to slightly below normal through next
  week. More seasonal temps and humidity return late week into
  next weekend.

&&

.DISCUSSION...
Issued at 109 PM CDT Sun Jun 21 2026

As of 1pm, widespread rain showers continue with the bulk of the
rain over south central to east central SD, with a sharp cutoff and
dry conditions mainly over the northern half of the CWA as the
center of the vort max spins over west central SD. Latest MRMS
accumulated precipitation indicates anywhere from a half inch to
about 1.75" over south central SD, highest from Stanley and
eastward though Sully/Hughes into Hyde/Hand Counties. KPIR ASOS
has reported 1.25", 0.05" at KMBG, 0.25" at KATY, with 0 at
KABR. The vort max that has been producing this moisture within
this overall embedded shortwave will continue to spin and drift
off towards the southeast this evening, with it hovering over
south central SD into NE by 00Z, per RAP/HREF. Widespread rain
will continue over south central SD and diminish northwest to
southeast as the wave aloft moves out of the region early
Monday morning. The last of the rain should exit far
Jones/Buffalo Counties by ~03-06Z Monday per CAMs with maybe
some spotty lingering precip lingering behind it through 12Z
here. Probability of additional rain>0.25" through late tonight
is 30-50% over south central SD, highest over southern
Jones/Lyman with about a 20-30% of exceeding a half inch.

Our attention then turns to the next system as a nearly stacked
closed low continues to spin over Alberta with its trough extending
southward over the northern Rockies. The surface low will quickly
track out of Canada Monday evening and over ND into MN through
Tuesday with its cold front sweeping northwest to southeast over the
CWA during this time. CAMs indicate spotty convection popping up
over the CWA during the afternoon per daytime heating with showers
and thunderstorms moving in over north central SD Monday evening
with additional development over south central SD Monday night with
this precip tracking eastward (and possibly phasing together) across
the CWA through Tuesday afternoon ahead of the cold front with
precip tapering off behind it as dry air moves in per high pressure
over the northern Rockies/Canada. Lingering wrap-around precip
behind the low will continue over far NESD/MN Tuesday
afternoon/evening. This will be high pops low QPF event as the
latest run of the NBM has pops of 60-95% along and ahead of the
fropa with the bulk of the precip falling between 00Z Tuesday to 00Z
Wednesday. With the quick speed of the clipper rain amounts will be
minimal with 24hr rainfall>0.25", ending 00Z Wednesday is 40-65%
with prob of 0.50" at 30-40% with the highest percentages over
NESD/MN. With the cold front hovering somewhere between the James
River and Sisseton Hills Tuesday afternoon, locations along and east
of the front through west central MN will have dewpoints still in
the upper 50s to lower 60s. CAPE values won`t be overly impressive,
up to 1000 j/kg, with shear of around 30-35kts out of the west.
However, with afternoon mixing into the cooler air aloft this could
be enough for a storm or two to become severe. Therefore, the SPC
has added a Marginal Risk (level 1/5) for the isolated threat of
severe storms along and east of a line from Britton to Doland with
the main threats being wind gusts of 60 mph and quarter size hail.
As the fropa tracks eastward the severe threat will diminish by the
evening.

By the middle of the week, northwest flow aloft and still some weak
upper level energy near the shortwave and surface low over MN/WI,
afternoon heating and mixing may lead to pop up convective showers
and thunderstorms over far NESD/MN Wednesday afternoon with the
threat diminishing by sunset with minimal pops of 15-20%. Otherwise
the rest of the CWA will be dry as a high continues to dominate the
area into Thursday. By Thursday evening and Friday the ridge that
has been over the western CONUS will track eastward over the central
CONUS Friday evening/Saturday, bringing in warmer air at the surface
and aloft per return flow. This along with a lee of Rockies boundary
setting up will bring the return of showers and thunderstorms over
far south central SD Thursday with rain/storms spreading north and
northeastward over the CWA Friday with NBM pops of 40-70%, which
have increased with the latest run. Still a bit early for specifics
but machine learning models do indicate a 5% chance of severe
weather mainly west of the Sisseton Hills with no outlook from
SPC.

By Saturday the ridge shifts east with models agreeing on this large
closed low over PacNW and trough extending over western CONUS with
the CWA in southwest flow. Strong winds aloft within a jet streak
circling the low will overspread the Northern Plains and return flow
700mb-surface will bring in ample amounts of warmer air and moisture
as dewpoints rise into the 60s on the WAA side of a low. This low is
forecast to track across the Northern Plains/Canada through
Sunday/Monday bringing showers and thunderstorms. Again way too
early for specifics but CIPS ML model shows a 5-15% chance of severe
weather with the highest percent over portions of central to western
SD Saturday and over eastern SD/western MN Sunday. However, as the
previous shift mentioned this warmer air moving in aloft will result
in 700mb temps ranging from ~10-13C Saturday afternoon which is
within the 90-93th percentile range per climo for this time of year
with these temps over eastern SD/MN for Sunday. This may put a
damper on severe potential but again, way too far out to nail down
at this time but something to keep watch of.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1224 PM CDT Sun Jun 21 2026

Terminals KABR,KATY,KPIR,KMBG

VFR cigs continue at KABR/KATY through the TAF period. Brief
drop to MVFR through the afternoon is possible at KMBG with
lower clouds and steady rain falling at KPIR where cigs are
MVFR/IFR. Widespread rain over south central to portions of east
central SD will continue to track southeastward this afternoon
and evening with the last of the rain at KPIR to move out by
03-04Z Monday. Cigs will improve to VFR/MVFR around midnight or
so through end of TAF period with overall dry conditons
expected at all terminals through Monday afternoon. Winds will
remain gusty out of the northwest between 20-30kts at KMBG/KPIR
through sunset.

&&

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

&&

$$

DISCUSSION...MMM
AVIATION...MMM