287
FXUS63 KFSD 061937
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
237 PM CDT Sun Jul 6 2025

.KEY MESSAGES...

- A few early day storms possible Monday with greater potential
  (50- 70%) for scattered thunderstorms late Monday into Monday
  night. Some of these storms could be severe, especially west
  of I-29 through the evening where a Level 2 of 5 risk for
  severe storms is in place. Hail up to hen egg size and wind
  gusts to 70 mph are the primary threats.

- Additional storms are again possible Wednesday night and then
  later Thursday into Friday. While details are uncertain, a few
  strong to severe storms may develop, so continue to monitor
  your local forecast for updates.

- Seasonal high temperatures in the upper 70s and 80s are
  expected through Tuesday, with highs in the 90s briefly
  returning to some areas west of I-29 midweek.

&&

.DISCUSSION...
Issued at 234 PM CDT Sun Jul 6 2025

Tonight: Bulk of the overnight period looks benign with light winds,
some upper level clouds filtering overhead, and low temperatures
largely in the 60s. The one exception to this will be a wave moving
through Nebraska that will likely be the driver for an eastward
moving complex of thunderstorms into the early morning hours.
Overall consensus is that this remains south of the immediate
forecast area but at least a few outlier models keep this wave far
enough north that portions of the MO River Valley could be clipped.

Monday: Afternoon/evening thunderstorm evolution could very well be
muddied by a few vorticity fragments that work through during the
morning and early afternoon hours. This may result in isolated to
scattered activity to fester through the day, perhaps most focused
north of I-90, and in turn inhibit full destabilization potential
prior to the arrival of the main wave and tandem surface boundary
late afternoon/evening.

Assuming minimal convective contamination through the daytime hours,
progged MLCAPE values AOA 1500 J/kg and 30-40 kts of deep layer
shear would set the stage for a severe risk. Initial development
would likely pose a large hail risk, with sounding analogs
indications at least some potential for very large hail (2+ inches
in diameter). Near the warm from through the MO River Valley, enough
of a backed surface wind may even allow for a low end tornado
potential. Given the linear forcing, would expect eventual upscale
growth to the initial discrete cells and thus a transition to
primarily a damaging wind threat with time.

Tuesday and Wednesday: Fairly flat ridging develops over the Rockies
by Tuesday and pushes east by Wednesday. This should allow for
mostly dry conditions and temperatures warming back to the 80s and
90s.

Wednesday Night and Thursday: First wave tries to top the ridge by
as early as Wednesday night and may result in a southeastward diving
MCS into early Thursday. A more pronounced wave lifts through late
Thursday and Thursday night and should reinvigorate thunderstorm
chances. SPC already delineates much of the central Dakotas in a Day
5 outlook with ML/AI probabilities suggesting some expansion of this
risk may occur with time.

Friday and Saturday: Pronounced upper low carves in moving toward
the weekend and may ultimately provide for rather nice conditions
with decreasing precipitation chances through the day Friday and
temperatures in the mid 70s to mid 80s.

&&

.AVIATION /18Z TAFS THROUGH 18Z MONDAY/...
Issued at 1129 AM CDT Sun Jul 6 2025

Decaying MCS working through central SD may bring a sprinkle to
KHON over the next few hours but otherwise aviation concerns
pretty minimal through the remainder of the daytime hours.

Predominantly light northerly winds today becoming variable
overnight. At least some indication of a rogue thunderstorm
working near KSUX around daybreak Monday morning but overall
confidence pretty low.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.

&&

$$

DISCUSSION...Kalin
AVIATION...Kalin