676
FXUS63 KFSD 311201
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
701 AM CDT Sun May 31 2026

.KEY MESSAGES...

- While confidence is low that additional storms will develop
  this afternoon, if storms develop, large hail up to ping pong
  balls and damaging winds to 65 mph would be the main hazards.
  A Level 1 of 5 risk for severe storms covers most of the area
  for this threat. Continue to monitor the latest forecast for
  the most up to date information.

- Similar to today, a conditional Level 1 of 5 risk for severe
  storms covers the forecast area Monday afternoon. The chance
  of development looks lower than today, but if a storm can
  form, large hail and isolated damaging winds could occur.

- Moderate chances (30-60%) for rain will persist through the
  bulk of next week. However, severe storm chances continue to
  look low (near 5% or less) through next week. The better
  chances for rainfall appear to be Wednesday and Wednesday
  night.

&&

.UPDATE...
Issued at 700 AM CDT Sun May 31 2026

Much of the morning activity has weakened though we do still
have small areas of thunderstorms within broader scattered
showers lifting north across the forecast area this morning.
Severe weather is not expected with this activity, but storms
may produce brief heavy downpours and of course lightning.

While confidence in exact timing/location of potential storm
development this afternoon remains low, CAMs do continue to hint
at isolated to scattered development within an unstable airmass.
Shear is on the weaker side, but cannot rule out an isolated
strong to severe storm with some support from a mid-upper level
trough swinging northeast across the region. Given the steep
lapse rates, large hail to ping pong ball size could occur.

An even more conditional threat exists for Monday afternoon, but
with rising mid-upper level heights, think potential for storm
development is even lower than today.

&&

.DISCUSSION...
Issued at 1256 PM CDT Sat May 30 2026

The latest runs of the models are more consistent on bringing a wave
northward tonight with a broken line of convection. With very weak
shear and CAPE values likely limited to 1000 J/kg or less, severe
weather is very unlikely. An isolated storm could produce wind gusts
to 60 mph or hail to the size of quarters, with the better chances
near the Missouri River, possibly as far north as the James River. A
few locations could pick up a little heavy rain, but for now storm
motion looks quick enough that this heavy rain will likely last an
hour or less at any one location. The better chances for this will
be late evening into the overnight hours, generally from about 11 pm
to 4 am for the stronger storms.

This wave should lift north of the area by late Sunday morning to
early afternoon. Some showery activity will be possible through the
morning, possibly lingering into the afternoon in southwest MN.

The next chance for showers and thunderstorms will be late Sunday
afternoon into Sunday evening. This is a much lower confidence
potential as the area could be muddled by cloud cover and even when
the cloud cover clears, the latest models are hinting at a decent
capping inversion. For now with only weak mid and upper level
support, this cap may hold. There could be a slightly better wave
move through Nebraska during this time which would bring a bit
better chance closer to the Missouri River into parts of northwest
IA. Also of note will be some low to mid level warm air advection
moving across the area Sunday late afternoon into the night,
starting in central SD late afternoon, which might be enough to
spark some isolated activity and aid in breaking the cap. All-in-all
a very low confidence set up during this time. In fact SPC just
downgraded the area from a Slight Risk to Marginal.

Upper level ridging will be in place on Monday and Tuesday and limit
any precipitation chances. Upper level troughing does spread into
North Dakota Tuesday night through Thursday and could bring some
showers and thunderstorms. The best chances should be Wednesday and
Wednesday night. Faster westerly flow remains in place through the
end of next week and this will likely support periodic chances for
showers and storms as well.

&&

.AVIATION /12Z TAFS THROUGH 12Z MONDAY/...
Issued at 700 AM CDT Sun May 31 2026

Scattered showers and isolated thunderstorms will lift north
across the area this morning. Heavier showers may result in a
period of MVFR-IFR visibility, but thunder will be limited in
coverage, possibly impacting KHON early in the period. Areas of
MVFR-IFR ceilings scattered throughout the area should improve
to VFR by midday.

Late afternoon/evening could bring a threat of additional storm
development. While exact timing is uncertain, attempted to target
most likely window for thunder chances at KFSD/KSUX during the
evening. Storm chances decrease after 01/06Z.

&&

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

&&

$$

UPDATE...JH
DISCUSSION...08
AVIATION...JH