716
FXUS63 KFSD 022347
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
647 PM CDT Mon Jun 2 2025

.KEY MESSAGES...

- Thunderstorms will develop from southwest to northeast late
  this afternoon into the evening. Weak shear and moderate
  instability should lead towards a few storms producing hail as
  large as 2 inches and wind gusts to 70 mph.

- Locally heavy rainfall is likely as well with a few stripes
  of 2- 5". Most locations south of a Wagner to Sioux Falls to
  Marshall MN line should receive 0.50" with the better chances
  for 1-2" south of a Yankton to Jackson MN line.

- Could see a brief return of Canadian wildfire smoke behind
  today`s cold frontal passage. Minor deterioration in
  visibility and air quality will be possible during the late
  evening hours mainly across southeastern South Dakota and
  portions of southwestern MN.

- Temperatures return to seasonal normals for the remainder of
  the week into the weekend, with some potential for scattered
  (20-40% chance) diurnal showers/thunderstorms each day.
  Currently the severe threat during this times looks low.

&&

.UPDATE...
Issued at 634 PM CDT Mon Jun 2 2025

Thunderstorms continue across northwestern IA into northern NE,
with additional thunderstorms across central MN. Narrow
corridor of instability keeps the severe threat in place for the
next couple of hours, and should wane toward sunset. Main
hazards are 2 inch hail and 70 mph winds.

Have received a few reports of localized flooding as well
rainfall rates of 1-2+ inches per hour and storms through the
overnight hours will be capable of producing heavy rainfall.

Additionally, we are seeing wildfire smoke mixing down behind
the front, with reported visibility as low as 2 miles.

&&

.DISCUSSION...
Issued at 234 PM CDT Mon Jun 2 2025

A quick moving mid level wave/MCV moving along highway 14 is
speeding up the low level front a bit this afternoon. If storm
development holds off until 6-7 pm, this may push the stronger
development a bit farther south. Environmentally, scattered severe
storms remain likely with about 2000 J/kg instability and only weak
shear. Suspect that the initial updrafts will have the potential for
golf ball to ping pong ball hail, but overall wind gusts around 65
mph and locally heavy rain should be the main threats. The best
chance for these strong to severe storms will be south of I-90 then
into parts of southwest MN. Low level boundary orientation relative
to the mid and upper level flow indicate some training of cells is
possible and given PWAT values around 1.5" and a warm cloud depth of
about 12 kft, 2-4" per hour rainfall rates will be likely, just
localized.

After sunset a wave to the south will work east and bring additional
rain and isolated thunderstorms to the area. For the most part
severe weather after about 3z should remain very isolated, with some
localized heavy rain the biggest threat, especially in northeast NE
and northwest IA.

Rain will gradually come to an end from west to east on Tuesday
morning, leading to a cooler and marginally breezy day. Highs should
be in the upper 60s to lower 70s most locations.

Near to slightly below normal temperatures will continue Wednesday
and Thursday as westerly flow aloft allows for additional weak waves
and periodic chances for showers and isolated thunderstorms. Right
now any thunderstorm activity does not look to be severe.

Saturday through Monday low pressure develops along the Canadian
border and will swing a couple of weak waves southward through the
area. This will bring spotty chances for showers and thunderstorms
with fairly low chances for severe weather. With west to northwest
flow aloft, mild temperatures near to above normal are expected,
generally highs in the 70s to lower 80s.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 634 PM CDT Mon Jun 2 2025

Strong to severe storms continue over northwestern IA into
northern NE through the evening hours, and should begin to
weaken toward sunset tonight. Otherwise, expect additional
showers and thunderstorms to develop this evening and overnight
back to the west toward the James River Valley. Expect MVFR to
IFR conditions with convection.

Additionally, wildfire smoke is sinking to the surface behind
the front with the return of northwesterly winds. Visibility
with the smoke is dropping to as low as 2 miles. Not sure how
long this will last, but have included mention at all three
sites.

Southerly winds ahead of the front continue to gust to around
35+ knots, with northwesterly winds behind the front gusting to
35 knots at times. Expect winds to begin to weaken overnight,
with continuing gusts around 20-25 knots through the period.

&&

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

&&

$$

UPDATE...SG
DISCUSSION...08
AVIATION...SG