101
FXUS63 KFSD 031152
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
652 AM CDT Wed Jun 3 2026

.KEY MESSAGES...

- Portions of southeast South Dakota will see a Level 2 of 5
  risk for severe storms this evening and again Thursday late
  afternoon and evening, with lesser risks farther east and
  south. Large hail and damaging winds are the primary threats,
  with an isolated tornado also possible.

- Pockets of heavy rainfall in excess of 2 inches are possible
  today through Thursday. Widespread flash flooding risks are
  low. However, flood prone areas and locations which received
  recent heavy rainfall could see isolated impacts.

- While details are far more uncertain, an isolated to scattered
  severe storm risk will linger into Friday. The greater risks
  at this time shift southeast into eastern Nebraska, Iowa and
  far southern Minnesota.

- Temperatures remain in the 80s through the week and rise
  towards the low 90s by the end of the weekend.

&&

.UPDATE...
Issued at 455 AM CDT Wed Jun 3 2026

Storms have moved into our far western counties early this
morning, but eastward progress will be slow as the instability
axis in central SD and only slowly expands east through this
morning. Recent HRRR runs show the line maintaining much farther
east than other CAMs and given stronger development at the south
end of the complex, there may be something to the HRRR trends.
Confidence is low, though, so will only maintain low 20-30%
pops about as far east of Highway 81 through midday for now.

This trend in the HRRR is also leading to a slower recovery for
the afternoon, resulting in a slower and slightly farther west
point of initiation along a slowly advancing cold front this
evening. While the HRRR is slower/farther west, the latest 3km
NAM has trended in the other direction, initiating storms along
our western CWA border by 3-4pm with a faster progression to the
east than we have seen in other solutions. While this is leading
to some uncertainty in exact timing of initiation, the overall
location and evolution of storms during the late afternoon and
evening remains on track. These initial discrete storms will
produce the greatest threat for large hail, perhaps 2 inches or
larger, for the first 1-3 hours after development. The storms
then evolve into one or more linear segments which will bring a
transition to a threat of damaging winds up to 70 mph as the
line moves southeast during the evening. Waning instability and
decreased shear over Nebraska/Iowa/Minnesota should result in
the severe threat diminishing after midnight.

Thursday could see a repeat of today in terms of severe storm
timing, but with a couple of glaring differences with regard to
evolution. First, the low level focus for storms looks to be
residual boundaries from tonight`s convection, perhaps more of a
west-east oriented quasi-warm front, rather than a southwest to
northeast oriented cold front. Second, confidence is much lower
regarding where the boundary/boundaries will be located, and
thus location of initiation is much more uncertain and is
subject to change.

By Friday, the upper level pattern transitions from southwest
flow to a more quasi-zonal flow, but embedded waves still look
to trigger at least isolated strong to severe storms by mid to
late afternoon. As alluded to in the SPC Day 3 outlook, if
recovery from Thursday night`s MCS is sufficient, a more
organized area of development is possible. This potential is
currently favored across southeast portions of our forecast
area, but like Thursday, details are uncertain and subject to
change as we see how storms evolve over the next couple of days.

&&

.DISCUSSION...
Issued at 148 PM CDT Tue Jun 2 2026

CURRENTS & TONIGHT: Another warm and breezy day continues! Taking a
look across the area, mostly clear and quiet conditions persist this
afternoon with breezy southeasterly winds. As some lingering
isentropic lift continues to progress through the area this
afternoon, can`t rule out a few spotty diurnally-driven showers to
thundershowers. While severe weather is not expected, any festering
activity mainly west of I-29 could produce locally heavy downpours
and an occasional stroke of lightning. From here, additional showers
and weakening thunderstorms will progress through portions of
southcentral SD this evening with a shortwave lifting out of the
Black Hills. While this activity is not expected to be severe, can`t
completely rule out up to 40 mph wind gust at times with any
stronger activity. Lastly, another warm night is expected with lows
mainly upper 50s to low 60s expected.

WEDNESDAY & THURSDAY: Looking into the midweek, could see an
additional shower or two linger in our far northwest around
daybreak. However, should see most of this activity weaken as it
lifts to the northeast. From here, quieter conditions will
temporarily return with more seasonal conditions as temperatures as
peak in the upper 70s to mid 80s for the day. Looking aloft, we`re
still on track for additional showers and thunderstorms to develop
along/ahead of an approaching cold front by late Wednesday
afternoon. With dew points in the low to mid 60s, developing
thunderstorm will have access to an decently unstable environment
characterized by 1000-2000 J/kg of MLCAPE with about 20-30 kts of
shear. With this in mind, a few stronger storms are expected with
the main hazards being up to golf ball sized hail and damaging winds
up to 65 mph. With currents guidance suggesting instability will
gradually weaken with southeastward extent, thinking the greatest
threat will be to areas along and west of I-29 from 4pm to 12am.
While there could be a lingering severe risk east of I-29 through 3
am with a strengthening nocturnal LLJ, thinking any stronger
activity would be isolated at best given the time of day.

Otherwise, scattered showers with isolated thunderstorm could linger
across areas east of I-29 through daybreak on Thursday as the front
pushes eastwards. Looking into the rest of Thursday, another warm
day is ahead with highs mainly in the low to mid 80s. Could see the
return of showers and thunderstorms by Thursday evening as an
approaching shortwave intersects a lingering cold/stationary
boundary draped roughly from northeastern SD into southcentral SD.
While areas along and north of I-90 look like the current area of
interest, its worth noting that most of this developing activity
should lift to east-northeast following the bulk shear vector.
Nonetheless, the environment will be very similar to Wednesday`s
with 1000-1800 J/kg of MLCAPE and 25-35 kts of shear. With this in
mind, expect additional chances for up to Ping-pong ball sized hail
and 60 mph winds with the strongest activity. Lastly, this activity
will continue progressing eastwards overnight with the potential for
some additional redevelopment across portions of northwestern IA
with a nocturnal LLJ late though confidence isn`t as high yet.

FRIDAY ONWARDS: Heading into the extended period, quasi-zonal flow
into the weekend will bring another shortwave through the region on
Friday. Given how Thursday`s event will likely run late, the main
question is if the atmosphere can recover in time for the arrival of
the next wave. With this in mind, confidence is low in organized
severe weather at this time, However, that will be subject to change
depending on how things go with the previously mentioned event.
Otherwise, heights will build by Saturday with an approaching mid-
level ridge keeping precipitation chances at bay through at least
late-Sunday as the ridging begins to break down. Lastly,
temperatures will begin to trend warmer into the weekend with highs
mainly in the mid to upper 80s and low 90s.

&&

.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/...
Issued at 644 AM CDT Wed Jun 3 2026

Showers and embedded thunderstorms mainly west of the James
River to start this period will struggle to move east of US Hwy
81 before diminishing. Southeast winds gusting 20-25kt will
develop ahead of a cool front this afternoon. This front will
trigger additional thunderstorms after 21Z which will then move
southeast across the area during the latter half of this period.
MVFR-IFR visibility and occasional MVFR ceilings will accompany
the storms. Scattered erratic wind gusts in excess of 40kt are
also possible, especially with early development toward central
SD.

&&

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

&&

$$

UPDATE...JH
DISCUSSION...05
AVIATION...JH