006
FXUS63 KFSD 030212
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
912 PM CDT Tue Jun 2 2026

.KEY MESSAGES...

- Unsettled conditions remain in the region through the week.
  Showers and storms look to push into locations west of the
  James River this evening and night. While a severe storm or
  two is possible, storms will be weakening with eastward
  extent.

- Portions of southeast South Dakota will see a Level 2 of 5
  risk for severe storms Wednesday evening and Thursday night,
  with lesser risks farther east and south. Damaging winds to 65
  mph are is primary threat, with the potential for a tornado
  and large hail up to ping pong ball size being the secondary
  threats.

- Wednesday also has the potential to see rainfall across a
  large swath of the area, with amounts potentially up to 0.5"
  to 1.0"+. Locally higher amounts remain possible depending on
  how storms track.

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

&&

.UPDATE...
Issued at 908 PM CDT Tue Jun 2 2026

Thunderstorms, some of which have become strong to severe are
currently tracking eastwards out of central and southwest South
Dakota. Remaining southeasterly flow across most of the area
continues to advect in drier, more stable are to the west. This will
push the instability gradient further to the west. These severe
storms may persist just long enough to cross the CWA border into
portions of Brule, Charles Mix, and Gregory counties between 10 pm
and midnight. These storms should quickly weaken once they push past
the instability gradient. At the same time, a second round of storms
across southwest South Dakota will continue to push eastwards and
enter the CWA later tonight around 2 to 3 am or so. The first storms
will use up some of the instability at the edge of the previously
mentioned gradient. Some additional instability could be advected
northwards as the low level jet (LLJ) will remain strong. Thus, this
second round of storms could survive a bit into the CWA but should
quickly weaken once it uses up and outruns the minor instability
that is left over.

An incoming cold front will be the trigger for another round of
strong to severe storms late tomorrow afternoon and evening. With
mean flow and parallel to this front, storms are expected to rapidly
grow upscale and develop into a line. Southerly surface flow will
help advect the warm sector to the east, providing the fuel
necessary for thunderstorm development and maintenance. Vertical
shear will be sufficient with deep layer shear values on the order
of about 40 knots. 0-3km shear vectors look to be oriented
perpendicularly to the line of storms, suggesting that a tornado
threat is possible with this line. Large hail is on the table as
well though hail up to ping pong ball size is most likely during the
initial updraft development. Damaging winds to 65 mph is the primary
hazard with this line as it pushes eastwards through the CWA. The
good news is that this line will be weakening with eastward extent
as it outruns the better shear. That said, some of the hi-res models
have been suggesting that locally heavy rain will be possible with
these storms. As of now, there is the potential for a larger swatch
of 0.5" to 1.0"+. This is supported by the REFS as it shows about a
50% chance for rainfall totals to exceed a half an inch for
Wednesday. Some of the latest hi-resolution models are suggesting
that there could be localized pockets of 2.0"+. This will all be
dependent on how the line of storms tracks through the CWA. Any
severe threat should be winding down by about midnight or so.

Another chance for severe weather persists through Thursday. Details
about this potential are uncertain because it depends on the
evolution of Wednesday`s storms and how the surface front sets up.
Continue to monitor the latest forecast for the most up to date
information.

&&

.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 /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 634 PM CDT Tue Jun 2 2026

Latest radar imagery shows a few showers around KHON. These showers
should push past the terminal over the next 1 to 2 hours. Another
round of showers and thunderstorms looks to move into locations west
of the James River later tonight. The storms will be on a weakening
trend as they push into the area though. So won`t seem them persist
much beyond the James River. Winds will veer to out of the south for
tomorrow afternoon with gusts up to 20-25 knots. Another round of
showers and storms look to develop at the very end of the period
across central South Dakota. Conditions will remain VFR but could
briefly drop to lower categories in showers and storms.

&&

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

&&

$$

UPDATE...Meyers
DISCUSSION...05
AVIATION...Meyers