473 
FXUS63 KFSD 080353
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1053 PM CDT Mon Sep 7 2026

.KEY MESSAGES...

- A line of storms continues to move east just north of the
  Missouri Valley late this evening. Wind gusts to 65 mph and
  quarter sized hail are possible. Tornado risk is low but not
  zero. Locally heavy rain and isolated flash flooding are also
  a concern.

- Additional scattered and possibly severe storms are possible
  into the overnight hours and again Tuesday afternoon/evening.
  The main threats remain quarter sized hail, wind gusts to 65 
  mph, and locally heavy rain. 

- Quiet but continued warm conditions are expected for the rest
  of the work week with the next better chance for  
  precipitation Saturday night into Sunday.


&&

.UPDATE...
Issued at 1040 PM CDT Mon Sep 7 2026

A few storms, some strong to severe, have been moving along the MO 
River this evening. Although generally trending downward, still may 
see some wind gusts to 65 mph and quarter sized hail as storms are 
beginning to show more linear characteristics over the last 30 
minutes with shear perpendicular to the storms. Tornado risk is low. 
Main threats may be shifting to wind and locally heavy rain/isolated 
flooding issues as the storms train over the same areas near the 700 
mb convergence, the 850 mb boundary, and the LLJ. Storm motion 
generally will be east to northeast. 

Next area to watch is with the next wave out of NE through the 
overnight hours. Guidance shows additional convective development 
with some weak to moderate instability. LLJ also may aid in keeping 
storms around through the overnight hours. Confidence is low in the 
severe potential given the decreasing shear and instability through 
the overnight hours into early Tuesday.

&&

.DISCUSSION...
Issued at 103 PM CDT Mon Sep 7 2026

Elevated showers and thunderstorms will continue to move
northeast through central SD into the afternoon. Locally heavy
rain and wind gusts to 50 mph will be the main threats.

Otherwise, showers and thunderstorms will likely be hard to 
come by this afternoon as strong capping is in place. The 
exception may be in central SD closer to increasing southwest 
flow aloft and slightly stronger surface heating. If these 
storms can develop, CAPE around 2000 J/kg as well as about 40 
knots of deep layer shear as well as decent turning from 
southeast to southwest in the lowest km. This will support all 
modes of severe weather with an isolated tornado, hail to ping 
pong ball and wind gusts to 70 mph. Unless the models are 
completely incorrect in handling the capping inversion, the 
chance for this very late afternoon and early evening convection
will be confined to areas west of the James River. One other
negative is the ongoing convection in central SD, which appears
to be taking a bite out of the daytime heating.

Farther east the threat will be more likely from about 8 pm to 2 am 
as storms could become more rooted in a stronger LLJ with increasing 
southwest flow aloft. This lay lead to a cluster of stronger
updrafts with half dollar sized hail, wind gusts to 60 mph and 
pockets of heavy rain the main threats.

Instability lingers through late tonight into early Tuesday 
morning as upper level support slowly moves through. Confidence 
is low on additional stronger convection, but with potentially 
1000-1500 J/kg of instability some isolated stronger storms will
be possible. For now the threat of heavy rain like the past 
couple of days looks pretty low as storms should be more 
progressive.

Instability is slow to shift southeast through the day on Tuesday 
and should result in additional showers and potentially stronger 
thunderstorms Tuesday afternoon. The better chance for this will 
likely be south of a Yankton to Jackson MN line, with the better 
chance from about 3 pm to 8 pm.

A stronger westerly jet aloft settles into the area Wednesday into 
Thursday, with a fast moving trough expected to move through 
Thursday night into Friday. This pattern should support dry 
conditions on Wednesday and Thursday with a chance for showers and 
thunderstorms late Thursday night, but more into Friday. Depending 
upon the timing of the front with this wave on Friday, highs could 
climb into the 90s in a few locations before a fairly strong shot of 
cooler air moves in for next weekend where highs in the 70s are more 
likely. Saturday night into Sunday will see a decent chance for 
showers and thunderstorms as models are fairly agreeable with a wave 
moving through, just not so much with the exact timing.

&&

.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 633 PM CDT Mon Sep 7 2026

Latest radar and satellite imagery shows remaining showers in and 
around KBKX pushing off to the northeast early this evening. At the 
same time, thunderstorms are developing southwest of KAGZ. These 
thunderstorms will continue to push off to the northeast through the 
rest of the evening hours. Will watch convective trends but the 
coverage of thunderstorms could also increase as well. Have kept 
PROB30/TEMPO groups in KFSD and KSUX's TAFs through most of the 
overnight hours. Lowered ceilings and visibilities are expected 
within the storms, potentially down to MVFR levels. Some of these 
storms could be strong to severe with large hail and damaging winds 
as the main hazards. Chances for storms looks to wane into tomorrow 
morning though showers may persist through the morning and into the 
afternoon timeframe. A cold front will be pushing through the 
forecast area tomorrow, turning winds to out of the northwest in its 
wake. This same front looks to develop another round of 
thunderstorms across northwest Iowa towards the end of the period 
tomorrow afternoon.

&&

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

&&

$$

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