850 
FXUS63 KFSD 080720
AFDFSD

Area Forecast Discussion
National Weather Service Sioux Falls SD
220 AM CDT Tue Sep 8 2026

.KEY MESSAGES...

- A couple areas of storms are moving east-northeast this
  morning. Although severe risk has diminished, a stronger storm
  could produce wind gusts around 55 mph. Locally heavy rain and
  isolated flash flooding are also a concern.

- Additional scattered are possible Tuesday afternoon/evening.
  Severe risk is low and focused southeast of a Sloan to
  Cherokee line. The main threats remain quarter sized hail,
  wind gusts to 60 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 219 AM CDT Tue Sep 8 2026

Continuing to see storms move across the area this morning, and 
watching the development continue in NE. Have seen steady downward 
trend over last hour or so with sporadic gusts around 50-55 mph. 
Storms appear to be elevated and tied more to the LLJ forcing now 
than earlier tonight. Expect periods of showers/storms to continue 
near and south of I-90 through the overnight hours as the next wave 
lifts out of NE and the LLJ remains over the area. Although storm 
motion is more progressive, high PWATs and still relatively 
deep warm layer support continued locally heavy rain. Will need 
to watch areas that have had multiple rounds of storms over the 
last few days. Temperatures thus far are remaining mild in the 
upper 60s to upper 70s this morning with wind gusts around 25-30
mph at times. Highs warm into the 80s.

Showers and storms linger through the day Tuesday with the surface 
cold front sagging south through the day and southwesterly flow 
aloft promoting waves through the pattern. Low end severe risk our 
far southeastern forecast area (southeast of Sloan to Cherokee) 
later this afternoon and evening. Anticipate that we'll struggle 
with destabilization due to morning convection and cloud debris, so 
any severe threat would be limited to a narrow window this afternoon 
and evening - likely a couple hour window between 3 and 8 PM 
(depending on if/how quickly we destabilize and where the surface 
boundary is). Shear may trail a bit behind any instability initially 
which would also limit the severe potential. 60 mph wind gusts, 
quarter sized hail, and brief heavy rain are the main threats. 
Storms should clear out through the evening hours, with a more 
seasonal night Tuesday night into Wednesday.

&&

.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 /06Z TAFS THROUGH 06Z WEDNESDAY/...
Issued at 1215 AM CDT Tue Sep 8 2026

Main aviation concern through Tuesday night will be periods of
showers and storms. One round of showers/storms is moving slowly
to the east-northeast at the time of this discussion near the
I-90 corridor and occasionally producing wind gusts around 45
knots. Also seeing some locally heavy rainfall as well. Some
patchy MVFR and lower conditions have been observed with these
storms. 

Next area to watch is across NE, and will move into the area
later in the overnight hours into Tuesday morning - these may be
remain south of I-90. Another chance for convection returns to
northwestern IA and adjacent portions of northern NE/far
southeastern SD during the afternoon and evening. An isolated
stronger storm may be possible. Convection may lead to MVFR and
lower conditions.

Outside of convection, expect shifting wind direction through
the period with a couple of boundaries in place. Synoptic non-
thunderstorm winds at times gust around 20-25 knots. Light winds
to end the period. VFR conditions prevail barring convection.

&&

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

&&

$$

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