Severe Thunderstorm Warning 20, NWS Sioux Falls, SD

Area Forecast Discussion
National Weather Service Sioux Falls SD
1257 PM CDT Thu Apr 23 2026

.KEY MESSAGES...

- Isolated severe storms will be possible this afternoon over
  parts of southwest MN and northwest IA. The main threat should
  come to an end by 4-5 pm.

- Near critical to critical fire weather concerns are expected
  this afternoon and evening especially across most southeastern
  SD and parts of southwestern MN. Avoid any outdoor burning!

- A return to more seasonable temperatures with highs in the
  mid 50s to lower 60s is expected Friday through the middle of
  next week.

- A very good chance (60%-90%) for showers and thunderstorms
  returns Sunday into Monday. Some locally heavier rain will be
  possible.

&&

.DISCUSSION...
Issued at 1256 PM CDT Thu Apr 23 2026

The severe weather threat for mainly northwest IA will gradually
come to an end late this afternoon as the dry line/cold front race
southeast. So far the front is a bit ahead of schedule so some
potential for most of the activity to be out of our area by 4-5pm.
The storms that do develop this afternoon will have about 1500-1750
J/kg CAPE and moderate shear so hail to the size of half dollars and
wind gusts to 60 mph seem like the main threats. With the
potential for some surface connection with the updrafts a very
isolated tornado cannot be ruled out.

The fire weather threat will diminish this evening as temperatures
fall and dew points increase behind the cold front. This will lead
in to a quiet and cooler Friday with highs mainly in the upper 50s
to mid 60s.

Rainfall probabilities for the weekend into Monday continue to
indicate good chances for a meaningful rain. Not completely ready to
jump on board just yet, but the data is starting to make it look
difficult to miss out. Both the Canadian and EC Ensemble indicate a
widespread 1" plus for pretty much the entire area while the GEFS
suggests there will be a sharper cutoff from northwest to southeast
with the higher amounts from northwest IA southward. Although the
latest GEFS has increased rainfall amounts compared to yesterday
across the entire area, just not as much as the Canadian and EC.
Even a quick look at the 10th percentile suggests pretty much a
quarter to a half an inch everywhere except closer to highway 14.

Right now the severe weather threat looks pretty low during this
time. Will keep an eye on Sunday night into Monday as low pressure
deepens and moves into the area. Maybe enough forcing to generate a
few stronger updrafts. But all in all the instability tends to stay
locked up from roughly I-80 southward.

The low pressure that brings the area the potentially meaningful
rainfall will drift east towards the Great Lakes Tuesday into
Thursday, leaving the area in drier northwest flow. This will
continue the trend of near to a bit below normal temperatures.
Precipitation chances will remain spotty through this time with a
few weak waves expected to rotate southeast through the strong
northwest flow.

&&

.AVIATION /18Z TAFS THROUGH 18Z FRIDAY/...
Issued at 1226 PM CDT Thu Apr 23 2026

Scattered showers and thunderstorms can be expected over parts
of northwest IA and southwest MN through about 22-23z, then most
of the activity will shift southeast of the area. Along and
ahead of this convection MVFR ceilings will be likely. Otherwise
strong westerly winds are expected behind this convection with
gusts of 30 to 40 mph likely through sunset across the entire
area. After sunset gusty winds to 25-30 mph will still be
possible but diminish further late tonight with VFR conditions
expected.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...Red Flag Warning until 8 PM CDT this evening for SDZ039-040-
     054>056-060>062-065>069.
     Red Flag Warning until 5 PM CDT this afternoon for SDZ038-050-
     052-053-057>059-063-064.
MN...Red Flag Warning until 8 PM CDT this evening for MNZ071-072-
     097.
IA...None.
NE...None.

&&

DISCUSSION...08
AVIATION...08

Hazardous Weather Outlook
National Weather Service Sioux Falls SD
330 AM CDT Thu Apr 23 2026

IAZ001>003-012>014-020>022-031-032-MNZ080-081-089-090-098-NEZ013-014-
SDZ071-240830-
Lyon-Osceola-Dickinson-Sioux-O'Brien-Clay-Plymouth-Cherokee-
Buena Vista-Woodbury-Ida-Murray-Cottonwood-Nobles-Jackson-Rock-Dixon-
Dakota-Union-
330 AM CDT Thu Apr 23 2026

This Hazardous Weather Outlook is for northwest Iowa, west central
Iowa, southwest Minnesota, northeast Nebraska and southeast South
Dakota.

.DAY ONE...Today and tonight.

Scattered showers and thunderstorms will be possible this afternoon
and evening. A few storms could become severe with large hail up to
half dollar size and damaging winds up to 60 mph being the primary
threats.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

No hazardous weather expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation may be needed.

MNZ071-072-097-SDZ038>040-050-052>070-240830-
Lincoln-Lyon-Pipestone-Beadle-Kingsbury-Brookings-Gregory-Jerauld-
Sanborn-Miner-Lake-Moody-Brule-Aurora-Davison-Hanson-McCook-
Minnehaha-Charles Mix-Douglas-Hutchinson-Turner-Bon Homme-Yankton-
Clay-
330 AM CDT Thu Apr 23 2026

This Hazardous Weather Outlook is for southwest Minnesota, central
South Dakota, east central South Dakota, south central South Dakota
and southeast South Dakota.

.DAY ONE...Today and tonight.

A few scattered showers with an occasional rumble of thunder will be
possible through the morning.

Elevated to critical fire danger is expected today as westerly to
northwesterly winds strengthen behind a cold front. This combined
with low relative humidity values will create a favorable environment
for fire spread. Avoid any outdoor burning and heed your local
restrictions.

.DAYS TWO THROUGH SEVEN...Friday through Wednesday.

No hazardous weather expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.