Alert archive / Iowa / Severe Thunderstorm Warnings in 2026

Severe Thunderstorm Warning 165, NWS La Crosse, WI

August 7, 2026Chickasaw County, Fayette County, Floyd County, Iowa

NWS La Crosse, WI issued this severe thunderstorm warning at Aug 7, 2026, 2:51 PM CDT for Chickasaw County, Fayette County, Floyd County, Iowa. It was in force for 54 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Aug 7, 2026, 2:51 PM CDT (19:51 UTC)
Expired
Aug 7, 2026, 3:45 PM CDT
In force
54 min
Issued by
NWS La Crosse, WI
Area
Storm-based polygon
Hail
1.0 in
Wind
60.0 mph

Counties Chickasaw County, IA, Fayette County, IA, Floyd County, IA

The radar

The La Crosse radar (KARX), 129 km from the middle of the area, began a volume at 19:55 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Aug 7, 1:40 PM CDTSevere Thunderstorm WatchSPC8 hr

The nearest sounding before it

Minneapolis, MN (KMPX), launched 12:00Z, 7.9 hours before the alert went out and 231 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-pSkew-T log-p diagram, Minneapolis, MN at 12:00Z on 2026-08-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 506 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Minneapolis, MN at 12:00Z on 2026-08-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 211 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
506 J/kg
Mixed-layer CIN
-343 J/kg
Mixed-layer LCL
1332 m above ground
0-6 km bulk shear
33 kt
0-1 km storm-relative helicity
211 m²/s²
0-3 km storm-relative helicity
250 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

Open this sounding in Storm Lab

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS La Crosse, WI wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 7, 1:11 PM CDT, 1 hour 40 minutes earlier. Its key messages:

  • Severe storm risk this afternoon remains a lower confidence forecast owing to early morning storms. Pockets of damaging winds and heavy rain would be the main threats, which look to be focusing over south-central MN and north-central IA.
  • Additional rounds of storms return to the forecast from early Sunday morning through midweek. There may exist a severe weather threat with these storms, but confidence in such details is low at this time.
  • Seasonal temperatures continue for the weekend with a slight cooling trend by midweek as the storm risk pushes south.
Area forecast discussion, Aug 7, 1:11 PM CDT, 1 hour 40 minutes before
Area Forecast Discussion
National Weather Service La Crosse WI
111 PM CDT Fri Aug 7 2026

.KEY MESSAGES...

- Severe storm risk this afternoon remains a lower confidence
  forecast owing to early morning storms. Pockets of damaging
  winds and heavy rain would be the main threats, which look to
  be focusing over south-central MN and north-central IA.

- Additional rounds of storms return to the forecast from early
  Sunday morning through midweek. There may exist a severe
  weather threat with these storms, but confidence in such
  details is low at this time.

- Seasonal temperatures continue for the weekend with a slight
  cooling trend by midweek as the storm risk pushes south.

&&

.DISCUSSION...
Issued at 110 PM CDT Fri Aug 7 2026

This Afternoon: Storm Details

Several rounds of storms have developed since sunrise on the
nose of a 850-700-mb theta-e ridge that is advancing eastward
just ahead of a surface cold front bifurcating Minnesota from
SW to NE. As expected, the complex hodographs and linear
forcing, coupled with a narrow instability axis in which storms
have little residence time, have resulted in transient storm
structures and a rapid upscale growth. The southern side of the
line has become the dominant feature as of 18Z and is making the
southeastward turn as the cold pool becomes established. This
trend will continue over the next few hours, with damaging winds
being the main threat.

Additional storms may form along the nose the the theta-e ridge,
but time is running out for this to occur before the cold front
arrives. The cold front may serve as a source for additional
convective initiation, but there has been ample anvil shading
along the front and any risk for these storms may be displaced
further north towards northern Wisconsin.

Sunday Morning: Next Round of Storms, Heavy Rain Threat?

Cooler and more stable air filters southward tonight in the wake of
the cold front and persists for much of Saturday as the front stalls
and pivots near I-80 in Iowa. Lee cyclogenesis along the Front Range
helps push this (now warm) front northward across the region once
again late Saturday night into Sunday morning. Aided by a 30-40 kt
LLJ, these storms could be more robust in nature and produce heavy
rainfall. While confidence is increasing that there will be some
sort of MCS across the region, the devil is in the details as to
when exactly it will form, which will dictate its track. Aided by
increasing Gulf moisture and PWATs of 1.5 to 2 inches, coupled with
an increasing line parallel storm motion, this complex could put
down efficient rainfall rates in short order and will need to be
monitored for any flooding risk.

Early Next Week: Continued Storm Risk

The lower tropospheric front stalls between central Iowa and
southern Minnesota for later Sunday through Tuesday, presenting
multiple windows of opportunities for convection that could
bring heavy rain. However, details of these storms remain very
nebulous and will be refined over the coming days.

Mid to Late Week: Drier and Cooler

The medium to longer range solutions are in general agreement
that a a polar airmass will build southward through mid to late
week as the surface baroclinic zone sags southward. This should
result in cooler and drier weather, though with the surface
front not far away, it will not take much of a wobble in the
forecast to bring this rain back northward.

&&

.AVIATION /18Z TAFS THROUGH 18Z SATURDAY/...
Issued at 1200 PM CDT Fri Aug 7 2026

Primary concern over the next 24 hours is the likelihood (60%)
for TS to move west to east across the area this afternoon and
evening, affecting both LSE/RST. Have maintained previous TAF
posture of TS mentions with TEMPO groups of IFR visibility but
with timing adjustments. After TS departs to the east,
northwesterly winds should be predominant and should (80%)
serve to keep stratus/fog concerns confined to the Wisconsin
River valley around OVS overnight into Saturday morning.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.

&&

DISCUSSION...Skow
AVIATION...Ferguson
Hazardous weather outlook, Aug 7, 9:08 AM CDT, 5 hours 43 minutes before
Hazardous Weather Outlook
National Weather Service La Crosse WI
908 AM CDT Fri Aug 7 2026

IAZ008>011-018-019-029-030-MNZ079-086>088-094>096-WIZ017-029-
032>034-041>044-053>055-061-081815-
Mitchell-Howard-Winneshiek-Allamakee-Floyd-Chickasaw-Fayette-
Clayton-Wabasha-Dodge-Olmsted-Winona-Mower-Fillmore-Houston-
Taylor-Clark-Buffalo-Trempealeau-Jackson-La Crosse-Monroe-Juneau-
Adams-Vernon-Crawford-Richland-Grant-
908 AM CDT Fri Aug 7 2026

This Hazardous Weather Outlook is for portions of northeast Iowa.

.DAY ONE...Today and Tonight

Strong storms are possible this afternoon and evening with
damaging winds (15% chance) as the main hazard.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday

Additional rounds of storms are possible on Sunday and into early
next week, some of which may approach severe levels and produce
heavy rain.

.SPOTTER INFORMATION STATEMENT...

No action needed.

.EMERGENCY MANAGEMENT COORDINATION...

No webinar is scheduled.

KDS

In the hours before

Special weather statement, Aug 7, 2:40 PM CDT, 11 minutes before
Special Weather Statement
National Weather Service La Crosse WI
240 PM CDT Fri Aug 7 2026

IAZ009-018-019-072015-
Floyd IA-Chickasaw IA-Howard IA-
240 PM CDT Fri Aug 7 2026

...STRONG THUNDERSTORMS WILL IMPACT SOUTHERN HOWARD...EASTERN FLOYD
AND CHICKASAW COUNTIES THROUGH 315 PM CDT...

At 239 PM CDT, Doppler radar was tracking strong thunderstorms along
a line extending from near Elma to near Charles City to 7 miles
southwest of Greene. Movement was east at 40 mph.

HAZARD...Wind gusts up to 50 mph and nickel size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible.

Strong thunderstorms will be near...
  Charles City and Elma around 245 PM CDT.
  Nashua and Ionia around 250 PM CDT.
  New Hampton and Jerico around 255 PM CDT.
  Protivin around 300 PM CDT.

Other locations impacted by these storms include Bradford,
Chickasaw, Oakwood, New Hampton Airport, Powersville, Republic,
Colwell County Park, and Alta Vista.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with these storms and may lead
to localized flooding. Do not drive your vehicle through flooded
roadways.

A Severe Thunderstorm Watch remains in effect until 1000 PM CDT for
north central and northeastern Iowa.

&&

LAT...LON 4300 9280 4321 9259 4321 9255 4325 9255
      4335 9245 4329 9208 4323 9208 4299 9233
      4291 9244 4291 9292
TIME...MOT...LOC 1939Z 275DEG 33KT 4329 9242 4300 9273 4284 9294

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...50 MPH

Ferguson

The office that day

Everything else NWS La Crosse, WI issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Aug 7, 3:20 AM CDTDense Fog AdvisoryARXCrawford, Grant, Richland, Vernon6 hr
Aug 7, 3:17 PM CDTSpecial Weather StatementARXJackson, Trempealeau28 min
Aug 7, 4:21 PM CDTSpecial Weather StatementARXAdams, Crawford, Jackson, Juneau, Monroe, Richland and 1 more84 min
Aug 7, 1:48 PM CDTSevere Thunderstorm WarningARXChickasaw, Floyd, Howard, Mitchell57 min
Aug 7, 2:40 PM CDTSpecial Weather StatementARXChickasaw35 min
Aug 7, 3:47 PM CDTSevere Thunderstorm WarningARXFayette58 min
Aug 7, 3:56 PM CDTTornado WarningARXFayette34 min

Nearby

Severe Thunderstorm Warnings in Iowa, 2026Every severe thunderstorm warning in 2026

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.