Hail and Damaging Wind in Iowa, July 15, 2024

Name: Hail and Damaging Wind in Iowa, July 15, 2024
Start: 2024-07-15T16:20
End: 2024-07-15T16:58
Location: Iowa

July 15, 2024 · NWS ARX · 2 events in 1 county or zone

On July 15th, a powerful line of destructive storms moved through portions of the Upper Midwest bringing widespread wind damage to portions of Iowa, Illinois and southern Wisconsin. This storm complex was later classified as a derecho by the Storm Prediction Center.

Where it happened

Every event with a place to put it. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: None recorded
Crop damage: None recorded
Events: 2

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS ARX wrote it up.

What forecasters said that day

The local office's own words before the first event, 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 the first event at Jul 15, 1:00 PM CST, 3 hours 20 minutes earlier. Its key messages:

Scattered to areas of storms from late afternoon into early evening. Some will be strong to severe with a damaging wind and hail threat.
Turning cooler and less humid for the rest of the week while also trending dry.

Area forecast discussion, Jul 15, 1:00 PM CST, 3 hours 20 minutes before

Area Forecast Discussion
National Weather Service La Crosse WI
200 PM AM CDT Mon Jul 15 2024

.KEY MESSAGES...

- Scattered to areas of storms from late afternoon into early
evening. Some will be strong to severe with a damaging wind and hail
threat.

- Turning cooler and less humid for the rest of the week while also
trending dry.

&&

.DISCUSSION...
Issued at 200 PM CDT Mon Jul 15 2024

* STORM CHANCES THIS AFTERNOON/TONIGHT - some strong to severe
  possible from late afternoon into early evening

CLouds and showers persisting for the early afternoon, tracking west
to east across southern MN through central WI - working to keep the
local environment relatively stable. Just south of there more sun has
been working on the juicy airmass over IA with the RAP suggesting
3500+ SBCAPE possible over northeast IA by 21z. Bit of shortwave
energy coupled with approaching sfc low and left over outflow
boundary will look to fire convection by mid/late afternoon - but
stout low level cap (per RAP/HRRR bufkit soundings) will keep a lid
on activity before those move in. This could hold off initiation
until after 4 pm. Mostly straight line hodograph in the RAP/HRRR
with 0-6km shear around 40 kts supporting convective updrafts and
some supercellular potential at outset. System could quickly morph
into a convective complex capable of swaths of damaging winds - but
more likely southeast of the local area. Ongoing clouds/showers
provide uncertainty as to northward extent of this particular area
of convection, and this region could change by the hour based on how
the afternoon unfolds. Some HRRR runs keep any significant
convection south/east of the local area. Currently, local severe
threat looks highest for northeast IA and southwest WI in the 4 to 7
pm time frame.

To the north, a cold front with another piece of upper level energy
will be slide cross northern portions of WI. Some clearing there
will increase instability and CAMS models trigger a broken line of
convection (tied to the front) that would drop southeast across the
forecast area. More multicellular with a mixed big of strong/severe
potential outcomes (hail, strong winds). Severe threat is lower with
these storms compared to the anticipated convection over IA.

All the storms would have the potential for locally heavy rain, but
all look to be moving at a good clip with no training of note via
the CAMS. Localized flooding issues could arise, but don't see a
widespread heavy rain/flooding threat that would warrant a Flood
Watch at this time.

* TUESDAY INTO THE WEEKEND - cooler and less humid, trending dry

Another lobe of upper level energy slated to rotate across the upper
mississippi river valley Tue afternoon/evening. Cold air advection a
loft will promote a ribbon of increased low level lapse rates with
perhaps 250-500 J/Kg of MUCAPE. Questions on whether there will be
enough saturation to play with results in mixed signals in the
various short term models (some produce spotty to scattered late
afternoon shower/storms...others don't). With a bit more support for
at least a smattering of light showers, will paint in some low pops
(20%) for the afternoon in a west-east running band, sliding
southward across the region and mostly south of the area by 00z.

Upper level blocking pattern then taking shape for the rest of the
week as ridge continues to amplify/hold firm across the rockies/west
coast while a trough holds over the new england states.

Much cooler and less humid air will flow in from Canada and set up
shop through the upcoming weekend, and could linger well into the
following week. EPS and GEFS members only show a few degree spread
between their 25-75% for highs - mostly topping out in the 70s
through Fri. Probabilities in the LREF start to push to 40-50% to
climb back into the 80s moving into the weekend, but certainly
nothing trending hot & humid.

Meanwhile, the current upper level layout would generally keep most
of the shortwave activity either into Canada or off to the west.
While can't completely rule out some small rain chances here and
there, it's looking like a dry spate of days for most of the region
through the weekend. A welcome break from the recent soggy
conditions.

&&

.AVIATION /18Z TAFS THROUGH 18Z TUESDAY/...
Issued at 1236 PM CDT Mon Jul 15 2024

A cold front will approach the area from the NW this afternoon
bringing shower and thunderstorm chances across the area. Due to the
cloud cover this morning, uncertainty continues on if we will see
thunderstorm chances impact LSE or RST directly. Will plan on
amending TAFs as needed for thunderstorms.

Tonight, there is another chance for fog to impact the river valleys
and LSE, but chances for dense fog are around 10 to 20% at this
time. Boundary layer winds look to be strong enough to stave off
widespread fog issues, but fog chances would increase considerably
if skies clear and winds go light until cold front swings through
and brings in drier air.

&&

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

&&

DISCUSSION...Rieck
AVIATION.....JAW

Hazardous weather outlook, Jul 15, 3:00 AM CST, 13 hours 20 minutes before

Hazardous Weather Outlook
National Weather Service La Crosse WI
400 AM CDT Mon Jul 15 2024

IAZ008>011-018-019-029-030-MNZ079-086>088-094>096-WIZ017-029-
032>034-041>044-053>055-061-161300-
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-
400 AM CDT Mon Jul 15 2024

This Hazardous Weather Outlook is for portions of southeast
Minnesota...northeast Iowa and southwest into central Wisconsin.

.DAY ONE...Today and Tonight

Thunderstorms are possible today into this evening. A few storms
may become severe, especially late this afternoon or early evening
with damaging winds, locally heavy rain, and hail possible.

Heat indices of 90 to 100 are expected near and south of
Interstate 94 this afternoon.

River rises or flooding continues along some area rivers. Please
see the latest flood statements for additional details.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter groups could be requested later this afternoon.

.EMERGENCY MANAGEMENT COORDINATION...

No webinar is scheduled.

In the hours before

Local storm report, Jul 15, 11:40 AM CST, 4 hours 40 minutes before

Preliminary Local Storm Report
National Weather Service La Crosse WI
1240 PM CDT Mon Jul 15 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0703 PM     Funnel Cloud     2 WNW Fillmore          43.76N 92.30W
07/13/2024                   Fillmore           MN   Emergency Mngr

            Delayed report. Video of a funnel cloud
            northeast of Spring Valley.

&&

Local storm report, Jul 15, 2:10 PM CST, 2 hours 10 minutes before

Preliminary Local Storm Report
National Weather Service La Crosse WI
310 PM CDT Mon Jul 15 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0552 PM     Hail             Goodview                44.07N 91.71W
07/13/2024  M2.00 Inch       Winona             MN   Public

0548 PM     Tstm Wnd Dmg     5 E New Rome            44.20N 89.80W
07/13/2024                   Adams              WI   Public

            Numerous trees down in the Lake Arrowhead
            and Lake Sherwood subdivisions.

&&

Special weather statement, Jul 15, 3:34 PM CST, 46 minutes before

Special Weather Statement
National Weather Service La Crosse WI
434 PM CDT Mon Jul 15 2024

IAZ029-152230-
Fayette IA-
434 PM CDT Mon Jul 15 2024

...STRONG THUNDERSTORMS WILL IMPACT SOUTHERN FAYETTE COUNTY THROUGH
530 PM CDT...

At 433 PM CDT, Doppler radar was tracking a cluster of strong
thunderstorms near Fairbank, or near Oelwein, moving east at 30 mph.

HAZARD...Wind gusts up to 30 mph and half inch hail.

SOURCE...Radar indicated.

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

This strong thunderstorm will be near...
  Oelwein and Maynard around 440 PM CDT.
  Arlington around 500 PM CDT.

Other locations impacted by this storm include Highway 93 And County
W 14, Highway 93 And County V 68, Volga River State Park, Wadena,
Randalia, Westgate, County Road W 33 And 187, and County Roads 3 And
W 13.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

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

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

A Severe Thunderstorm Watch remains in effect until 1100 PM CDT for
northeastern Iowa.

&&

LAT...LON 4264 9208 4290 9208 4289 9161 4265 9161
TIME...MOT...LOC 2133Z 273DEG 26KT 4272 9201

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...30 MPH

Rieck

Special weather statement, Jul 15, 4:07 PM CST, 13 minutes before

Special Weather Statement
National Weather Service La Crosse WI
507 PM CDT Mon Jul 15 2024

IAZ029-030-152315-
Clayton IA-Fayette IA-
507 PM CDT Mon Jul 15 2024

...A STRONG THUNDERSTORM WILL IMPACT SOUTHERN CLAYTON AND
SOUTHEASTERN FAYETTE COUNTIES THROUGH 615 PM CDT...

At 506 PM CDT, Doppler radar was tracking a strong thunderstorm near
Lamont, or 13 miles east of Oelwein, moving east at 35 mph.

HAZARD...Wind gusts up to 50 mph and half inch hail.

SOURCE...Radar indicated.

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

This strong thunderstorm will be near...
  Strawberry Point around 510 PM CDT.

Other locations impacted by this storm include Camp C.S. Klaus,
Mederville, Highways 3 And 187, Turkey River, Bixby State Park,
Highway 13 And County C 24, Fairview, Osborne, and Millville.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

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

Frequent cloud to ground lightning is occurring with this storm.
Lightning can strike 10 miles away from a thunderstorm. Seek a safe
shelter inside a building or vehicle.

A Severe Thunderstorm Watch remains in effect until 1100 PM CDT for
northeastern Iowa...and southwestern Wisconsin.

&&

LAT...LON 4264 9185 4278 9186 4282 9108 4274 9105
      4269 9095 4268 9090 4265 9090
TIME...MOT...LOC 2206Z 266DEG 32KT 4266 9165

MAX HAIL SIZE...0.50 IN
MAX WIND GUST...50 MPH

Rieck

The radar

The La Crosse radar (KARX), 126 km away, was scanning. The volume nearest the first event began at 22:21 UTC.

Open the radar archive at this moment

Event by event

1 hail, 1 thunderstorm wind. Local standard time, as filed.

Hail, Clayton

When: July 15, 4:20 PM CST
Where: Clayton County, 2.03 mi E of Millville
Measured: 0.88 in hail
Reported by: Public
Coordinates: 42.700, -91.030

The public reported nickel sized hail 2 miles west of Cassville.

Thunderstorm Wind, Clayton

When: July 15, 4:58 PM CST
Where: Clayton County, North Buena Vista
Measured: 65 kt (75 mph) estimated gust
Reported by: Law Enforcement
Coordinates: 42.680, -90.960

Law enforcement estimated a 75 mph wind gust near North Buena Vista.

What these are

Hail: Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
Thunderstorm Wind: Winds from a thunderstorm of 50 knots (58 mph) or more, or lower winds that caused damage or casualties. Measured gusts are marked MG, estimated EG.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Iowa in 2024 Every state in 2024 This day in weather history Warnings in Iowa, July 2024

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 1201989, 1201990.