May 24, 2024: Summary of Derecho and Severe Weather Outbreak

Tornadoes

• 16 tornadoes were documented from this event in the NWS Quad Cities County Warning Area (CWA).
• The four strongest tornadoes all had maximum winds near 110 mph (EF1), and those were the Delta, IA; Wellman to Frytown, IA; Bennett to Lowden, IA; and Coyne Center, IL tornadoes.
• This was the most tornadoes in a single event for the CWA since the March 31, 2023 outbreak.
• This overall event from central Nebraska through northwest Illinois was documented as a derecho (widespread, long-lived complex of wind-producing severe thunderstorms), and derechos can produce numerous tornadoes during their lifecycle.

Damage Assessment Toolkit Viewer

Damage including Tornado Tracks KMZ File for NWS Quad Cities, IA/IL CWA

Individual Tornado Details (listed in chronological order)

The Enhanced Fujita (EF) Scale classifies tornadoes into the following categories:

EF0 Weak 65-85 mph	EF1 Moderate 86-110 mph	EF2 Significant 111-135 mph	EF3 Severe 136-165 mph	EF4 Extreme 166-200 mph	EF5 Catastrophic 200+ mph

Forecasts

NWS Storm Prediction Center (SPC) Day 1 Outlook (issued at 8 A.M. CDT)
SPC Convective Outlook	SPC Tornado Probability Outlook	SPC Wind Probability Outlook	SPC Hail Probability Outlook

NWS Severe Thunderstorm Watches
May 24, 2:42 A.M.:  Severe Thunderstorm Watch for Central and much of Eastern Iowa	May 24, 6:08 A.M.:  Severe Thunderstorm Watch for far Eastern Iowa and all of Northern Illinois

NWS Quad Cities Weather Story Graphics
May 23 Afternoon:  Weather Story Graphic issued highlighting timing	May 23 Evening:  Weather Story Graphic highlighting key messages, threat, and threat area	May 24 Pre-Dawn:  Weather Story Graphic highlighting storms and timing

Photos

View from NWS Quad Cities at passage of shelf cloud. Photo:  NWS Employee.		Shelf cloud view from near border of Henderson and Knox Counties in Illinois. Photo: NWS Employee.
Delta, IA (NWS Survey)	Wellman, IA (NWS Survey)	Riverside, IA (NWS Survey)	Near Ground Mound, IA (NWS Survey)

	Coyne Center, IL (NWS Survey)

Radar

Radar Loop from 1 A.M. through 12 P.M. CDT on May 24 (courtesy of College of DuPage)

IEM Radar Loop

Storm Reports

SPC Storm Reports:  May 23 (through 7 A.M. CDT May 24) |   May 24 (after 7 A.M. CDT)

IEM Local Storm Reports

Rainfall

Friday and Friday Night Rainfall Totals	Composite Method of Precipitation Totals Friday and Friday Night

for eastern Iowa, northwest and west central Illinois,
and northeast Missouri. Reported between Midnight and 9 AM,
Saturday May 25, 2024.

....IOWA....
Bellevue LD12                    1.80
Bellevue 12.2 NW                 1.70
Dubuque Arpt                     1.63
Parnell 0.1 SSW                  1.55
Dubuque #3 7 SW                  1.50
Asbury 0.6 S                     1.40
Dyersville 1.7 ESE               1.38
Solon 0.4 WNW                    1.34
Central City 6.7 W               1.31
Anamosa 3 SSW                    1.30
Calamus 2.0 NE                   1.26
Dubuque 1.0 SE                   1.24
Davenport Arpt                   1.20
Cedar Rapids 2.1 NW              1.18
Dubuque 1.4 WNW                  1.15
Iowa City Arpt                   1.15
Dubuque LD11                     1.14
Yarmouth 1.9 SW                  1.12
Eldridge 0.7 SSW                 1.12
Monticello 1 E                   1.10
De Witt                          1.08
Solon 0.3 ESE                    1.07
Danville 2.9 W                   1.03
Park View 0.2 WSW                1.02
Lowden                           1.01
Wapello 5.4 SE                   1.00
Cedar Rapids Arpt                0.96
Muscatine 3.0 NE                 0.94
Farmington 3.5 W                 0.92
Farmington 2.4 W                 0.91
Muscatine 1.7 N                  0.91
Donnellson                       0.91
Muscatine 2N                     0.91
Farmington 0.3 NW                0.90
Farmington 0.4 NNW               0.89
Wapello 0.2 S                    0.88
Iowa City 2.3 E                  0.87
Fort Madison 0.9 NE              0.85
Davenport 0.9 WNW                0.84
Marion 1.7 NNW                   0.82
Davenport 4.3 NE                 0.75
New London 1.5 SW                0.73
Davenport 2.1 N                  0.70
Salem 1S                         0.70
Fort Madison 4.5 NNW             0.65
Burlington 6.5 SSW               0.64
Camanche 1.2 W                   0.62
Marion 0.9 NE                    0.62
Strawberry Point                 0.61
Anamosa 0.6 ESE                  0.59
Burlington Arpt                  0.58
Mount Auburn 2.2 NNW             0.56
Dundee 1.4 NNE                   0.55
Guttenberg Dam 10                0.47
Iowa City 2.7 E                  0.46
Robins 0.8 SE                    0.42
Belle Plaine                     0.38
Marion 0.4 NNW                   0.36
Rathbun Reservoir 2 N            0.35
Iowa City                        0.33
Centerville 0 NE                 0.32
Washington 5.8 SW                0.26
Oelwein AWOS                     0.23
Washington                       0.23
Tiffin 1.2 NE                    0.22
Pella 4 N                        0.22
Allerton 2 S                     0.22
North Liberty 0.7 SSW            0.20
Oelwein 1E                       0.20
Pella AWOS 2 WSW                 0.19
Waterloo ASOS 5 NW               0.19
Hayesville 0.2 SW                0.18
Ames US 30 2 SSE                 0.18
Ottumwa ASOS 6 NNW               0.17
Mason City 1 NNE                 0.14
Grinnell AWOS 2 SSW              0.13
Fairfield                        0.13
Oskaloosa AWOS 9 ESE             0.10
Williamsburg                     0.10
Hampton 1 N                      0.07
Marshalltown 1 NW                0.06
Marshalltown ASOS 4 N            0.03
Mason City ASOS 6 W              0.03
NWS Johnston* 5 NNW              0.01

....ILLINOIS....
Stockton 4.5 N                   2.21
Stockton 3.4 NNE                 2.12
Stockton 3 NNE                   2.12
Stockton 4.6 NW                  1.85
Lanark 5.3 N                     1.78
Elizabeth                        1.78
Decatur Airport                  1.78
Hanover 0.2 NW                   1.71
Stockton 5.9 WNW                 1.66
East Dubuque 1.7 SE              1.65
Freeport                         1.65
Davis 0.5 N                      1.62
Ogden                            1.60
Lena 0.3 SSE                     1.56
Freeport 2.9 WSW                 1.47
Winslow 4.3 ESE                  1.42
Mount Carroll 6.8 NNW            1.41
Viola 0.4 E                      1.20
Shannon 2.7 E                    1.16
La Harpe                         1.12
New Boston LD17                  1.05
Moline 0.7 NNE                   0.99
Illinois City 6.7 SW             0.97
Stronghurst 0.4 SSW              0.96
Ill. City LD16 3 WNW             0.96
Sterling 5.9 NNE                 0.90
Rock Falls 3.1 S                 0.87
Aledo                            0.87
Quad City Arpt                   0.79
Galva 0.4 NW                     0.78
Fulton LD13                      0.78
Gladstone LD18                   0.75
Colona 0.5 ESE                   0.72
Kewanee 1 E                      0.65
Tuscola                          0.62
Galesburg                        0.60
Geneseo 2.0 NW                   0.59
Windsor                          0.53
Romeoville                       0.50
Joliet Arpt                      0.47
Rockford Arpt                    0.43
Colchester 3.5 NE                0.28
Lincoln NWS                      0.28
Bloomington Airport              0.27
Quincy Arpt                      0.25
Macomb 3.8 NW                    0.24
Peoria Arpt                      0.22
Rochelle Arpt                    0.22
Macomb                           0.20
McNabb 1.4 NW                    0.19
Steward                          0.13
St Anne                          0.00
Ottawa 4 SW                      0.00
Augusta                          0.00
Jacksonville Arpt                0.00

....MISSOURI....
Chillicothe Arpt                 0.40
Kirksville Arpt                  0.33
Columbia Arpt                    0.09

....WISCONSIN....
Madison Arpt                     2.25
Brodhead 1 SW                    1.45
Beloit-College                   1.05
Whitewater                       0.88
Sullivan-NWS 2 SE                0.59
Steuben 4SE 3 NE                 0.49
Prairie du Chien AWOS            0.44
Viroqua                          0.17
La Crosse WFO                    0.15
Watertown-Arpt                   0.02

Science & Environment

Understanding Damaging Wind Thunderstorm Complexes

Surface Weather Map

4 A.M. CDT 5/24/24 Surface Weather Map.  Despite the time of day, temperatures and especially dew points were increasing markedly from the south as strong low pressure lifting into the Upper Midwest. Gusty southeast surface winds in response over the NWS Quad Cities CWA resulted in high values of low-level shear and helicity (i.e. strong turning winds with height). Dew points were reaching 70 degrees, which is notably high for a May early morning at this latitude.

Weather Balloon Soundings

7 A.M. CDT (12Z) 5/24/24 DVN Sounding	1 P.M. CDT (18Z) 5/24/24 DVN Sounding

KDMX VAD Wind Profiler (VWP)

3 A.M. through 5 A.M. CDT (from right to left) 5/24/24 KDMX Radar VAD Wind Profile (VWP). This was immediately upstream of the NWS Quad Cities CWA, and represents the environment immediately ahead of the derecho (extreme values of low-level helicity) as well as the rear-inflow jet of 70-80 kt (80-95 mph) supporting it in the last two samples.

NWS Storm Prediction Center (SPC) Mesoscale Discussions

MD 925	MD 926	MD 927

Links

• Western to Central Nebraska Summary  (NWS North Platte)
• South Central Nebraska Summary  (NWS Hastings)
• Eastern Nebraska and Western Iowa Summary  (NWS Omaha)
• Central Iowa Summary  (NWS Des Moines)
• NWS Storm Prediction Center Event Page  (SPC)