Overview
Scattered thunderstorms developed over northwest Indiana in the early evening. One of the storms produced a brief EF-0 tornado over eastern Benton and western White Counties. As the evening progressed the storms became widespread as they moved across northern Indiana, resulting in heavy rainfall and flooding.Tornadoes:
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Tornado - Southwest of Wolcott, IN
Track Map  
Downloadable KMZ File |
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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 |
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Flooding
The combination of a warm front lifting northward, much above normal moisture for late May, and an upper level system approaching from the west resulted in some heavy rainfall across the area. The image below represents radar rainfall estimates for May 20th (see Rainfall tab for actual rainfall observations). A couple of swaths of heavy rainfall can be noted from the radar estimates. The first swath extends from northern White county into southwest Elkhart county, with a second area of heavy rainfall from southern Miami county across the western portions of Huntington county. Rainfall amounts in these heaviest axes were in the 1.5 to 4 inch range.
Radar Estimated Rainfall
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Photos & Video:
Tornado/Damage Pictures
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| SSW of Wolcott (Courtesy Devin Pitts) | Tornado Damage SSW of Wolcott (Courtesy of John Allen Ph.D.) | South of Remington (Courtesy Kyle Gillett) | Coming Soon |
Radar:
Reflectivity (Z)/Storm Relative Motion (SRM) Images
The SRM at 729 pm shows broad, but decent circulation with the storm over eastern Benton County. In the next frame a rapid tightening of the circulation is seen (brightest red and green together-Gate to gate). Tornado develop was likely in progress at this point, crossing into White county around 734 pm. The intensity varied through 738 pm. Keep in mind that the lowest slice of the radar data was sampling around 8000 ft
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| 729 pm | 732 pm | 736 pm | 738 pm |
Volumetric (3-D) View
These "3-D" images are a representation of the wind fields within the supercell. Your eyes should be drawn to the light blue color increasing in height and size through each of these frames. What is being seen is not the tornado itself, but a rapidly strengthening updraft which often coincides with an increased risk of tornadic development. Horizontal vorticity likely existed in the area of the storm as a result of the nearby warm front. The updraft drew this vorticity into a vertical axis and rapidly spun up a tornado. Even at 742 pm the updraft is still strong, but field reports indicate the tornado had dissipated at this time.
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| 729 pm | 732 pm | 736 pm | 742 pm |
Storm Reports
PRELIMINARY LOCAL STORM REPORT...SUMMARY
NATIONAL WEATHER SERVICE NORTHERN INDIANA
1234 AM EDT SUN MAY 21 2017
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0735 PM TORNADO 8 SSW WOLCOTT 40.65N 87.09W
05/20/2017 WHITE IN TRAINED SPOTTER
TRAINED SPOTTER REPORTS SLENDER/ROPE CONE
TORNADO.
0914 PM HEAVY RAIN 1 WNW INDIANA BEACH 40.80N 86.79W
05/20/2017 M2.01 INCH WHITE IN MESONET
1004 PM HEAVY RAIN 2 E WINAMAC 41.06N 86.57W
05/20/2017 E4.00 INCH PULASKI IN PUBLIC
RELAYED FROM BROADCAST MEDIA. ANOTHER PERSON
HAD ENTIRE FRONT YARD UNDER WATER AND
BASEMENT FLOODING.
1024 PM HEAVY RAIN 1 ESE NAPPANEE 41.44N 85.97W
05/20/2017 M2.57 INCH ELKHART IN MESONET
SINCE MIDNIGHT.
1024 PM HEAVY RAIN 3 SW BOURBON 41.27N 86.15W
05/20/2017 M3.24 INCH MARSHALL IN MESONET
SINCE MIDNIGHT.
1102 PM FLOOD 3 E LINCOLNVILLE 40.76N 85.62W
05/20/2017 HUNTINGTON IN TRAINED SPOTTER
WATER ACROSS ROADWAY SOUTH OF CHAPEL RD AND
SR 105.
1110 PM FLOOD 4 NNW MOUNT ETNA 40.80N 85.58W
05/20/2017 HUNTINGTON IN TRAINED SPOTTER
WATER ACROSS ROADWAY.
1121 PM HEAVY RAIN 1 ESE NAPPANEE 41.44N 85.97W
05/20/2017 M3.17 INCH ELKHART IN MESONET
SINCE MIDNIGHT.
1122 PM HEAVY RAIN GOSHEN 41.58N 85.84W
05/20/2017 M2.47 INCH ELKHART IN MESONET
SINCE MIDNIGHT.
1124 PM HEAVY RAIN 2 ESE SOMERSET 40.66N 85.79W
05/20/2017 M2.74 INCH WABASH IN MESONET
SINCE MIDNIGHT.
1124 PM HEAVY RAIN 3 WSW AMBOY 40.59N 85.98W
05/20/2017 M2.63 INCH MIAMI IN MESONET
SINCE MIDNIGHT.
1126 PM HEAVY RAIN 2 NW MARION 40.57N 85.69W
05/20/2017 M1.63 INCH GRANT IN MESONET
SINCE MIDNIGHT.
1127 PM HEAVY RAIN WINONA LAKE 41.22N 85.82W
05/20/2017 M1.94 INCH KOSCIUSKO IN MESONET
SINCE MIDNIGHT.
1129 PM HEAVY RAIN 1 NNW LARWILL 41.19N 85.63W
05/20/2017 M1.81 INCH WHITLEY IN MESONET
SINCE MIDNIGHT.
1130 PM HEAVY RAIN 2 SE CENTREVILLE 41.90N 85.49W
05/20/2017 M1.61 INCH ST. JOSEPH MI MESONET
SINCE MIDNIGHT.
1134 PM HEAVY RAIN 1 SW GOSHEN 41.57N 85.85W
05/20/2017 M2.05 INCH ELKHART IN COCORAHS
SINCE MIDNIGHT.
1136 PM FLOOD 4 S HUNTINGTON 40.83N 85.51W
05/20/2017 HUNTINGTON IN TRAINED SPOTTER
WATER ACROSS THE ROADWAY.
Rain Reports
Public Information Statement National Weather Service Northern Indiana 141 AM EDT Sun May 21 2017 ...Rainfall Reports Last 24 Hours... Location Amount Time/Date Lat/Lon ...Indiana... ...Elkhart County... 1 ESE Nappanee 3.17 in 1121 PM 05/20 41.44N/85.97W 1 ESE Nappanee 2.57 in 1024 PM 05/20 41.44N/85.97W Goshen 2.47 in 1122 PM 05/20 41.58N/85.84W 1 SW Goshen 2.05 in 1134 PM 05/20 41.57N/85.85W ...Huntington County... 1 ENE Bowerstown 1.79 in 0100 AM 05/21 40.90N/85.41W 3 SSW Huntington 1.76 in 0118 AM 05/21 40.83N/85.53W ...Kosciusko County... Northern Indiana Wfo 2.13 in 1200 AM 05/21 41.36N/85.70W Winona Lake 1.94 in 1127 PM 05/20 41.22N/85.82W 2 SW Warsaw 1.66 in 0112 AM 05/21 41.21N/85.87W Tippecanoe Lake 1.65 in 0115 AM 05/21 41.33N/85.77W 2 N North Webster 1.63 in 0112 AM 05/21 41.36N/85.70W 2 WSW Syracuse 1.59 in 0117 AM 05/21 41.41N/85.79W ...Marshall County... Plymouth 3.67 in 0117 AM 05/21 41.34N/86.31W 3 SW Bourbon 3.24 in 1024 PM 05/20 41.27N/86.15W 2 W Mentone 1.57 in 0118 AM 05/21 41.18N/86.08W ...Miami County... 3 WSW Amboy 2.63 in 1124 PM 05/20 40.59N/85.98W 3 W Amboy 2.63 in 0120 AM 05/21 40.59N/85.98W ...Noble County... 3 NE Avilla 1.70 in 0114 AM 05/21 41.40N/85.20W 1 E Big Lake 1.57 in 0106 AM 05/21 41.28N/85.47W ...Pulaski County... 2 E Winamac 4.00 in 1004 PM 05/20 41.06N/86.57W ...Steuben County... 1 SE Crooked Lake 1.76 in 0118 AM 05/21 41.66N/85.02W 2 W Silver Lake 1.69 in 1215 AM 05/21 41.63N/85.11W ...Wabash County... 2 ESE Somerset 3.26 in 0118 AM 05/21 40.66N/85.79W Somerset 2.93 in 0120 AM 05/21 40.66N/85.81W 2 ESE Somerset 2.74 in 1124 PM 05/20 40.66N/85.79W 2 ESE Lagro 1.77 in 1215 AM 05/21 40.81N/85.68W ...White County... Norway 2.57 in 1145 PM 05/20 40.78N/86.76W 1 WNW Indiana Beach 2.01 in 0914 PM 05/20 40.80N/86.79W 1 WNW Indiana Beach 1.90 in 0115 AM 05/21 40.80N/86.79W ...Whitley County... 1 NNW Larwill 1.81 in 1129 PM 05/20 41.19N/85.63W Tri-lakes 1.60 in 0107 AM 05/21 41.22N/85.48W 2 NE Tri-Lakes 1.54 in 0113 AM 05/21 41.25N/85.45W Observations are collected from a variety of sources with varying equipment and exposures. We thank all volunteer weather observers for their dedication. Not all data listed are considered official.
Environment
A very moist air mass moved into the area Saturday setting the stage for heavy rainfall Saturday evening. The strongest thunderstorms were located across southern portions of the forecast area where the greatest instability was located to the north of the warm front.
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| 8pm May 20 Surface Analysis | 8pm May 20 Precipitable Water | 8pm May 20 Most Unstable CAPE |
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