Alert archive / Indiana / Severe Thunderstorm Watches in 2017

Severe Thunderstorm Watch 478

September 4, 201744 counties in Indiana; 11 counties in Michigan; 20 counties in Ohio

The Storm Prediction Center issued this severe thunderstorm watch at Sep 4, 2017, 4:32 PM EDT for 44 counties in Indiana; 11 counties in Michigan; 20 counties in Ohio. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Sep 4, 2017, 4:32 PM EDT (20:32 UTC)
Expired
Sep 4, 2017, 11:00 PM EDT
In force
6 hr
Issued by
the Storm Prediction Center
Largest hail expected
1.5 in
Strongest gust expected
60 kt
All 75 counties

Adams County, IN, Allen County, IN, Blackford County, IN, Boone County, IN, Carroll County, IN, Cass County, IN, Clay County, IN, Clinton County, IN, DeKalb County, IN, Delaware County, IN, Fountain County, IN, Fulton County, IN, Grant County, IN, Hamilton County, IN, Hancock County, IN, Hendricks County, IN, Henry County, IN, Howard County, IN, Huntington County, IN, Jay County, IN, Johnson County, IN, Kosciusko County, IN, LaGrange County, IN, Madison County, IN, Marion County, IN, Miami County, IN, Montgomery County, IN, Morgan County, IN, Noble County, IN, Owen County, IN, Parke County, IN, Putnam County, IN, Randolph County, IN, Shelby County, IN, Steuben County, IN, Sullivan County, IN, Tippecanoe County, IN, Tipton County, IN, Vermillion County, IN, Vigo County, IN, Wabash County, IN, Warren County, IN, Wells County, IN, Whitley County, IN, Branch County, MI, Hillsdale County, MI, Jackson County, MI, Lenawee County, MI, Livingston County, MI, Macomb County, MI, Monroe County, MI, Oakland County, MI, Saint Clair County, MI, Washtenaw County, MI, Wayne County, MI, Allen County, OH, Auglaize County, OH, Defiance County, OH, Erie County, OH, Fulton County, OH, Hancock County, OH, Hardin County, OH, Henry County, OH, Huron County, OH, Lucas County, OH, Mercer County, OH, Ottawa County, OH, Paulding County, OH, Putnam County, OH, Sandusky County, OH, Seneca County, OH, Van Wert County, OH, Williams County, OH, Wood County, OH, Wyandot County, OH

The radar

The Northern Indiana radar (KIWX), 59 km from the middle of the area, began a volume at 20:35 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.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes
10%
One or more EF2 to EF5 tornadoes
2%
Ten or more severe wind reports
80%
One or more gusts of 65 knots or more
20%
Ten or more severe hail reports
30%
One or more hailstones of 2 inches or more
10%
Six or more combined severe hail and wind reports
95%

Warnings issued inside it

12 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Sep 4, 5:23 PM EDTSevere Thunderstorm WarningDTXLivingston, Oakland, Washtenaw50 min
Sep 4, 5:59 PM EDTSevere Thunderstorm WarningDTXLenawee61 min
Sep 4, 6:34 PM EDTSevere Thunderstorm WarningINDCarroll56 min
Sep 4, 6:45 PM EDTSevere Thunderstorm WarningCLELucas, Wood60 min
Sep 4, 6:47 PM EDTSevere Thunderstorm WarningDTXLenawee, Monroe43 min
Sep 4, 6:52 PM EDTSevere Thunderstorm WarningIWXFulton23 min
Sep 4, 7:18 PM EDTSevere Thunderstorm WarningINDCarroll, Clinton, Howard, Tipton42 min
Sep 4, 7:20 PM EDTSevere Thunderstorm WarningCLEOttawa, Sandusky55 min
Sep 4, 9:25 PM EDTSevere Thunderstorm WarningCLECrawford, Wyandot65 min
Sep 4, 9:27 PM EDTSevere Thunderstorm WarningINDDelaware, Henry, Randolph33 min
Sep 4, 10:30 PM EDTSevere Thunderstorm WarningCLECrawford, Wyandot45 min
Sep 4, 10:36 PM EDTFlash Flood WarningCLECrawford, Hancock, Wyandot6 hr

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Detroit, MI (KDTX), launched 12:00Z, 8.5 hours before the alert went out and 262 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, Detroit, MI at 12:00Z on 2017-09-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Detroit, MI at 12:00Z on 2017-09-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 112 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1687 m above ground
0-6 km bulk shear
40 kt
0-1 km storm-relative helicity
112 m²/s²
0-3 km storm-relative helicity
169 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 4, 3:17 PM EDTMesoscale DiscussionSPCAdams, Allen, Benton, Blackford, Boone, Carroll and 35 more118 min
Sep 4, 6:50 PM EDTMesoscale DiscussionSPCAdams, Allen, Blackford, Boone, Carroll, Cass and 30 more115 min
Sep 4, 7:05 PM EDTMesoscale DiscussionSPCVermillion115 min

Nearby

Severe Thunderstorm Watches in Indiana, 2017Severe Thunderstorm Watches in Ohio, 2017Severe Thunderstorm Watches in Michigan, 2017Every severe thunderstorm watch in 2017

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.