Alert archive / Michigan / Severe Thunderstorm Watches in 2021

Severe Thunderstorm Watch 298

June 21, 202114 counties in Indiana; 20 counties in Michigan; 17 counties in Ohio

The Storm Prediction Center issued this severe thunderstorm watch at Jun 21, 2021, 1:00 AM EDT for 14 counties in Indiana; 20 counties in Michigan; 17 counties in Ohio. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Jun 21, 2021, 1:00 AM EDT (05:00 UTC)
Expired
Jun 21, 2021, 8:00 AM EDT
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
60 kt
All 51 counties

Allen County, IN, DeKalb County, IN, Elkhart County, IN, Fulton County, IN, Kosciusko County, IN, LaGrange County, IN, LaPorte County, IN, Marshall County, IN, Noble County, IN, Pulaski County, IN, Saint Joseph County, IN, Starke County, IN, Steuben County, IN, Whitley County, IN, Allegan County, MI, Barry County, MI, Berrien County, MI, Branch County, MI, Calhoun County, MI, Cass County, MI, Eaton County, MI, Hillsdale County, MI, Ingham County, MI, Jackson County, MI, Kalamazoo County, MI, Lenawee County, MI, Livingston County, MI, Macomb County, MI, Monroe County, MI, Oakland County, MI, Saint Joseph County, MI, Van Buren County, MI, Washtenaw County, MI, Wayne County, MI, Ashtabula County, OH, Cuyahoga County, OH, Defiance County, OH, Erie County, OH, Fulton County, OH, Geauga County, OH, Henry County, OH, Huron County, OH, Lake County, OH, Lorain County, OH, Lucas County, OH, Medina County, OH, Ottawa County, OH, Paulding County, OH, Sandusky County, OH, Williams County, OH, Wood County, OH

The radar

The Northern Indiana radar (KIWX), 78 km from the middle of the area, began a volume at 05:00 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
20%
One or more EF2 to EF5 tornadoes
10%
Ten or more severe wind reports
60%
One or more gusts of 65 knots or more
10%
Ten or more severe hail reports
20%
One or more hailstones of 2 inches or more
5%
Six or more combined severe hail and wind reports
90%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Jun 21, 1:12 AM EDTTornado WarningGRRVan Buren36 min
Jun 21, 1:21 AM EDTTornado WarningIWXLaPorte24 min
Jun 21, 1:26 AM EDTTornado WarningIWXBerrien, Cass, Saint Joseph34 min
Jun 21, 1:30 AM EDTSevere Thunderstorm WarningIWXElkhart, Fulton, LaPorte, Marshall, Pulaski, Saint Joseph and 1 more45 min
Jun 21, 1:30 AM EDTSevere Thunderstorm WarningGRRKalamazoo60 min
Jun 21, 1:31 AM EDTTornado WarningIWXLaPorte, Starke29 min
Jun 21, 1:33 AM EDTSevere Thunderstorm WarningGRRCalhoun57 min
Jun 21, 1:58 AM EDTSevere Thunderstorm WarningIWXBranch, Cass, Saint Joseph34 min
Jun 21, 2:26 AM EDTSevere Thunderstorm WarningIWXElkhart, Kosciusko, LaGrange, Noble21 min
Jun 21, 3:35 AM EDTSevere Thunderstorm WarningDTXLenawee40 min
Jun 21, 3:39 AM EDTSevere Thunderstorm WarningIWXDefiance, Fulton, Henry, Williams38 min
Jun 21, 3:52 AM EDTSevere Thunderstorm WarningCLELucas, Ottawa, Sandusky, Wood68 min
Jun 21, 3:54 AM EDTSevere Thunderstorm WarningDTXMonroe51 min
Jun 21, 5:17 AM EDTSevere Thunderstorm WarningCLEErie, Huron, Sandusky, Seneca43 min
Jun 21, 5:38 AM EDTSevere Thunderstorm WarningCLECuyahoga, Lorain67 min
Jun 21, 6:26 AM EDTSevere Thunderstorm WarningCLEGeauga, Lake49 min
Jun 21, 6:43 AM EDTSevere Thunderstorm WarningCLEGeauga, Portage, Summit47 min
Jun 21, 6:51 AM EDTSevere Thunderstorm WarningCLEAshtabula, Trumbull54 min

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 00:00Z, 5.0 hours before the alert went out and 178 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 00:00Z on 2021-06-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 133 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, Detroit, MI at 00:00Z on 2021-06-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 52 square meters per square second.19395878Sfc1 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
133 J/kg
Mixed-layer CIN
-112 J/kg
Mixed-layer LCL
1501 m above ground
0-6 km bulk shear
41 kt
0-1 km storm-relative helicity
52 m²/s²
0-3 km storm-relative helicity
102 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted.

371 
WWUS20 KWNS 210458
SEL8  
SPC WW 210458
INZ000-MIZ000-OHZ000-LEZ000-LMZ000-211000-

URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 298
NWS Storm Prediction Center Norman OK
100 AM EDT Mon Jun 21 2021

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of 
  Northern Indiana
  Southern Lower Michigan
  Northwest Ohio
  Lake Erie
  Lake Michigan

* Effective this Monday morning from 100 AM until 600 AM EDT.

* Primary threats include...
  Scattered damaging wind gusts to 70 mph likely
  Isolated large hail events to 1 inch in diameter possible
  A tornado or two possible

SUMMARY...A secondary round of severe storms are expected to
steadily develop west-to-east across the region overnight,
particularly across far northern Indiana and southern Lower Michigan
into northwest Ohio. Damaging winds are the primary concern,
although a tornado or two could occur with any line-embedded
circulations.

The severe thunderstorm watch area is approximately along and 65
statute miles north and south of a line from 30 miles west of South
Bend IN to 20 miles southeast of Detroit MI. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU8).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 295...WW 296...WW 297...

AVIATION...A few severe thunderstorms with hail surface and aloft to
1 inch. Extreme turbulence and surface wind gusts to 60 knots. A few
cumulonimbi with maximum tops to 550. Mean storm motion vector
27035.

...Guyer

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 20, 8:14 PM EDTMesoscale DiscussionSPCAdams, Allen, Blackford, Boone, Carroll, Cass and 30 more61 min
Jun 20, 10:40 PM EDTSevere Thunderstorm WatchSPCBenton, Jasper, Lake, Newton, Porter4 hr
Jun 20, 11:51 PM EDTMesoscale DiscussionSPCAdams, Allen, Cass, DeKalb, Elkhart, Fulton and 14 more54 min
Jun 21, 2:14 AM EDTMesoscale DiscussionSPCAllen, DeKalb, Elkhart, Fulton, Kosciusko, LaGrange and 8 more2 hr
Jun 21, 11:59 AM EDTMesoscale DiscussionSPCAshland, Ashtabula, Athens, Belmont, Carroll, Columbiana and 31 more91 min
Jun 21, 12:31 PM EDTSevere Thunderstorm WatchSPCAdams, Ashtabula, Athens, Belmont, Carroll, Columbiana and 33 more7 hr

Nearby

Severe Thunderstorm Watches in Michigan, 2021Severe Thunderstorm Watches in Ohio, 2021Severe Thunderstorm Watches in Indiana, 2021Every severe thunderstorm watch in 2021

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.