Alert archive / Indiana / Mesoscale Discussions in 2021

Mesoscale Discussion 1117

June 26, 20214 states

The Storm Prediction Center issued this mesoscale discussion at Jun 26, 2021, 8:23 PM CDT for 4 states. It was in force for 67 min.

The area

The outline as issued.

The facts

Issued
Jun 26, 2021, 8:23 PM CDT (01:23 UTC)
Expired
Jun 26, 2021, 9:30 PM CDT
In force
67 min
Issued by
the Storm Prediction Center
Concerning
Tornado watch 322
All 81 counties

Champaign County, IL, Clark County, IL, Coles County, IL, Cumberland County, IL, Douglas County, IL, Edgar County, IL, Moultrie County, IL, Shelby County, IL, Vermilion County, IL, Allen County, IN, Benton County, IN, Boone County, IN, Carroll County, IN, Cass County, IN, Clinton County, IN, DeKalb County, IN, Elkhart County, IN, Fountain County, IN, Fulton County, IN, Grant County, IN, Howard County, IN, Huntington County, IN, Jasper County, IN, Kosciusko County, IN, LaGrange County, IN, LaPorte County, IN, Marshall County, IN, Miami County, IN, Montgomery County, IN, Newton County, IN, Noble County, IN, Parke County, IN, Pulaski County, IN, Putnam County, IN, Saint Joseph County, IN, Starke County, IN, Steuben County, IN, Tippecanoe County, IN, Tipton County, IN, Vermillion County, IN, Vigo County, IN, Wabash County, IN, Warren County, IN, Wells County, IN, White County, IN, Whitley County, IN, Arenac County, MI, Barry County, MI, Bay County, MI, Branch County, MI, Calhoun County, MI, Cass County, MI, Clinton County, MI, Eaton County, MI, Genesee County, MI, Gratiot County, MI, Hillsdale County, MI, Huron County, MI, Ingham County, MI, Ionia County, MI, Jackson County, MI, Kalamazoo County, MI, Lapeer County, MI, Lenawee County, MI, Livingston County, MI, Macomb County, MI, Midland County, MI, Monroe County, MI, Oakland County, MI, Saginaw County, MI, Saint Clair County, MI, Saint Joseph County, MI, Sanilac County, MI, Shiawassee County, MI, Tuscola County, MI, Washtenaw County, MI, Wayne County, MI, Defiance County, OH, Fulton County, OH, Paulding County, OH, Williams County, OH

The radar

The Northern Indiana radar (KIWX), 40 km from the middle of the area, began a volume at 01:26 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.

The nearest sounding before it

Lincoln, IL (KILX), launched 00:00Z, 1.4 hours before the alert went out and 240 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, Lincoln, IL at 00:00Z on 2021-06-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 33 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, Lincoln, IL at 00:00Z on 2021-06-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 97 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
33 J/kg
Mixed-layer CIN
-122 J/kg
Mixed-layer LCL
1160 m above ground
0-6 km bulk shear
35 kt
0-1 km storm-relative helicity
97 m²/s²
0-3 km storm-relative helicity
134 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.7

Open this sounding in Storm Lab

The text

As transmitted.

911 
ACUS11 KWNS 270123
SWOMCD
SPC MCD 270123 
MIZ000-OHZ000-INZ000-ILZ000-270230-

Mesoscale Discussion 1117
NWS Storm Prediction Center Norman OK
0823 PM CDT Sat Jun 26 2021

Areas affected...east-central Illinois northeast into Lower Michigan

Concerning...Tornado Watch 322...

Valid 270123Z - 270230Z

The severe weather threat for Tornado Watch 322 continues.

SUMMARY...Overall convective trends indicate a diminishing threat of
organized severe potential. Brief/localized gusty winds may be
possible across portions of the region, but the isolated nature of
the threat should not preclude the expiration of Tornado Watches 321
and 322 at 10PM EDT and 9 PM CDT.

DISCUSSION...A small convective bowing segment is expected to
continue weakening as it moves across Lower Michigan this evening.
This is supported by a substantial decrease in lightning activity
and warming cloud tops as the segment moves into an airmass already
overturned by earlier convection. Gusty winds may continue to occur
over the next 1-2 hours as the segment continues to move northeast,
between Lansing and Ann Arbor, but given the overall downward
trends, Tornado Watch 322 should be able to expire at 02Z.

Farther south, a more robust convective bowing segment has developed
as it exited portions of east-central Illinois and (locally
extended) Tornado Watch 321 and into west-central Indiana and Severe
Thunderstorm Watch 325. However, the loss of diurnal heating and
development of a nocturnal boundary layer should begin to increase
near-ground stability sufficiently to decrease the likelihood of
sustained severe-criterion surface winds with time. Before this
happens, strong, gusty thunderstorm winds will continue to be
possible for the next couple of hours. Otherwise, convective
intensity continues to diminish across Tornado Watch 321 and thus
the watch should be able to expire at 02Z.

..Marsh.. 06/27/2021

...Please see www.spc.noaa.gov for graphic product...

ATTN...WFO...CLE...DTX...APX...IWX...GRR...IND...LOT...ILX...
LSX...

LAT...LON   39348914 42988542 44318347 44158208 42418273 40748496
            39608689 39158798 39218874 39348914

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jun 27, 11:36 AM CDTMesoscale DiscussionSPCBond, Calhoun, Champaign, Christian, DeWitt, Douglas and 16 more2 hr

Nearby

Mesoscale Discussions in Indiana, 2021Mesoscale Discussions in Michigan, 2021Mesoscale Discussions in Illinois, 2021Every mesoscale discussion 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.