Alert archive / Indiana / Mesoscale Discussions in 2017

Mesoscale Discussion 528

April 20, 201743 counties in Indiana; 14 counties in Michigan; 34 counties in Ohio

The Storm Prediction Center issued this mesoscale discussion at Apr 20, 2017, 4:31 PM EDT for 43 counties in Indiana; 14 counties in Michigan; 34 counties in Ohio. It was in force for 119 min.

The area

The outline as issued.

The facts

Issued
Apr 20, 2017, 4:31 PM EDT (20:31 UTC)
Expired
Apr 20, 2017, 6:30 PM EDT
In force
119 min
Issued by
the Storm Prediction Center
All 91 counties

Adams County, IN, Allen County, IN, Blackford County, IN, Boone County, IN, Carroll County, IN, Cass County, IN, Clinton County, IN, DeKalb County, IN, Delaware County, IN, Elkhart County, IN, Fayette 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, Kosciusko County, IN, LaGrange County, IN, Madison County, IN, Marion County, IN, Marshall County, IN, Miami County, IN, Montgomery County, IN, Noble County, IN, Parke County, IN, Putnam County, IN, Randolph County, IN, Rush County, IN, Shelby County, IN, Steuben County, IN, Tippecanoe County, IN, Tipton County, IN, Union County, IN, Wabash County, IN, Wayne County, IN, Wells County, IN, White County, IN, Whitley County, IN, Branch County, MI, Calhoun County, MI, Eaton County, MI, Hillsdale County, MI, Ingham County, MI, Jackson County, MI, Lenawee County, MI, Livingston County, MI, Macomb County, MI, Monroe County, MI, Oakland County, MI, Saint Joseph County, MI, Washtenaw County, MI, Wayne County, MI, Allen County, OH, Auglaize County, OH, Champaign County, OH, Crawford County, OH, Darke County, OH, Defiance County, OH, Delaware County, OH, Erie County, OH, Fulton County, OH, Hancock County, OH, Hardin County, OH, Henry County, OH, Huron County, OH, Logan County, OH, Lorain County, OH, Lucas County, OH, Marion County, OH, Mercer County, OH, Miami County, OH, Montgomery County, OH, Morrow County, OH, Ottawa County, OH, Paulding County, OH, Preble County, OH, Putnam County, OH, Richland County, OH, Sandusky County, OH, Seneca County, OH, Shelby County, OH, Union County, OH, Van Wert County, OH, Williams County, OH, Wood County, OH, Wyandot County, OH

The radar

The Northern Indiana radar (KIWX), 75 km from the middle of the area, began a volume at 20:30 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

Detroit, MI (KDTX), launched 12:00Z, 8.5 hours before the alert went out and 199 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 2017-04-20Temperature 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 2017-04-20The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 595 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
543 m above ground
0-6 km bulk shear
68 kt
0-1 km storm-relative helicity
595 m²/s²
0-3 km storm-relative helicity
665 m²/s²
Significant tornado parameter
0.0
Supercell composite
2.4

Open this sounding in Storm Lab

The text

As transmitted.

844 
ACUS11 KWNS 202031
SWOMCD
SPC MCD 202031 
OHZ000-MIZ000-INZ000-202230-

Mesoscale Discussion 0528
NWS Storm Prediction Center Norman OK
0331 PM CDT Thu Apr 20 2017

Areas affected...Parts of Indiana/Ohio/southern Lower Michigan

Concerning...Severe Thunderstorm Watch 151...

Valid 202031Z - 202230Z

The severe weather threat for Severe Thunderstorm Watch 151
continues.

SUMMARY...Isolated severe risk continues in and near WW #151.

DISCUSSION...Latest radar loop shows several bands of storms moving
across southern Lower Michigan/Indiana/western Ohio at this time,
with a new band of storms developing along the immediate frontal
zone.  This band of storms -- now entering northwest portions of WW
#151 -- likely marks the back edge of severe risk, which will
gradually advance eastward across the watch over the next few hours.
 Meanwhile, risk for locally damaging winds and hail continues, as
an amply sheared and unstable warm sector remains in place in and
near the WW area.

..Goss.. 04/20/2017

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

ATTN...WFO...CLE...ILN...DTX...IWX...GRR...IND...LOT...

LAT...LON   41988574 42828471 42938305 41828200 40428258 39568471
            39468737 40308741 41988574

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 20, 1:36 PM EDTMesoscale DiscussionSPCAdams, Allen, Blackford, DeKalb, Delaware, Elkhart and 15 more84 min
Apr 20, 2:08 PM EDTSevere Thunderstorm WatchSPCAdams, Allen, Blackford, DeKalb, Grant, Huntington and 6 more6 hr
Apr 20, 7:01 PM EDTMesoscale DiscussionSPCAdams, Allen, Blackford, DeKalb, Jay, Steuben and 1 more59 min
Apr 20, 2:40 PM EDTMesoscale DiscussionSPCAshtabula, Belmont, Carroll, Columbiana, Coshocton, Cuyahoga and 19 more65 min

Nearby

Mesoscale Discussions in Indiana, 2017Mesoscale Discussions in Ohio, 2017Mesoscale Discussions in Michigan, 2017Every mesoscale discussion 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.