Alert archive / Indiana / Mesoscale Discussions in 2012

Mesoscale Discussion 1237

June 21, 201230 counties in Indiana; 10 counties in Michigan; 6 counties in Ohio

The Storm Prediction Center issued this mesoscale discussion at Jun 21, 2012, 3:31 PM EDT for 30 counties in Indiana; 10 counties in Michigan; 6 counties in Ohio. It was in force for 59 min.

The area

The outline as issued.

The facts

Issued
Jun 21, 2012, 3:31 PM EDT (19:31 UTC)
Expired
Jun 21, 2012, 4:30 PM EDT
In force
59 min
Issued by
the Storm Prediction Center
Chance of a watch
20%
All 46 counties

Adams County, IN, Allen County, IN, Blackford County, IN, Boone County, IN, Clinton County, IN, DeKalb County, IN, Delaware County, IN, Grant County, IN, Hamilton County, IN, Hancock County, IN, Hendricks County, IN, Howard County, IN, Huntington County, IN, Jay County, IN, Johnson County, IN, LaGrange County, IN, Madison County, IN, Marion County, IN, Miami County, IN, Montgomery County, IN, Morgan County, IN, Noble County, IN, Parke County, IN, Putnam County, IN, Steuben County, IN, Tipton County, IN, Vigo County, IN, Wabash County, IN, Wells County, IN, Whitley County, IN, Branch County, MI, Hillsdale County, MI, Ingham County, MI, Jackson County, MI, Lenawee County, MI, Livingston County, MI, Monroe County, MI, Oakland County, MI, Washtenaw County, MI, Wayne County, MI, Defiance County, OH, Fulton County, OH, Henry County, OH, Paulding County, OH, Van Wert County, OH, Williams County, OH

The radar

The Northern Indiana radar (KIWX), 55 km from the middle of the area, began a volume at 19:31 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, 7.5 hours before the alert went out and 197 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 2012-06-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 25 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Detroit, MI at 12:00Z on 2012-06-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -15 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
25 J/kg
Mixed-layer CIN
-212 J/kg
Mixed-layer LCL
1531 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
-15 m²/s²
0-3 km storm-relative helicity
67 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

673 
ACUS11 KWNS 211932
SWOMCD
SPC MCD 211931
MIZ000-OHZ000-INZ000-ILZ000-212030-

MESOSCALE DISCUSSION 1237
NWS STORM PREDICTION CENTER NORMAN OK
0231 PM CDT THU JUN 21 2012

AREAS AFFECTED...SE MI...NE/CNTRL IND...FAR NW OH

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 211931Z - 212030Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...ISOLATED TO SCATTERED THUNDERSTORMS ARE EXPECTED THIS
AFTERNOON ACROSS PORTIONS OF SE MI...NE/CNTRL IND AND FAR NW OH. A
FEW OF THESE STORMS MAY BE BRIEFLY SEVERE WITH THE PRIMARY THREATS
OF STRONG WINDS AND HAIL. ISOLATED/BRIEF NATURE OF THE SEVERE THREAT
IS EXPECTED TO PRECLUDE THE NEED FOR A WW.

DISCUSSION...ISOLATED THUNDERSTORMS ARE BEGINNING TO DEVELOP ALONG A
FRONTAL BOUNDARY MOVING EWD ACROSS THE UPPER GREAT LAKES/WRN OHIO
VALLEY. 18Z SURFACE ANALYSIS DEPICTED THE FRONT ALONG A LINE FROM
BAX SWWD TO LAF. THE ENVIRONMENT AHEAD OF THE FRONT IS CHARACTERIZED
BY TEMPERATURES IN THE UPPER 80S TO LOW 90S AND DEWPOINTS AROUND 60.
THIS WARM...MODERATELY MOIST ENVIRONMENT WILL CONTINUE TO PROMOTE
MLCAPE VALUES NEAR 500-1000 J/KG. THIS MODEST INSTABILITY COMBINED
WITH EFFECTIVE SHEAR VALUES AROUND 20 TO 30 KTS WILL SUPPORT BRIEF
STORM ORGANIZATION AND A FEW STORMS CAPABLE OF PRODUCING SEVERE
WIND/HAIL. ONE FACTOR WORKING AGAINST SEVERE STORM DEVELOPMENT IS
THE WARM TEMPERATURES ALOFT /AROUND 8 DEG C AT 700 MB BASED ON THE
LATEST MESOANALYSIS/ WHICH ARE EXPECTED TO KEEP CAPE PROFILES THIN
AND LIMIT THE OVERALL COVERAGE OF THUNDERSTORMS. ISOLATED/BRIEF
NATURE OF THE SEVERE THREAT IS EXPECTED TO PRECLUDE THE NEED FOR A
WW.

..MOSIER/HART.. 06/21/2012

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

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

LAT...LON   41958517 42208494 42888425 42958355 42508303 41518372
            40438483 39348630 39468786 40428663 41958517

Nearby

Mesoscale Discussions in Indiana, 2012Mesoscale Discussions in Michigan, 2012Mesoscale Discussions in Ohio, 2012Every mesoscale discussion in 2012

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.