Alert archive / Indiana / Mesoscale Discussions in 2012

Mesoscale Discussion 634

April 30, 201244 counties in Indiana; 44 counties in Kentucky; 21 counties in Ohio

The Storm Prediction Center issued this mesoscale discussion at Apr 30, 2012, 4:52 PM EDT for 44 counties in Indiana; 44 counties in Kentucky; 21 counties in Ohio. It was in force for 83 min.

The area

The outline as issued.

The facts

Issued: Apr 30, 2012, 4:52 PM EDT (20:52 UTC)
Expired: Apr 30, 2012, 6:15 PM EDT
In force: 83 min
Issued by: the Storm Prediction Center

All 109 counties

Adams County, IN, Bartholomew County, IN, Blackford County, IN, Brown County, IN, Clark County, IN, Crawford County, IN, Dearborn County, IN, Decatur County, IN, Delaware County, IN, Dubois County, IN, Fayette County, IN, Floyd County, IN, Franklin County, IN, Grant County, IN, Hamilton County, IN, Hancock County, IN, Harrison County, IN, Hendricks County, IN, Henry County, IN, Jackson County, IN, Jay County, IN, Jefferson County, IN, Jennings County, IN, Johnson County, IN, Lawrence County, IN, Madison County, IN, Marion County, IN, Martin County, IN, Monroe County, IN, Morgan County, IN, Ohio County, IN, Orange County, IN, Perry County, IN, Randolph County, IN, Ripley County, IN, Rush County, IN, Scott County, IN, Shelby County, IN, Spencer County, IN, Switzerland County, IN, Tipton County, IN, Union County, IN, Washington County, IN, Wayne County, IN, Anderson County, KY, Barren County, KY, Boone County, KY, Bracken County, KY, Breckinridge County, KY, Bullitt County, KY, Butler County, KY, Campbell County, KY, Carroll County, KY, Daviess County, KY, Edmonson County, KY, Franklin County, KY, Gallatin County, KY, Grant County, KY, Grayson County, KY, Green County, KY, Hancock County, KY, Hardin County, KY, Harrison County, KY, Hart County, KY, Henry County, KY, Hopkins County, KY, Jefferson County, KY, Kenton County, KY, Larue County, KY, Marion County, KY, McLean County, KY, Meade County, KY, Mercer County, KY, Metcalfe County, KY, Muhlenberg County, KY, Nelson County, KY, Ohio County, KY, Oldham County, KY, Owen County, KY, Pendleton County, KY, Scott County, KY, Shelby County, KY, Spencer County, KY, Taylor County, KY, Trimble County, KY, Warren County, KY, Washington County, KY, Woodford County, KY, Allen County, OH, Auglaize County, OH, Brown County, OH, Butler County, OH, Champaign County, OH, Clark County, OH, Clermont County, OH, Clinton County, OH, Darke County, OH, Fayette County, OH, Greene County, OH, Hamilton County, OH, Hardin County, OH, Logan County, OH, Madison County, OH, Mercer County, OH, Miami County, OH, Montgomery County, OH, Preble County, OH, Shelby County, OH, Warren County, OH

The radar

The Indianapolis radar (KIND), 73 km from the middle of the area, began a volume at 20:53 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 watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

Severe Thunderstorm Watch 211Apr 30, 6:05 PM EDT

The nearest sounding before it

Cncnati-Daytn, OH (KILN), launched 12:00Z, 8.9 hours before the alert went out and 173 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 12 J/kg
Mixed-layer CIN: -296 J/kg
Mixed-layer LCL: 1163 m above ground
0-6 km bulk shear: 42 kt
0-1 km storm-relative helicity: 206 m²/s²
0-3 km storm-relative helicity: 215 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.3

Open this sounding in Storm Lab

The text

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

831 
ACUS11 KWNS 302052
SWOMCD
SPC MCD 302052 
OHZ000-KYZ000-INZ000-302215-

MESOSCALE DISCUSSION 0634
NWS STORM PREDICTION CENTER NORMAN OK
0352 PM CDT MON APR 30 2012

AREAS AFFECTED...CENTRAL/SOUTHERN INDIANA AND MUCH OF KY/OH TO WV

CONCERNING...SEVERE THUNDERSTORM WATCH 208...

VALID 302052Z - 302215Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 208
CONTINUES.

SEVERE TSTM WATCH 208 CONTINUES UNTIL 02Z...WITH POTENTIAL FOR
DAMAGING WINDS/SEVERE HAIL. AN ADDITIONAL WATCH MAY BE NEEDED TO THE
EAST OF WW 208 LATE THIS AFTERNOON/EVENING...POTENTIALLY INCLUDING
ADDITIONAL PORTIONS OF KY AS WELL AS OH/WV.

AN EXTENSIVE NNE-SSW ORIENTED BROKEN BAND OF TSTMS CONTINUES TO
STEADILY PROGRESS EASTWARD ACROSS CENTRAL/SOUTHWEST INDIANA AND
WESTERN PORTIONS OF KY/TN AS OF 2030Z. THESE TSTMS ARE OCCURRING IN
ASSOCIATION WITH AN EASTWARD PROPAGATING OUTFLOW BAND/ZONE OF
CONFLUENCE...WITH AID OF ONE OR MORE EASTWARD-TRANSITIONING LOW
AMPLITUDE SHORTWAVE TROUGHS/SMALL SCALE MID-LEVEL IMPULSES PER WATER
VAPOR IMAGERY.

THUS FAR...CLOUD COVER/MORE MODEST DESTABILIZATION HAS TEMPERED
UPDRAFT INTENSITY ESPECIALLY WITH NORTHWARD EXTENT ACROSS WW 208
COINCIDENT WITH THE STRONGER DEEP LAYER WESTERLIES. HOWEVER...WITH
AMPLE HEATING STILL OCCURRING AHEAD OF THE LINE...STORMS SHOULD
CONTINUE TO EXPAND/CONGEAL AS THEY STEADILY SPREAD EASTWARD. GIVEN
THIS...SUFFICIENTLY STRONG/CONVECTIVE CLUSTER-PERPENDICULAR FLOW
SHOULD ALLOW FOR THE MATURATION OF WELL-ORGANIZED LINE
SEGMENTS/SMALL-SCALE BOWS CAPABLE OF WIND DAMAGE ASIDE FROM SEVERE
HAIL. CONVECTIVE TRENDS WILL BE MONITORED OVER THE NEXT COUPLE OF
HOURS FOR THE POSSIBILITY OF AN ADDITIONAL WATCH TO THE EAST OF WW
208.

..GUYER.. 04/30/2012

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

ATTN...WFO...CLE...ILN...LMK...IWX...IND...PAH...

LAT...LON   39878660 40648588 40918370 39688319 36918559 36918775
            38658692 39878660

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 30, 1:03 PM EDT	Mesoscale Discussion	SPC	Bartholomew, Brown, Clark, Clay, Crawford, Daviess and 35 more	117 min
Apr 30, 3:07 PM EDT	Severe Thunderstorm Watch	SPC	Adams, Bartholomew, Blackford, Boone, Brown, Carroll and 56 more	9 hr
Apr 30, 6:04 PM EDT	Severe Thunderstorm Watch	SPC	Dearborn, Fayette, Franklin, Ohio, Ripley, Switzerland and 2 more	7 hr

Nearby

Mesoscale Discussions in Indiana, 2012 Mesoscale Discussions in Kentucky, 2012 Mesoscale Discussions in Ohio, 2012 Every 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.