Alert archive / Indiana / Mesoscale Discussions in 2012

Mesoscale Discussion 645

May 1, 201235 counties in Indiana; 9 counties in Ohio

The Storm Prediction Center issued this mesoscale discussion at May 1, 2012, 2:44 PM EDT for 35 counties in Indiana; 9 counties in Ohio. It was in force for 61 min.

The area

The outline as issued.

The facts

Issued: May 1, 2012, 2:44 PM EDT (18:44 UTC)
Expired: May 1, 2012, 3:45 PM EDT
In force: 61 min
Issued by: the Storm Prediction Center
Chance of a watch: 95%

All 44 counties

Bartholomew County, IN, Boone County, IN, Brown County, IN, Clay County, IN, Daviess County, IN, Dearborn County, IN, Decatur County, IN, Delaware County, IN, Fayette County, IN, Franklin County, IN, Greene County, IN, Hamilton County, IN, Hancock County, IN, Hendricks County, IN, Henry County, IN, Jackson 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, Owen County, IN, Putnam County, IN, Randolph County, IN, Ripley County, IN, Rush County, IN, Shelby County, IN, Sullivan County, IN, Tipton County, IN, Union County, IN, Wayne County, IN, Butler County, OH, Clark County, OH, Darke County, OH, Greene County, OH, Hamilton County, OH, Miami County, OH, Montgomery County, OH, Preble County, OH, Warren County, OH

The radar

The Indianapolis radar (KIND), 38 km from the middle of the area, began a volume at 18:47 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.

The nearest sounding before it

Cncnati-Daytn, OH (KILN), launched 12:00Z, 6.7 hours before the alert went out and 188 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: 15 J/kg
Mixed-layer CIN: -1 J/kg
Mixed-layer LCL: 516 m above ground
0-6 km bulk shear: 36 kt
0-1 km storm-relative helicity: 47 m²/s²
0-3 km storm-relative helicity: 93 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.

237 
ACUS11 KWNS 011845
SWOMCD
SPC MCD 011844
OHZ000-KYZ000-INZ000-011945-

MESOSCALE DISCUSSION 0645
NWS STORM PREDICTION CENTER NORMAN OK
0144 PM CDT TUE MAY 01 2012

AREAS AFFECTED...SOUTHERN INDIANA/OH

CONCERNING...SEVERE POTENTIAL...WATCH NEEDED SOON

VALID 011844Z - 011945Z

PROBABILITY OF WATCH ISSUANCE...95 PERCENT

SUMMARY...SEVERE POTENTIAL IS EXPECTED TO INCREASE ACROSS
CENTRAL/SOUTHERN PORTIONS OF INDIANA INTO OH THIS AFTERNOON. A
TORNADO WATCH WILL LIKELY BE ISSUED SOON.

DISCUSSION...TSTMS HAVE SHOWN A RECENT INCREASE IN COVERAGE/VIGOR
EITHER SIDE OF A WARM FRONT ACROSS SOUTH-CENTRAL INDIANA. AS CLOUD
BREAKS ALLOW FOR FURTHER HEATING ALONG/SOUTH OF THE WARM
FRONT...THIS SAME UPWARD COVERAGE/INTENSITY TREND SHOULD CONTINUE
THROUGH MID-AFTERNOON AHEAD OF AN EASTWARD-MOVING MCV ACROSS
NORTHERN/CENTRAL IL. REGIONAL PROFILERS/WSR-88D DERIVED WINDS ARE
INDICATIVE OF ENHANCED LOW-MID TROPOSPHERIC FLOW ON THE E/SE
PERIPHERY OF THE MCV...WITH LOW LEVEL SRH ESPECIALLY ENHANCED
ALONG/NORTH OF THE WARM FRONT WHERE NEAR-SURFACE WINDS ARE BACKED TO
EAST-SOUTHEASTERLY. RECENT WSR-88D VWP DATA FROM INDIANAPOLIS
REFLECTS 0-1 KM SRH OF 300+ M2/S2. AS SUCH...A TORNADO THREAT MAY
INCREASE ACROSS THE REGION ASIDE FROM SEVERE HAIL/WIND.

..GUYER/MEAD.. 05/01/2012

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

ATTN...WFO...ILN...LMK...IWX...IND...

LAT...LON   39148761 40358612 40328376 39118383 38628699 39148761

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 1, 2:44 PM EDT	Severe Thunderstorm Watch	SPC	Crawford, Dubois, Floyd, Harrison, Perry	6 hr
May 1, 3:01 PM EDT	Tornado Watch	SPC	Bartholomew, Boone, Brown, Carroll, Clark, Clay and 46 more	7 hr
May 1, 4:39 PM EDT	Mesoscale Discussion	SPC	Benton, Clay, Fountain, Parke, Vermillion, Vigo and 1 more	2 hr
May 1, 6:31 PM EDT	Tornado Watch	SPC	Dearborn, Fayette, Franklin, Ohio, Ripley, Switzerland and 2 more	5 hr
May 1, 6:55 PM EDT	Mesoscale Discussion	SPC	Bartholomew, Boone, Brown, Carroll, Clark, Clay and 32 more	65 min
Apr 30, 9:07 PM EDT	Mesoscale Discussion	SPC	Adams, Ashland, Athens, Belmont, Brown, Butler and 53 more	53 min
May 1, 6:13 PM EDT	Mesoscale Discussion	SPC	Athens, Fairfield, Gallia, Hocking, Jackson, Lawrence and 8 more	62 min

Nearby

Mesoscale Discussions in Indiana, 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.