Alert archive / Indiana / Mesoscale Discussions in 2012

Mesoscale Discussion 662

May 2, 20128 counties in Illinois; 30 counties in Indiana; 12 counties in Ohio

The Storm Prediction Center issued this mesoscale discussion at May 2, 2012, 2:46 PM CDT for 8 counties in Illinois; 30 counties in Indiana; 12 counties in Ohio. It was in force for 119 min.

The area

The outline as issued.

The facts

Issued: May 2, 2012, 2:46 PM CDT (19:46 UTC)
Expired: May 2, 2012, 4:45 PM CDT
In force: 119 min
Issued by: the Storm Prediction Center
Chance of a watch: 40%

All 50 counties

Clark County, IL, Coles County, IL, Crawford County, IL, Cumberland County, IL, Edgar County, IL, Effingham County, IL, Jasper County, IL, Shelby County, IL, Bartholomew County, IN, Boone County, IN, Brown County, IN, Clay 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, Jay County, IN, Johnson County, IN, Madison County, IN, Marion County, IN, Monroe County, IN, Morgan County, IN, Owen County, IN, Parke County, IN, Putnam County, IN, Randolph County, IN, Rush County, IN, Shelby County, IN, Sullivan County, IN, Union County, IN, Vermillion County, IN, Vigo County, IN, Wayne County, IN, Auglaize County, OH, Champaign County, OH, Clark County, OH, Darke 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

The radar

The Indianapolis radar (KIND), 28 km from the middle of the area, began a volume at 19:48 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 12:00Z, 7.8 hours before the alert went out and 179 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: 1122 J/kg
Mixed-layer CIN: -88 J/kg
Mixed-layer LCL: 950 m above ground
0-6 km bulk shear: 33 kt
0-1 km storm-relative helicity: 257 m²/s²
0-3 km storm-relative helicity: 277 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 4.1

Open this sounding in Storm Lab

The text

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

008 
ACUS11 KWNS 021947
SWOMCD
SPC MCD 021946
OHZ000-INZ000-ILZ000-022145-

MESOSCALE DISCUSSION 0662
NWS STORM PREDICTION CENTER NORMAN OK
0246 PM CDT WED MAY 02 2012

AREAS AFFECTED...EAST-CENTRAL IL TO CENTRAL/SOUTHERN INDIANA AND OH

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 021946Z - 022145Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...ISOLATED STRONG/POTENTIALLY SEVERE TSTMS SHOULD INCREASE
THROUGH LATE AFTERNOON WITHIN A CORRIDOR FROM EAST-CENTRAL IL INTO
CENTRAL/SOUTHERN INDIANA AND EVENTUALLY OH...WITH HAIL/WIND
POSSIBLE. WHILE A SEVERE TSTM WATCH DOES NOT SEEM
LIKELY/IMMINENT...DEVELOPMENTAL TRENDS WILL CONTINUE TO BE MONITORED
FOR A POSSIBLE WATCH.

DISCUSSION...CONGESTED/DEEPENING CU FIELD AND A FEW TSTMS ARE NOTED
AS OF 1930Z ESPECIALLY ACROSS EAST-CENTRAL IL INTO CENTRAL
INDIANA...ROUGHLY ALONG/JUST NORTH OF THE I-70 CORRIDOR. THIS
DEVELOPMENT COINCIDES WITH A DECELERATING/INCREASINGLY SHALLOW
OUTFLOW BOUNDARY AS IT INTERCEPTS A WARM/MOIST AND WEAKLY
CAPPED/UNSTABLE BOUNDARY LAYER. IN THE PRESENCE OF STEEP LOW-MID
LEVEL LAPSE RATES...LATEST SPC OBJECTIVE ANALYSIS IS INDICATIVE OF
MLCAPE OF 2000-2750 J/KG ACROSS A BROAD CORRIDOR FROM DOWNSTATE
IL/INDIANA INTO MUCH OF OH. THIS CORRIDOR IS ALSO ON THE SOUTHERN
PERIPHERY OF MODERATELY STRONG/NEARLY UNIDIRECTIONAL LOW-MID
TROPOSPHERIC FLOW /BENEATH WEAK HIGH LEVEL WINDS/...WHICH WILL BE
CONDUCIVE FOR SOME SUSTAINED/POTENTIALLY OUTFLOW DOMINATED
MULTICELLS. WHERE DEEP CONVECTIVE DEVELOPMENT DOES OCCUR THIS
AFTERNOON...AT LEAST MARGINAL/EPISODIC SEVERE HAIL/WIND WILL BE
POSSIBLE...ALTHOUGH LACK OF MORE ROBUST CONVERGENCE/SLOWLY RISING
HEIGHTS ALOFT SHOULD TEMPER THE MAGNITUDE/EXTENT OF THE THREAT.

..GUYER.. 05/02/2012

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

ATTN...WFO...ILN...IWX...IND...ILX...

LAT...LON   39558893 40128647 40798359 39878337 38948627 38878865
            39558893

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 1, 8:33 PM CDT	Mesoscale Discussion	SPC	Bartholomew, Boone, Brown, Carroll, Clinton, Dearborn and 26 more	57 min
May 2, 3:56 PM CDT	Mesoscale Discussion	SPC	Ashtabula, Carroll, Columbiana, Cuyahoga, Geauga, Lake and 8 more	2 hr

Nearby

Mesoscale Discussions in Indiana, 2012 Mesoscale Discussions in Ohio, 2012 Mesoscale Discussions in Illinois, 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.