Alert archive / Indiana / Mesoscale Discussions in 2012

Mesoscale Discussion 736

May 6, 20124 counties in Illinois; 15 counties in Indiana

The Storm Prediction Center issued this mesoscale discussion at May 6, 2012, 5:07 PM CDT for 4 counties in Illinois; 15 counties in Indiana. It was in force for 53 min.

The area

The outline as issued.

The facts

Issued: May 6, 2012, 5:07 PM CDT (22:07 UTC)
Expired: May 6, 2012, 6:00 PM CDT
In force: 53 min
Issued by: the Storm Prediction Center

Counties Clark County, IL, Edgar County, IL, Iroquois County, IL, Vermilion County, IL, Benton County, IN, Boone County, IN, Clay County, IN, Clinton County, IN, Fountain County, IN, Hendricks County, IN, Montgomery County, IN, Owen County, IN, Parke County, IN, Putnam County, IN, Tippecanoe County, IN, Vermillion County, IN, Vigo County, IN, Warren County, IN, White County, IN

The radar

The Indianapolis radar (KIND), 99 km from the middle of the area, began a volume at 22:08 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 260May 6, 5:30 PM CDT

The nearest sounding before it

Lincoln, IL (KILX), launched 12:00Z, 10.1 hours before the alert went out and 109 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: 2922 J/kg
Mixed-layer CIN: -37 J/kg
Mixed-layer LCL: 576 m above ground
0-6 km bulk shear: 14 kt
0-1 km storm-relative helicity: 48 m²/s²
0-3 km storm-relative helicity: 98 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.

756 
ACUS11 KWNS 062208
SWOMCD
SPC MCD 062207
INZ000-ILZ000-062300-

MESOSCALE DISCUSSION 0736
NWS STORM PREDICTION CENTER NORMAN OK
0507 PM CDT SUN MAY 06 2012

AREAS AFFECTED...NERN/E-CNTRL IL...W-CNTRL IND

CONCERNING...SEVERE THUNDERSTORM WATCH 258...

VALID 062207Z - 062300Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 258
CONTINUES.

SUMMARY...SLOW-MOVING TSTM CLUSTER OVER NERN/E-CNTRL IL MAY
PROPAGATE SEWD INTO PORTIONS OF W-CNTRL IND...SE OF WW 258. THIS
AREA IS BEING MONITORED FOR A POSSIBLE SEVERE TSTM WATCH ISSUANCE.

DISCUSSION...TSTM CLUSTER APPROACHING THE I-74 CORRIDOR IN E-CNTRL
IL IS GRADUALLY DEVELOPING SEWD ALONG A QUASI-STATIONARY FRONT
ANALYZED FROM NEAR LAF TO LUK. CORES HAVE ALSO STRENGTHENED ALONG A
REMNANT OUTFLOW/WEAK CONFLUENCE AXIS EXTENDING SWD THROUGH ERN IL.
ON THE FRINGE OF STRONG INSTABILITY WITH MODIFIED 18Z ILX RAOB
SUGGESTIVE OF MLCAPE AROUND 3500 J/KG...BUT MODEST DEEP-LAYER
SHEAR...STRENGTH OF THE SURFACE COLD POOL MAY BE SUFFICIENT TO
MAINTAIN THE CLUSTER EVOLVING INTO W-CNTRL IND. BUT WITH CONVECTIVE
OUTFLOW ALREADY SURGING 10-15 NM AHEAD OF THE WRN PORTION OF THE
CLUSTER...PRIMARY THREATS SHOULD REMAIN LOCALLY DAMAGING WINDS AND
MARGINALLY SEVERE HAIL WITH LEADING CONVECTION.

..GRAMS.. 05/06/2012

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

ATTN...WFO...IWX...IND...LOT...ILX...

LAT...LON   40928787 40928733 40768682 40508648 40038627 39398661
            39148714 39148759 39308791 39458796 40588804 40928787

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 6, 8:40 AM CDT	Mesoscale Discussion	SPC	Bureau, Fulton, Hancock, Henderson, Henry, Knox and 12 more	65 min
May 6, 9:29 AM CDT	Severe Thunderstorm Watch	SPC	Bureau, Carroll, Fulton, Hancock, Henderson, Henry and 11 more	4 hr
May 6, 1:22 PM CDT	Mesoscale Discussion	SPC	Adams, Brown, Cass, Fulton, Grundy, Hancock and 20 more	53 min
May 6, 1:42 PM CDT	Severe Thunderstorm Watch	SPC	Adams, Brown, Bureau, Cass, Champaign, Cook and 35 more	7 hr
May 6, 3:56 PM CDT	Mesoscale Discussion	SPC	Adams, Brown, Cass, Champaign, DeWitt, Ford and 32 more	64 min
May 6, 5:29 PM CDT	Severe Thunderstorm Watch	SPC	Boone, Carroll, Clinton, Fountain, Montgomery, Parke and 3 more	3 hr

Nearby

Mesoscale Discussions in Indiana, 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.