Alert archive / Indiana / Mesoscale Discussions in 2016

Mesoscale Discussion 1306

July 17, 2016Clark County, Edgar County, Illinois; 33 counties in Indiana

The Storm Prediction Center issued this mesoscale discussion at Jul 17, 2016, 12:20 PM CDT for Clark County, Edgar County, Illinois; 33 counties in Indiana. It was in force for 115 min.

The area

The outline as issued.

The facts

Issued: Jul 17, 2016, 12:20 PM CDT (17:20 UTC)
Expired: Jul 17, 2016, 2:15 PM CDT
In force: 115 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

All 35 counties

Clark County, IL, Edgar County, IL, Bartholomew County, IN, Boone County, IN, Brown County, IN, Clay County, IN, Clinton County, IN, Decatur County, IN, Fayette County, IN, Fountain 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, Madison County, IN, Marion County, IN, Monroe County, IN, Montgomery County, IN, Morgan County, IN, Owen County, IN, Parke County, IN, Putnam County, IN, Ripley County, IN, Rush County, IN, Shelby County, IN, Sullivan County, IN, Tippecanoe County, IN, Tipton County, IN, Vermillion County, IN, Vigo County, IN

The radar

The Indianapolis radar (KIND), 25 km from the middle of the area, began a volume at 17:23 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, 5.3 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: 592 J/kg
Mixed-layer CIN: -96 J/kg
Mixed-layer LCL: 884 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 214 m²/s²
0-3 km storm-relative helicity: 254 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 3.7

Open this sounding in Storm Lab

The text

As transmitted.

303 
ACUS11 KWNS 171720
SWOMCD
SPC MCD 171720 
INZ000-ILZ000-171915-

MESOSCALE DISCUSSION 1306
NWS STORM PREDICTION CENTER NORMAN OK
1220 PM CDT SUN JUL 17 2016

AREAS AFFECTED...EXTREME EAST-CENTRAL IL...CENTRAL/SRN INDIANA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 171720Z - 171915Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...THUNDERSTORMS ACROSS THE DISCUSSION AREA MAY PRODUCE
DAMAGING WINDS THIS AFTERNOON. THE OVERALL THREAT SHOULD REMAIN
SOMEWHAT ISOLATED AND A WATCH IS NOT CURRENTLY ANTICIPATED.

DISCUSSION...THE SOUTHERN PORTION OF A LONG-LIVED LINE
SEGMENT...CURRENTLY MOVING INTO WEST-CENTRAL INDIANA...HAS RECENTLY
BECOME BETTER ORGANIZED WITH THE DEVELOPMENT OF A BOOKEND VORTEX AND
REPORTS OF WIND GUSTS JUST BELOW SEVERE LEVELS. THIS PORTION OF THE
LINE SEGMENT WAS LOCATED WITHIN A GRADIENT IN SURFACE-BASED
INSTABILITY AND A ZONE OF LOW-LEVEL WARM ADVECTION. ALTHOUGH THE
IMMEDIATE DOWNSTREAM ENVIRONMENT WILL CONTINUE TO DESTABILIZE...THE
STORMS WILL INCREASINGLY MOVE SOUTH OF THE STRONGER LARGE-SCALE FLOW
AND DEEP-LAYER SHEAR...CASTING SOME UNCERTAINTY ON BOWING SEGMENT
LONGEVITY. CURRENT THINKING IS THAT THE THREAT SHOULD REMAIN
SOMEWHAT ISOLATED/CONFINED TO A SMALL SPATIAL CORRIDOR AND A WATCH
IS NOT ANTICIPATED.  CONVECTIVE TRENDS WILL CONTINUE TO BE
MONITORED.

..BUNTING/HART.. 07/17/2016

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

ATTN...WFO...ILN...IND...LOT...ILX...

LAT...LON   38988732 39308797 39658823 39978757 40438726 40538691
            40518655 40398602 40248569 39918517 39478489 39108516
            38868587 38988732

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 17, 7:00 AM CDT	Mesoscale Discussion	SPC	Boone, Bureau, Carroll, Cook, DeKalb, DuPage and 24 more	2 hr
Jul 17, 3:05 PM CDT	Mesoscale Discussion	SPC	Clark, Clay, Coles, Crawford, Cumberland, Edgar and 14 more	115 min

Nearby

Mesoscale Discussions in Indiana, 2016 Mesoscale Discussions in Illinois, 2016 Every mesoscale discussion in 2016

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.