Alert archive / Indiana / Mesoscale Discussions in 2012

Mesoscale Discussion 612

April 28, 20124 states

The Storm Prediction Center issued this mesoscale discussion at Apr 28, 2012, 2:56 PM CDT for 4 states. It was in force for 64 min.

The area

The outline as issued.

The facts

Issued: Apr 28, 2012, 2:56 PM CDT (19:56 UTC)
Expired: Apr 28, 2012, 4:00 PM CDT
In force: 64 min
Issued by: the Storm Prediction Center

All 53 counties

Bond County, IL, Clark County, IL, Clay County, IL, Clinton County, IL, Crawford County, IL, Cumberland County, IL, Edwards County, IL, Effingham County, IL, Fayette County, IL, Jasper County, IL, Jersey County, IL, Lawrence County, IL, Macoupin County, IL, Madison County, IL, Marion County, IL, Montgomery County, IL, Richland County, IL, Wabash County, IL, Wayne County, IL, Bartholomew County, IN, Brown County, IN, Clark County, IN, Crawford County, IN, Daviess County, IN, Dubois County, IN, Floyd County, IN, Gibson County, IN, Greene County, IN, Harrison County, IN, Jackson County, IN, Jefferson County, IN, Jennings County, IN, Knox County, IN, Lawrence County, IN, Martin County, IN, Monroe County, IN, Ohio County, IN, Orange County, IN, Owen County, IN, Pike County, IN, Ripley County, IN, Scott County, IN, Sullivan County, IN, Switzerland County, IN, Washington County, IN, Carroll County, KY, Henry County, KY, Jefferson County, KY, Oldham County, KY, Trimble County, KY, City of Saint Louis, MO, Saint Charles County, MO, Saint Louis County, MO

The radar

The Evansville,IN radar (KVWX), 51 km from the middle of the area, began a volume at 20:00 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

Lincoln, IL (KILX), launched 12:00Z, 7.9 hours before the alert went out and 174 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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 1019 m above ground
0-6 km bulk shear: 63 kt
0-1 km storm-relative helicity: 681 m²/s²
0-3 km storm-relative helicity: 811 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 2.0

Open this sounding in Storm Lab

The text

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

012 
ACUS11 KWNS 281957
SWOMCD
SPC MCD 281956
KYZ000-INZ000-ILZ000-MOZ000-282100-

MESOSCALE DISCUSSION 0612
NWS STORM PREDICTION CENTER NORMAN OK
0256 PM CDT SAT APR 28 2012

AREAS AFFECTED...E-CNTRL MO...SRN IL/IND...FAR NRN KY

CONCERNING...SEVERE THUNDERSTORM WATCH 197...

VALID 281956Z - 282100Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 197
CONTINUES.

NEAR-TERM SEVERE HAIL THREAT IS GREATEST WITH SUPERCELL MOVING INTO
THE SAINT LOUIS METRO AREA. DOWNSTREAM...SHOWERS ARE INCREASING
ACROSS SRN IL ALONG THE WARM FRONTAL ZONE. AS THIS ACTIVITY LIKELY
DEEPENS INTO SUSTAINED TSTMS...A NEW WW WILL PROBABLY BE ISSUED E OF
WW 197 BY 21Z.

SUPERCELL ALONG THE I-70 CORRIDOR IN E-CNTRL MO HAS PRODUCED REPORTS
OF UP TO GOLF-BALL SIZED HAIL ON APPROACH TO THE SAINT LOUIS METRO
AREA. THIS CELL APPEARS TO BE JUST N OF A WEAK ELONGATED CYCLONE
ALONG THE QUASI-STATIONARY/WARM FRONT THAT ARCS ACROSS SRN IL INTO
SWRN IND/NRN KY. DESPITE WEAK/VEERED NEAR-SURFACE WINDS SAMPLED IN
THE LSX VWP...STRONG SPEED SHEAR FROM 2-7 KM AGL WILL REMAIN
SUFFICIENT FOR ORGANIZED UPDRAFTS PRIMARILY PRODUCING LARGE HAIL.

FARTHER EAST...AN INCREASE IN SHOWERS HAS BEEN NOTED INTO S-CNTRL
IL. THESE SHOULD DEEPEN INTO TSTMS SHORTLY AS SURFACE HEATING
RESULTS IN FURTHER DESTABILIZATION WITH MLCAPE 1500 TO 2500 J/KG.
PRIMARY INITIAL THREAT SHOULD BE SEVERE HAIL...BUT A TORNADO CANNOT
BE RULED OUT...ESPECIALLY WITH ANY SUPERCELL THAT CAN BECOME
ANCHORED ALONG THE FRONT.

..GRAMS.. 04/28/2012

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

ATTN...WFO...ILN...LMK...IND...PAH...ILX...LSX...

LAT...LON   38919094 39328979 39368720 39298609 39038495 38618485
            38358502 38188565 38128617 38308751 38518903 38549019
            38609065 38919094

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Apr 28, 1:17 PM CDT	Mesoscale Discussion	SPC	Bond, Calhoun, Clay, Clinton, Crawford, Cumberland and 24 more	88 min
Apr 28, 1:48 PM CDT	Severe Thunderstorm Watch	SPC	Bond, Calhoun, Clark, Clay, Clinton, Crawford and 20 more	7 hr
Apr 28, 5:15 PM CDT	Tornado Watch	SPC	Clinton, Edwards, Franklin, Gallatin, Hamilton, Jackson and 12 more	5 hr
Apr 28, 5:59 PM CDT	Mesoscale Discussion	SPC	Bond, Calhoun, Clark, Clay, Clinton, Crawford and 20 more	2 hr
Apr 28, 6:12 PM CDT	Mesoscale Discussion	SPC	Franklin, Hamilton, Jefferson, Monroe, Perry, Randolph and 3 more	2 hr
Apr 28, 3:33 PM CDT	Severe Thunderstorm Watch	SPC	Bartholomew, Brown, Clark, Clay, Crawford, Daviess and 20 more	6 hr
Apr 27, 7:00 PM CDT	Mesoscale Discussion	SPC	Andrew, Buchanan, Caldwell, Cass, Clay, Clinton and 6 more	30 min
Apr 27, 7:18 PM CDT	Severe Thunderstorm Watch	SPC	Bates, Buchanan, Cass, Clay, Clinton, Jackson and 1 more	95 min

Nearby

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