Alert archive / Indiana / Mesoscale Discussions in 2013

Mesoscale Discussion 521

April 18, 20135 states

The Storm Prediction Center issued this mesoscale discussion at Apr 18, 2013, 11:14 AM CDT for 5 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Apr 18, 2013, 11:14 AM CDT (16:14 UTC)
Expired
Apr 18, 2013, 1:15 PM CDT
In force
2 hr
Issued by
the Storm Prediction Center
All 117 counties

Clark County, IL, Clay County, IL, Crawford County, IL, Jasper County, IL, Lawrence County, IL, Marion County, IL, Randolph County, IL, Richland County, IL, Washington County, IL, Wayne County, IL, Adams County, IN, Allen County, IN, Bartholomew County, IN, Blackford County, IN, Boone County, IN, Brown County, IN, Clay County, IN, Clinton County, IN, Daviess County, IN, Decatur County, IN, DeKalb County, IN, Delaware County, IN, Fayette County, IN, Franklin County, IN, Grant County, IN, Greene County, IN, Hamilton County, IN, Hancock County, IN, Hendricks County, IN, Henry County, IN, Howard County, IN, Huntington County, IN, Jackson County, IN, Jay County, IN, Jennings County, IN, Johnson County, IN, Knox County, IN, Kosciusko County, IN, LaGrange County, IN, Lawrence County, IN, Madison County, IN, Marion County, IN, Martin County, IN, Miami County, IN, Monroe County, IN, Montgomery County, IN, Morgan County, IN, Noble County, IN, Owen County, IN, Parke County, IN, Putnam County, IN, Randolph County, IN, Rush County, IN, Shelby County, IN, Steuben County, IN, Sullivan County, IN, Tipton County, IN, Union County, IN, Vigo County, IN, Wabash County, IN, Wayne County, IN, Wells County, IN, Whitley County, IN, Barry County, MI, Bay County, MI, Branch County, MI, Calhoun County, MI, Clinton County, MI, Eaton County, MI, Genesee County, MI, Gratiot County, MI, Hillsdale County, MI, Huron County, MI, Ingham County, MI, Ionia County, MI, Isabella County, MI, Jackson County, MI, Kalamazoo County, MI, Kent County, MI, Lapeer County, MI, Lenawee County, MI, Livingston County, MI, Macomb County, MI, Midland County, MI, Monroe County, MI, Montcalm County, MI, Oakland County, MI, Saginaw County, MI, Saint Clair County, MI, Saint Joseph County, MI, Sanilac County, MI, Shiawassee County, MI, Tuscola County, MI, Washtenaw County, MI, Wayne County, MI, Iron County, MO, Madison County, MO, Saint Francois County, MO, Sainte Genevieve County, MO, Allen County, OH, Auglaize County, OH, Darke County, OH, Defiance County, OH, Fulton County, OH, Hancock County, OH, Hardin County, OH, Henry County, OH, Lucas County, OH, Mercer County, OH, Miami County, OH, Paulding County, OH, Preble County, OH, Putnam County, OH, Shelby County, OH, Van Wert County, OH, Williams County, OH, Wood County, OH

The radar

The Northern Indiana radar (KIWX), 26 km from the middle of the area, began a volume at 16:16 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

Cncnati-Daytn, OH (KILN), launched 12:00Z, 4.2 hours before the alert went out and 243 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-pSkew-T log-p diagram, Cncnati-Daytn, OH at 12:00Z on 2013-04-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 448 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Cncnati-Daytn, OH at 12:00Z on 2013-04-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 108 square meters per square second.193958Sfc1 km3 km6 km9 kmRMLM
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
448 J/kg
Mixed-layer CIN
-120 J/kg
Mixed-layer LCL
911 m above ground
0-6 km bulk shear
22 kt
0-1 km storm-relative helicity
108 m²/s²
0-3 km storm-relative helicity
79 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.

209 
ACUS11 KWNS 181615
SWOMCD
SPC MCD 181614 COR
MIZ000-OHZ000-INZ000-ILZ000-MOZ000-181815-

MESOSCALE DISCUSSION 0521
NWS STORM PREDICTION CENTER NORMAN OK
1114 AM CDT THU APR 18 2013

AREAS AFFECTED...PORTIONS LOWER MI...WRN OH...INDIANA EXCEPT NWRN
PORTIONS...SRN IL...SERN MO.

CONCERNING...TORNADO WATCH 122...123...124...

VALID 181614Z - 181815Z

CORRECTED FOR GEOGRAPHIC HEADER

THE SEVERE WEATHER THREAT FOR TORNADO WATCH
122...123...124...CONTINUES.

SUMMARY...REMAINDER WW 122 HAS BEEN EXTENDED UNTIL 18Z WITH ADDITION
OF REYNOLDS COUNTY MO...PER COORD W/LSX WFO.  WWS 123-124 MAY BE
CLEARED BEHIND PRIMARY CONVECTIVE BAND...WITH POSSIBLE EXCEPTION OF
SRN PORTIONS WW 124 AHEAD OF CONVECTION MOVING NEWD FROM WW 122. 
PORTIONS OH E OF WW 123 ARE BEING MONITORED FOR POSSIBLE WW BASED ON
CONVECTIVE/DESTABILIZATION TRENDS.

DISCUSSION...BAND OF TSTMS FROM LM SHORE OF LOWER MI SSWWD ACROSS
NWRN INDIANA TO SERN MO -- WELL AHEAD OF SYNOPTIC SFC COLD FRONT AND
LOW -- WILL CONTINUE MOVING ACROSS REMAINDER WW AREAS.  NET EWD
MOTION HAS BEEN ABOUT 25 KT...WITH CONSIDERABLE LOCAL
VARIABILITY...AND NEWD 40-50 KT SPEEDS ON EMBEDDED CONVECTIVE
ELEMENTS.  MAIN THREAT WILL CONTINUE TO BE DAMAGING WIND...WITH OCNL
TORNADOES POSSIBLE IN EITHER QLCS CIRCULATIONS OR EMBEDDED/BOW-ECHO
MESOVORTICES.  

BOTH VERTICAL SHEAR AND LOW-LEVEL MOISTURE WEAKEN WITH EWD EXTENT
ATTM.  HOWEVER...COMBINATION OF MOIST/WARM ADVECTION AND DIABATIC
SFC HEATING E OF CONVECTION WILL YIELD FAVORABLE BUOYANCY -- I.E.
MLCAPE 500-1000 J/KG.  THAT WILL BE JUXTAPOSED WITH NARROW AREA OF
45-55 KT EFFECTIVE SHEAR MAGNITUDES THAT SHOULD SHIFT EWD GENERALLY
IN STEP WITH MOST OF CONVECTIVE PLUME.  HOWEVER...FASTER SEGMENTS OF
SQUALL LINE MAY OUTPACE OPTIMAL MOISTENING...ESPECIALLY ACROSS
PORTIONS NERN INDIANA AND SERN LOWER MI.  MEANWHILE...WEAK SFC
INFLECTION POINT AND COLLOCATED MESOLOW WAS ANALYZED OVER SERN MO
OZARKS...MOVING NEWD ALONG CONVECTIVE BOUNDARY TOWARD SRN/ERN IL. 
AS SUCH...SEGMENT OF CONVECTIVE BOUNDARY ACROSS PORTIONS ERN
IL...AND PERHAPS SWRN/CENTRAL INDIANA...MAY STALL OR EVEN RETREAT
SLIGHTLY NWD.

..EDWARDS/MARSH.. 04/18/2013

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

ATTN...WFO...CLE...ILN...DTX...APX...LMK...IWX...GRR...IND...
PAH...ILX...LSX...SGF...

LAT...LON   37119111 37869057 38588940 39628736 41258586 42818579
            43548523 43958382 43708386 43658369 43868345 44028299
            43988269 43528254 42958240 42618254 42328300 41878335
            40988329 39878420 39028548 38578646 38368908 37369040
            37119111

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 17, 8:21 PM CDTMesoscale DiscussionSPCCass, Champaign, Christian, Coles, DeWitt, Douglas and 21 more84 min
Apr 17, 8:53 PM CDTMesoscale DiscussionSPCCalhoun, Greene, Jersey, Pike, Scott97 min
Apr 17, 9:57 PM CDTTornado WatchSPCAdams, Brown, Pike7 hr
Apr 17, 10:48 PM CDTMesoscale DiscussionSPCChampaign, Christian, Coles, DeWitt, Douglas, Edgar and 12 more57 min
Apr 17, 11:46 PM CDTMesoscale DiscussionSPCCalhoun, Greene, Morgan, Pike, Scott89 min
Apr 18, 2:01 AM CDTMesoscale DiscussionSPCCalhoun, Jersey89 min
Apr 18, 4:02 AM CDTMesoscale DiscussionSPCCalhoun, Greene, Jersey, Monroe58 min
Apr 18, 5:36 AM CDTMesoscale DiscussionSPCBond, Clinton, Fayette, Madison, Monroe, Montgomery and 3 more54 min
Apr 18, 5:42 AM CDTTornado WatchSPCBond, Clinton, Fayette, Jersey, Macoupin, Madison and 6 more8 hr
Apr 18, 7:25 AM CDTMesoscale DiscussionSPCChampaign, Clark, Clay, Coles, Crawford, Cumberland and 17 more95 min
Apr 18, 8:31 AM CDTTornado Watch PDSSPCClark, Clay, Coles, Crawford, Cumberland, Douglas and 6 more7 hr
Apr 18, 9:25 AM CDTTornado WatchSPCAlexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 13 more8 hr
Apr 18, 12:48 PM CDTMesoscale DiscussionSPCAlexander, Edwards, Franklin, Gallatin, Hamilton, Hardin and 13 more87 min
Apr 18, 2:47 PM CDTMesoscale DiscussionSPCClark, Crawford, Lawrence88 min
Apr 18, 3:32 PM CDTTornado WatchSPCAdams, Bartholomew, Blackford, Boone, Brown, Clay and 27 more3 hr
Apr 18, 5:33 PM CDTMesoscale DiscussionSPCAdams, Allen, Bartholomew, Blackford, Boone, Brown and 43 more117 min
Apr 18, 8:48 AM CDTMesoscale DiscussionSPCAllegan, Barry, Bay, Calhoun, Clinton, Eaton and 29 more27 min
Apr 18, 9:06 AM CDTTornado WatchSPCAllegan, Barry, Bay, Calhoun, Clinton, Eaton and 30 more6 hr
Apr 18, 7:26 AM CDTMesoscale DiscussionSPCBollinger, Butler, Cape Girardeau, Carter, Dunklin, Howell and 9 more2 hr

Nearby

Mesoscale Discussions in Indiana, 2013Mesoscale Discussions in Michigan, 2013Mesoscale Discussions in Ohio, 2013Every mesoscale discussion in 2013

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.