Alert archive / Tennessee / Mesoscale Discussions in 2013

Mesoscale Discussion 490

April 17, 20134 states

The Storm Prediction Center issued this mesoscale discussion at Apr 17, 2013, 9:30 AM CDT for 4 states. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Apr 17, 2013, 9:30 AM CDT (14:30 UTC)
Expired
Apr 17, 2013, 11:30 AM CDT
In force
2 hr
Issued by
the Storm Prediction Center
Chance of a watch
40%
All 97 counties

Hardin County, IL, Perry County, IN, Spencer County, IN, Vanderburgh County, IN, Warrick County, IN, Adair County, KY, Allen County, KY, Barren County, KY, Breckinridge County, KY, Butler County, KY, Caldwell County, KY, Calloway County, KY, Christian County, KY, Clinton County, KY, Crittenden County, KY, Cumberland County, KY, Daviess County, KY, Edmonson County, KY, Grayson County, KY, Green County, KY, Hancock County, KY, Hardin County, KY, Hart County, KY, Henderson County, KY, Hopkins County, KY, Larue County, KY, Livingston County, KY, Logan County, KY, Lyon County, KY, Marion County, KY, Marshall County, KY, McLean County, KY, Meade County, KY, Metcalfe County, KY, Monroe County, KY, Muhlenberg County, KY, Nelson County, KY, Ohio County, KY, Russell County, KY, Simpson County, KY, Taylor County, KY, Todd County, KY, Trigg County, KY, Union County, KY, Warren County, KY, Wayne County, KY, Webster County, KY, Bedford County, TN, Benton County, TN, Bledsoe County, TN, Cannon County, TN, Cheatham County, TN, Clay County, TN, Coffee County, TN, Cumberland County, TN, Davidson County, TN, Decatur County, TN, DeKalb County, TN, Dickson County, TN, Fentress County, TN, Franklin County, TN, Giles County, TN, Grundy County, TN, Hamilton County, TN, Henry County, TN, Hickman County, TN, Houston County, TN, Humphreys County, TN, Jackson County, TN, Lawrence County, TN, Lewis County, TN, Lincoln County, TN, Macon County, TN, Marion County, TN, Marshall County, TN, Maury County, TN, Montgomery County, TN, Moore County, TN, Morgan County, TN, Overton County, TN, Perry County, TN, Pickett County, TN, Putnam County, TN, Rhea County, TN, Robertson County, TN, Rutherford County, TN, Sequatchie County, TN, Smith County, TN, Stewart County, TN, Sumner County, TN, Trousdale County, TN, Van Buren County, TN, Warren County, TN, Wayne County, TN, White County, TN, Williamson County, TN, Wilson County, TN

The radar

The Nashville radar (KOHX), 30 km from the middle of the area, began a volume at 14:31 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

Nashville Metro, TN (KBNA), launched 12:00Z, 2.5 hours before the alert went out and 42 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, Nashville Metro, TN at 12:00Z on 2013-04-17Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1987 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, Nashville Metro, TN at 12:00Z on 2013-04-17The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 130 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
1987 J/kg
Mixed-layer CIN
-28 J/kg
Mixed-layer LCL
747 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
130 m²/s²
0-3 km storm-relative helicity
108 m²/s²
Significant tornado parameter
0.6
Supercell composite
3.7

Open this sounding in Storm Lab

The text

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

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 16, 8:02 PM CDTMesoscale DiscussionSPCEdwards, Gallatin, Hamilton, Hardin, Saline, Wabash and 1 more88 min
Apr 16, 8:44 PM CDTMesoscale DiscussionSPCBond, Calhoun, Champaign, Christian, Clark, Clay and 35 more2 hr
Apr 17, 8:49 AM CDTMesoscale DiscussionSPCAdams, Brown, Bureau, Cass, DeWitt, Ford and 32 more56 min
Apr 17, 9:14 AM CDTSevere Thunderstorm WatchSPCBoone, Bureau, Carroll, Cook, DeKalb, DuPage and 30 more10 hr
Apr 17, 11:11 AM CDTTornado WatchSPCAdams, Brown, Calhoun, Greene, Jersey, Macoupin and 1 more11 hr
Apr 17, 12:39 PM CDTSevere Thunderstorm WatchSPCHardin, Pope5 hr
Apr 17, 1:33 PM CDTMesoscale DiscussionSPCBoone, Bureau, Carroll, Cook, DeKalb, DuPage and 30 more57 min
Apr 17, 3:04 PM CDTMesoscale DiscussionSPCCass, Champaign, Christian, Clark, Coles, Cumberland and 26 more56 min
Apr 17, 3:33 PM CDTTornado WatchSPCCass, Champaign, Christian, Coles, DeWitt, Douglas and 24 more8 hr
Apr 17, 3:38 PM CDTMesoscale DiscussionSPCAdams, Brown, Calhoun, Greene, Jersey, Macoupin and 1 more97 min
Apr 17, 3:53 PM CDTMesoscale DiscussionSPCHardin, Pope67 min
Apr 17, 6:02 PM CDTMesoscale DiscussionSPCCalhoun, Greene, Jersey, Pike88 min
Apr 17, 6:46 PM CDTMesoscale DiscussionSPCCass, Champaign, Christian, Coles, DeWitt, Douglas and 18 more89 min
Apr 17, 4:39 PM CDTMesoscale DiscussionSPCBartholomew, Brown, Clay, Daviess, Dubois, Greene and 12 more96 min

Nearby

Mesoscale Discussions in Tennessee, 2013Mesoscale Discussions in Kentucky, 2013Mesoscale Discussions in Indiana, 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.