Alert archive / Tennessee / Mesoscale Discussions in 2009

Mesoscale Discussion 739

May 6, 20094 states

The Storm Prediction Center issued this mesoscale discussion at May 6, 2009, 11:44 PM EDT for 4 states. It was in force for 91 min.

The area

The outline as issued.

The facts

Issued: May 6, 2009, 11:44 PM EDT (03:44 UTC)
Expired: May 7, 2009, 1:15 AM EDT
In force: 91 min
Issued by: the Storm Prediction Center

All 55 counties

Catoosa County, GA, Dawson County, GA, Fannin County, GA, Gilmer County, GA, Gordon County, GA, Habersham County, GA, Lumpkin County, GA, Murray County, GA, Pickens County, GA, Rabun County, GA, Stephens County, GA, Towns County, GA, Union County, GA, White County, GA, Whitfield County, GA, Buncombe County, NC, Burke County, NC, Cherokee County, NC, Clay County, NC, Graham County, NC, Haywood County, NC, Henderson County, NC, Jackson County, NC, Macon County, NC, Madison County, NC, McDowell County, NC, Mitchell County, NC, Polk County, NC, Rutherford County, NC, Swain County, NC, Transylvania County, NC, Yancey County, NC, Anderson County, SC, Greenville County, SC, Oconee County, SC, Pickens County, SC, Spartanburg County, SC, Anderson County, TN, Bledsoe County, TN, Blount County, TN, Bradley County, TN, Cocke County, TN, Hamilton County, TN, Jefferson County, TN, Knox County, TN, Loudon County, TN, McMinn County, TN, Meigs County, TN, Monroe County, TN, Polk County, TN, Rhea County, TN, Roane County, TN, Sequatchie County, TN, Sevier County, TN, Unicoi County, TN

The radar

The Knoxville radar (KMRX), 88 km from the middle of the area, began a volume at 03:48 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

Greensboro/Hi Pt, NC (KGSO), launched 00:00Z, 3.7 hours before the alert went out and 342 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: 1430 J/kg
Mixed-layer CIN: -10 J/kg
Mixed-layer LCL: 653 m above ground
0-6 km bulk shear: 50 kt
0-1 km storm-relative helicity: 306 m²/s²
0-3 km storm-relative helicity: 370 m²/s²
Significant tornado parameter: 2.3
Supercell composite: 13.6

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.

Issued	Product	Office	Counties	Lasted
May 7, 8:47 AM EDT	Mesoscale Discussion	SPC	Baker, Calhoun, Clay, Dougherty, Mitchell, Quitman and 3 more	58 min
May 7, 2:21 PM EDT	Mesoscale Discussion	SPC	Calhoun, Clay, Decatur, Early, Miller, Quitman and 2 more	54 min
May 6, 8:26 PM EDT	Tornado Watch	SPC	Alamance, Anson, Bertie, Camden, Caswell, Chatham and 30 more	8 hr
May 6, 10:50 PM EDT	Mesoscale Discussion	SPC	Alamance, Caswell, Durham, Franklin, Granville, Halifax and 8 more	55 min
May 7, 12:10 AM EDT	Mesoscale Discussion	SPC	Alamance, Caswell, Chatham, Durham, Franklin, Granville and 9 more	95 min
May 7, 5:17 AM EDT	Mesoscale Discussion	SPC	Alamance, Anson, Beaufort, Bertie, Bladen, Brunswick and 58 more	118 min
May 7, 3:03 PM EDT	Mesoscale Discussion	SPC	Alamance, Anson, Bertie, Cabarrus, Caswell, Chatham and 38 more	117 min
May 7, 6:10 PM EDT	Severe Thunderstorm Watch	SPC	Beaufort, Bladen, Brunswick, Carteret, Columbus, Craven and 21 more	6 hr
May 7, 7:33 PM EDT	Mesoscale Discussion	SPC	Beaufort, Bertie, Bladen, Brunswick, Camden, Carteret and 32 more	57 min

Nearby

Mesoscale Discussions in Tennessee, 2009 Mesoscale Discussions in North Carolina, 2009 Mesoscale Discussions in Georgia, 2009 Every mesoscale discussion in 2009

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.