Alert archive / Tennessee / Severe Thunderstorm Watches in 2011

Severe Thunderstorm Watch 500

June 18, 20115 states

The Storm Prediction Center issued this severe thunderstorm watch at Jun 18, 2011, 11:05 AM EDT for 5 states. It was in force for 9 hr.

The area

The outline as issued.

The facts

Issued: Jun 18, 2011, 11:05 AM EDT (15:05 UTC)
Expired: Jun 18, 2011, 7:39 PM EDT
In force: 9 hr
Issued by: the Storm Prediction Center
Largest hail expected: 2 in
Strongest gust expected: 70 kt

All 106 counties

Banks County, GA, Bartow County, GA, Catoosa County, GA, Chattooga County, GA, Cherokee County, GA, Dade County, GA, Dawson County, GA, Fannin County, GA, Floyd County, GA, Forsyth County, GA, Franklin County, GA, Gilmer County, GA, Gordon County, GA, Habersham County, GA, Hall County, GA, Hart County, GA, Lumpkin County, GA, Murray County, GA, Pickens County, GA, Rabun County, GA, Stephens County, GA, Towns County, GA, Union County, GA, Walker County, GA, White County, GA, Whitfield County, GA, Alexander County, NC, Avery County, NC, Buncombe County, NC, Burke County, NC, Cabarrus County, NC, Caldwell County, NC, Catawba County, NC, Cherokee County, NC, Clay County, NC, Cleveland County, NC, Davie County, NC, Gaston County, NC, Graham County, NC, Haywood County, NC, Henderson County, NC, Iredell County, NC, Jackson County, NC, Lincoln County, NC, Macon County, NC, Madison County, NC, McDowell County, NC, Mecklenburg County, NC, Mitchell County, NC, Polk County, NC, Rowan County, NC, Rutherford County, NC, Swain County, NC, Transylvania County, NC, Union County, NC, Yancey County, NC, Anderson County, SC, Cherokee County, SC, Chester County, SC, Greenville County, SC, Laurens County, SC, Oconee County, SC, Pickens County, SC, Spartanburg County, SC, Union County, SC, York County, SC, Anderson County, TN, Bledsoe County, TN, Blount County, TN, Bradley County, TN, Campbell County, TN, Carter County, TN, Claiborne County, TN, Cocke County, TN, Grainger County, TN, Greene County, TN, Hamblen County, TN, Hamilton County, TN, Hancock County, TN, Hawkins County, TN, Jefferson County, TN, Johnson County, TN, Knox County, TN, Loudon County, TN, Marion County, TN, McMinn County, TN, Meigs County, TN, Monroe County, TN, Morgan County, TN, Polk County, TN, Rhea County, TN, Roane County, TN, Scott County, TN, Sequatchie County, TN, Sevier County, TN, Sullivan County, TN, Unicoi County, TN, Union County, TN, Washington County, TN, City of Bristol, VA, City of Norton, VA, Lee County, VA, Russell County, VA, Scott County, VA, Washington County, VA, Wise County, VA

The radar

The Knoxville radar (KMRX), 94 km from the middle of the area, began a volume at 15:07 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.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes: 20%
One or more EF2 to EF5 tornadoes: 5%
Ten or more severe wind reports: 90%
One or more gusts of 65 knots or more: 50%
Ten or more severe hail reports: 70%
One or more hailstones of 2 inches or more: 20%
Six or more combined severe hail and wind reports: 95%

Warnings issued inside it

39 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
Jun 18, 11:52 AM EDT	Severe Thunderstorm Warning	MRX	Morgan	38 min
Jun 18, 1:17 PM EDT	Severe Thunderstorm Warning	GSP	Buncombe, Graham, Haywood, Jackson, Macon, Madison and 1 more	73 min
Jun 18, 1:43 PM EDT	Severe Thunderstorm Warning	GSP	Oconee, Pickens	62 min
Jun 18, 1:51 PM EDT	Severe Thunderstorm Warning	GSP	Avery, Mitchell, Yancey	54 min
Jun 18, 1:56 PM EDT	Severe Thunderstorm Warning	GSP	Rabun	64 min
Jun 18, 2:24 PM EDT	Severe Thunderstorm Warning	GSP	Burke, Caldwell, McDowell, Polk, Rutherford	81 min
Jun 18, 2:29 PM EDT	Severe Thunderstorm Warning	GSP	Graham, Jackson, Macon, Swain	48 min
Jun 18, 2:35 PM EDT	Severe Thunderstorm Warning	GSP	Greenville, Oconee, Pickens, Spartanburg	70 min
Jun 18, 2:59 PM EDT	Severe Thunderstorm Warning	GSP	Alexander, Catawba, Cleveland, Gaston, Lincoln	61 min
Jun 18, 3:07 PM EDT	Severe Thunderstorm Warning	GSP	Cherokee	68 min
Jun 18, 3:11 PM EDT	Severe Thunderstorm Warning	GSP	Henderson, Transylvania	25 min
Jun 18, 3:18 PM EDT	Severe Thunderstorm Warning	MRX	Bledsoe, Hamilton, Meigs, Rhea, Sequatchie	57 min
Jun 18, 3:23 PM EDT	Severe Thunderstorm Warning	MRX	Marion	67 min
Jun 18, 3:34 PM EDT	Severe Thunderstorm Warning	GSP	Iredell	56 min
Jun 18, 3:36 PM EDT	Severe Thunderstorm Warning	GSP	Anderson, Greenville	69 min
Jun 18, 3:42 PM EDT	Severe Thunderstorm Warning	GSP	Oconee, Pickens	48 min
Jun 18, 3:43 PM EDT	Severe Thunderstorm Warning	GSP	Greenville, Spartanburg	77 min
Jun 18, 3:50 PM EDT	Severe Thunderstorm Warning	MRX	Bradley, McMinn, Meigs, Monroe, Polk	55 min
Jun 18, 3:56 PM EDT	Severe Thunderstorm Warning	FFC	Catoosa, Dade, Walker	49 min
Jun 18, 3:56 PM EDT	Severe Thunderstorm Warning	GSP	Catawba, Cleveland, Gaston, Lincoln, Mecklenburg	79 min
Jun 18, 3:58 PM EDT	Severe Thunderstorm Warning	GSP	Abbeville, Greenville, Greenwood, Laurens	77 min
Jun 18, 3:59 PM EDT	Severe Thunderstorm Warning	MRX	Bradley, Hamilton, Polk, Sequatchie	61 min
Jun 18, 4:01 PM EDT	Severe Thunderstorm Warning	GSP	Union	74 min
Jun 18, 4:03 PM EDT	Severe Thunderstorm Warning	GSP	Cabarrus, Davie, Rowan	72 min
Jun 18, 4:11 PM EDT	Tornado Warning	MRX	Bradley, McMinn, Polk	49 min
Jun 18, 4:27 PM EDT	Severe Thunderstorm Warning	FFC	Catoosa, Gordon, Murray, Walker, Whitfield	48 min
Jun 18, 4:28 PM EDT	Severe Thunderstorm Warning	GSP	Chester	53 min
Jun 18, 4:30 PM EDT	Severe Thunderstorm Warning	GSP	Union	67 min
Jun 18, 4:34 PM EDT	Severe Thunderstorm Warning	GSP	Abbeville, Greenwood, Laurens	71 min
Jun 18, 4:38 PM EDT	Severe Thunderstorm Warning	MRX	Cherokee	67 min
Jun 18, 5:03 PM EDT	Severe Thunderstorm Warning	FFC	Fannin, Gilmer, Gordon, Murray	42 min
Jun 18, 5:05 PM EDT	Severe Thunderstorm Warning	MRX	Clay	40 min
Jun 18, 5:18 PM EDT	Severe Thunderstorm Warning	FFC	Cherokee, Gilmer, Pickens	42 min
Jun 18, 5:30 PM EDT	Severe Thunderstorm Warning	FFC	Cherokee, Dawson, Gilmer, Lumpkin, Pickens	30 min
Jun 18, 5:39 PM EDT	Severe Thunderstorm Warning	GSP	Franklin, Habersham, Stephens	81 min
Jun 18, 5:41 PM EDT	Severe Thunderstorm Warning	GSP	Abbeville, Greenwood, Laurens	64 min
Jun 18, 5:59 PM EDT	Severe Thunderstorm Warning	FFC	Barrow, Forsyth, Gwinnett, Hall, Jackson	46 min
Jun 18, 6:11 PM EDT	Severe Thunderstorm Warning	GSP	Oconee	51 min
Jun 18, 6:28 PM EDT	Severe Thunderstorm Warning	GSP	Hart	62 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Nashville Metro, TN (KBNA), launched 12:00Z, 3.1 hours before the alert went out and 238 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: 2056 J/kg
Mixed-layer CIN: -99 J/kg
Mixed-layer LCL: 822 m above ground
0-6 km bulk shear: 31 kt
0-1 km storm-relative helicity: 191 m²/s²
0-3 km storm-relative helicity: 223 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 5.9

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 18, 9:38 AM EDT	Mesoscale Discussion	SPC	Banks, Bartow, Catoosa, Chattooga, Cherokee, Cobb and 22 more	97 min
Jun 18, 2:21 PM EDT	Mesoscale Discussion	SPC	Banks, Bartow, Catoosa, Chattooga, Cherokee, Dawson and 20 more	84 min
Jun 18, 3:55 PM EDT	Mesoscale Discussion	SPC	Barrow, Carroll, Clarke, Clayton, Cobb, Columbia and 25 more	35 min
Jun 18, 4:08 PM EDT	Severe Thunderstorm Watch	SPC	Baldwin, Barrow, Burke, Butts, Carroll, Clarke and 51 more	6 hr
Jun 18, 6:49 PM EDT	Mesoscale Discussion	SPC	Baldwin, Barrow, Bibb, Bleckley, Bulloch, Burke and 55 more	86 min
Jun 18, 7:20 PM EDT	Severe Thunderstorm Watch	SPC	Bryan, Bulloch, Candler, Chatham, Effingham, Evans and 6 more	5 hr
Jun 18, 3:38 PM EDT	Severe Thunderstorm Watch	SPC	Alamance, Anson, Caswell, Chatham, Davidson, Durham and 17 more	4 hr
Jun 18, 5:46 PM EDT	Mesoscale Discussion	SPC	Alamance, Anson, Caswell, Chatham, Cumberland, Durham and 19 more	59 min
Jun 18, 10:39 AM EDT	Severe Thunderstorm Watch	SPC	Bedford, Benton, Carroll, Chester, Coffee, Crockett and 30 more	7 hr

Nearby

Severe Thunderstorm Watches in Tennessee, 2011 Severe Thunderstorm Watches in North Carolina, 2011 Severe Thunderstorm Watches in Georgia, 2011 Every severe thunderstorm watch in 2011

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.