Alert archive / Tennessee / Mesoscale Discussions in 2003

Mesoscale Discussion 1819

July 13, 2003Jackson County, Alabama; 7 counties in Georgia; 17 counties in Tennessee

The Storm Prediction Center issued this mesoscale discussion at Jul 13, 2003, 5:26 PM CDT for Jackson County, Alabama; 7 counties in Georgia; 17 counties in Tennessee. It was in force for 94 min.

The area

The outline as issued.

The facts

Issued: Jul 13, 2003, 5:26 PM CDT (22:26 UTC)
Expired: Jul 13, 2003, 7:00 PM CDT
In force: 94 min
Issued by: the Storm Prediction Center

All 25 counties

Jackson County, AL, Catoosa County, GA, Chattooga County, GA, Dade County, GA, Gordon County, GA, Murray County, GA, Walker County, GA, Whitfield County, GA, Anderson County, TN, Bledsoe County, TN, Blount County, TN, Bradley County, TN, Cumberland County, TN, Grundy County, TN, Hamilton County, TN, Knox County, TN, Loudon County, TN, Marion County, TN, McMinn County, TN, Meigs County, TN, Monroe County, TN, Polk County, TN, Rhea County, TN, Roane County, TN, Sequatchie County, TN

The radar

The Knoxville radar (KMRX), 129 km from the middle of the area, began a volume at 22:26 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

Nashville Metro, TN (KBNA), launched 12:00Z, 10.4 hours before the alert went out and 196 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: 1439 J/kg
Mixed-layer CIN: -42 J/kg
Mixed-layer LCL: 779 m above ground
0-6 km bulk shear: 34 kt
0-1 km storm-relative helicity: 51 m²/s²
0-3 km storm-relative helicity: 80 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 1.3

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
Jul 13, 11:02 AM CDT	Mesoscale Discussion	SPC	Bibb, Choctaw, Clarke, Dallas, Fayette, Greene and 12 more	118 min
Jul 13, 11:55 AM CDT	Severe Thunderstorm Watch	SPC	Colbert, Lauderdale	6 hr
Jul 13, 3:05 PM CDT	Severe Thunderstorm Watch	SPC	Blount, Calhoun, Cherokee, Cullman, DeKalb, Etowah and 12 more	5 hr
Jul 13, 3:53 PM CDT	Mesoscale Discussion	SPC	Colbert, Lauderdale	67 min
Jul 13, 5:55 PM CDT	Severe Thunderstorm Watch	SPC	Colbert, Franklin, Lamar, Lauderdale, Lawrence, Limestone and 1 more	4 hr
Jul 13, 11:50 AM CDT	Mesoscale Discussion	SPC	Baldwin, Bibb, Burke, Columbia, Crawford, Glascock and 16 more	115 min
Jul 13, 11:30 AM CDT	Mesoscale Discussion	SPC	Fayette, Shelby	2 hr
Jul 13, 12:16 PM CDT	Mesoscale Discussion	SPC	Anderson, Bledsoe, Blount, Bradley, Campbell, Carter and 39 more	119 min

Nearby

Mesoscale Discussions in Tennessee, 2003 Mesoscale Discussions in Georgia, 2003 Mesoscale Discussions in Alabama, 2003 Every mesoscale discussion in 2003

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.