Alert archive / Virginia / Mesoscale Discussions in 2003

Mesoscale Discussion 1940

July 21, 20035 states

The Storm Prediction Center issued this mesoscale discussion at Jul 21, 2003, 2:41 PM EDT for 5 states. It was in force for 64 min.

The area

The outline as issued.

The facts

Issued
Jul 21, 2003, 2:41 PM EDT (18:41 UTC)
Expired
Jul 21, 2003, 3:45 PM EDT
In force
64 min
Issued by
the Storm Prediction Center
All 119 counties

Bell County, KY, Floyd County, KY, Harlan County, KY, Knott County, KY, Leslie County, KY, Letcher County, KY, Martin County, KY, Perry County, KY, Pike County, KY, Alexander County, NC, Alleghany County, NC, Ashe County, NC, Avery County, NC, Buncombe County, NC, Burke County, NC, Caldwell County, NC, Catawba County, NC, Graham County, NC, Haywood County, NC, Henderson County, NC, Jackson County, NC, Madison County, NC, McDowell County, NC, Mitchell County, NC, Polk County, NC, Rutherford County, NC, Stokes County, NC, Surry County, NC, Swain County, NC, Transylvania County, NC, Watauga County, NC, Wilkes County, NC, Yadkin County, NC, Yancey County, NC, Anderson County, TN, Blount County, TN, Campbell County, TN, Carter County, TN, Claiborne County, TN, Cocke County, TN, Grainger County, TN, Greene County, TN, Hamblen County, TN, Hancock County, TN, Hawkins County, TN, Jefferson County, TN, Johnson County, TN, Knox County, TN, Loudon County, TN, Monroe County, TN, Roane County, TN, Sevier County, TN, Sullivan County, TN, Unicoi County, TN, Union County, TN, Washington County, TN, Alleghany County, VA, Amherst County, VA, Augusta County, VA, Bath County, VA, Bedford County, VA, Bland County, VA, Botetourt County, VA, Buchanan County, VA, Carroll County, VA, City of Bristol, VA, City of Buena Vista, VA, City of Covington, VA, City of Galax, VA, City of Lexington, VA, City of Lynchburg, VA, City of Martinsville, VA, City of Norton, VA, City of Radford, VA, City of Roanoke, VA, City of Salem, VA, City of Staunton, VA, City of Waynesboro, VA, Craig County, VA, Dickenson County, VA, Floyd County, VA, Franklin County, VA, Giles County, VA, Grayson County, VA, Henry County, VA, Highland County, VA, Lee County, VA, Montgomery County, VA, Nelson County, VA, Patrick County, VA, Pulaski County, VA, Roanoke County, VA, Rockbridge County, VA, Russell County, VA, Scott County, VA, Smyth County, VA, Tazewell County, VA, Washington County, VA, Wise County, VA, Wythe County, VA, Boone County, WV, Braxton County, WV, Clay County, WV, Fayette County, WV, Greenbrier County, WV, Kanawha County, WV, Logan County, WV, McDowell County, WV, Mercer County, WV, Mingo County, WV, Monroe County, WV, Nicholas County, WV, Pendleton County, WV, Pocahontas County, WV, Raleigh County, WV, Randolph County, WV, Summers County, WV, Webster County, WV, Wyoming County, WV

The radar

The Roanoke radar (KFCX), 139 km from the middle of the area, began a volume at 18:41 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

Greensboro/Hi Pt, NC (KGSO), launched 12:00Z, 6.7 hours before the alert went out and 204 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, Greensboro/Hi Pt, NC at 12:00Z on 2003-07-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2475 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, Greensboro/Hi Pt, NC at 12:00Z on 2003-07-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 3 square meters per square second.1939Sfc1 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
2475 J/kg
Mixed-layer CIN
-7 J/kg
Mixed-layer LCL
548 m above ground
0-6 km bulk shear
9 kt
0-1 km storm-relative helicity
3 m²/s²
0-3 km storm-relative helicity
-9 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.

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 21, 6:03 AM EDTMesoscale DiscussionSPCBoone, Campbell, Carroll, Gallatin, Grant, Henry and 5 more117 min
Jul 21, 6:10 AM EDTSevere Thunderstorm WatchSPCBoone, Bracken, Campbell, Carroll, Gallatin, Grant and 2 more6 hr
Jul 21, 7:39 AM EDTMesoscale DiscussionSPCBoyd, Bracken, Carter, Fleming, Greenup, Harrison and 5 more96 min
Jul 21, 8:03 AM EDTMesoscale DiscussionSPCAllen, Anderson, Barren, Breckinridge, Bullitt, Butler and 31 more117 min
Jul 21, 8:40 AM EDTSevere Thunderstorm WatchSPCBath, Boyd, Carter, Elliott, Greenup, Lawrence and 3 more5 hr
Jul 21, 11:27 AM EDTMesoscale DiscussionSPCBoone, Breckinridge, Bullitt, Butler, Caldwell, Carroll and 33 more2 hr
Jul 21, 12:55 PM EDTSevere Thunderstorm WatchSPCAdair, Allen, Barren, Boyle, Butler, Caldwell and 34 more6 hr
Jul 21, 4:14 PM EDTMesoscale DiscussionSPCAllen, Christian, Cumberland, Logan, Monroe, Muhlenberg and 3 more2 hr
Jul 21, 4:50 PM EDTSevere Thunderstorm WatchSPCAnderson, Bledsoe, Blount, Bradley, Campbell, Claiborne and 21 more4 hr

Nearby

Mesoscale Discussions in Virginia, 2003Mesoscale Discussions in North Carolina, 2003Mesoscale Discussions in Tennessee, 2003Every 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.