Alert archive / Virginia / Severe Thunderstorm Watches in 2011

Severe Thunderstorm Watch 110

April 8, 20114 states

The Storm Prediction Center issued this severe thunderstorm watch at Apr 8, 2011, 11:07 PM EDT for 4 states. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Apr 8, 2011, 11:07 PM EDT (03:07 UTC)
Expired
Apr 9, 2011, 5:00 AM EDT
In force
6 hr
Issued by
the Storm Prediction Center
Largest hail expected
1.5 in
Strongest gust expected
60 kt
All 43 counties

Breathitt County, KY, Estill County, KY, Floyd County, KY, Knott County, KY, Lee County, KY, Letcher County, KY, Magoffin County, KY, Owsley County, KY, Perry County, KY, Pike County, KY, Powell County, KY, Wolfe County, KY, Alleghany County, NC, Ashe County, NC, Rockingham County, NC, Stokes County, NC, Surry County, NC, Watauga County, NC, Wilkes County, NC, Yadkin County, NC, Bland County, VA, Buchanan County, VA, Carroll County, VA, City of Bristol, VA, City of Galax, VA, City of Martinsville, VA, City of Norton, VA, City of Radford, VA, Dickenson County, VA, Floyd County, VA, Giles County, VA, Grayson County, VA, Henry County, VA, Patrick County, VA, Pulaski County, VA, Russell County, VA, Smyth County, VA, Tazewell County, VA, Washington County, VA, Wise County, VA, Wythe County, VA, McDowell County, WV, Mercer County, WV

The radar

The Jackson,KY radar (KJKL), 136 km from the middle of the area, began a volume at 03:09 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
30%
One or more gusts of 65 knots or more
5%
Ten or more severe hail reports
40%
One or more hailstones of 2 inches or more
5%
Six or more combined severe hail and wind reports
60%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Apr 8, 11:11 PM EDTSevere Thunderstorm WarningRNKBland, Smyth, Tazewell, Wythe49 min
Apr 8, 11:26 PM EDTSevere Thunderstorm WarningJKLBreathitt, Lee, Magoffin, Wolfe49 min
Apr 8, 11:53 PM EDTSevere Thunderstorm WarningJKLFloyd, Knott, Letcher, Pike37 min
Apr 8, 11:58 PM EDTSevere Thunderstorm WarningRNKRockingham, Stokes32 min
Apr 9, 12:00 AM EDTSevere Thunderstorm WarningRNKBland, Carroll, Grayson, Smyth, Wythe30 min
Apr 9, 12:03 AM EDTSevere Thunderstorm WarningJKLBreathitt, Knott, Perry42 min
Apr 9, 12:03 AM EDTSevere Thunderstorm WarningRLXBuchanan, Dickenson42 min
Apr 9, 12:27 AM EDTSevere Thunderstorm WarningRNKAlleghany, Surry48 min
Apr 9, 12:46 AM EDTSevere Thunderstorm WarningMRXRussell, Washington, Wise59 min
Apr 9, 12:56 AM EDTTornado WarningRNKAlleghany, Surry34 min
Apr 9, 1:26 AM EDTSevere Thunderstorm WarningRNKStokes, Surry, Yadkin35 min
Apr 9, 1:28 AM EDTSevere Thunderstorm WarningRNKAlleghany, Surry, Wilkes, Yadkin35 min
Apr 9, 2:34 AM EDTSevere Thunderstorm WarningRNKAlleghany, Ashe41 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

Greensboro/Hi Pt, NC (KGSO), launched 00:00Z, 3.1 hours before the alert went out and 212 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 00:00Z on 2011-04-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 42 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 00:00Z on 2011-04-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 279 square meters per square second.1939587897Sfc1 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
42 J/kg
Mixed-layer CIN
-165 J/kg
Mixed-layer LCL
1618 m above ground
0-6 km bulk shear
56 kt
0-1 km storm-relative helicity
279 m²/s²
0-3 km storm-relative helicity
424 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.3

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 9, 12:42 AM EDTMesoscale DiscussionSPCKnott, Letcher, Perry93 min
Apr 9, 7:41 AM EDTMesoscale DiscussionSPCAdair, Allen, Anderson, Barren, Bourbon, Boyle and 72 more2 hr
Apr 9, 8:25 AM EDTSevere Thunderstorm WatchSPCAdair, Allen, Anderson, Ballard, Barren, Bourbon and 72 more6 hr
Apr 9, 12:07 PM EDTMesoscale DiscussionSPCBath, Bell, Breathitt, Clark, Clay, Clinton and 25 more83 min
Apr 9, 12:34 PM EDTSevere Thunderstorm WatchSPCBath, Bell, Boyd, Breathitt, Carter, Clay and 30 more4 hr
Apr 9, 2:00 PM EDTTornado WatchSPCBell, Boyd, Breathitt, Carter, Clay, Elliott and 27 more7 hr
Apr 8, 9:10 PM EDTMesoscale DiscussionSPCAlamance, Caswell, Chatham, Davidson, Durham, Forsyth and 11 more65 min
Apr 9, 3:23 AM EDTMesoscale DiscussionSPCAlexander, Alleghany, Ashe, Avery, Burke, Cabarrus and 19 more67 min
Apr 9, 2:44 PM EDTSevere Thunderstorm WatchSPCAlexander, Anson, Cabarrus, Catawba, Cleveland, Davie and 7 more6 hr
Apr 9, 4:21 PM EDTMesoscale DiscussionSPCAshe, Avery, Buncombe, Burke, Caldwell, Cherokee and 15 more84 min
Apr 9, 5:36 PM EDTMesoscale DiscussionSPCCleveland, Gaston, Lincoln, Mecklenburg, Polk, Rutherford and 1 more54 min
Apr 9, 6:16 PM EDTTornado WatchSPCBuncombe, Burke, Cleveland, Gaston, Haywood, Henderson and 10 more6 hr
Apr 9, 7:59 PM EDTMesoscale DiscussionSPCAnson, Buncombe, Burke, Cabarrus, Catawba, Cleveland and 13 more61 min

Nearby

Severe Thunderstorm Watches in Virginia, 2011Severe Thunderstorm Watches in Kentucky, 2011Severe Thunderstorm Watches in North Carolina, 2011Every 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.