Alert archive / Virginia / Severe Thunderstorm Watches in 2011
Severe Thunderstorm Watch 107
The Storm Prediction Center issued this severe thunderstorm watch at Apr 8, 2011, 6:15 PM EDT for 8 counties in North Carolina; 20 counties in Tennessee; 21 counties in Virginia. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 8, 2011, 6:15 PM EDT (22:15 UTC)
- Expired
- Apr 9, 2011, 12:00 AM EDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
All 49 counties
Alleghany County, NC, Ashe County, NC, Rockingham County, NC, Stokes County, NC, Surry County, NC, Watauga County, NC, Wilkes County, NC, Yadkin 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, Scott County, TN, Sevier County, TN, Sullivan County, TN, Unicoi County, TN, Union County, TN, Washington County, TN, Bland 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, Floyd County, VA, Giles County, VA, Grayson County, VA, Henry County, VA, Lee County, VA, Patrick County, VA, Pulaski County, VA, Russell County, VA, Scott County, VA, Smyth County, VA, Tazewell County, VA, Washington County, VA, Wise County, VA, Wythe County, VA
The radar
The Knoxville radar (KMRX), 139 km from the middle of the area, began a volume at 22:15 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
- 10%
- One or more EF2 to EF5 tornadoes
- 2%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 5%
- Ten or more severe hail reports
- 30%
- One or more hailstones of 2 inches or more
- 20%
- Six or more combined severe hail and wind reports
- 60%
Warnings issued inside it
22 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 8, 6:25 PM EDT | Severe Thunderstorm Warning | MRX | Russell, Washington | 65 min |
| Apr 8, 6:26 PM EDT | Severe Thunderstorm Warning | RNK | Craig, Giles, Montgomery, Roanoke | 20 min |
| Apr 8, 6:29 PM EDT | Severe Thunderstorm Warning | RNK | Bland, Giles, Pulaski | 61 min |
| Apr 8, 7:17 PM EDT | Severe Thunderstorm Warning | RNK | Bland, Pulaski, Wythe | 28 min |
| Apr 8, 7:19 PM EDT | Severe Thunderstorm Warning | MRX | Johnson | 47 min |
| Apr 8, 7:32 PM EDT | Tornado Warning | RNK | Carroll, Floyd, Pulaski | 28 min |
| Apr 8, 7:55 PM EDT | Severe Thunderstorm Warning | RNK | Alleghany, Ashe, Wilkes | 24 min |
| Apr 8, 7:59 PM EDT | Tornado Warning | RNK | Floyd, Patrick | 31 min |
| Apr 8, 8:29 PM EDT | Tornado Warning | RNK | Rockingham, Stokes | 31 min |
| Apr 8, 8:30 PM EDT | Severe Thunderstorm Warning | RNK | Rockingham | 30 min |
| Apr 8, 9:00 PM EDT | Severe Thunderstorm Warning | RNK | Caswell, Rockingham | 41 min |
| Apr 8, 9:29 PM EDT | Severe Thunderstorm Warning | RNK | Bland, Giles | 31 min |
| Apr 8, 9:50 PM EDT | Severe Thunderstorm Warning | RNK | Giles, Montgomery, Pulaski, City of Radford | 25 min |
| Apr 8, 9:58 PM EDT | Severe Thunderstorm Warning | RNK | Bland, Pulaski, Wythe | 32 min |
| Apr 8, 10:00 PM EDT | Severe Thunderstorm Warning | RNK | Bland | 30 min |
| Apr 8, 10:15 PM EDT | Severe Thunderstorm Warning | RNK | Floyd, Montgomery, Pulaski | 30 min |
| Apr 8, 10:29 PM EDT | Severe Thunderstorm Warning | RNK | Bland, Wythe | 14 min |
| Apr 8, 10:37 PM EDT | Severe Thunderstorm Warning | RNK | Carroll, Floyd, Pulaski | 23 min |
| Apr 8, 10:59 PM EDT | Severe Thunderstorm Warning | RNK | Stokes | 31 min |
| Apr 8, 11:11 PM EDT | Severe Thunderstorm Warning | RNK | Bland, Smyth, Tazewell, Wythe | 49 min |
| Apr 8, 11:58 PM EDT | Severe Thunderstorm Warning | RNK | Rockingham, Stokes | 32 min |
| Apr 9, 12:00 AM EDT | Severe Thunderstorm Warning | RNK | Bland, Carroll, Grayson, Smyth, Wythe | 30 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 12:00Z, 10.3 hours before the alert went out and 203 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.
- Mixed-layer CAPE
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1553 m above ground
- 0-6 km bulk shear
- 72 kt
- 0-1 km storm-relative helicity
- 159 m²/s²
- 0-3 km storm-relative helicity
- 315 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 8, 1:02 PM EDT | Mesoscale Discussion | SPC | Adair, Anderson, Barren, Bath, Boone, Bourbon and 85 more | 118 min |
| Apr 8, 2:53 PM EDT | Severe Thunderstorm Watch | SPC | Adair, Allen, Anderson, Barren, Bath, Bell and 80 more | 8 hr |
| Apr 8, 4:51 PM EDT | Mesoscale Discussion | SPC | Adair, Anderson, Barren, Bell, Boyd, Boyle and 59 more | 84 min |
| Apr 8, 7:35 PM EDT | Mesoscale Discussion | SPC | Bell, Breathitt, Clay, Elliott, Estill, Floyd and 25 more | 55 min |
Nearby
Severe Thunderstorm Watches in Virginia, 2011Severe Thunderstorm Watches in Tennessee, 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.