Alert archive / Virginia / Tornado Watches in 2011
Tornado Watch 361
The Storm Prediction Center issued this tornado watch at May 24, 2011, 4:43 PM EDT for 14 counties in North Carolina; 19 counties in Virginia. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- May 24, 2011, 4:43 PM EDT (20:43 UTC)
- Expired
- May 24, 2011, 10:00 PM EDT
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
All 33 counties
Alamance County, NC, Alleghany County, NC, Ashe County, NC, Caswell County, NC, Forsyth County, NC, Guilford County, NC, Orange County, NC, Person County, NC, Rockingham County, NC, Stokes County, NC, Surry County, NC, Watauga County, NC, Wilkes County, NC, Yadkin County, NC, Bland County, VA, Carroll County, VA, City of Danville, VA, City of Galax, VA, City of Martinsville, VA, City of Radford, VA, Floyd County, VA, Franklin County, VA, Giles County, VA, Grayson County, VA, Halifax County, VA, Henry County, VA, Montgomery County, VA, Patrick County, VA, Pittsylvania County, VA, Pulaski County, VA, Smyth County, VA, Tazewell County, VA, Wythe County, VA
The radar
The Roanoke radar (KFCX), 36 km from the middle of the area, began a volume at 20:44 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
- 40%
- One or more EF2 to EF5 tornadoes
- 20%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 30%
- Ten or more severe hail reports
- 40%
- One or more hailstones of 2 inches or more
- 30%
- Six or more combined severe hail and wind reports
- 70%
Warnings issued inside it
21 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 24, 5:29 PM EDT | Severe Thunderstorm Warning | RNK | Carroll, Floyd, Grayson, Pulaski, Wythe, City of Galax | 61 min |
| May 24, 5:33 PM EDT | Severe Thunderstorm Warning | RNK | Alleghany, Ashe, Surry, Watauga, Wilkes | 57 min |
| May 24, 5:47 PM EDT | Severe Thunderstorm Warning | RNK | Ashe, Watauga, Wilkes | 58 min |
| May 24, 5:51 PM EDT | Tornado Warning | RNK | Alleghany, Ashe, Wilkes | 39 min |
| May 24, 6:05 PM EDT | Severe Thunderstorm Warning | RNK | Carroll, Floyd, Franklin, Henry, Patrick, City of Martinsville | 55 min |
| May 24, 6:08 PM EDT | Flash Flood Warning | RNK | Alleghany, Ashe, Watauga, Wilkes | 5 hr |
| May 24, 6:20 PM EDT | Flash Flood Warning | RNK | Carroll, Floyd, Franklin, Grayson, Patrick, City of Galax | 5 hr |
| May 24, 6:22 PM EDT | Severe Thunderstorm Warning | RNK | Carroll, Henry, Patrick | 53 min |
| May 24, 6:25 PM EDT | Severe Thunderstorm Warning | RNK | Alleghany, Ashe, Watauga, Wilkes | 65 min |
| May 24, 6:35 PM EDT | Severe Thunderstorm Warning | RNK | Stokes, Surry | 55 min |
| May 24, 6:46 PM EDT | Severe Thunderstorm Warning | RNK | Franklin, Henry, Pittsylvania | 59 min |
| May 24, 6:47 PM EDT | Tornado Warning | RNK | Wilkes | 28 min |
| May 24, 6:55 PM EDT | Severe Thunderstorm Warning | RNK | Alleghany, Stokes, Surry, Wilkes, Yadkin | 65 min |
| May 24, 7:14 PM EDT | Severe Thunderstorm Warning | RNK | Caswell | 61 min |
| May 24, 7:14 PM EDT | Tornado Warning | RNK | Wilkes, Yadkin | 46 min |
| May 24, 7:23 PM EDT | Severe Thunderstorm Warning | RNK | Surry, Wilkes, Yadkin | 67 min |
| May 24, 7:38 PM EDT | Severe Thunderstorm Warning | RNK | Campbell, Charlotte, Halifax, Pittsylvania | 52 min |
| May 24, 7:40 PM EDT | Severe Thunderstorm Warning | RNK | Rockingham, Stokes | 65 min |
| May 24, 7:56 PM EDT | Severe Thunderstorm Warning | RNK | Yadkin | 49 min |
| May 24, 8:10 PM EDT | Severe Thunderstorm Warning | RNK | Caswell, Rockingham | 43 min |
| May 24, 8:25 PM EDT | Tornado Warning | RNK | Caswell, Rockingham | 34 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, 8.7 hours before the alert went out and 93 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
- 451 J/kg
- Mixed-layer CIN
- -124 J/kg
- Mixed-layer LCL
- 1350 m above ground
- 0-6 km bulk shear
- 35 kt
- 0-1 km storm-relative helicity
- 4 m²/s²
- 0-3 km storm-relative helicity
- 99 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- -0.2
The text
As transmitted, in the capitals the NWS used until 2016.
142
WWUS20 KWNS 242038
SEL1
SPC WW 242038
NCZ000-VAZ000-250200-
URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 361
NWS STORM PREDICTION CENTER NORMAN OK
440 PM EDT TUE MAY 24 2011
THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF
NORTHERN NORTH CAROLINA
SOUTH CENTRAL VIRGINIA
EFFECTIVE THIS TUESDAY AFTERNOON AND EVENING FROM 440 PM UNTIL
1000 PM EDT.
TORNADOES...HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.
THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 45 STATUTE
MILES NORTH AND SOUTH OF A LINE FROM 50 MILES SOUTHWEST OF
BLUEFIELD WEST VIRGINIA TO 40 MILES NORTH NORTHEAST OF RALEIGH
NORTH CAROLINA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU1).
REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.
OTHER WATCH INFORMATION...CONTINUE...WW 354...WW 355...WW
356...WW 357...WW 358...WW 359...WW 360...
DISCUSSION...ISOLATED THUNDERSTORMS ARE TRACK EASTWARD IN VICINITY
OF AN EXISTING OUTFLOW BOUNDARY OVER NORTHERN NC. OTHER STORMS ARE
SPREADING EASTWARD ACROSS EXTREME SOUTHWEST VA. DEEP LAYER VERTICAL
SHEAR IS SUFFICIENTLY STRONG TO PROMOTE SUPERCELL STORM
STRUCTURES...WHILE LOW LEVEL SHEAR NEAR THE BOUNDARY WILL POSE SOME
RISK OF BRIEF TORNADOES. LARGE HAIL AND DAMAGING WINDS WILL ALSO BE
POSSIBLE.
AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 27025.
...HARTSPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 24, 8:34 AM EDT | Mesoscale Discussion | SPC | Alamance, Alexander, Alleghany, Ashe, Avery, Caldwell and 13 more | 116 min |
| May 24, 10:00 AM EDT | Severe Thunderstorm Watch | SPC | Alleghany, Ashe, Caswell, Rockingham, Stokes, Surry and 3 more | 7 hr |
| May 24, 12:15 PM EDT | Mesoscale Discussion | SPC | Alamance, Bertie, Camden, Caswell, Chowan, Durham and 24 more | 90 min |
| May 24, 12:42 PM EDT | Severe Thunderstorm Watch | SPC | Alamance, Bertie, Camden, Chowan, Currituck, Durham and 20 more | 5 hr |
| May 24, 3:33 PM EDT | Mesoscale Discussion | SPC | Alamance, Alexander, Alleghany, Ashe, Avery, Bertie and 30 more | 87 min |
| May 24, 7:33 PM EDT | Mesoscale Discussion | SPC | Alamance, Alleghany, Ashe, Caswell, Durham, Forsyth and 11 more | 57 min |
| May 24, 7:01 AM EDT | Severe Thunderstorm Watch | SPC | Lee, Russell, Scott, Washington, Wise, City of Bristol and 1 more | 8 hr |
| May 24, 12:55 PM EDT | Mesoscale Discussion | SPC | Lee, Scott, Wise, City of Norton | 65 min |
| May 24, 1:57 PM EDT | Severe Thunderstorm Watch | SPC | Buchanan, Dickenson, Lee, Russell, Scott, Washington and 3 more | 6 hr |
| May 24, 4:27 PM EDT | Mesoscale Discussion | SPC | Buchanan, Dickenson, Lee, Russell, Scott, Tazewell and 4 more | 63 min |
| May 24, 7:46 PM EDT | Mesoscale Discussion | SPC | Lee, Russell, Scott, Washington, Wise, City of Bristol and 1 more | 59 min |
| May 23, 8:07 PM EDT | Mesoscale Discussion | SPC | Brooke, Hancock | 83 min |
| May 23, 8:31 PM EDT | Severe Thunderstorm Watch | SPC | Brooke, Cabell, Calhoun, Doddridge, Gilmer, Hancock and 15 more | 3 hr |
Nearby
Tornado Watches in Virginia, 2011Tornado Watches in North Carolina, 2011Every tornado 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.