Alert archive / Virginia / Severe Thunderstorm Watches in 2012
Severe Thunderstorm Watch 441
The Storm Prediction Center issued this severe thunderstorm watch at Jul 1, 2012, 9:44 AM EDT for 4 states. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 1, 2012, 9:44 AM EDT (13:44 UTC)
- Expired
- Jul 1, 2012, 2:52 PM EDT
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 2 in
- Strongest gust expected
- 60 kt
All 43 counties
Alleghany County, NC, Ashe County, NC, Caswell County, NC, Rockingham County, NC, Stokes County, NC, Surry County, NC, Watauga County, NC, Wilkes County, NC, Yadkin County, NC, Carter County, TN, Johnson County, TN, Sullivan County, TN, Bland County, VA, Buchanan County, VA, Carroll County, VA, City of Bristol, VA, City of Danville, VA, City of Galax, VA, City of Martinsville, VA, City of Norton, VA, City of Radford, VA, City of Roanoke, VA, City of Salem, VA, Dickenson County, VA, Floyd County, VA, Franklin County, VA, Giles County, VA, Grayson County, VA, Henry County, VA, Montgomery County, VA, Patrick County, VA, Pittsylvania County, VA, Pulaski County, VA, Roanoke County, VA, Russell County, VA, Scott 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 Roanoke radar (KFCX), 80 km from the middle of the area, began a volume at 13:45 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
- 50%
- One or more gusts of 65 knots or more
- 40%
- Ten or more severe hail reports
- 50%
- One or more hailstones of 2 inches or more
- 30%
- Six or more combined severe hail and wind reports
- 90%
Warnings issued inside it
14 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 1, 9:46 AM EDT | Severe Thunderstorm Warning | RLX | Buchanan, Dickenson | 44 min |
| Jul 1, 10:06 AM EDT | Severe Thunderstorm Warning | RLX | Buchanan | 39 min |
| Jul 1, 10:09 AM EDT | Severe Thunderstorm Warning | MRX | Russell | 51 min |
| Jul 1, 10:10 AM EDT | Severe Thunderstorm Warning | RNK | Smyth, Tazewell | 65 min |
| Jul 1, 10:29 AM EDT | Severe Thunderstorm Warning | RLX | Buchanan, Dickenson | 18 min |
| Jul 1, 10:36 AM EDT | Severe Thunderstorm Warning | MRX | Washington | 39 min |
| Jul 1, 10:56 AM EDT | Severe Thunderstorm Warning | RNK | Bland, Grayson, Smyth, Tazewell, Wythe | 50 min |
| Jul 1, 11:20 AM EDT | Severe Thunderstorm Warning | RNK | Bland, Carroll, Grayson, Patrick, Pulaski, Wythe and 1 more | 55 min |
| Jul 1, 11:38 AM EDT | Severe Thunderstorm Warning | RNK | Alleghany, Ashe, Stokes, Surry, Wilkes, Yadkin | 52 min |
| Jul 1, 11:55 AM EDT | Severe Thunderstorm Warning | RNK | Carroll, Floyd, Patrick, Pulaski, Wythe | 52 min |
| Jul 1, 12:26 PM EDT | Severe Thunderstorm Warning | RNK | Rockingham, Stokes, Surry, Yadkin | 45 min |
| Jul 1, 12:53 PM EDT | Severe Thunderstorm Warning | RNK | Caswell, Rockingham, Stokes | 52 min |
| Jul 1, 1:22 PM EDT | Severe Thunderstorm Warning | RNK | Campbell, Charlotte, Halifax, Pittsylvania | 36 min |
| Jul 1, 1:45 PM EDT | Severe Thunderstorm Warning | RNK | Caswell | 60 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
Roanoke, VA (KRNK), launched 12:00Z, 1.7 hours before the alert went out and 149 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
- 1644 J/kg
- Mixed-layer CIN
- -125 J/kg
- Mixed-layer LCL
- 1572 m above ground
- 0-6 km bulk shear
- 36 kt
- 0-1 km storm-relative helicity
- 3 m²/s²
- 0-3 km storm-relative helicity
- 51 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- -0.1
The text
As transmitted, in the capitals the NWS used until 2016.
162
WWUS20 KWNS 011345
SEL1
SPC WW 011345
NCZ000-TNZ000-VAZ000-WVZ000-011900-
URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 441
NWS STORM PREDICTION CENTER NORMAN OK
945 AM EDT SUN JUL 1 2012
THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
EXTREME NORTHWEST NORTH CAROLINA
EXTREME NORTHEAST TENNESSEE
SOUTHWEST VIRGINIA
EXTREME SOUTHERN WEST VIRGINIA
EFFECTIVE THIS SUNDAY MORNING AND AFTERNOON FROM 945 AM UNTIL 300
PM EDT.
HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.
THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 40
STATUTE MILES NORTH AND SOUTH OF A LINE FROM 40 MILES NORTH OF
BRISTOL TENNESSEE TO 50 MILES SOUTHEAST OF ROANOKE VIRGINIA. FOR
A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU1).
REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR 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. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.
DISCUSSION...A CLUSTER OF ELEVATED THUNDERSTORMS THIS MORNING WILL
CONTINUE TO MOVE ESEWD TOWARD SW VA WITH AN ATTENDANT RISK FOR LARGE
HAIL. THESE STORMS ARE EMBEDDED IN A BELT OF 35-45 KT MIDLEVEL
FLOW...WITH VERY STEEP MIDLEVEL LAPSE RATES OBSERVED IN 12Z
SOUNDINGS. ONCE THE BOUNDARY LAYER WARMS INTO THE 90S ACROSS SW
VA/NW NC...CONVECTION WILL LIKELY BECOME SURFACE-BASED WITH THE
POTENTIAL FOR SOME UPSCALE GROWTH AND AN INCREASE IN DAMAGING WIND
POTENTIAL.
AVIATION...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 550. MEAN STORM
MOTION VECTOR 29035.
...THOMPSONSPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 1, 9:27 AM EDT | Mesoscale Discussion | SPC | Alleghany, Ashe, Forsyth, Rockingham, Stokes, Surry and 3 more | 63 min |
| Jul 1, 11:38 AM EDT | Mesoscale Discussion | SPC | Alamance, Alexander, Alleghany, Ashe, Avery, Caldwell and 12 more | 97 min |
| Jul 1, 12:56 PM EDT | Severe Thunderstorm Watch | SPC | Alamance, Anson, Beaufort, Bertie, Camden, Carteret and 51 more | 7 hr |
| Jul 1, 1:39 PM EDT | Mesoscale Discussion | SPC | Alexander, Anson, Buncombe, Burke, Cabarrus, Catawba and 24 more | 96 min |
| Jul 1, 2:01 PM EDT | Severe Thunderstorm Watch | SPC | Bladen, Brunswick, Cabarrus, Catawba, Cleveland, Columbus and 12 more | 9 hr |
| Jul 1, 2:53 PM EDT | Mesoscale Discussion | SPC | Beaufort, Bertie, Bladen, Camden, Carteret, Chowan and 37 more | 97 min |
| Jul 1, 4:15 PM EDT | Mesoscale Discussion | SPC | Bladen, Brunswick, Columbus, Duplin, New Hanover, Pender and 3 more | 90 min |
| Jul 1, 7:04 PM EDT | Mesoscale Discussion | SPC | Alamance, Beaufort, Bertie, Camden, Carteret, Caswell and 40 more | 56 min |
| Jul 1, 7:39 PM EDT | Mesoscale Discussion | SPC | Anson, Bladen, Brunswick, Cabarrus, Cleveland, Columbus and 14 more | 96 min |
| Jul 1, 2:08 PM EDT | Mesoscale Discussion | SPC | Bradley, Franklin, Giles, Grundy, Hamilton, Hardin and 7 more | 3 hr |
| Jul 1, 4:32 PM EDT | Severe Thunderstorm Watch | SPC | Boone, Brooke, Cabell, Calhoun, Clay, Doddridge and 18 more | 6 hr |
| Jul 1, 7:22 PM EDT | Mesoscale Discussion | SPC | Brooke, Hancock, Ohio | 83 min |
Nearby
Severe Thunderstorm Watches in Virginia, 2012Severe Thunderstorm Watches in North Carolina, 2012Severe Thunderstorm Watches in Tennessee, 2012Every severe thunderstorm watch in 2012
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.