Alert archive / North Carolina / Tornado Watches in 2011
Tornado Watch 846
The Storm Prediction Center issued this tornado watch at Sep 6, 2011, 9:51 AM EDT for 19 counties in North Carolina; 5 counties in South Carolina. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Sep 6, 2011, 9:51 AM EDT (13:51 UTC)
- Expired
- Sep 6, 2011, 4:16 PM EDT
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 0.5 in
- Strongest gust expected
- 60 kt
All 24 counties
Alexander County, NC, Avery County, NC, Burke County, NC, Cabarrus County, NC, Caldwell County, NC, Catawba County, NC, Cleveland County, NC, Davie County, NC, Gaston County, NC, Iredell County, NC, Lincoln County, NC, McDowell County, NC, Mecklenburg County, NC, Mitchell County, NC, Polk County, NC, Rowan County, NC, Rutherford County, NC, Union County, NC, Yancey County, NC, Cherokee County, SC, Chester County, SC, Spartanburg County, SC, Union County, SC, York County, SC
The radar
The Greer radar (KGSP), 107 km from the middle of the area, began a volume at 13:51 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
- 5%
- One or more hailstones of 2 inches or more
- 5%
- Six or more combined severe hail and wind reports
- 70%
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, 1.9 hours before the alert went out and 142 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
- 1434 J/kg
- Mixed-layer CIN
- 0 J/kg
- Mixed-layer LCL
- 515 m above ground
- 0-6 km bulk shear
- 40 kt
- 0-1 km storm-relative helicity
- 246 m²/s²
- 0-3 km storm-relative helicity
- 274 m²/s²
- Significant tornado parameter
- 1.9
- Supercell composite
- 11.1
The text
As transmitted, in the capitals the NWS used until 2016.
828
WWUS20 KWNS 061344
SEL6
SPC WW 061344
NCZ000-SCZ000-070000-
URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 846
NWS STORM PREDICTION CENTER NORMAN OK
945 AM EDT TUE SEP 6 2011
THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF
WESTERN NORTH CAROLINA
NORTHWEST SOUTH CAROLINA
EFFECTIVE THIS TUESDAY MORNING AND EVENING FROM 945 AM UNTIL 800
PM EDT.
TORNADOES...HAIL TO 0.5 INCH IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.
THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 60 STATUTE
MILES EAST AND WEST OF A LINE FROM 30 MILES NORTHEAST OF HICKORY
NORTH CAROLINA TO 40 MILES SOUTH SOUTHWEST OF CHARLOTTE NORTH
CAROLINA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU6).
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 845...
DISCUSSION...TSTMS SHOULD GRADUALLY INCREASE IN COVERAGE THIS
MORNING IN ADVANCE OF DEEP-LAYER CYCLONE LIFTING NWD THROUGH THE SRN
APPALACHIANS. 12Z RNK/GSO SOUNDINGS INDICATE THAT ENVIRONMENT IS
ALREADY NEARLY UNCAPPED AND FURTHER DAYTIME HEATING SHOULD BOOST
MLCAPE VALUES TO AOA 1000-1500 J/KG. GIVEN THAT THE WATCH AREA WILL
RESIDE BENEATH 50-60 KT SLY FLOW AT 500 MB WITH A SELY LOW-LEVEL
WIND FIELD...SUFFICIENT VERTICAL SHEAR WILL EXIST FOR SUPERCELLS
CAPABLE OF DAMAGING WINDS AND PERHAPS A COUPLE OF TORNADOES.
AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 0.5 INCH. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
400. MEAN STORM MOTION VECTOR 19030.
...MEADSPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 5, 8:36 PM EDT | Mesoscale Discussion | SPC | Anson, Cumberland, Hoke, Montgomery, Moore, Richmond and 3 more | 84 min |
| Sep 5, 11:47 PM EDT | Mesoscale Discussion | SPC | Stokes, Surry | 88 min |
| Sep 6, 3:30 AM EDT | Mesoscale Discussion | SPC | Rockingham, Stokes | 60 min |
| Sep 6, 4:36 AM EDT | Mesoscale Discussion | SPC | Alamance, Anson, Cabarrus, Caswell, Chatham, Davidson and 22 more | 84 min |
| Sep 6, 5:17 AM EDT | Tornado Watch | SPC | Alamance, Alleghany, Anson, Bladen, Brunswick, Caswell and 43 more | 9 hr |
| Sep 6, 8:35 AM EDT | Mesoscale Discussion | SPC | Alamance, Anson, Bladen, Brunswick, Cabarrus, Catawba and 42 more | 85 min |
| Sep 6, 12:41 PM EDT | Mesoscale Discussion | SPC | Alamance, Alleghany, Anson, Beaufort, Bertie, Bladen and 55 more | 64 min |
| Sep 6, 1:32 PM EDT | Tornado Watch | SPC | Alamance, Anson, Beaufort, Bertie, Bladen, Brunswick and 48 more | 7 hr |
| Sep 6, 4:41 PM EDT | Mesoscale Discussion | SPC | Alamance, Anson, Beaufort, Bertie, Bladen, Brunswick and 46 more | 64 min |
| Sep 6, 7:33 PM EDT | Mesoscale Discussion | SPC | Beaufort, Bertie, Bladen, Brunswick, Camden, Carteret and 38 more | 117 min |
| Sep 6, 10:11 AM EDT | Tornado Watch | SPC | Allendale, Bamberg, Barnwell, Beaufort, Berkeley, Calhoun and 15 more | 7 hr |
Nearby
Tornado Watches in North Carolina, 2011Tornado Watches in South 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.