Alert archive / Virginia / Severe Thunderstorm Watches in 2011
Severe Thunderstorm Watch 897
The Storm Prediction Center issued this severe thunderstorm watch at Dec 7, 2011, 5:56 PM EST for 33 counties in North Carolina; 45 counties in Virginia. It was in force for 4 hr.
The area
The outline as issued.
The facts
- Issued
- Dec 7, 2011, 5:56 PM EST (22:56 UTC)
- Expired
- Dec 7, 2011, 9:40 PM EST
- In force
- 4 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 0.5 in
- Strongest gust expected
- 60 kt
All 78 counties
Beaufort County, NC, Bertie County, NC, Camden County, NC, Carteret County, NC, Chowan County, NC, Craven County, NC, Currituck County, NC, Dare County, NC, Duplin County, NC, Edgecombe County, NC, Franklin County, NC, Gates County, NC, Greene County, NC, Halifax County, NC, Hertford County, NC, Hyde County, NC, Johnston County, NC, Jones County, NC, Lenoir County, NC, Martin County, NC, Nash County, NC, Northampton County, NC, Onslow County, NC, Pamlico County, NC, Pasquotank County, NC, Perquimans County, NC, Pitt County, NC, Sampson County, NC, Tyrrell County, NC, Warren County, NC, Washington County, NC, Wayne County, NC, Wilson County, NC, Accomack County, VA, Amelia County, VA, Brunswick County, VA, Charles City County, VA, Chesterfield County, VA, City of Chesapeake, VA, City of Colonial Heights, VA, City of Emporia, VA, City of Franklin, VA, City of Hampton, VA, City of Hopewell, VA, City of Newport News, VA, City of Norfolk, VA, City of Petersburg, VA, City of Poquoson, VA, City of Portsmouth, VA, City of Richmond, VA, City of Suffolk, VA, City of Virginia Beach, VA, City of Williamsburg, VA, Dinwiddie County, VA, Essex County, VA, Gloucester County, VA, Greensville County, VA, Hanover County, VA, Henrico County, VA, Isle of Wight County, VA, James City County, VA, King and Queen County, VA, King William County, VA, Lancaster County, VA, Lunenburg County, VA, Mathews County, VA, Mecklenburg County, VA, Middlesex County, VA, New Kent County, VA, Northampton County, VA, Northumberland County, VA, Nottoway County, VA, Prince George County, VA, Richmond County, VA, Southampton County, VA, Surry County, VA, Sussex County, VA, York County, VA
The radar
The Norfolk radar (KAKQ), 105 km from the middle of the area, began a volume at 22:55 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
- 10%
- 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
- 60%
Warnings issued inside it
6 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Dec 7, 6:06 PM EST | Severe Thunderstorm Warning | RAH | Edgecombe, Johnston, Sampson, Wayne, Wilson | 39 min |
| Dec 7, 6:10 PM EST | Severe Thunderstorm Warning | RAH | Edgecombe, Franklin, Halifax, Nash, Warren | 65 min |
| Dec 7, 6:11 PM EST | Severe Thunderstorm Warning | AKQ | Amelia, Cumberland, Lunenburg, Nottoway, Powhatan, Prince Edward | 19 min |
| Dec 7, 7:01 PM EST | Severe Thunderstorm Warning | AKQ | Charles City, Chesterfield, Hanover, Henrico, New Kent, Prince George and 2 more | 30 min |
| Dec 7, 7:28 PM EST | Severe Thunderstorm Warning | AKQ | Charles City, Gloucester, James City, King and Queen, King William, Middlesex and 2 more | 47 min |
| Dec 7, 8:31 PM EST | Severe Thunderstorm Warning | AKQ | City of Chesapeake, City of Norfolk, City of Virginia Beach | 29 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
Newport, NC (KMHX), launched 12:00Z, 10.9 hours before the alert went out and 141 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
- 27 J/kg
- Mixed-layer CIN
- -7 J/kg
- Mixed-layer LCL
- 594 m above ground
- 0-6 km bulk shear
- 46 kt
- 0-1 km storm-relative helicity
- 112 m²/s²
- 0-3 km storm-relative helicity
- 163 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 |
|---|---|---|---|---|
| Dec 7, 4:56 PM EST | Mesoscale Discussion | SPC | Beaufort, Bertie, Camden, Chowan, Edgecombe, Franklin and 20 more | 94 min |
| Dec 7, 5:42 PM EST | Mesoscale Discussion | SPC | Beaufort, Bertie, Camden, Chowan, Currituck, Edgecombe and 19 more | 33 min |
| Dec 7, 2:44 PM EST | Mesoscale Discussion | SPC | Highland | 3 hr |
Nearby
Severe Thunderstorm Watches in Virginia, 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.