Alert archive / Virginia / Severe Thunderstorm Watches in 2011
Severe Thunderstorm Watch 59
The Storm Prediction Center issued this severe thunderstorm watch at Mar 23, 2011, 6:04 PM EDT for 22 counties in North Carolina; 43 counties in Virginia. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- Mar 23, 2011, 6:04 PM EDT (22:04 UTC)
- Expired
- Mar 24, 2011, 1:00 AM EDT
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 60 kt
All 65 counties
Alamance County, NC, Bertie County, NC, Chatham County, NC, Davidson County, NC, Durham County, NC, Edgecombe County, NC, Forsyth County, NC, Franklin County, NC, Gates County, NC, Granville County, NC, Guilford County, NC, Halifax County, NC, Hertford County, NC, Nash County, NC, Northampton County, NC, Orange County, NC, Person County, NC, Randolph County, NC, Vance County, NC, Wake County, NC, Warren County, NC, Wilson County, NC, Amelia County, VA, Brunswick County, VA, Caroline County, VA, Charles City County, VA, Chesterfield County, 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 Petersburg, VA, City of Poquoson, VA, City of Richmond, VA, City of Suffolk, VA, City of Williamsburg, VA, Cumberland County, VA, Dinwiddie County, VA, Essex County, VA, Fluvanna County, VA, Gloucester County, VA, Goochland 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, Louisa County, VA, Lunenburg County, VA, Mathews County, VA, Mecklenburg County, VA, Middlesex County, VA, New Kent County, VA, Nottoway County, VA, Powhatan County, VA, Prince Edward County, VA, Prince George County, VA, Southampton County, VA, Surry County, VA, Sussex County, VA, York County, VA
The radar
The Norfolk radar (KAKQ), 80 km from the middle of the area, began a volume at 22:04 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
- 30%
- 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
- 70%
Warnings issued inside it
7 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 23, 6:51 PM EDT | Severe Thunderstorm Warning | RAH | Alamance, Durham, Guilford, Orange, Person | 39 min |
| Mar 23, 6:54 PM EDT | Severe Thunderstorm Warning | AKQ | Amelia, Nottoway | 51 min |
| Mar 23, 7:06 PM EDT | Severe Thunderstorm Warning | AKQ | Amelia, Chesterfield, Dinwiddie, Powhatan | 39 min |
| Mar 23, 7:31 PM EDT | Severe Thunderstorm Warning | RAH | Durham, Franklin, Granville, Orange, Vance, Wake | 59 min |
| Mar 23, 9:13 PM EDT | Severe Thunderstorm Warning | RAH | Granville, Person | 47 min |
| Mar 23, 9:39 PM EDT | Severe Thunderstorm Warning | AKQ | Essex, King and Queen, King William, Lancaster, Middlesex, Northumberland and 1 more | 21 min |
| Mar 23, 10:44 PM EDT | Severe Thunderstorm Warning | RAH | Durham, Franklin, Granville, Wake | 46 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, 10.1 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 1256 m above ground
- 0-6 km bulk shear
- 67 kt
- 0-1 km storm-relative helicity
- 199 m²/s²
- 0-3 km storm-relative helicity
- 271 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 |
|---|---|---|---|---|
| Mar 23, 3:38 PM EDT | Mesoscale Discussion | SPC | Alleghany, Ashe, Avery, Caldwell, Mitchell, Watauga and 2 more | 37 min |
| Mar 23, 3:45 PM EDT | Tornado Watch | SPC | Alexander, Alleghany, Ashe, Avery, Buncombe, Burke and 21 more | 6 hr |
| Mar 23, 4:48 PM EDT | Mesoscale Discussion | SPC | Alamance, Alexander, Alleghany, Anson, Ashe, Avery and 53 more | 57 min |
| Mar 23, 7:10 PM EDT | Mesoscale Discussion | SPC | Alamance, Alexander, Alleghany, Anson, Ashe, Avery and 53 more | 65 min |
| Mar 23, 12:02 PM EDT | Mesoscale Discussion | SPC | Buchanan, Dickenson | 88 min |
| Mar 23, 1:13 PM EDT | Tornado Watch | SPC | Buchanan, Dickenson | 7 hr |
| Mar 23, 3:54 PM EDT | Mesoscale Discussion | SPC | Albemarle, Alleghany, Amherst, Appomattox, Augusta, Bath and 51 more | 96 min |
| Mar 23, 4:13 PM EDT | Severe Thunderstorm Watch | SPC | Albemarle, Arlington, Augusta, Clarke, Culpeper, Fairfax and 27 more | 5 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.