Alert archive / Virginia / Severe Thunderstorm Watches in 2011
Severe Thunderstorm Watch 49
The Storm Prediction Center issued this severe thunderstorm watch at Mar 10, 2011, 1:25 PM EST for 37 counties in North Carolina; 89 counties in Virginia. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- Mar 10, 2011, 1:25 PM EST (18:25 UTC)
- Expired
- Mar 10, 2011, 7:56 PM EST
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1 in
- Strongest gust expected
- 60 kt
All 126 counties
Alamance County, NC, Bertie County, NC, Caswell County, NC, Chatham County, NC, Cumberland County, NC, Duplin County, NC, Durham County, NC, Edgecombe County, NC, Franklin County, NC, Gates County, NC, Granville County, NC, Greene County, NC, Guilford County, NC, Halifax County, NC, Harnett County, NC, Hertford County, NC, Hoke County, NC, Johnston County, NC, Lee County, NC, Lenoir County, NC, Martin County, NC, Montgomery County, NC, Moore County, NC, Nash County, NC, Northampton County, NC, Orange County, NC, Person County, NC, Pitt County, NC, Randolph County, NC, Richmond County, NC, Rockingham County, NC, Sampson County, NC, Vance County, NC, Wake County, NC, Warren County, NC, Wayne County, NC, Wilson County, NC, Albemarle County, VA, Alleghany County, VA, Amelia County, VA, Amherst County, VA, Appomattox County, VA, Arlington County, VA, Augusta County, VA, Bath County, VA, Bedford County, VA, Botetourt County, VA, Brunswick County, VA, Buckingham County, VA, Campbell County, VA, Caroline County, VA, Charles City County, VA, Charlotte County, VA, Chesterfield County, VA, City of Alexandria, VA, City of Buena Vista, VA, City of Charlottesville, VA, City of Colonial Heights, VA, City of Covington, VA, City of Danville, VA, City of Emporia, VA, City of Fairfax, VA, City of Falls Church, VA, City of Franklin, VA, City of Fredericksburg, VA, City of Harrisonburg, VA, City of Hopewell, VA, City of Lexington, VA, City of Lynchburg, VA, City of Manassas, VA, City of Manassas Park, VA, City of Martinsville, VA, City of Petersburg, VA, City of Richmond, VA, City of Roanoke, VA, City of Salem, VA, City of Staunton, VA, City of Suffolk, VA, City of Waynesboro, VA, Culpeper County, VA, Cumberland County, VA, Dinwiddie County, VA, Essex County, VA, Fairfax County, VA, Fauquier County, VA, Fluvanna County, VA, Franklin County, VA, Goochland County, VA, Greene County, VA, Greensville County, VA, Halifax County, VA, Hanover County, VA, Henrico County, VA, Henry County, VA, Highland County, VA, Isle of Wight County, VA, James City County, VA, King and Queen County, VA, King George County, VA, King William County, VA, Loudoun County, VA, Louisa County, VA, Lunenburg County, VA, Madison County, VA, Mecklenburg County, VA, Nelson County, VA, New Kent County, VA, Nottoway County, VA, Orange County, VA, Page County, VA, Pittsylvania County, VA, Powhatan County, VA, Prince Edward County, VA, Prince George County, VA, Prince William County, VA, Rappahannock County, VA, Richmond County, VA, Roanoke County, VA, Rockbridge County, VA, Rockingham County, VA, Southampton County, VA, Spotsylvania County, VA, Stafford County, VA, Surry County, VA, Sussex County, VA, Westmoreland County, VA
The radar
The Roanoke radar (KFCX), 123 km from the middle of the area, began a volume at 18:25 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
- 60%
- One or more gusts of 65 knots or more
- 20%
- Ten or more severe hail reports
- 20%
- One or more hailstones of 2 inches or more
- 5%
- Six or more combined severe hail and wind reports
- 80%
Warnings issued inside it
24 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 10, 2:35 PM EST | Flash Flood Warning | LWX | Albemarle, Augusta, Nelson, City of Charlottesville, City of Staunton, City of Waynesboro | 4 hr |
| Mar 10, 3:05 PM EST | Flash Flood Warning | RNK | Amherst, Botetourt, Rockbridge, City of Buena Vista, City of Lexington | 5 hr |
| Mar 10, 3:38 PM EST | Severe Thunderstorm Warning | RNK | Charlotte, Halifax | 41 min |
| Mar 10, 3:47 PM EST | Severe Thunderstorm Warning | AKQ | Lunenburg, Mecklenburg, Prince Edward | 58 min |
| Mar 10, 4:10 PM EST | Severe Thunderstorm Warning | AKQ | Cumberland, Prince Edward | 50 min |
| Mar 10, 4:16 PM EST | Severe Thunderstorm Warning | RNK | Appomattox, Buckingham | 46 min |
| Mar 10, 4:36 PM EST | Flash Flood Warning | LWX | Albemarle, Culpeper, Fauquier, Greene, King George, Madison and 5 more | 3 hr |
| Mar 10, 4:38 PM EST | Severe Thunderstorm Warning | AKQ | Northampton | 52 min |
| Mar 10, 4:50 PM EST | Severe Thunderstorm Warning | RAH | Edgecombe, Nash, Wayne, Wilson | 55 min |
| Mar 10, 5:02 PM EST | Severe Thunderstorm Warning | LWX | Culpeper, Fauquier, Madison, Page, Rappahannock, Warren | 58 min |
| Mar 10, 5:15 PM EST | Severe Thunderstorm Warning | AKQ | Caroline, Goochland, Hanover, Louisa, Powhatan | 60 min |
| Mar 10, 5:18 PM EST | Severe Thunderstorm Warning | LWX | Culpeper, Fauquier, Madison, Orange, Spotsylvania, Stafford and 1 more | 57 min |
| Mar 10, 5:26 PM EST | Severe Thunderstorm Warning | RAH | Edgecombe, Halifax, Nash | 42 min |
| Mar 10, 5:28 PM EST | Severe Thunderstorm Warning | AKQ | Charles City, Chesterfield, Dinwiddie, Hanover, Henrico, New Kent and 6 more | 47 min |
| Mar 10, 5:34 PM EST | Severe Thunderstorm Warning | LWX | Clarke, Fauquier, Frederick, Loudoun, Warren, City of Winchester | 41 min |
| Mar 10, 5:48 PM EST | Flash Flood Warning | LWX | Arlington, Fairfax, Fauquier, King George, Loudoun, Prince William and 6 more | 4 hr |
| Mar 10, 6:07 PM EST | Flash Flood Warning | LWX | Loudoun | 3 hr |
| Mar 10, 6:10 PM EST | Severe Thunderstorm Warning | AKQ | Charles City, Essex, Gloucester, Hanover, Henrico, James City and 7 more | 50 min |
| Mar 10, 6:10 PM EST | Severe Thunderstorm Warning | LWX | Culpeper, Fairfax, Fauquier, King George, Loudoun, Orange and 7 more | 65 min |
| Mar 10, 6:14 PM EST | Tornado Warning | LWX | Fauquier, Prince William | 31 min |
| Mar 10, 6:20 PM EST | Severe Thunderstorm Warning | AKQ | Caroline, Essex, King and Queen, King William, Richmond, Westmoreland | 40 min |
| Mar 10, 6:53 PM EST | Severe Thunderstorm Warning | AKQ | Essex, Gloucester, King and Queen, Lancaster, Mathews, Middlesex and 4 more | 52 min |
| Mar 10, 6:58 PM EST | Tornado Warning | LWX | Fairfax, Loudoun, Prince William, City of Manassas, City of Manassas Park | 32 min |
| Mar 10, 7:06 PM EST | Severe Thunderstorm Warning | LWX | Fairfax | 54 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, 6.4 hours before the alert went out and 55 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
- 8 J/kg
- Mixed-layer CIN
- -47 J/kg
- Mixed-layer LCL
- 486 m above ground
- 0-6 km bulk shear
- 77 kt
- 0-1 km storm-relative helicity
- 170 m²/s²
- 0-3 km storm-relative helicity
- 217 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
461
WWUS20 KWNS 101825
SEL9
SPC WW 101825
NCZ000-VAZ000-110100-
URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 49
NWS STORM PREDICTION CENTER NORMAN OK
125 PM EST THU MAR 10 2011
THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
LARGE PART OF CENTRAL AND EASTERN NORTH CAROLINA
A LARGE PART OF CENTRAL AND SOUTHERN VIRGINIA
EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 125 PM UNTIL
800 PM EST.
HAIL TO 1 INCH 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 65
STATUTE MILES EAST AND WEST OF A LINE FROM 35 MILES NORTH OF
CHARLOTTESVILLE VIRGINIA TO 10 MILES SOUTH SOUTHWEST OF
FAYETTEVILLE NORTH CAROLINA. FOR A COMPLETE DEPICTION OF THE
WATCH SEE THE ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU9).
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...AS STRONG UPPER TROUGH APPROACHES AREA FROM THE
SW...AIR MASS HAS BECOME SUFFICIENTLY UNSTABLE TO SUPPORT
THUNDERSTORMS. WITH 50-60KT BRN SHEAR...THUNDERSTORMS WILL DEVELOP
INTO SHORT LINE SEGMENTS/BOWS AS THEY MOVE RAPIDLY NEWD. PRIMARY
THREAT WILL BE DAMAGING WINDS...HOWEVER A BRIEF TORNADO OR TWO IS
POSSIBLE GIVEN THE STRONG LOW LEVEL SHEAR.
AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 1 INCH. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60 KNOTS.
A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 400. MEAN STORM MOTION
VECTOR 22035.
...HALESSPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 10, 12:51 PM EST | Mesoscale Discussion | SPC | Alamance, Bladen, Caswell, Chatham, Columbus, Cumberland and 22 more | 114 min |
| Mar 10, 4:26 PM EST | Mesoscale Discussion | SPC | Northampton | 94 min |
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.