Alert archive / Virginia / Tornado Watches in 2011

Tornado Watch 32

February 28, 201110 counties in Maryland; 73 counties in Virginia; 12 counties in West Virginia

The Storm Prediction Center issued this tornado watch at Feb 28, 2011, 8:57 AM EST for 10 counties in Maryland; 73 counties in Virginia; 12 counties in West Virginia. It was in force for 9 hr.

The area

The outline as issued.

The facts

Issued: Feb 28, 2011, 8:57 AM EST (13:57 UTC)
Expired: Feb 28, 2011, 5:51 PM EST
In force: 9 hr
Issued by: the Storm Prediction Center
Largest hail expected: 0.5 in
Strongest gust expected: 60 kt

All 95 counties

Allegany County, MD, Calvert County, MD, Carroll County, MD, Charles County, MD, Frederick County, MD, Howard County, MD, Montgomery County, MD, Prince George's County, MD, Saint Mary's County, MD, Washington County, MD, Albemarle County, VA, Alleghany County, VA, Amherst County, VA, Appomattox County, VA, Arlington County, VA, Augusta County, VA, Bath County, VA, Bedford County, VA, Bland County, VA, Botetourt County, VA, Buckingham County, VA, Campbell County, VA, Carroll County, VA, Charlotte County, VA, City of Alexandria, VA, City of Buena Vista, VA, City of Charlottesville, VA, City of Covington, VA, City of Danville, VA, City of Fairfax, VA, City of Falls Church, VA, City of Fredericksburg, VA, City of Galax, VA, City of Harrisonburg, VA, City of Lexington, VA, City of Lynchburg, VA, City of Manassas, VA, City of Manassas Park, VA, City of Martinsville, VA, City of Radford, VA, City of Roanoke, VA, City of Salem, VA, City of Staunton, VA, City of Waynesboro, VA, City of Winchester, VA, Clarke County, VA, Craig County, VA, Culpeper County, VA, Fairfax County, VA, Fauquier County, VA, Floyd County, VA, Fluvanna County, VA, Franklin County, VA, Frederick County, VA, Giles County, VA, Grayson County, VA, Greene County, VA, Halifax County, VA, Henry County, VA, Highland County, VA, King George County, VA, Loudoun County, VA, Louisa County, VA, Madison County, VA, Montgomery County, VA, Nelson County, VA, Orange County, VA, Page County, VA, Patrick County, VA, Pittsylvania County, VA, Prince William County, VA, Pulaski County, VA, Rappahannock County, VA, Roanoke County, VA, Rockbridge County, VA, Rockingham County, VA, Shenandoah County, VA, Smyth County, VA, Spotsylvania County, VA, Stafford County, VA, Tazewell County, VA, Warren County, VA, Wythe County, VA, Berkeley County, WV, Grant County, WV, Greenbrier County, WV, Hampshire County, WV, Hardy County, WV, Jefferson County, WV, Mercer County, WV, Mineral County, WV, Monroe County, WV, Morgan County, WV, Pendleton County, WV, Summers County, WV

The radar

The Sterling radar (KLWX), 158 km from the middle of the area, began a volume at 13:57 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: 40%
One or more gusts of 65 knots or more: 30%
Ten or more severe hail reports: 10%
One or more hailstones of 2 inches or more: 5%
Six or more combined severe hail and wind reports: 70%

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
Feb 28, 9:24 AM EST	Severe Thunderstorm Warning	RNK	Greenbrier, Summers	66 min
Feb 28, 9:40 AM EST	Severe Thunderstorm Warning	LWX	Allegany, Frederick, Washington	50 min
Feb 28, 10:13 AM EST	Severe Thunderstorm Warning	LWX	Highland	32 min
Feb 28, 10:40 AM EST	Severe Thunderstorm Warning	RNK	Giles	35 min
Feb 28, 12:39 PM EST	Severe Thunderstorm Warning	LWX	Calvert, Charles, Prince George's, Saint Mary's	32 min
Feb 28, 2:42 PM EST	Severe Thunderstorm Warning	RNK	Carroll, Patrick	33 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, 2.0 hours before the alert went out and 140 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.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 4 J/kg
Mixed-layer CIN: -263 J/kg
Mixed-layer LCL: 825 m above ground
0-6 km bulk shear: 57 kt
0-1 km storm-relative helicity: 268 m²/s²
0-3 km storm-relative helicity: 373 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

023 
WWUS20 KWNS 281358
SEL2
SPC WW 281358
DCZ000-MDZ000-VAZ000-WVZ000-CWZ000-282100-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 32
NWS STORM PREDICTION CENTER NORMAN OK
900 AM EST MON FEB 28 2011

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF

       DISTRICT OF COLUMBIA
       MARYLAND
       WESTERN AND CENTRAL VIRGINIA
       SOUTHEAST WEST VIRGINIA
       COASTAL WATERS

EFFECTIVE THIS MONDAY MORNING AND AFTERNOON FROM 900 AM UNTIL 400
PM EST.

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 20 MILES NORTH OF MARTINSBURG
WEST VIRGINIA TO 45 MILES SOUTH SOUTHEAST OF DUBLIN VIRGINIA.
FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU2).

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 29...WW 30...WW 31...

DISCUSSION...QLCS CURRENTLY MOVING THROUGH THE CNTRL APPALACHIANS IS
EXPECTED TO MOVE E OF THE BLUE RIDGE BY LATE MORNING.  AIR MASS E OF
THE HIGHER TERRAIN IS CHARACTERIZED BY STEEP MIDLEVEL LAPSE RATES
AND A WARMING/MOISTENING BOUNDARY LAYER.  GIVEN THE STRONG VERTICAL
SHEAR IN PLACE...SETUP WILL REMAIN FAVORABLE FOR EMBEDDED BOWING
AND/OR SUPERCELL FEATURES WITH THE THREAT FOR DAMAGING WINDS AND
PERHAPS A TORNADO OR TWO.

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 26040.


...MEAD

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Feb 28, 8:36 AM EST	Mesoscale Discussion	SPC	Allegany, Carroll, Frederick, Garrett, Howard, Montgomery and 1 more	24 min
Feb 28, 12:49 PM EST	Mesoscale Discussion	SPC	Calvert, Caroline, Charles, Dorchester, Saint Mary's, Somerset and 2 more	56 min
Feb 28, 5:47 AM EST	Tornado Watch	SPC	Buchanan, Dickenson, Lee, Russell, Scott, Washington and 3 more	5 hr
Feb 28, 6:59 AM EST	Tornado Watch	SPC	Lee, Russell, Scott, Washington, Wise, City of Bristol and 1 more	7 hr
Feb 28, 12:25 PM EST	Mesoscale Discussion	SPC	Russell, Scott, Washington, City of Bristol	95 min
Feb 28, 4:36 PM EST	Mesoscale Discussion	SPC	City of Danville	84 min
Feb 28, 5:31 AM EST	Mesoscale Discussion	SPC	Boone, Braxton, Brooke, Cabell, Calhoun, Clay and 27 more	29 min

Nearby

Tornado Watches in Virginia, 2011 Tornado Watches in West Virginia, 2011 Tornado Watches in Maryland, 2011 Every 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.