Alert archive / Virginia / Tornado Watches in 2004

Tornado Watch 846

September 28, 20047 counties in Maryland; 9 counties in North Carolina; 51 counties in Virginia

The Storm Prediction Center issued this tornado watch at Sep 28, 2004, 11:25 AM EDT for 7 counties in Maryland; 9 counties in North Carolina; 51 counties in Virginia. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued: Sep 28, 2004, 11:25 AM EDT (15:25 UTC)
Expired: Sep 28, 2004, 5:00 PM EDT
In force: 6 hr
Issued by: the Storm Prediction Center

All 67 counties

Calvert County, MD, Charles County, MD, Dorchester County, MD, Saint Mary's County, MD, Somerset County, MD, Wicomico County, MD, Worcester County, MD, Camden County, NC, Chowan County, NC, Currituck County, NC, Gates County, NC, Halifax County, NC, Hertford County, NC, Northampton County, NC, Pasquotank County, NC, Perquimans County, NC, Accomack County, VA, Amelia County, VA, Brunswick County, VA, Caroline 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 Fredericksburg, 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, 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 George County, VA, King William County, VA, Lancaster County, VA, Louisa County, VA, Mathews County, VA, Middlesex County, VA, New Kent County, VA, Northampton County, VA, Northumberland County, VA, Powhatan County, VA, Prince George County, VA, Richmond County, VA, Southampton County, VA, Spotsylvania County, VA, Stafford County, VA, Surry County, VA, Sussex County, VA, Westmoreland County, VA, York County, VA

The radar

The Norfolk radar (KAKQ), 15 km from the middle of the area, began a volume at 15:25 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.

Warnings issued inside it

4 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
Sep 28, 11:44 AM EDT	Tornado Warning	AKQ	Camden, Pasquotank	16 min
Sep 28, 12:29 PM EDT	Tornado Warning	AKQ	Chesterfield	16 min
Sep 28, 2:00 PM EDT	Severe Thunderstorm Warning	AKQ	Essex, King and Queen	30 min
Sep 28, 2:17 PM EDT	Severe Thunderstorm Warning	AKQ	Richmond, Westmoreland	28 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

Wallops Is Stn, VA (KWAL), launched 12:00Z, 3.4 hours before the alert went out and 162 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: 1005 J/kg
Mixed-layer CIN: -7 J/kg
Mixed-layer LCL: 483 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 93 m²/s²
0-3 km storm-relative helicity: 119 m²/s²
Significant tornado parameter: 0.3
Supercell composite: 2.1

Open this sounding in Storm Lab

The text

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

000 
WWUS20 KWNS 281527
SEL6  
SPC WW 281525
MDZ000-NCZ000-VAZ000-CWZ000-282100-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 846...CORRECTED
NWS STORM PREDICTION CENTER NORMAN OK
1125 AM EDT TUE SEP 28 2004

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

       SOUTHEAST MARYLAND
       NORTHEAST NORTH CAROLINA
       EASTERN VIRGINIA
       COASTAL WATERS

EFFECTIVE THIS TUESDAY MORNING AND AFTERNOON FROM 1125 AM UNTIL
500 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 ALONG AND 75 STATUTE MILES EAST AND WEST
OF A LINE FROM 20 MILES NORTH NORTHWEST OF PATUXENT RIVER MARYLAND
TO 30 MILES WEST SOUTHWEST OF ELIZABETH CITY NORTH CAROLINA.

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.

DISCUSSION...AIRMASS OVER WATCH AREA IS SLOWLY DESTABILIZING WITH
DEWPOINTS NOW IN THE MID 70S AND MUCAPE VALUES OVER 2000 J/KG. LOCAL
VAD PROFILES ALSO SHOW STRONG LOW LEVEL VERTICAL SHEAR PROFILES ARE
IN PLACE OVER THIS REGION.  ISOLATED MINI-SUPERCELLS AND THE THREAT
OF TORNADOES WILL INCREASE THROUGH THE AFTERNOON AS FURTHER
DESTABILIZATION OCCURS.

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 500.
MEAN STORM MOTION VECTOR 18035.

...HART

383,0750 360,0751 360,0780 383,0775

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Sep 28, 8:56 AM EDT	Mesoscale Discussion	SPC	Dorchester, Somerset, Wicomico, Worcester	2 hr
Sep 28, 1:49 PM EDT	Mesoscale Discussion	SPC	Anne Arundel, Baltimore, Calvert, Caroline, Cecil, Charles and 13 more	116 min
Sep 28, 2:25 PM EDT	Tornado Watch	SPC	Anne Arundel, Baltimore, Caroline, Cecil, Harford, Howard and 5 more	7 hr
Sep 28, 4:36 PM EDT	Mesoscale Discussion	SPC	Anne Arundel, Baltimore, Calvert, Caroline, Carroll, Cecil and 13 more	114 min
Sep 27, 9:10 PM EDT	Tornado Watch	SPC	Anson, Bladen, Brunswick, Chatham, Columbus, Cumberland and 15 more	7 hr
Sep 28, 12:46 AM EDT	Mesoscale Discussion	SPC	Anson, Bladen, Brunswick, Cabarrus, Chatham, Columbus and 16 more	89 min
Sep 28, 2:59 AM EDT	Mesoscale Discussion	SPC	Chatham, Cumberland, Durham, Harnett, Johnston, Lee and 5 more	2 hr

Nearby

Tornado Watches in Virginia, 2004 Tornado Watches in North Carolina, 2004 Tornado Watches in Maryland, 2004 Every tornado watch in 2004

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.