Alert archive / Virginia / Severe Thunderstorm Watches in 2004

Severe Thunderstorm Watch 586

July 7, 200417 counties in Maryland; 9 counties in Pennsylvania; 54 counties in Virginia

The Storm Prediction Center issued this severe thunderstorm watch at Jul 7, 2004, 1:15 PM EDT for 17 counties in Maryland; 9 counties in Pennsylvania; 54 counties in Virginia. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Jul 7, 2004, 1:15 PM EDT (17:15 UTC)
Expired
Jul 7, 2004, 6:00 PM EDT
In force
5 hr
Issued by
the Storm Prediction Center
All 80 counties

Anne Arundel County, MD, Baltimore County, MD, Calvert County, MD, Carroll County, MD, Cecil County, MD, Charles County, MD, City of Baltimore, MD, Dorchester County, MD, Frederick County, MD, Harford County, MD, Howard County, MD, Kent County, MD, Montgomery County, MD, Prince George's County, MD, Queen Anne's County, MD, Saint Mary's County, MD, Talbot County, MD, Adams County, PA, Berks County, PA, Chester County, PA, Cumberland County, PA, Dauphin County, PA, Lancaster County, PA, Lebanon County, PA, Perry County, PA, York County, PA, Amelia County, VA, Arlington County, VA, Brunswick County, VA, Caroline County, VA, Charles City County, VA, Chesterfield County, VA, City of Alexandria, VA, City of Colonial Heights, VA, City of Emporia, VA, City of Fairfax, VA, City of Falls Church, VA, City of Franklin, VA, City of Fredericksburg, VA, City of Hopewell, VA, City of Manassas, VA, City of Manassas Park, VA, City of Newport News, VA, City of Petersburg, VA, City of Poquoson, VA, City of Portsmouth, VA, City of Richmond, VA, City of Suffolk, VA, City of Williamsburg, VA, Dinwiddie County, VA, Essex County, VA, Fairfax 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, Loudoun County, VA, Mathews County, VA, Middlesex County, VA, New Kent County, VA, Northumberland County, VA, Nottoway County, VA, Powhatan County, VA, Prince George County, VA, Prince William 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 Sterling radar (KLWX), 98 km from the middle of the area, began a volume at 17:14 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

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

IssuedProductOfficeCountiesLasted
Jul 7, 1:25 PM EDTSevere Thunderstorm WarningLWXFrederick, Washington50 min
Jul 7, 1:35 PM EDTSevere Thunderstorm WarningAKQCaroline, Essex, King and Queen25 min
Jul 7, 2:01 PM EDTSevere Thunderstorm WarningAKQPrince George29 min
Jul 7, 2:10 PM EDTSevere Thunderstorm WarningAKQEssex, Lancaster, Northumberland, Richmond, Westmoreland50 min
Jul 7, 2:19 PM EDTSevere Thunderstorm WarningAKQSurry, Sussex26 min
Jul 7, 2:30 PM EDTSevere Thunderstorm WarningAKQPrince George30 min
Jul 7, 2:39 PM EDTSevere Thunderstorm WarningLWXSaint Mary's51 min
Jul 7, 2:42 PM EDTSevere Thunderstorm WarningAKQSurry33 min
Jul 7, 2:46 PM EDTSevere Thunderstorm WarningAKQDinwiddie, Greensville, Southampton, Sussex, City of Emporia29 min
Jul 7, 2:51 PM EDTSevere Thunderstorm WarningLWXAnne Arundel39 min
Jul 7, 2:57 PM EDTSevere Thunderstorm WarningLWXBaltimore, City of Baltimore63 min
Jul 7, 3:17 PM EDTSevere Thunderstorm WarningAKQSouthampton, Sussex28 min
Jul 7, 3:20 PM EDTSevere Thunderstorm WarningLWXFairfax, City of Fairfax40 min
Jul 7, 3:27 PM EDTSevere Thunderstorm WarningLWXMontgomery48 min
Jul 7, 3:28 PM EDTSevere Thunderstorm WarningAKQIsle of Wight, Surry32 min
Jul 7, 3:29 PM EDTFlash Flood WarningLWXBaltimore, City of Baltimore3 hr
Jul 7, 3:54 PM EDTSevere Thunderstorm WarningAKQIsle of Wight, Surry21 min
Jul 7, 3:55 PM EDTSevere Thunderstorm WarningAKQJames City, York, City of Hampton, City of Newport News, City of Poquoson, City of Williamsburg35 min
Jul 7, 4:19 PM EDTSevere Thunderstorm WarningLWXPrince George's41 min
Jul 7, 4:34 PM EDTSevere Thunderstorm WarningLWXAnne Arundel56 min
Jul 7, 4:38 PM EDTSevere Thunderstorm WarningAKQCity of Chesapeake, City of Norfolk, City of Portsmouth22 min
Jul 7, 4:46 PM EDTSevere Thunderstorm WarningAKQCity of Suffolk29 min
Jul 7, 4:47 PM EDTSevere Thunderstorm WarningLWXCity of Baltimore43 min
Jul 7, 4:59 PM EDTSevere Thunderstorm WarningLWXBaltimore46 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

Washington/Dulle, VA (KIAD), launched 12:00Z, 5.3 hours before the alert went out and 93 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-pSkew-T log-p diagram, Washington/Dulle, VA at 12:00Z on 2004-07-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 455 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Washington/Dulle, VA at 12:00Z on 2004-07-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 36 square meters per square second.1939Sfc1 km3 km6 km9 kmRMLM
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
455 J/kg
Mixed-layer CIN
-139 J/kg
Mixed-layer LCL
1252 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
36 m²/s²
0-3 km storm-relative helicity
73 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 7, 11:49 AM EDTMesoscale DiscussionSPCCalvert, Charles, Saint Mary's56 min
Jul 7, 2:35 PM EDTMesoscale DiscussionSPCAnne Arundel, Baltimore, Calvert, Carroll, Cecil, Charles and 11 more55 min

Nearby

Severe Thunderstorm Watches in Virginia, 2004Severe Thunderstorm Watches in Maryland, 2004Severe Thunderstorm Watches in Pennsylvania, 2004Every severe thunderstorm 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.