Alert archive / Virginia / Severe Thunderstorm Watches in 2004

Severe Thunderstorm Watch 521

June 25, 20046 states

The Storm Prediction Center issued this severe thunderstorm watch at Jun 25, 2004, 1:45 PM EDT for 6 states. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued: Jun 25, 2004, 1:45 PM EDT (17:45 UTC)
Expired: Jun 25, 2004, 9:00 PM EDT
In force: 7 hr
Issued by: the Storm Prediction Center

All 86 counties

Kent County, DE, New Castle County, DE, Anne Arundel County, MD, Baltimore County, MD, Calvert County, MD, Caroline 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, Washington County, MD, Burlington County, NJ, Camden County, NJ, Cumberland County, NJ, Gloucester County, NJ, Mercer County, NJ, Monmouth County, NJ, Ocean County, NJ, Salem County, NJ, Adams County, PA, Bucks County, PA, Chester County, PA, Cumberland County, PA, Delaware County, PA, Franklin County, PA, Fulton County, PA, Lancaster County, PA, Lebanon County, PA, Montgomery County, PA, Philadelphia County, PA, York County, PA, Albemarle County, VA, Arlington County, VA, Augusta County, VA, Bath County, VA, Caroline County, VA, City of Alexandria, VA, City of Charlottesville, VA, City of Fairfax, VA, City of Falls Church, VA, City of Fredericksburg, VA, City of Harrisonburg, VA, City of Manassas, VA, City of Manassas Park, VA, City of Staunton, VA, City of Waynesboro, VA, City of Winchester, VA, Clarke County, VA, Culpeper County, VA, Essex County, VA, Fairfax County, VA, Fauquier County, VA, Frederick County, VA, Greene County, VA, Highland County, VA, King George County, VA, Loudoun County, VA, Louisa County, VA, Madison County, VA, Orange County, VA, Page County, VA, Prince William County, VA, Rappahannock County, VA, Richmond County, VA, Rockingham County, VA, Shenandoah County, VA, Spotsylvania County, VA, Stafford County, VA, Warren County, VA, Westmoreland County, VA, Berkeley County, WV, Hampshire County, WV, Hardy County, WV, Jefferson County, WV, Morgan County, WV, Pendleton County, WV

The radar

The Sterling radar (KLWX), 16 km from the middle of the area, began a volume at 17:47 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

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

Issued	Product	Office	Counties	Lasted
Jun 25, 3:17 PM EDT	Flash Flood Warning	PHI	New Castle	85 days
Jun 25, 3:24 PM EDT	Severe Thunderstorm Warning	PHI	New Castle	51 min
Jun 25, 3:45 PM EDT	Severe Thunderstorm Warning	CTP	Cumberland	45 min
Jun 25, 4:25 PM EDT	Flash Flood Warning	LWX	Calvert	3 hr
Jun 25, 5:11 PM EDT	Flash Flood Warning	PHI	Kent	85 days
Jun 25, 6:29 PM EDT	Severe Thunderstorm Warning	PHI	Bucks	61 min
Jun 25, 6:53 PM EDT	Severe Thunderstorm Warning	CTP	Lancaster	37 min
Jun 25, 7:25 PM EDT	Flash Flood Warning	PHI	Berks, Chester, Delaware	85 days

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, 5.8 hours before the alert went out and 22 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: 375 J/kg
Mixed-layer CIN: -86 J/kg
Mixed-layer LCL: 1108 m above ground
0-6 km bulk shear: 37 kt
0-1 km storm-relative helicity: -6 m²/s²
0-3 km storm-relative helicity: 43 m²/s²
Significant tornado parameter: -0.0
Supercell composite: -0.4

Open this sounding in Storm Lab

The text

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

000 
WWUS20 KWNS 251752
SEL1  
SPC WW 251745
DCZ000-DEZ000-MDZ000-NJZ000-PAZ000-VAZ000-WVZ000-260100-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 521
NWS STORM PREDICTION CENTER NORMAN OK
145 PM EDT FRI JUN 25 2004

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

       DISTRICT OF COLUMBIA
       DELAWARE
       NORTHERN AND PART OF EASTERN MARYLAND
       CENTRAL AND SOUTHERN NEW JERSEY
       SOUTHEAST AND SOUTH CENTRAL PENNSYLVANIA
       NORTHERN VIRGINIA
       EASTERN WEST VIRGINIA PANHANDLE

EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 145 PM UNTIL 900
PM EDT.

HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE SEVERE THUNDERSTORM WATCH AREA IS ALONG AND 110 STATUTE MILES
EAST AND WEST OF A LINE FROM 55 MILES EAST NORTHEAST OF HARRISBURG
PENNSYLVANIA TO 20 MILES SOUTHEAST OF CHARLOTTESVILLE VIRGINIA.

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...SEVERE THUNDERSTORM THREAT EXPECTED TO INCREASE OVER
THE NEXT FEW HOURS ACROSS THIS REGION AS AIR MASS UNDERGOES FURTHER
DESTABILIZATION AND CAP WEAKENS.  STORMS WILL CONTINUE TO SPREAD NWD
OUT OF CENTRAL VA AND DEVELOP INVOF STATIONARY SURFACE FRONT/HIGHER
TERRAIN ACROSS SRN/ERN PA AND POSSIBLY INTO NRN NJ.  SHEAR REMAINS
MODEST...THOUGH STILL SUFFICIENT...FOR ORGANIZED CLUSTERS/LINES. 
PRIMARY SEVERE THREATS WILL BE FROM DAMAGING WINDS AND ISOLATED
LARGE HAIL AS STORMS DEVELOP/MOVE ENEWD THROUGH THE EARLY EVENING.

AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. MEAN STORM
MOTION VECTOR 24020.


...EVANS

402,0734 375,0760 375,0801 402,0775

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 25, 1:08 PM EDT	Mesoscale Discussion	SPC	Kent, New Castle	2 hr
Jun 25, 4:14 PM EDT	Mesoscale Discussion	SPC	New Castle	2 hr
Jun 24, 8:10 PM EDT	Severe Thunderstorm Watch	SPC	Allegheny, Armstrong, Beaver, Blair, Butler, Cambria and 26 more	5 hr
Jun 24, 10:28 PM EDT	Mesoscale Discussion	SPC	Allegheny, Armstrong, Beaver, Blair, Butler, Cambria and 23 more	2 hr
Jun 25, 12:34 PM EDT	Mesoscale Discussion	SPC	Accomack, Brunswick, Charles City, Dinwiddie, Gloucester, Greensville and 29 more	116 min

Nearby

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