Alert archive / Virginia / Severe Thunderstorm Watches in 2000

Severe Thunderstorm Watch 192

April 21, 20004 states

The Storm Prediction Center issued this severe thunderstorm watch at Apr 21, 2000, 12:00 PM EDT for 4 states. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Apr 21, 2000, 12:00 PM EDT (16:00 UTC)
Expired
Apr 21, 2000, 5:00 PM EDT
In force
5 hr
Issued by
the Storm Prediction Center
All 80 counties

New Castle County, DE, 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, Washington County, MD, Amelia County, VA, Arlington County, VA, Brunswick County, VA, Buckingham County, VA, Caroline County, VA, Charles City County, VA, Charlotte 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 Petersburg, VA, City of Richmond, VA, City of Williamsburg, VA, Clarke County, VA, Culpeper County, VA, Cumberland County, VA, Dinwiddie County, VA, Essex County, VA, Fairfax County, VA, Fauquier County, VA, Fluvanna 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, Louisa County, VA, Lunenburg County, VA, Mecklenburg County, VA, Middlesex County, VA, New Kent County, VA, Northumberland County, VA, Nottoway County, VA, Orange County, VA, Powhatan County, VA, Prince Edward 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, Jefferson County, WV

The radar

The Norfolk radar (KAKQ), 105 km from the middle of the area, began a volume at 16:02 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

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

IssuedProductOfficeCountiesLasted
Apr 21, 12:49 PM EDTSevere Thunderstorm WarningAKQDorchester31 min
Apr 21, 1:18 PM EDTSevere Thunderstorm WarningAKQCumberland, Powhatan32 min
Apr 21, 1:32 PM EDTSevere Thunderstorm WarningLWXCulpeper, Fauquier, Spotsylvania, Stafford43 min
Apr 21, 1:53 PM EDTSevere Thunderstorm WarningAKQGoochland32 min
Apr 21, 2:10 PM EDTSevere Thunderstorm WarningLWXCharles, Prince George's50 min
Apr 21, 2:10 PM EDTSevere Thunderstorm WarningLWXPrince William50 min
Apr 21, 2:21 PM EDTSevere Thunderstorm WarningLWXSpotsylvania, City of Fredericksburg24 min
Apr 21, 2:24 PM EDTSevere Thunderstorm WarningAKQHanover, Henrico31 min
Apr 21, 2:33 PM EDTTornado WarningLWXCharles27 min
Apr 21, 2:43 PM EDTSevere Thunderstorm WarningAKQAmelia, Nottoway32 min
Apr 21, 2:49 PM EDTSevere Thunderstorm WarningAKQCaroline, King William31 min
Apr 21, 3:03 PM EDTSevere Thunderstorm WarningLWXAnne Arundel, Prince George's57 min
Apr 21, 3:03 PM EDTSevere Thunderstorm WarningLWXCharles57 min
Apr 21, 3:20 PM EDTSevere Thunderstorm WarningAKQChesterfield, Dinwiddie30 min
Apr 21, 3:23 PM EDTSevere Thunderstorm WarningAKQEssex, King and Queen32 min
Apr 21, 3:48 PM EDTSevere Thunderstorm WarningAKQHenrico32 min
Apr 21, 4:04 PM EDTSevere Thunderstorm WarningPHIQueen Anne's, Talbot41 min
Apr 21, 4:10 PM EDTSevere Thunderstorm WarningAKQNew Kent30 min
Apr 21, 4:16 PM EDTSevere Thunderstorm WarningLWXHoward, Montgomery59 min
Apr 21, 4:35 PM EDTSevere Thunderstorm WarningAKQNorthumberland, Westmoreland30 min
Apr 21, 4:39 PM EDTSevere Thunderstorm WarningLWXPrince George's36 min

The nearest sounding before it

Washington/Dulle, VA (KIAD), launched 12:00Z, 4.0 hours before the alert went out and 127 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 2000-04-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2000-04-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 230 square meters per square second.19395878Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
626 m above ground
0-6 km bulk shear
52 kt
0-1 km storm-relative helicity
230 m²/s²
0-3 km storm-relative helicity
254 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.

959 
WWUS9 KMKC 211543
SEL2  
MKC WW 211542 COR
DCZ000-MDZ000-VAZ000-212100-

URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 192
STORM PREDICTION CENTER NORMAN OK
1133 AM EDT FRI APR 21 2000

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

   DISTRICT OF COLUMBIA
   MARYLAND                           
   CHESAPEAKE BAY          
   EASTERN VIRGINIA                           

EFFECTIVE THIS FRIDAY AFTERNOON FROM NOON EDT UNTIL 500 PM EDT.

HAIL TO 2 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 60 STATUTE MILES
EAST AND WEST OF A LINE FROM 70 MILES SOUTH SOUTHWEST OF RICHMOND
VIRGINIA TO 35 MILES NORTH OF BALTIMORE MARYLAND.

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.


DISCUSSION...UPPER LOW OH VALLEY SPREADING MID LEVEL COLD ADVECTION
AND STRONG MID/UPPER WIND FIELDS ACROSS MID ATLANTIC STATES. 
AIRMASS RAPIDLY DESTABILIZING WITH ONLY A WEAK CAP. STORMS SHOULD
DEVELOP QUICKLY WITH INITIALLY LARGE HAIL POTENTIAL SPREADING EWD
ACROSS VA AND NRN MD.  SUPERCELL POTENTIAL WILL DEVELOP AS STORMS
MOVE INTO ERN VA WHERE SHEAR PROFILES AND INSTABILITY WILL BE
GREATER DURING THE AFTERNOON.


AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 2 INCHES.  EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 450.  MEAN STORM
MOTION VECTOR 24035.


...HALES

363,0785 394,0774 394,0753 363,0764

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 21, 4:00 PM EDTSevere Thunderstorm WatchSPCKent, New Castle, Sussex6 hr

Nearby

Severe Thunderstorm Watches in Virginia, 2000Severe Thunderstorm Watches in Maryland, 2000Severe Thunderstorm Watches in Delaware, 2000Every severe thunderstorm watch in 2000

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.