Alert archive / Virginia / Mesoscale Discussions in 2004

Mesoscale Discussion 2189

September 8, 2004Charles County, Maryland; 30 counties in North Carolina; 63 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at Sep 8, 2004, 12:00 PM EDT for Charles County, Maryland; 30 counties in North Carolina; 63 counties in Virginia. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Sep 8, 2004, 12:00 PM EDT (16:00 UTC)
Expired
Sep 8, 2004, 2:00 PM EDT
In force
2 hr
Issued by
the Storm Prediction Center
All 94 counties

Charles County, MD, Alamance County, NC, Bladen County, NC, Caswell County, NC, Chatham County, NC, Cumberland County, NC, Duplin County, NC, Durham County, NC, Edgecombe County, NC, Franklin County, NC, Granville County, NC, Greene County, NC, Halifax County, NC, Harnett County, NC, Hertford County, NC, Hoke County, NC, Johnston County, NC, Lee County, NC, Lenoir County, NC, Martin County, NC, Nash County, NC, Northampton County, NC, Orange County, NC, Person County, NC, Pitt County, NC, Sampson County, NC, Vance County, NC, Wake County, NC, Warren County, NC, Wayne County, NC, Wilson County, NC, Albemarle County, VA, Amelia County, VA, Amherst County, VA, Appomattox County, VA, Arlington County, VA, Brunswick County, VA, Buckingham County, VA, Campbell County, VA, Caroline County, VA, Charles City County, VA, Charlotte County, VA, Chesterfield County, VA, City of Alexandria, VA, City of Charlottesville, VA, City of Colonial Heights, VA, City of Danville, 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 Lynchburg, VA, City of Manassas, VA, City of Manassas Park, VA, City of Petersburg, VA, City of Richmond, VA, City of Waynesboro, VA, Culpeper County, VA, Cumberland County, VA, Dinwiddie County, VA, Essex County, VA, Fairfax County, VA, Fauquier County, VA, Fluvanna County, VA, Goochland County, VA, Greene County, VA, Greensville County, VA, Halifax County, VA, Hanover County, VA, Henrico County, VA, King and Queen County, VA, King George County, VA, King William County, VA, Louisa County, VA, Lunenburg County, VA, Madison County, VA, Mecklenburg County, VA, Nelson County, VA, New Kent County, VA, Nottoway County, VA, Orange County, VA, Pittsylvania County, VA, Powhatan County, VA, Prince Edward County, VA, Prince George County, VA, Prince William County, VA, Rappahannock County, VA, Southampton County, VA, Spotsylvania County, VA, Stafford County, VA, Surry County, VA, Sussex County, VA

The radar

The Raleigh/Durham radar (KRAX), 88 km from the middle of the area, began a volume at 16:01 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.

The watches that followed

Watches SPC issued over any of the same counties within four hours of this discussion.

The nearest sounding before it

Roanoke, VA (KRNK), launched 12:00Z, 4.0 hours before the alert went out and 141 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, Roanoke, VA at 12:00Z on 2004-09-08Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 171 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, Roanoke, VA at 12:00Z on 2004-09-08The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 233 square meters per square second.193958Sfc1 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
171 J/kg
Mixed-layer CIN
-4 J/kg
Mixed-layer LCL
539 m above ground
0-6 km bulk shear
38 kt
0-1 km storm-relative helicity
233 m²/s²
0-3 km storm-relative helicity
346 m²/s²
Significant tornado parameter
0.2
Supercell composite
1.2

Open this sounding in Storm Lab

The text

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

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 8, 12:50 PM EDTTornado WatchSPCCharles, Prince George's6 hr
Sep 8, 3:39 PM EDTMesoscale DiscussionSPCAnne Arundel, Baltimore, Calvert, Charles, Howard, Montgomery and 3 more2 hr
Sep 8, 6:40 PM EDTTornado WatchSPCAllegany, Anne Arundel, Calvert, Carroll, Charles, Frederick and 6 more5 hr
Sep 7, 10:09 PM EDTMesoscale DiscussionSPCAnson, Bladen, Cabarrus, Cleveland, Columbus, Cumberland and 14 more96 min
Sep 8, 12:30 AM EDTTornado WatchSPCAlexander, Anson, Avery, Bladen, Brunswick, Burke and 31 more7 hr
Sep 8, 3:38 AM EDTMesoscale DiscussionSPCAlexander, Anson, Avery, Bladen, Brunswick, Burke and 31 more3 hr
Sep 8, 6:50 AM EDTTornado WatchSPCAlamance, Anson, Bladen, Cabarrus, Caswell, Chatham and 42 more7 hr
Sep 8, 8:41 AM EDTMesoscale DiscussionSPCAlamance, Anson, Bladen, Cabarrus, Caswell, Chatham and 44 more2 hr

Nearby

Mesoscale Discussions in Virginia, 2004Mesoscale Discussions in North Carolina, 2004Mesoscale Discussions in Maryland, 2004Every mesoscale discussion 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.