Alert archive / Virginia / Mesoscale Discussions in 2003

Mesoscale Discussion 2387

September 18, 20035 counties in Maryland; 8 counties in North Carolina; 58 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at Sep 18, 2003, 6:44 PM EDT for 5 counties in Maryland; 8 counties in North Carolina; 58 counties in Virginia. It was in force for 91 min.

The area

The outline as issued.

The facts

Issued: Sep 18, 2003, 6:44 PM EDT (22:44 UTC)
Expired: Sep 18, 2003, 8:15 PM EDT
In force: 91 min
Issued by: the Storm Prediction Center

All 71 counties

Calvert County, MD, Charles County, MD, Dorchester County, MD, Saint Mary's County, MD, Somerset County, MD, Camden County, NC, Currituck County, NC, Gates County, NC, Hertford County, NC, Northampton County, NC, Pasquotank County, NC, Perquimans County, NC, Warren County, NC, Accomack County, VA, Amelia County, VA, Brunswick County, VA, Buckingham 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, Cumberland County, VA, Dinwiddie County, VA, Essex 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, Louisa County, VA, Lunenburg County, VA, Mathews County, VA, Mecklenburg County, VA, Middlesex County, VA, New Kent County, VA, Northampton County, VA, Northumberland County, VA, Nottoway County, VA, Powhatan County, VA, Prince Edward 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), 50 km from the middle of the area, began a volume at 22:45 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 nearest sounding before it

Wallops Is Stn, VA (KWAL), launched 12:00Z, 10.7 hours before the alert went out and 149 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: 173 J/kg
Mixed-layer CIN: -2 J/kg
Mixed-layer LCL: 484 m above ground
0-6 km bulk shear: 44 kt
0-1 km storm-relative helicity: 229 m²/s²
0-3 km storm-relative helicity: 266 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 1.0

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.

Issued	Product	Office	Counties	Lasted
Sep 18, 4:04 AM EDT	Mesoscale Discussion	SPC	Dorchester, Somerset, Wicomico, Worcester	3 hr
Sep 18, 7:44 AM EDT	Mesoscale Discussion	SPC	Calvert, Dorchester, Saint Mary's, Somerset, Talbot, Wicomico and 1 more	2 hr
Sep 18, 8:25 AM EDT	Tornado Watch	SPC	Saint Mary's, Somerset, Worcester	12 hr
Sep 18, 12:03 PM EDT	Mesoscale Discussion	SPC	Saint Mary's, Somerset, Worcester	117 min
Sep 18, 4:03 PM EDT	Mesoscale Discussion	SPC	Saint Mary's, Somerset, Wicomico, Worcester	117 min

Nearby

Mesoscale Discussions in Virginia, 2003 Mesoscale Discussions in North Carolina, 2003 Mesoscale Discussions in Maryland, 2003 Every mesoscale discussion in 2003

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.