Alert archive / Virginia / Mesoscale Discussions in 2008

Mesoscale Discussion 1874

July 23, 200818 counties in North Carolina; 25 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at Jul 23, 2008, 10:38 AM EDT for 18 counties in North Carolina; 25 counties in Virginia. It was in force for 67 min.

The area

The outline as issued.

The facts

Issued: Jul 23, 2008, 10:38 AM EDT (14:38 UTC)
Expired: Jul 23, 2008, 11:45 AM EDT
In force: 67 min
Issued by: the Storm Prediction Center

All 43 counties

Alamance County, NC, Cabarrus County, NC, Caswell County, NC, Chatham County, NC, Durham County, NC, Franklin County, NC, Granville County, NC, Guilford County, NC, Lee County, NC, Montgomery County, NC, Moore County, NC, Orange County, NC, Person County, NC, Randolph County, NC, Stanly County, NC, Vance County, NC, Wake County, NC, Warren County, NC, Amelia County, VA, Brunswick County, VA, Charles City County, VA, Charlotte County, VA, Chesterfield County, VA, City of Colonial Heights, VA, City of Emporia, VA, City of Hopewell, VA, City of Petersburg, VA, City of Richmond, VA, City of Williamsburg, VA, Dinwiddie County, VA, Greensville County, VA, Halifax County, VA, Henrico County, VA, James City County, VA, King and Queen County, VA, King William County, VA, Lunenburg County, VA, Mecklenburg County, VA, New Kent County, VA, Nottoway County, VA, Prince George County, VA, Surry County, VA, Sussex County, VA

The watches that followed

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

Severe Thunderstorm Watch 736Jul 23, 12:45 PM EDT

The nearest sounding before it

Roanoke, VA (KRNK), launched 12:00Z, 2.6 hours before the alert went out and 122 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: 217 J/kg
Mixed-layer CIN: -75 J/kg
Mixed-layer LCL: 800 m above ground
0-6 km bulk shear: 26 kt
0-1 km storm-relative helicity: -35 m²/s²
0-3 km storm-relative helicity: 77 m²/s²
Significant tornado parameter: 0.0
Supercell composite: -0.1

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
Jul 23, 12:44 PM EDT	Severe Thunderstorm Watch	SPC	Alamance, Beaufort, Bertie, Camden, Chatham, Chowan and 41 more	7 hr
Jul 23, 1:28 PM EDT	Mesoscale Discussion	SPC	Alleghany, Ashe, Avery, Mitchell, Watauga	62 min
Jul 23, 3:25 PM EDT	Severe Thunderstorm Watch	SPC	Alamance, Alexander, Alleghany, Anson, Ashe, Avery and 36 more	8 hr
Jul 23, 3:54 PM EDT	Mesoscale Discussion	SPC	Alamance, Beaufort, Bertie, Camden, Chatham, Chowan and 41 more	66 min
Jul 23, 7:28 PM EDT	Mesoscale Discussion	SPC	Beaufort, Bertie, Camden, Chatham, Chowan, Craven and 35 more	62 min
Jul 23, 12:33 PM EDT	Mesoscale Discussion	SPC	Accomack, Gloucester, Isle of Wight, James City, Lancaster, Mathews and 13 more	57 min

Nearby

Mesoscale Discussions in Virginia, 2008 Mesoscale Discussions in North Carolina, 2008 Every mesoscale discussion in 2008

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.