Alert archive / Virginia / Mesoscale Discussions in 2011
Mesoscale Discussion 422
The Storm Prediction Center issued this mesoscale discussion at Apr 12, 2011, 1:56 PM EDT for Somerset County, Worcester County, Maryland; 6 counties in North Carolina; 27 counties in Virginia. It was in force for 64 min.
The area
The outline as issued.
The facts
- Issued
- Apr 12, 2011, 1:56 PM EDT (17:56 UTC)
- Expired
- Apr 12, 2011, 3:00 PM EDT
- In force
- 64 min
- Issued by
- the Storm Prediction Center
All 35 counties
Somerset County, MD, Worcester County, MD, Camden County, NC, Chowan County, NC, Currituck County, NC, Gates County, NC, Pasquotank County, NC, Perquimans County, NC, Accomack County, VA, Charles City County, VA, City of Chesapeake, VA, City of Franklin, VA, City of Hampton, VA, City of Newport News, VA, City of Norfolk, VA, City of Poquoson, VA, City of Portsmouth, VA, City of Suffolk, VA, City of Virginia Beach, VA, City of Williamsburg, VA, Essex County, VA, Gloucester County, VA, Isle of Wight County, VA, James City County, VA, King and Queen County, VA, King William County, VA, Lancaster County, VA, Mathews County, VA, Middlesex County, VA, New Kent County, VA, Northampton County, VA, Northumberland County, VA, Richmond County, VA, Surry County, VA, York County, VA
The radar
The Norfolk radar (KAKQ), 79 km from the middle of the area, began a volume at 17:58 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, 5.9 hours before the alert went out and 115 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.
- Mixed-layer CAPE
- 25 J/kg
- Mixed-layer CIN
- -139 J/kg
- Mixed-layer LCL
- 1296 m above ground
- 0-6 km bulk shear
- 59 kt
- 0-1 km storm-relative helicity
- 99 m²/s²
- 0-3 km storm-relative helicity
- 187 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
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</html>SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 11, 8:08 PM EDT | Tornado Watch | SPC | Avery, Buncombe, Cherokee, Clay, Graham, Haywood and 8 more | 7 hr |
| Apr 11, 9:23 PM EDT | Mesoscale Discussion | SPC | Buncombe, Cherokee, Clay, Graham, Haywood, Henderson and 7 more | 97 min |
| Apr 12, 2:39 AM EDT | Mesoscale Discussion | SPC | Alexander, Alleghany, Ashe, Avery, Buncombe, Burke and 21 more | 36 min |
Nearby
Mesoscale Discussions in Virginia, 2011Mesoscale Discussions in North Carolina, 2011Mesoscale Discussions in Maryland, 2011Every mesoscale discussion in 2011
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.