Alert archive / Virginia / Mesoscale Discussions in 2011

Mesoscale Discussion 667

April 28, 20115 counties in Maryland; 26 counties in North Carolina; 37 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at Apr 28, 2011, 6:33 PM EDT for 5 counties in Maryland; 26 counties in North Carolina; 37 counties in Virginia. It was in force for 57 min.

The area

The outline as issued.

The facts

Issued
Apr 28, 2011, 6:33 PM EDT (22:33 UTC)
Expired
Apr 28, 2011, 7:30 PM EDT
In force
57 min
Issued by
the Storm Prediction Center
All 68 counties

Dorchester County, MD, Saint Mary's County, MD, Somerset County, MD, Wicomico County, MD, Worcester County, MD, Beaufort County, NC, Bertie County, NC, Camden County, NC, Carteret County, NC, Chowan County, NC, Craven County, NC, Currituck County, NC, Dare County, NC, Duplin County, NC, Gates County, NC, Greene County, NC, Hertford County, NC, Hyde County, NC, Jones County, NC, Lenoir County, NC, Martin County, NC, New Hanover County, NC, Northampton County, NC, Onslow County, NC, Pamlico County, NC, Pasquotank County, NC, Pender County, NC, Perquimans County, NC, Pitt County, NC, Tyrrell County, NC, Washington County, NC, Accomack County, VA, Charles City County, VA, City of Chesapeake, VA, City of Colonial Heights, VA, City of Emporia, VA, City of Franklin, 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 Suffolk, VA, City of Virginia Beach, VA, City of Williamsburg, VA, Essex County, VA, Gloucester County, VA, Greensville County, VA, Henrico 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, Prince George County, VA, Richmond County, VA, Southampton County, VA, Surry County, VA, Sussex County, VA, Westmoreland County, VA, York County, VA

The radar

The Norfolk radar (KAKQ), 108 km from the middle of the area, began a volume at 22:36 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

Newport, NC (KMHX), launched 12:00Z, 10.6 hours before the alert went out and 162 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, Newport, NC at 12:00Z on 2011-04-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1638 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, Newport, NC at 12:00Z on 2011-04-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 227 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
1638 J/kg
Mixed-layer CIN
-4 J/kg
Mixed-layer LCL
502 m above ground
0-6 km bulk shear
29 kt
0-1 km storm-relative helicity
227 m²/s²
0-3 km storm-relative helicity
220 m²/s²
Significant tornado parameter
1.0
Supercell composite
6.8

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
Apr 27, 8:15 PM EDTSevere Thunderstorm WatchSPCCaroline, Cecil, Kent, Queen Anne's, Talbot8 hr
Apr 28, 12:27 AM EDTMesoscale DiscussionSPCAllegany, Frederick, Howard, Montgomery, Washington63 min
Apr 28, 12:41 AM EDTTornado WatchSPCAllegany, Anne Arundel, Baltimore, Calvert, Carroll, Charles and 8 more7 hr
Apr 28, 4:05 AM EDTSevere Thunderstorm WatchSPCCaroline, Cecil, Kent, Queen Anne's, Talbot6 hr
Apr 28, 7:38 AM EDTTornado WatchSPCAnne Arundel, Baltimore, Calvert, Carroll, Charles, Dorchester and 10 more7 hr
Apr 28, 9:45 AM EDTSevere Thunderstorm WatchSPCCaroline, Cecil, Kent, Queen Anne's, Talbot6 hr
Apr 28, 10:44 AM EDTMesoscale DiscussionSPCAnne Arundel, Baltimore, Calvert, Caroline, Carroll, Cecil and 13 more61 min
Apr 28, 11:49 AM EDTMesoscale DiscussionSPCCecil, Kent, Queen Anne's56 min
Apr 28, 2:00 PM EDTMesoscale DiscussionSPCAnne Arundel, Calvert, Caroline, Charles, Dorchester, Kent and 7 more60 min
Apr 28, 2:41 PM EDTTornado WatchSPCDorchester, Somerset, Wicomico, Worcester6 hr
Apr 27, 10:12 PM EDTMesoscale DiscussionSPCAlleghany, Ashe, Forsyth, Rockingham, Stokes, Surry and 3 more63 min
Apr 28, 12:09 AM EDTMesoscale DiscussionSPCAlexander, Alleghany, Ashe, Avery, Buncombe, Burke and 25 more36 min
Apr 28, 12:56 AM EDTTornado WatchSPCAlexander, Avery, Buncombe, Burke, Cabarrus, Caldwell and 21 more4 hr
Apr 28, 3:30 AM EDTMesoscale DiscussionSPCAlexander, Anson, Burke, Cabarrus, Catawba, Cleveland and 10 more90 min
Apr 28, 4:30 AM EDTTornado WatchSPCAlamance, Anson, Bladen, Chatham, Cumberland, Davidson and 27 more10 hr
Apr 28, 8:05 AM EDTMesoscale DiscussionSPCAnson, Chatham, Cumberland, Durham, Edgecombe, Franklin and 15 more85 min
Apr 28, 8:48 AM EDTTornado WatchSPCBeaufort, Bladen, Brunswick, Carteret, Columbus, Craven and 15 more7 hr
Apr 28, 11:22 AM EDTMesoscale DiscussionSPCBeaufort, Bertie, Bladen, Brunswick, Chowan, Columbus and 29 more53 min
Apr 28, 3:19 PM EDTTornado WatchSPCBladen, Brunswick, Columbus, New Hanover, Pender4 hr
Apr 27, 9:22 PM EDTMesoscale DiscussionSPCBuchanan, Dickenson, Lee, Russell, Scott, Smyth and 5 more53 min
Apr 28, 12:34 AM EDTMesoscale DiscussionSPCBuchanan, Dickenson, Lee, Russell, Scott, Tazewell and 3 more26 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.