Alert archive / Virginia / Mesoscale Discussions in 2011
Mesoscale Discussion 358
The Storm Prediction Center issued this mesoscale discussion at Apr 5, 2011, 2:13 AM EDT for 4 states. It was in force for 32 min.
The area
The outline as issued.
The facts
- Issued
- Apr 5, 2011, 2:13 AM EDT (06:13 UTC)
- Expired
- Apr 5, 2011, 2:45 AM EDT
- In force
- 32 min
- Issued by
- the Storm Prediction Center
All 120 counties
Kent County, DE, Sussex County, DE, Anne Arundel County, MD, Calvert County, MD, Caroline County, MD, Charles County, MD, City of Baltimore, MD, Dorchester County, MD, Howard County, MD, Kent County, MD, Montgomery County, MD, Prince George's County, MD, Queen Anne's County, MD, Saint Mary's County, MD, Somerset County, MD, Talbot County, MD, Wicomico County, MD, Worcester County, MD, Forsyth County, NC, Rockingham County, NC, Stokes County, NC, Surry County, NC, Yadkin County, NC, Accomack County, VA, Albemarle County, VA, Amelia County, VA, Amherst County, VA, Appomattox County, VA, Arlington County, VA, Bedford County, VA, Botetourt County, VA, Brunswick County, VA, Buckingham County, VA, Campbell County, VA, Caroline County, VA, Carroll County, VA, Charles City County, VA, Charlotte County, VA, Chesterfield County, VA, City of Alexandria, VA, City of Buena Vista, VA, City of Charlottesville, VA, City of Chesapeake, 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 Hampton, VA, City of Hopewell, VA, City of Lexington, VA, City of Lynchburg, VA, City of Manassas, VA, City of Manassas Park, VA, City of Martinsville, 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 Roanoke, VA, City of Salem, VA, City of Suffolk, VA, City of Virginia Beach, VA, City of Waynesboro, VA, City of Williamsburg, VA, Culpeper County, VA, Cumberland County, VA, Dinwiddie County, VA, Essex County, VA, Fairfax County, VA, Fauquier County, VA, Floyd County, VA, Fluvanna County, VA, Franklin County, VA, Gloucester County, VA, Goochland County, VA, Greene County, VA, Greensville County, VA, Halifax County, VA, Hanover County, VA, Henrico County, VA, Henry 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, Madison County, VA, Mathews County, VA, Mecklenburg County, VA, Middlesex County, VA, Nelson County, VA, New Kent County, VA, Northampton County, VA, Northumberland County, VA, Nottoway County, VA, Orange County, VA, Patrick County, VA, Pittsylvania County, VA, Powhatan County, VA, Prince Edward County, VA, Prince George County, VA, Prince William County, VA, Rappahannock County, VA, Richmond County, VA, Rockbridge 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), 121 km from the middle of the area, began a volume at 06:14 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 00:00Z, 6.2 hours before the alert went out and 106 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 2731 m above ground
- 0-6 km bulk shear
- 58 kt
- 0-1 km storm-relative helicity
- 258 m²/s²
- 0-3 km storm-relative helicity
- 349 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
882
ACUS11 KWNS 050614
SWOMCD
SPC MCD 050613
DEZ000-MDZ000-VAZ000-NCZ000-DCZ000-050645-
MESOSCALE DISCUSSION 0358
NWS STORM PREDICTION CENTER NORMAN OK
0113 AM CDT TUE APR 05 2011
AREAS AFFECTED...PORTIONS VA...MD...DC...DE...NWRN NC.
CONCERNING...SEVERE THUNDERSTORM WATCH 99...
VALID 050613Z - 050645Z
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 99
CONTINUES.
WW IS BEING REPLACED TO COVER INCREASING QLCS-TORNADO AND EMBEDDED
SUPERCELL THREAT...ESPECIALLY INVOF BOUNDARY DESCRIBED BELOW...AND
ALSO DAMAGING WIND THREAT EXTENDING AS FAR AS ATLANTIC COAST OF
DELMARVA REGION AND VA TIDEWATER BY ABOUT 13Z. PERSISTENT/SVR BAND
OF TSTMS OVER WRN PORTIONS NC/VA WILL CONTINUE MOVING EWD THROUGH WW
AREA...AND SHOULD CLEAR WW BY ABOUT 830Z. NEW WW MAY BE CLEARED
BEHIND THIS LINE.
SFC MESOANALYSIS SHOWS OUTFLOW BOUNDARY FROM EARLIER CONVECTION FROM
NEAR DCA ARCHING SWWD ACROSS FVX...THEN WSWWD ACROSS SRN TIER OF VA
COUNTIES...INTERSECTING QLCS INVOF NC/VA BORDER W MTV. STG SFC
PRESSURE FALLS WERE ANALYZED NEAR THAT INTERSECTION...INDICATING
POSSIBLE MESOLOW DEVELOPMENT IN ADDITION TO FALLS ASSOCIATED WITH
WAA/AIR MASS RECOVERY FROM EARLIER COLD POOL IMMEDIATELY TO ITS E.
LOW-LEVEL VORTICITY WILL BE MAXIMIZED ALONG AND JUST N OF OUTFLOW
BOUNDARY...AS WILL HODOGRAPH SIZE AND SRH...INDICATING ENHANCED
POTENTIAL FOR LOW-MIDDLE LEVEL/STORM-SCALE ROTATION AND RELATIVELY
MAXIMIZED TORNADO PROBABILITIES. EMBEDDED/SMALL-SCALE VORTICES ALSO
MAY DEVELOP IN OTHER SEGMENTS OF THIS LINE. INFLOW-LAYER
INSTABILITY WILL REMAIN MRGL BUT SUFFICIENT...AND WILL INCREASE
ACROSS PORTIONS CENTRAL/ERN VA INTO DELMARVA REGION. LOW-LEVEL
THETAE ADVECTION WILL INCREASE MLCAPE TO 100-500 J/KG RANGE AS DEW
POINTS RISE THROUGH 50S...WITH LOW-MID 60S OVER PORTIONS SRN VA.
THIS PROCESS ALSO SHOULD ACT TO REDUCE CINH...ESPECIALLY FOR
STRONGLY FORCED PARCELS ALONG LEADING EDGE OF LINE.
..EDWARDS.. 04/05/2011
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...PHI...AKQ...LWX...RAH...RNK...
LAT...LON 36588090 37767965 39357720 39487568 38347506 37117587
36537587 36507934 36127998 36098094 36588090SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Apr 5, 2:18 AM EDT | Tornado Watch | SPC | Kent, New Castle, Sussex | 8 hr |
| Apr 5, 3:34 AM EDT | Mesoscale Discussion | SPC | Kent, New Castle, Sussex | 116 min |
| Apr 5, 5:07 AM EDT | Severe Thunderstorm Watch | SPC | Cecil | 2 hr |
| Apr 4, 9:32 PM EDT | Mesoscale Discussion | SPC | Alexander, Buncombe, Burke, Catawba, Cleveland, Gaston and 8 more | 58 min |
| Apr 4, 9:45 PM EDT | Severe Thunderstorm Watch | SPC | Alexander, Avery, Buncombe, Burke, Cabarrus, Caldwell and 22 more | 5 hr |
| Apr 5, 12:21 AM EDT | Mesoscale Discussion | SPC | Alamance, Anson, Chatham, Cumberland, Harnett, Hoke and 7 more | 84 min |
| Apr 5, 12:36 AM EDT | Severe Thunderstorm Watch | SPC | Alleghany, Caswell, Rockingham, Stokes, Surry, Wilkes and 1 more | 111 min |
| Apr 5, 12:48 AM EDT | Tornado Watch | SPC | Alamance, Anson, Bladen, Chatham, Cumberland, Davidson and 27 more | 5 hr |
| Apr 5, 2:24 AM EDT | Mesoscale Discussion | SPC | Cabarrus, Mecklenburg, Rowan | 66 min |
| Apr 5, 4:00 AM EDT | Tornado Watch | SPC | Beaufort, Bladen, Brunswick, Carteret, Columbus, Craven and 15 more | 6 hr |
| Apr 5, 7:08 AM EDT | Mesoscale Discussion | SPC | Beaufort, Brunswick, Carteret, Craven, Currituck, Dare and 10 more | 2 hr |
| Apr 5, 10:15 AM EDT | Mesoscale Discussion | SPC | Beaufort, Bertie, Bladen, Brunswick, Camden, Carteret and 26 more | 90 min |
Nearby
Mesoscale Discussions in Virginia, 2011Mesoscale Discussions in Maryland, 2011Mesoscale Discussions in North Carolina, 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.