Alert archive / Virginia / Mesoscale Discussions in 2012
Mesoscale Discussion 156
The Storm Prediction Center issued this mesoscale discussion at Feb 24, 2012, 12:43 PM EST for 4 states. It was in force for 92 min.
The area
The outline as issued.
The facts
- Issued
- Feb 24, 2012, 12:43 PM EST (17:43 UTC)
- Expired
- Feb 24, 2012, 2:15 PM EST
- In force
- 92 min
- Issued by
- the Storm Prediction Center
All 129 counties
Calvert County, MD, Charles County, MD, Saint Mary's County, MD, Somerset County, MD, Alamance County, NC, Anson County, NC, Beaufort County, NC, Bertie County, NC, Bladen County, NC, Brunswick County, NC, Camden County, NC, Carteret County, NC, Chatham County, NC, Chowan County, NC, Columbus County, NC, Craven County, NC, Cumberland County, NC, Currituck County, NC, Dare County, NC, Duplin County, NC, Durham County, NC, Edgecombe County, NC, Franklin County, NC, Gates County, NC, Granville County, NC, Greene County, NC, Halifax County, NC, Harnett County, NC, Hertford County, NC, Hoke County, NC, Hyde County, NC, Johnston County, NC, Jones County, NC, Lee County, NC, Lenoir County, NC, Martin County, NC, Montgomery County, NC, Moore County, NC, Nash County, NC, New Hanover County, NC, Northampton County, NC, Onslow County, NC, Orange County, NC, Pamlico County, NC, Pasquotank County, NC, Pender County, NC, Perquimans County, NC, Person County, NC, Pitt County, NC, Randolph County, NC, Richmond County, NC, Robeson County, NC, Sampson County, NC, Scotland County, NC, Tyrrell County, NC, Vance County, NC, Wake County, NC, Warren County, NC, Washington County, NC, Wayne County, NC, Wilson County, NC, Darlington County, SC, Dillon County, SC, Florence County, SC, Georgetown County, SC, Horry County, SC, Marion County, SC, Marlboro County, SC, Williamsburg County, SC, Accomack County, VA, Amelia County, VA, Brunswick 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, Culpeper County, 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, Madison County, VA, Mathews County, VA, Mecklenburg County, VA, Middlesex County, VA, New Kent County, VA, Northampton County, VA, Northumberland County, VA, Nottoway County, VA, Orange 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 Raleigh/Durham radar (KRAX), 38 km from the middle of the area, began a volume at 17:43 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
Newport, NC (KMHX), launched 12:00Z, 5.7 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.
- Mixed-layer CAPE
- 436 J/kg
- Mixed-layer CIN
- -101 J/kg
- Mixed-layer LCL
- 540 m above ground
- 0-6 km bulk shear
- 67 kt
- 0-1 km storm-relative helicity
- 399 m²/s²
- 0-3 km storm-relative helicity
- 456 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 2.7
The text
As transmitted, in the capitals the NWS used until 2016.
736
ACUS11 KWNS 241743
SWOMCD
SPC MCD 241743
MDZ000-VAZ000-NCZ000-SCZ000-241915-
MESOSCALE DISCUSSION 0156
NWS STORM PREDICTION CENTER NORMAN OK
1143 AM CST FRI FEB 24 2012
AREAS AFFECTED...NERN SC...CNTRL/ERN NC...ERN VA...SRN MD
CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY
VALID 241743Z - 241915Z
THE THREAT FOR SVR STORMS WILL INCREASE ACROSS NERN SC...CNTRL/ERN
NC...ERN VA...AND SRN MD EARLY THIS AFTERNOON...AND A TORNADO WATCH
WILL LIKELY BE REQUIRED BETWEEN 18Z AND 19Z.
A WARM/UNSTABLE SECTOR WILL CONTINUE TO EXPAND NORTHWARD TOWARD NRN
VA AND SRN MD THIS AFTERNOON AHEAD OF A COLD FRONT CURRENTLY
CROSSING THE APPALACHIANS. CONVERGENCE ALONG THE FRONT AND
INCREASING PRE-FRONTAL LARGE-SCALE ASCENT -- INDICATED BY SFC
PRESSURE FALLS AROUND 2 MB PER 2 HRS -- WILL CONTINUE TO SUPPORT
CONVECTION BOTH ALONG AND AHEAD OF THE FRONT. A VERY STRONG
MID-LEVEL JET CORE CROSSING THE REGION WILL CONTRIBUTE TO EFFECTIVE
BULK SHEAR MAGNITUDES EXCEEDING 60 KT...WHICH WILL PROMOTE BANDS AND
CLUSTERS OF FAST-MOVING THUNDERSTORMS CAPABLE OF PRODUCING
WIDESPREAD DAMAGING WINDS. WITH 0-1-KM BULK SHEAR MAGNITUDES OF
30-45 KT...TORNADOES WILL BE POSSIBLE...PARTICULARLY IN ASSOCIATION
WITH ANY LEWP PATTERNS AND CONVECTION WELL IN ADVANCE OF THE FRONT
WHERE SFC WINDS ARE SOMEWHAT MORE BACKED RELATIVE TO THE WLY FLOW
ALOFT. UNCERTAINTY IN THE NRN EXTENT OF THE UNSTABLE SECTOR
EXISTS...AS WELL AS THE IMPACT OF MID/HIGH CLOUDS OVER CNTRL/ERN NC
AND NERN SC. HOWEVER...IN BOTH INSTANCES...INSTABILITY IS EXPECTED
TO BE SUFFICIENT...GIVEN THE MAGNITUDE OF FORCING FOR ASCENT...SUCH
THAT A SVR/TORNADO THREAT WILL LIKELY EVOLVE.
..COHEN.. 02/24/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...AKQ...MHX...LWX...RAH...ILM...RNK...CHS...CAE...
LAT...LON 33187901 33497998 34938019 35587997 36697864 38457836
38797706 38137555 36897561 35147564 33877786 33187901SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Feb 24, 1:19 PM EST | Tornado Watch | SPC | Charles, Dorchester, Saint Mary's, Somerset, Wicomico, Worcester | 7 hr |
| Feb 24, 4:45 PM EST | Mesoscale Discussion | SPC | Somerset, Worcester | 90 min |
| Feb 24, 6:56 AM EST | Mesoscale Discussion | SPC | Cherokee, Clay, Cleveland, Haywood, Henderson, Jackson and 4 more | 94 min |
| Feb 24, 9:05 AM EST | Mesoscale Discussion | SPC | Alexander, Alleghany, Ashe, Avery, Buncombe, Burke and 29 more | 25 min |
| Feb 24, 9:17 AM EST | Tornado Watch | SPC | Alexander, Avery, Buncombe, Burke, Cabarrus, Caldwell and 22 more | 7 hr |
| Feb 24, 11:10 AM EST | Mesoscale Discussion | SPC | Bladen, Brunswick, Columbus, New Hanover, Onslow, Pender and 1 more | 65 min |
| Feb 24, 12:00 PM EST | Mesoscale Discussion | SPC | Alexander, Alleghany, Ashe, Avery, Buncombe, Burke and 27 more | 60 min |
| Feb 24, 1:50 PM EST | Mesoscale Discussion | SPC | Bladen, Brunswick, Columbus, Robeson | 85 min |
| Feb 24, 3:24 PM EST | Mesoscale Discussion | SPC | Alexander, Alleghany, Ashe, Avery, Buncombe, Burke and 27 more | 66 min |
| Feb 24, 8:48 AM EST | Tornado Watch | SPC | Abbeville, Aiken, Bamberg, Barnwell, Calhoun, Chester and 17 more | 7 hr |
| Feb 24, 10:49 AM EST | Mesoscale Discussion | SPC | Aiken | 56 min |
| Feb 24, 12:04 PM EST | Tornado Watch | SPC | Allendale, Beaufort, Berkeley, Charleston, Colleton, Dorchester and 2 more | 7 hr |
| Feb 24, 4:11 PM EST | Mesoscale Discussion | SPC | Allendale, Beaufort, Berkeley, Charleston, Colleton, Dorchester and 2 more | 64 min |
| Feb 24, 2:00 AM EST | Mesoscale Discussion | SPC | Buchanan, Dickenson, Lee, Scott, Wise, City of Norton | 2 hr |
Nearby
Mesoscale Discussions in Virginia, 2012Mesoscale Discussions in North Carolina, 2012Mesoscale Discussions in South Carolina, 2012Every mesoscale discussion in 2012
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.