Alert archive / North Carolina / Mesoscale Discussions in 2012
Mesoscale Discussion 1632
The Storm Prediction Center issued this mesoscale discussion at Jul 28, 2012, 2:18 PM EDT for 67 counties in North Carolina; 12 counties in South Carolina; 26 counties in Virginia. It was in force for 117 min.
The area
The outline as issued.
The facts
- Issued
- Jul 28, 2012, 2:18 PM EDT (18:18 UTC)
- Expired
- Jul 28, 2012, 4:15 PM EDT
- In force
- 117 min
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 40%
All 105 counties
Alamance County, NC, Anson County, NC, Beaufort County, NC, Bertie County, NC, Bladen County, NC, Brunswick County, NC, Cabarrus 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, Davidson County, NC, Davie County, NC, Duplin County, NC, Durham County, NC, Edgecombe County, NC, Forsyth County, NC, Franklin County, NC, Gaston County, NC, Gates County, NC, Granville County, NC, Greene County, NC, Guilford County, NC, Halifax County, NC, Harnett County, NC, Hertford County, NC, Hoke County, NC, Hyde County, NC, Iredell County, NC, Johnston County, NC, Jones County, NC, Lee County, NC, Lenoir County, NC, Martin County, NC, Mecklenburg 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, Rowan County, NC, Sampson County, NC, Scotland County, NC, Stanly County, NC, Tyrrell County, NC, Union County, NC, Vance County, NC, Wake County, NC, Warren County, NC, Washington County, NC, Wayne County, NC, Wilson County, NC, Chester County, SC, Chesterfield County, SC, Darlington County, SC, Dillon County, SC, Fairfield County, SC, Florence County, SC, Kershaw County, SC, Lancaster County, SC, Lee County, SC, Marion County, SC, Marlboro County, SC, York County, SC, Amelia County, VA, Brunswick 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 Hampton, VA, City of Hopewell, VA, City of Newport News, VA, City of Norfolk, VA, City of Petersburg, VA, City of Portsmouth, VA, City of Suffolk, VA, City of Williamsburg, VA, Dinwiddie County, VA, Greensville County, VA, Isle of Wight County, VA, Lunenburg County, VA, Mecklenburg County, VA, Nottoway County, VA, Prince George County, VA, Southampton County, VA, Surry County, VA, Sussex County, VA
The radar
The Raleigh/Durham radar (KRAX), 51 km from the middle of the area, began a volume at 18:20 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, 6.3 hours before the alert went out and 141 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
- 2134 J/kg
- Mixed-layer CIN
- -49 J/kg
- Mixed-layer LCL
- 866 m above ground
- 0-6 km bulk shear
- 28 kt
- 0-1 km storm-relative helicity
- 64 m²/s²
- 0-3 km storm-relative helicity
- 100 m²/s²
- Significant tornado parameter
- 0.5
- Supercell composite
- 4.7
The text
As transmitted, in the capitals the NWS used until 2016.
998
ACUS11 KWNS 281819
SWOMCD
SPC MCD 281818
NCZ000-VAZ000-SCZ000-282015-
MESOSCALE DISCUSSION 1632
NWS STORM PREDICTION CENTER NORMAN OK
0118 PM CDT SAT JUL 28 2012
AREAS AFFECTED...PORTIONS NC EXCEPT FAR W...SRN VA...NRN SC.
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 281818Z - 282015Z
PROBABILITY OF WATCH ISSUANCE...40 PERCENT
SUMMARY...SCATTERED/LOCALLY NUMEROUS TSTMS IN BANDS AND CLUSTERS MAY
DEVELOP DURING REMAINDER AFTERNOON SW AND S OF WW 535...WITH MAIN
CONCERN BEING DAMAGING GUSTS.
DISCUSSION...VIS IMAGERY SHOWED EARLIER SW/NE-ALIGNED BAND OF
MID-HIGH CLOUDS BREAKING/THINNING OVER ERN CAROLINAS. WELL-DEFINED
DIFFERENTIAL-HEATING ZONES DEVELOPED ON EITHER SIDE THROUGH MID-LATE
MORNING. NARROW CORRIDOR OF RELATIVELY STG HEATING TO ITS E MAY
COMBINE WITH COASTAL SEA BREEZE TO ENHANCE CONVECTIVE POTENTIAL OVER
THAT AREA. MEANWHILE...WRN DIFFERENTIAL-HEATING ZONE HAS BECOME
MORE ILL-DEFINED BECAUSE OF CLOUD-BAND DIFFUSION...BUT ALSO...IS NOW
ESSENTIALLY COLLOCATED WITH ANTECEDENT SFC TROUGH/CONFLUENCE LINE
ANALYZED FROM FVX-TDF-HBI LINE AND WWD INTO WEAK LOW NEAR HKY.
CU/TCU ALREADY ARE DEEPENING ACROSS PORTIONS CENTRAL/NRN NC INVOF
LATTER FEATURE. BOUNDARY LAYER REMAINS VERY MOIST OVER
PIEDMONT/COASTAL PLAIN AREAS WITH SFC DEW POINTS COMMONLY LOW-MID
70S F. THAT MOISTURE COMBINES WITH STG DIABATIC HEATING AND
LARGE-SCALE ASCENT/DESTABILIZATION ALOFT TO YIELD MLCAPE RANGING
FROM AROUND 2500 J/KG OVER NRN SC TO 1500-2000 J/KG IN SERN VA. SLGT
ENHANCEMENT TO MIDLEVEL WINDS IMMEDIATELY AHEAD OF UPPER TROUGH
RESULTS IN RELATIVE MAX OF DEEP-LAYER SHEAR OVER CENTRAL/ERN NC AND
SERN VA...BUT WITH EFFECTIVE VALUES STILL ONLY 25-35 KT.
ADDITIONAL ACTIVITY CANNOT BE RULED OUT OVER HIGHER TERRAIN OF SWRN
VA ALONG/AHEAD OF WEAK/RESIDUAL SFC COLD FRONT. HOWEVER...FROM THAT
AREA DOWNSHEAR ACROSS PORTIONS S-CENTRAL VA...ENVIRONMENT IS BEHIND
MID-UPPER TROUGH WITH SUBSIDENCE ALOFT EVIDENT VIA MOISTURE CHANNEL
IMAGERY...AND IS CHARACTERIZED BY RELATIVE WEAKNESS OF BOTH BUOYANCY
AND DEEP SHEAR.
..EDWARDS/CORFIDI.. 07/28/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...AKQ...MHX...RAH...ILM...RNK...CAE...GSP...
LAT...LON 35038144 35848087 36118052 36307913 37567813 37457736
37217638 36447591 35647579 35017611 34537653 34697663
34637715 34367763 33967789 33767798 33907805 33907856
33988026 34348116 35038144SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 28, 1:57 PM EDT | Mesoscale Discussion | SPC | Avery, Buncombe, Burke, Caldwell, Cherokee, Clay and 16 more | 3 hr |
| Jul 28, 4:01 PM EDT | Severe Thunderstorm Watch | SPC | Beaufort, Bladen, Brunswick, Carteret, Columbus, Craven and 17 more | 6 hr |
| Jul 28, 7:28 PM EDT | Mesoscale Discussion | SPC | Bladen, Brunswick, Carteret, Columbus, Craven, Duplin and 6 more | 32 min |
| Jul 27, 8:28 PM EDT | Mesoscale Discussion | SPC | Buchanan | 2 hr |
| Jul 28, 12:26 PM EDT | Mesoscale Discussion | SPC | Arlington, Caroline, Culpeper, Essex, Fairfax, Fauquier and 13 more | 2 hr |
| Jul 28, 1:36 PM EDT | Severe Thunderstorm Watch | SPC | Accomack, Albemarle, Arlington, Caroline, Clarke, Culpeper and 40 more | 8 hr |
| Jul 28, 4:18 PM EDT | Mesoscale Discussion | SPC | Accomack, Arlington, Caroline, Clarke, Culpeper, Essex and 28 more | 87 min |
Nearby
Mesoscale Discussions in North Carolina, 2012Mesoscale Discussions in Virginia, 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.