Alert archive / North Carolina / Mesoscale Discussions in 2012
Mesoscale Discussion 1940
The Storm Prediction Center issued this mesoscale discussion at Sep 8, 2012, 7:10 PM EDT for 29 counties in North Carolina; 9 counties in Virginia. It was in force for 65 min.
The area
The outline as issued.
The facts
- Issued
- Sep 8, 2012, 7:10 PM EDT (23:10 UTC)
- Expired
- Sep 8, 2012, 8:15 PM EDT
- In force
- 65 min
- Issued by
- the Storm Prediction Center
All 38 counties
Beaufort County, NC, Bertie County, NC, Bladen County, NC, Chowan County, NC, Craven County, NC, Cumberland County, NC, Duplin County, NC, Edgecombe County, NC, Franklin County, NC, Gates County, NC, Greene County, NC, Halifax County, NC, Harnett County, NC, Hertford County, NC, Johnston County, NC, Jones County, NC, Lee County, NC, Lenoir County, NC, Martin County, NC, Nash County, NC, Northampton County, NC, Onslow County, NC, Pender County, NC, Pitt County, NC, Sampson County, NC, Wake County, NC, Warren County, NC, Wayne County, NC, Wilson County, NC, City of Emporia, VA, City of Franklin, VA, City of Suffolk, VA, Greensville County, VA, Isle of Wight County, VA, Prince George County, VA, Southampton County, VA, Surry County, VA, Sussex County, VA
The radar
The Raleigh/Durham radar (KRAX), 56 km from the middle of the area, began a volume at 23:11 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, 11.2 hours before the alert went out and 133 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
- 1300 J/kg
- Mixed-layer CIN
- -10 J/kg
- Mixed-layer LCL
- 752 m above ground
- 0-6 km bulk shear
- 11 kt
- 0-1 km storm-relative helicity
- 29 m²/s²
- 0-3 km storm-relative helicity
- 51 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
571
ACUS11 KWNS 082311
SWOMCD
SPC MCD 082310
NCZ000-VAZ000-090015-
MESOSCALE DISCUSSION 1940
NWS STORM PREDICTION CENTER NORMAN OK
0610 PM CDT SAT SEP 08 2012
AREAS AFFECTED...SE VA AND ERN NC
CONCERNING...SEVERE THUNDERSTORM WATCH 638...
VALID 082310Z - 090015Z
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 638
CONTINUES.
SUMMARY...SEVERE THREAT WILL CONTINUE ACROSS EASTERN PORTIONS OF WW
638 THE NEXT FEW HOURS. GIVEN THE INCREASE IN STORM INTENSITY FROM
CNTRL NC INTO SE VA...AN EWD EXTENSION OF THE WATCH IS POSSIBLE IF
STORM INTENSITY PERSISTS.
DISCUSSION...CONVECTION AHEAD OF THE COLD FRONT APPEARS TO HAVE
INCREASED IN INTENSITY OVER THE LAST 30 MINUTES OR SO FROM SE VA
INTO CNTRL NC. ALSO NOTED ON KRAX WSR-88D WAS THE WESTWARD ADVANCING
SEA BREEZE BOUNDARY JUST TO THE EAST OF THE CURRENT WATCH BOUNDARY.
IT APPEARS OUTFLOW FROM CURRENT CONVECTION AND THIS BOUNDARY MY
INTERSECT NEAR THE EASTERN MARGINS OF THE WATCH AREA FROM SOUTHWEST
OF RDU NORTHEASTWARD TOWARD THE NC/VA BORDER. THIS MAY HELP
REINFORCE THUNDERSTORM INTENSITY AND ENHANCE DAMAGING WIND POTENTIAL
GIVEN MODERATE DOWNSTREAM INSTABILITY AND ADEQUATELY STEEP LOW LEVEL
LAPSE RATES AROUND 7 DEG C/KM. DEPENDING ON TRENDS...AN EWD
EXTENSION OF WW 638 MAY BE NEEDED.
..LEITMAN.. 09/08/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...AKQ...MHX...RAH...ILM...
LAT...LON 36007847 37277733 37107661 36797637 35657670 35237691
34607758 34297842 34427892 35137916 35447949 36007847SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 8, 12:20 PM EDT | Mesoscale Discussion | SPC | Alamance, Alexander, Alleghany, Caswell, Davidson, Davie and 10 more | 115 min |
| Sep 8, 1:14 PM EDT | Mesoscale Discussion | SPC | Cabarrus, Catawba, Cleveland, Gaston, Iredell, Lincoln and 6 more | 2 hr |
| Sep 8, 1:48 PM EDT | Severe Thunderstorm Watch | SPC | Alamance, Alexander, Anson, Cabarrus, Caswell, Catawba and 44 more | 7 hr |
| Sep 8, 3:25 PM EDT | Mesoscale Discussion | SPC | Alamance, Alexander, Cabarrus, Caswell, Catawba, Chatham and 33 more | 65 min |
| Sep 8, 11:38 AM EDT | Mesoscale Discussion | SPC | Arlington, Clarke, Culpeper, Fairfax, Fauquier, Frederick and 16 more | 97 min |
| Sep 8, 12:15 PM EDT | Severe Thunderstorm Watch | SPC | Albemarle, Arlington, Augusta, Clarke, Culpeper, Fairfax and 27 more | 9 hr |
| Sep 8, 2:12 PM EDT | Mesoscale Discussion | SPC | Arlington, Culpeper, Fairfax, Fauquier, Loudoun, Prince William and 8 more | 93 min |
Nearby
Mesoscale Discussions in North Carolina, 2012Mesoscale Discussions in Virginia, 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.