Alert archive / Virginia / Mesoscale Discussions in 2011
Mesoscale Discussion 2140
The Storm Prediction Center issued this mesoscale discussion at Sep 5, 2011, 11:47 PM EDT for Stokes County, Surry County, North Carolina; 22 counties in Virginia. It was in force for 88 min.
The area
The outline as issued.
The facts
- Issued
- Sep 5, 2011, 11:47 PM EDT (03:47 UTC)
- Expired
- Sep 6, 2011, 1:15 AM EDT
- In force
- 88 min
- Issued by
- the Storm Prediction Center
All 24 counties
Stokes County, NC, Surry County, NC, Amherst County, VA, Appomattox County, VA, Bedford County, VA, Buckingham County, VA, Campbell County, VA, Carroll County, VA, Charlotte County, VA, City of Danville, VA, City of Galax, VA, City of Lynchburg, VA, City of Martinsville, VA, City of Roanoke, VA, Cumberland County, VA, Floyd County, VA, Fluvanna County, VA, Franklin County, VA, Halifax County, VA, Henry County, VA, Nelson County, VA, Patrick County, VA, Pittsylvania County, VA, Prince Edward County, VA
The radar
The Roanoke radar (KFCX), 45 km from the middle of the area, began a volume at 03:48 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
Roanoke, VA (KRNK), launched 00:00Z, 3.8 hours before the alert went out and 35 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
- 272 J/kg
- Mixed-layer CIN
- -18 J/kg
- Mixed-layer LCL
- 634 m above ground
- 0-6 km bulk shear
- 42 kt
- 0-1 km storm-relative helicity
- 108 m²/s²
- 0-3 km storm-relative helicity
- 170 m²/s²
- Significant tornado parameter
- 0.2
- Supercell composite
- 1.0
The text
As transmitted, in the capitals the NWS used until 2016.
130 ACUS11 KWNS 060347 SWOMCD SPC MCD 060347 VAZ000-NCZ000-060515- MESOSCALE DISCUSSION 2140 NWS STORM PREDICTION CENTER NORMAN OK 1047 PM CDT MON SEP 05 2011 AREAS AFFECTED...PORTIONS NWRN NC...SRN/CENTRAL VA. CONCERNING...TORNADO WATCH 844... VALID 060347Z - 060515Z THE SEVERE WEATHER THREAT FOR TORNADO WATCH 844 CONTINUES. PORTIONS WW HAVE BEEN CLEARED FROM S-N IN STEP WITH CONVECTIVE TRENDS. REMAINDER WW MAY BE CLEARED BEFORE SCHEDULED 08Z EXPIRATION. WHILE SOME TORNADO POTENTIAL STILL EXISTS...IT IS BECOMING MORE MRGL/CONDITIONAL WITH TIME GIVEN TWO PRIMARY TRENDS... 1. STABILIZING EFFECTS OF PERSISTENT PRECIP GENERALLY W OF CHO-ROA-MKJ LINE...WHICH HAS REINFORCED PRE-EXISTING BAROCLINIC ZONE...AND MAINTAINED OR EVEN INCREASED BOTH BOUNDARY-LAYER STATIC STABILITY AND MLCINH. 2. GEN DECREASE IN OVERALL CONVECTIVE COVERAGE/DEPTH FARTHER UPSHEAR OVER CAROLINAS/GA...RELATED TO COMBINATION OF LACK OF LOW-LEVEL CONVERGENCE AND STABILIZING EFFECTS OF EARLIER PREFRONTAL MCS ACROSS SC. POCKETS OF MRGL INSTABILITY MAY STILL LINGER ACROSS THIS AREA...WITH MLCAPE 250-800 J/KG...AND PERSISTENCE OF ENHANCED LOW-LEVEL SRH CORRIDOR NEAR AND E OF BLUE RIDGE. ANY PERSISTENT CELLS THAT FORM IN THIS ENVIRONMENT MAY ROTATE...HOWEVER LOW-LEVEL FORCING FOR ASCENT E OF FRONT REMAINS RATHER NEBULOUS. ..EDWARDS.. 09/06/2011 ...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT... ATTN...WFO...AKQ...LWX...RAH...RNK... LAT...LON 36668104 38037876 37747797 36497893 36268087 36668104
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 5, 8:36 PM EDT | Mesoscale Discussion | SPC | Anson, Cumberland, Hoke, Montgomery, Moore, Richmond and 3 more | 84 min |
| Sep 6, 3:30 AM EDT | Mesoscale Discussion | SPC | Rockingham, Stokes | 60 min |
| Sep 6, 4:36 AM EDT | Mesoscale Discussion | SPC | Alamance, Anson, Cabarrus, Caswell, Chatham, Davidson and 22 more | 84 min |
| Sep 6, 5:17 AM EDT | Tornado Watch | SPC | Alamance, Alleghany, Anson, Bladen, Brunswick, Caswell and 43 more | 9 hr |
| Sep 6, 8:35 AM EDT | Mesoscale Discussion | SPC | Alamance, Anson, Bladen, Brunswick, Cabarrus, Catawba and 42 more | 85 min |
| Sep 6, 9:51 AM EDT | Tornado Watch | SPC | Alexander, Avery, Burke, Cabarrus, Caldwell, Catawba and 13 more | 6 hr |
| Sep 6, 12:41 PM EDT | Mesoscale Discussion | SPC | Alamance, Alleghany, Anson, Beaufort, Bertie, Bladen and 55 more | 64 min |
| Sep 6, 1:32 PM EDT | Tornado Watch | SPC | Alamance, Anson, Beaufort, Bertie, Bladen, Brunswick and 48 more | 7 hr |
| Sep 6, 4:41 PM EDT | Mesoscale Discussion | SPC | Alamance, Anson, Beaufort, Bertie, Bladen, Brunswick and 46 more | 64 min |
| Sep 6, 7:33 PM EDT | Mesoscale Discussion | SPC | Beaufort, Bertie, Bladen, Brunswick, Camden, Carteret and 38 more | 117 min |
Nearby
Mesoscale Discussions in Virginia, 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.