Alert archive / Virginia / Mesoscale Discussions in 2011
Mesoscale Discussion 2108
The Storm Prediction Center issued this mesoscale discussion at Sep 3, 2011, 1:29 PM EDT for 6 counties in North Carolina; 40 counties in Virginia; 9 counties in West Virginia. It was in force for 91 min.
The area
The outline as issued.
The facts
- Issued
- Sep 3, 2011, 1:29 PM EDT (17:29 UTC)
- Expired
- Sep 3, 2011, 3:00 PM EDT
- In force
- 91 min
- Issued by
- the Storm Prediction Center
All 55 counties
Alleghany County, NC, Ashe County, NC, Stokes County, NC, Surry County, NC, Watauga County, NC, Wilkes County, NC, Albemarle County, VA, Alleghany County, VA, Amherst County, VA, Appomattox County, VA, Augusta County, VA, Bath County, VA, Bedford County, VA, Bland County, VA, Botetourt County, VA, Campbell County, VA, Carroll County, VA, City of Buena Vista, VA, City of Covington, VA, City of Galax, VA, City of Harrisonburg, VA, City of Lexington, VA, City of Lynchburg, VA, City of Martinsville, VA, City of Radford, VA, City of Roanoke, VA, City of Salem, VA, City of Staunton, VA, City of Waynesboro, VA, Craig County, VA, Floyd County, VA, Franklin County, VA, Giles County, VA, Grayson County, VA, Henry County, VA, Highland County, VA, Montgomery County, VA, Nelson County, VA, Patrick County, VA, Pittsylvania County, VA, Pulaski County, VA, Roanoke County, VA, Rockbridge County, VA, Rockingham County, VA, Smyth County, VA, Wythe County, VA, Greenbrier County, WV, Mercer County, WV, Monroe County, WV, Pendleton County, WV, Pocahontas County, WV, Randolph County, WV, Summers County, WV, Upshur County, WV, Webster County, WV
The radar
The Roanoke radar (KFCX), 65 km from the middle of the area, began a volume at 17:31 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 12:00Z, 5.5 hours before the alert went out and 73 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
- 1125 J/kg
- Mixed-layer CIN
- -63 J/kg
- Mixed-layer LCL
- 471 m above ground
- 0-6 km bulk shear
- 6 kt
- 0-1 km storm-relative helicity
- 104 m²/s²
- 0-3 km storm-relative helicity
- 116 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
355
ACUS11 KWNS 031730
SWOMCD
SPC MCD 031729
VAZ000-WVZ000-NCZ000-TNZ000-031900-
MESOSCALE DISCUSSION 2108
NWS STORM PREDICTION CENTER NORMAN OK
1229 PM CDT SAT SEP 03 2011
AREAS AFFECTED...SERN WV...PORTIONS OF WRN/CNTRL VA...FAR NWRN NC
CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY
VALID 031729Z - 031900Z
ISOLATED TO SCATTERED THUNDERSTORMS ARE EXPECTED TO INCREASE OVER
THE HIGHER TERRAIN OF SERN WV AND WRN/CNTRL VA OVER THE NEXT COUPLE
OF HOURS. THESE STORMS WILL TRACK SLOWLY SWD WITH STRONG/GUSTY WINDS
BEING THE MAIN THREAT.
LATEST VISIBLE SATELLITE AND RADAR INDICATED CONVECTION WAS
BEGINNING TO DEVELOP ALONG THE HIGHER TERRAIN OF SERN WV AND WILL
CONTINUE TO INCREASE OVER THE NEXT COUPLE OF HOURS. ISOLATED TO
SCATTERED STORMS WILL DEVELOP SWD WITH CONTINUED HEATING ACROSS WRN
AND CNTRL VA INTO FAR NWRN NC. WITH DEWPOINTS IN THE UPPER 60S TO
LOWER 70S...SBCAPE VALUES WERE ALREADY APPROACHING 2500 J/KG ACROSS
THIS REGION. ADDITIONALLY...MORNING ROABS FROM RNK AND GSO INDICATED
AN EML ABOVE THE 850 MB LAYER WITH 700-500 MB LAPSE RATES
APPROACHING 7 C/KM. COUPLED WITH A VERY UNSTABLE AIR MASS...AT LEAST
A FEW STRONG TO SEVERE STORMS ARE EXPECTED. WEAK DEEP LAYER FLOW
WILL RESULT IN SLOW MOVING STORMS PRESENTING MAINLY A DOWNBURST
THREAT. HOWEVER...SOME MARGINALLY SEVERE HAIL IS POSSIBLE WITH
STRONGER STORMS.
GIVEN A LACK OF STRONGER FLOW OR UPPER LEVEL FORCING FOR
ASCENT...THREAT IS NOT EXPECTED TO BE WIDESPREAD OR ORGANIZED.
..LEITMAN.. 09/03/2011
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...AKQ...LWX...RNK...PBZ...RLX...GSP...MRX...
LAT...LON 38618053 38838039 39038000 39047983 39037932 38977896
38707871 38257850 37937848 37517855 37027878 36757912
36417986 36228069 36108140 36068183 36148194 36298191
36668168 37008154 38008099 38618053Nearby
Mesoscale Discussions in Virginia, 2011Mesoscale Discussions in West 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.