Alert archive / North Carolina / Mesoscale Discussions in 2012

Mesoscale Discussion 155

February 24, 20126 states

The Storm Prediction Center issued this mesoscale discussion at Feb 24, 2012, 12:00 PM EST for 6 states. It was in force for 60 min.

The area

The outline as issued.

The facts

Issued
Feb 24, 2012, 12:00 PM EST (17:00 UTC)
Expired
Feb 24, 2012, 1:00 PM EST
In force
60 min
Issued by
the Storm Prediction Center
All 84 counties

Fannin County, GA, Rabun County, GA, Towns County, GA, Union County, GA, Alexander County, NC, Alleghany County, NC, Ashe County, NC, Avery County, NC, Buncombe County, NC, Burke County, NC, Caldwell County, NC, Catawba County, NC, Cherokee County, NC, Clay County, NC, Cleveland County, NC, Davie County, NC, Forsyth County, NC, Graham County, NC, Haywood County, NC, Henderson County, NC, Iredell County, NC, Jackson County, NC, Lincoln County, NC, Macon County, NC, Madison County, NC, McDowell County, NC, Mitchell County, NC, Polk County, NC, Rutherford County, NC, Stokes County, NC, Surry County, NC, Swain County, NC, Transylvania County, NC, Watauga County, NC, Wilkes County, NC, Yadkin County, NC, Yancey County, NC, Cherokee County, SC, Greenville County, SC, Pickens County, SC, Spartanburg County, SC, Carter County, TN, Cocke County, TN, Greene County, TN, Johnson County, TN, Sullivan County, TN, Unicoi County, TN, Washington County, TN, Amherst County, VA, Appomattox County, VA, Bedford County, VA, Bland County, VA, Botetourt County, VA, Buckingham County, VA, Campbell County, VA, Carroll County, VA, City of Bristol, VA, City of Buena Vista, VA, City of Covington, VA, City of Galax, 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, Craig County, VA, Floyd County, VA, Franklin County, VA, Giles County, VA, Grayson County, VA, Henry County, VA, Montgomery County, VA, Patrick County, VA, Pittsylvania County, VA, Pulaski County, VA, Roanoke County, VA, Smyth County, VA, Tazewell County, VA, Washington County, VA, Wythe County, VA, Mercer County, WV, Monroe County, WV, Summers County, WV

The radar

The Knoxville radar (KMRX), 124 km from the middle of the area, began a volume at 17:04 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

Greensboro/Hi Pt, NC (KGSO), launched 12:00Z, 5.0 hours before the alert went out and 192 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.

Skew-T log-pSkew-T log-p diagram, Greensboro/Hi Pt, NC at 12:00Z on 2012-02-24Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 150 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Greensboro/Hi Pt, NC at 12:00Z on 2012-02-24The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 271 square meters per square second.1939587897117136Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
150 J/kg
Mixed-layer CIN
-118 J/kg
Mixed-layer LCL
742 m above ground
0-6 km bulk shear
68 kt
0-1 km storm-relative helicity
271 m²/s²
0-3 km storm-relative helicity
345 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.3

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

872 
ACUS11 KWNS 241700
SWOMCD
SPC MCD 241700 
VAZ000-NCZ000-WVZ000-SCZ000-TNZ000-GAZ000-241800-

MESOSCALE DISCUSSION 0155
NWS STORM PREDICTION CENTER NORMAN OK
1100 AM CST FRI FEB 24 2012

AREAS AFFECTED...PORTIONS OF THE CNTRL APPALACHIANS INTO CNTRL VA/NC

CONCERNING...TORNADO WATCH 36...

VALID 241700Z - 241800Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 36 CONTINUES.

...NEW TORNADO WATCH WILL LIKELY BE REQUIRED ACROSS THE MIDDLE
ATLANTIC IN THE NEXT FEW HOURS...

STRONG FORCING IS BEGINNING TO OVERSPREAD THE CNTRL
APPALACHIANS...PER POST FRONTAL BAND OF WEAK SHOWERS THAT ARE
EXPANDING FROM SRN OH/ERN KY INTO WV/WRN VA. 
DOWNSTREAM...CONVECTION IS SLOWLY INTENSIFYING OVER THE HIGHER
ELEVATIONS ALONG THE VA/WV BORDER...SWWD ALONG A SHARPENING SURGING
FRONTAL ZONE.  LATEST OA FIELDS EXHIBIT VERY STEEP LOW LEVEL LAPSE
RATES SOUTH OF THE WARM FRONT ACROSS VA/NC WHERE SFC-3KM VALUES ARE
NOW APPROACHING 8C/KM.  IT APPEARS BOUNDARY LAYER PARCELS ARE
NEARING THEIR CONVECTIVE TEMPERATURES WITH READINGS WELL INTO THE
MID 70S ACROSS LOWER ELEVATIONS.  LATEST THINKING IS FRONTAL
CONVECTION WILL CONTINUE TO INTENSIFY AS IT PROGRESSES EAST OF THE
MOUNTAINS SUPPORTED IN THE LARGE SCALE BY STRONG FORCING AHEAD OF
DEEPENING TROUGH.

..DARROW.. 02/24/2012

...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...

ATTN...WFO...AKQ...LWX...RAH...RNK...RLX...GSP...MRX...FFC...

LAT...LON   34808471 37798091 37787797 34818188 34808471

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Feb 24, 6:56 AM ESTMesoscale DiscussionSPCBaldwin, Banks, Barrow, Bartow, Bibb, Butts and 79 more94 min
Feb 24, 8:48 AM ESTTornado WatchSPCBaldwin, Banks, Barrow, Bibb, Bleckley, Burke and 64 more7 hr
Feb 24, 9:17 AM ESTTornado WatchSPCFranklin, Habersham, Hart, Rabun, Stephens7 hr
Feb 24, 10:49 AM ESTMesoscale DiscussionSPCBaldwin, Bibb, Bleckley, Burke, Butts, Calhoun and 57 more56 min
Feb 24, 12:04 PM ESTTornado WatchSPCAppling, Atkinson, Bacon, Baker, Ben Hill, Berrien and 52 more7 hr
Feb 24, 1:50 PM ESTMesoscale DiscussionSPCAppling, Atkinson, Bacon, Baker, Baldwin, Ben Hill and 86 more85 min
Feb 24, 3:24 PM ESTMesoscale DiscussionSPCFannin, Rabun, Towns, Union66 min
Feb 24, 4:11 PM ESTMesoscale DiscussionSPCAppling, Atkinson, Bacon, Baker, Ben Hill, Berrien and 56 more64 min
Feb 24, 9:05 AM ESTMesoscale DiscussionSPCAlexander, Alleghany, Ashe, Avery, Buncombe, Burke and 29 more25 min
Feb 24, 11:10 AM ESTMesoscale DiscussionSPCBladen, Brunswick, Columbus, New Hanover, Onslow, Pender and 1 more65 min
Feb 24, 12:43 PM ESTMesoscale DiscussionSPCAlamance, Anson, Beaufort, Bertie, Bladen, Brunswick and 51 more92 min
Feb 24, 1:19 PM ESTTornado WatchSPCAlamance, Anson, Beaufort, Bertie, Bladen, Brunswick and 55 more7 hr
Feb 24, 4:45 PM ESTMesoscale DiscussionSPCAlamance, Beaufort, Bertie, Bladen, Brunswick, Camden and 51 more90 min
Feb 23, 10:46 PM ESTMesoscale DiscussionSPCCheatham, Clay, Jackson, Macon, Overton, Pickett and 5 more89 min
Feb 24, 2:00 AM ESTMesoscale DiscussionSPCAnderson, Bledsoe, Blount, Bradley, Campbell, Claiborne and 31 more2 hr

Nearby

Mesoscale Discussions in North Carolina, 2012Mesoscale Discussions in Virginia, 2012Mesoscale Discussions in Tennessee, 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.