Alert archive / North Carolina / Mesoscale Discussions in 2011

Mesoscale Discussion 723

May 11, 20114 states

The Storm Prediction Center issued this mesoscale discussion at May 11, 2011, 2:37 AM EDT for 4 states. It was in force for 23 min.

The area

The outline as issued.

The facts

Issued
May 11, 2011, 2:37 AM EDT (06:37 UTC)
Expired
May 11, 2011, 3:00 AM EDT
In force
23 min
Issued by
the Storm Prediction Center
All 46 counties

Alexander County, NC, Ashe County, NC, Avery County, NC, Buncombe County, NC, Burke County, NC, Caldwell County, NC, Catawba County, NC, Cleveland County, NC, Gaston County, NC, Haywood County, NC, Henderson County, NC, Lincoln County, NC, Madison County, NC, McDowell County, NC, Mecklenburg County, NC, Mitchell County, NC, Polk County, NC, Rutherford County, NC, Watauga County, NC, Yancey County, NC, Cherokee County, SC, Chester County, SC, Greenville County, SC, Laurens County, SC, Spartanburg County, SC, Union County, SC, York County, SC, Carter County, TN, Cocke County, TN, Greene County, TN, Hamblen County, TN, Hancock County, TN, Hawkins County, TN, Johnson County, TN, Sullivan County, TN, Unicoi County, TN, Washington County, TN, Buchanan County, VA, City of Bristol, VA, City of Norton, VA, Dickenson County, VA, Lee County, VA, Russell County, VA, Scott County, VA, Washington County, VA, Wise County, VA

The radar

The Greer radar (KGSP), 106 km from the middle of the area, began a volume at 06:40 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

Greensboro/Hi Pt, NC (KGSO), launched 00:00Z, 6.6 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 00:00Z on 2011-05-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 694 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 00:00Z on 2011-05-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 109 square meters per square second.19395878Sfc1 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
694 J/kg
Mixed-layer CIN
-146 J/kg
Mixed-layer LCL
1286 m above ground
0-6 km bulk shear
50 kt
0-1 km storm-relative helicity
109 m²/s²
0-3 km storm-relative helicity
420 m²/s²
Significant tornado parameter
0.3
Supercell composite
11.6

Open this sounding in Storm Lab

The text

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

471 
ACUS11 KWNS 110637
SWOMCD
SPC MCD 110637 
NCZ000-SCZ000-VAZ000-TNZ000-KYZ000-110700-

MESOSCALE DISCUSSION 0723
NWS STORM PREDICTION CENTER NORMAN OK
0137 AM CDT WED MAY 11 2011

AREAS AFFECTED...SWRN VA...PARTS OF EXTREME ERN TN AND WRN NC

CONCERNING...SEVERE THUNDERSTORM WATCH 273...

VALID 110637Z - 110700Z

THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 273
CONTINUES.

A NEW SEVERE TSTM WATCH MAY BE NEEDED ACROSS SWRN VA...PARTS OF
EXTREME ERN TN AND WRN NC.  THE STRONGEST ACTIVITY ACROSS ERN KY
SHOULD MOVE S OF WW 275 AROUND 08Z.  GIVEN THIS FACTOR...WW 273 WILL
BE ALLOWED TO EXPIRE AND/OR BE CANCELLED EARLY...WITH CONTINUED
MONITORING OF UPSTREAM CONVECTIVE TRENDS FOR INCREASE IN STRONGER
CORES.  IF THIS OCCURS...THEN A NEW WW WOULD LIKELY BE NEEDED S OF
WW 275.

05Z SURFACE ANALYSIS SHOWED A WARM FRONT EXTENDING FROM JUST N OF
CHICAGO SEWD THROUGH CENTRAL IND...FAR SWRN OH AND THEN SSEWD
THROUGH CENTRAL/ERN KY TO ERN TN AND NERN-ERN GA.  REGIONAL RADAR
IMAGERY SHOWED A PROGRESSIVE MCS TRACKING SSEWD THROUGH CENTRAL SC. 
DESPITE STABILIZATION OF THE BOUNDARY LAYER IN THE WAKE OF THIS MCS
UPSTREAM ACROSS UPSTATE SC TO WRN NC...NEW TSTMS CONTINUE TO DEVELOP
AND TRACK SSEWD ACROSS ERN KY TOWARD FAR SWRN VA.  THIS LATTER
ACTIVITY IS BEING FED BY A WLY 20-30 KT LLJ WITH MUCAPE 1000-2000
J/KG.  THIS COMBINED WITH EFFECTIVE BULK SHEAR AROUND 35 KT AND THIS
REGION RESIDING ALONG THE ERN EXTENT OF EML/STEEP MID LEVEL LAPSE
RATES...THE POTENTIAL REMAINS FOR ORGANIZED STORMS PRODUCING HAIL
AND STRONG WIND GUSTS...AS ACTIVITY MOVES SSEWD.  AS THE LLJ VEERS
TO NWLY OVERNIGHT THROUGH 12Z...ACTIVITY OVER ERN KY SHOULD CONTINUE
TO DEVELOP AND TRACK INTO SWRN VA...ERN TN/WRN NC WITH POTENTIAL FOR
AT LEAST ISOLATED SEVERE STORMS.  IF ERN KY ACTIVITY IS
SUSTAINED...THEN A NEW WW WOULD BE POSSIBLE.

..PETERS.. 05/11/2011

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

ATTN...WFO...RNK...RLX...CAE...GSP...MRX...JKL...

LAT...LON   35298064 34688089 34318203 35098264 35748321 36548343
            36958310 37448197 36848157 35298064

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 10, 9:01 PM EDTMesoscale DiscussionSPCAlexander, Alleghany, Anson, Ashe, Avery, Bladen and 46 more59 min
May 10, 10:18 PM EDTMesoscale DiscussionSPCAlexander, Ashe, Avery, Buncombe, Burke, Caldwell and 16 more27 min
May 10, 10:42 PM EDTSevere Thunderstorm WatchSPCAlexander, Avery, Buncombe, Burke, Caldwell, Catawba and 13 more4 hr
May 11, 12:14 AM EDTMesoscale DiscussionSPCAlexander, Alleghany, Ashe, Avery, Buncombe, Burke and 17 more61 min
May 11, 6:06 PM EDTMesoscale DiscussionSPCBuncombe, Haywood, Henderson, Jackson, Polk, Transylvania54 min
May 11, 12:41 AM EDTSevere Thunderstorm WatchSPCAiken, Bamberg, Barnwell, Calhoun, Chesterfield, Clarendon and 11 more3 hr
May 11, 1:35 AM EDTMesoscale DiscussionSPCBerkeley, Charleston, Darlington, Dorchester, Florence, Georgetown and 2 more25 min
May 11, 1:41 AM EDTSevere Thunderstorm WatchSPCBerkeley, Charleston, Darlington, Dillon, Dorchester, Florence and 5 more3 hr
May 11, 3:34 AM EDTMesoscale DiscussionSPCBerkeley, Charleston, Chesterfield, Colleton, Darlington, Dillon and 7 more56 min
May 10, 11:17 PM EDTMesoscale DiscussionSPCBland, Buchanan, Dickenson, Floyd, Giles, Montgomery and 7 more58 min

Nearby

Mesoscale Discussions in North Carolina, 2011Mesoscale Discussions in Tennessee, 2011Mesoscale Discussions in Virginia, 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.