Alert archive / North Carolina / Mesoscale Discussions in 2011

Mesoscale Discussion 2145

September 6, 201152 counties in North Carolina; 9 counties in South Carolina; 13 counties in Virginia

The Storm Prediction Center issued this mesoscale discussion at Sep 6, 2011, 4:41 PM EDT for 52 counties in North Carolina; 9 counties in South Carolina; 13 counties in Virginia. It was in force for 64 min.

The area

The outline as issued.

The facts

Issued
Sep 6, 2011, 4:41 PM EDT (20:41 UTC)
Expired
Sep 6, 2011, 5:45 PM EDT
In force
64 min
Issued by
the Storm Prediction Center
All 74 counties

Alamance County, NC, Anson County, NC, Beaufort County, NC, Bertie County, NC, Bladen County, NC, Brunswick County, NC, Caswell County, NC, Chatham County, NC, Chowan County, NC, Columbus County, NC, Craven County, NC, Cumberland County, NC, Duplin County, NC, Durham County, NC, Edgecombe County, NC, Franklin County, NC, Gates County, NC, Granville County, NC, Greene County, NC, Guilford County, NC, Halifax County, NC, Harnett County, NC, Hertford County, NC, Hoke County, NC, Johnston County, NC, Jones County, NC, Lee County, NC, Lenoir County, NC, Martin County, NC, Montgomery County, NC, Moore County, NC, Nash County, NC, New Hanover County, NC, Northampton County, NC, Onslow County, NC, Orange County, NC, Pamlico County, NC, Pender County, NC, Person County, NC, Pitt County, NC, Randolph County, NC, Richmond County, NC, Robeson County, NC, Rockingham County, NC, Sampson County, NC, Scotland County, NC, Vance County, NC, Wake County, NC, Warren County, NC, Washington County, NC, Wayne County, NC, Wilson County, NC, Chesterfield County, SC, Darlington County, SC, Dillon County, SC, Florence County, SC, Georgetown County, SC, Horry County, SC, Marion County, SC, Marlboro County, SC, Williamsburg County, SC, Brunswick County, VA, City of Emporia, VA, City of Franklin, VA, City of Newport News, VA, City of Poquoson, VA, City of Portsmouth, VA, City of Suffolk, VA, Greensville County, VA, Isle of Wight County, VA, Mecklenburg County, VA, Southampton County, VA, Surry County, VA, Sussex County, VA

The radar

The Raleigh/Durham radar (KRAX), 46 km from the middle of the area, began a volume at 20:43 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, 8.7 hours before the alert went out and 132 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, Newport, NC at 12:00Z on 2011-09-06Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2357 joules per kilogram.LCLEL10008507005003002001001 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, Newport, NC at 12:00Z on 2011-09-06The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 66 square meters per square second.1939Sfc1 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
2357 J/kg
Mixed-layer CIN
0 J/kg
Mixed-layer LCL
472 m above ground
0-6 km bulk shear
18 kt
0-1 km storm-relative helicity
66 m²/s²
0-3 km storm-relative helicity
64 m²/s²
Significant tornado parameter
0.5
Supercell composite
3.3

Open this sounding in Storm Lab

The text

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

947 
ACUS11 KWNS 062042
SWOMCD
SPC MCD 062041
NCZ000-VAZ000-SCZ000-062145-

MESOSCALE DISCUSSION 2145
NWS STORM PREDICTION CENTER NORMAN OK
0341 PM CDT TUE SEP 06 2011

AREAS AFFECTED...NERN SC/CENTRAL AND ERN NC/SERN VA

CONCERNING...TORNADO WATCH 847...848...

VALID 062041Z - 062145Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 847...848...CONTINUES.

THE SEVERE WEATHER THREAT /PRIMARILY STRONG WIND GUSTS...LOCALLY
EXCEEDING SEVERE LEVELS/ PERSISTS ACROSS WW 848 AND THE FAR ERN
EXTENT OF WW 847.

MID AFTERNOON SURFACE ANALYSES MAINTAINED AN AREA OF LOW PRESSURE
OVER FAR NERN TN WITH THE TRAILING COLD FRONT HAVING ADVANCED EWD
THROUGH WRN NC AND MUCH OF CENTRAL SC BY 2030Z.  THE DELINEATING
BOUNDARY FOR THE NRN EXTENT OF THE SEVERE WEATHER THREAT CONTINUES
TO BE THE BAROCLINIC ZONE WHICH EXTENDED WSWWD FROM FAR SERN VA
THROUGH FAR NORTH CENTRAL NC TO NWRN NC WHERE THIS BOUNDARY
INTERSECTED THE EWD ADVANCING COLD FRONT.  THE ERN EXTENT OF
STRONGER MERIDIONAL FLOW IS JUXTAPOSED WITH THE WRN EXTENT OF
STRONGER INSTABILITY SUCH THAT ORGANIZED LINE SEGMENTS CONTINUE TO
DEVELOP.  ALTHOUGH STORM MOTION IS TO THE NNE AROUND 40 KT...
STRONGER WIND GUSTS HAVE BEEN LIMITED TO REACHING THE SURFACE...WITH
THIS LIKELY DUE TO RELATIVELY WEAKER LOW LEVEL LAPSE RATES.
EFFECTIVE SRH OF 200-300 M2/S2 REMAINS SUFFICIENT FOR LOW LEVEL
STORM ROTATION...BUT AGAIN THE WEAKER LOW LEVEL LAPSE RATES MAY TEND
TO LIMIT THIS THREAT AS WELL.

..PETERS.. 09/06/2011

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

ATTN...WFO...AKQ...MHX...RAH...ILM...RNK...CHS...CAE...

LAT...LON   32947886 33528005 34718020 35838014 36327992 36717908
            36827818 36987741 37267660 37177627 36437644 35347651
            34707681 34557721 33607771 32947886

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 5, 8:36 PM EDTMesoscale DiscussionSPCAnson, Cumberland, Hoke, Montgomery, Moore, Richmond and 3 more84 min
Sep 5, 11:47 PM EDTMesoscale DiscussionSPCStokes, Surry88 min
Sep 6, 3:30 AM EDTMesoscale DiscussionSPCRockingham, Stokes60 min
Sep 6, 4:36 AM EDTMesoscale DiscussionSPCAlamance, Anson, Cabarrus, Caswell, Chatham, Davidson and 22 more84 min
Sep 6, 5:17 AM EDTTornado WatchSPCAlamance, Alleghany, Anson, Bladen, Brunswick, Caswell and 43 more9 hr
Sep 6, 8:35 AM EDTMesoscale DiscussionSPCAlamance, Anson, Bladen, Brunswick, Cabarrus, Catawba and 42 more85 min
Sep 6, 9:51 AM EDTTornado WatchSPCAlexander, Avery, Burke, Cabarrus, Caldwell, Catawba and 13 more6 hr
Sep 6, 12:41 PM EDTMesoscale DiscussionSPCAlamance, Alleghany, Anson, Beaufort, Bertie, Bladen and 55 more64 min
Sep 6, 1:32 PM EDTTornado WatchSPCAlamance, Anson, Beaufort, Bertie, Bladen, Brunswick and 48 more7 hr
Sep 6, 7:33 PM EDTMesoscale DiscussionSPCBeaufort, Bertie, Bladen, Brunswick, Camden, Carteret and 38 more117 min
Sep 6, 10:11 AM EDTTornado WatchSPCAllendale, Bamberg, Barnwell, Beaufort, Berkeley, Calhoun and 15 more7 hr

Nearby

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