Alert archive / North Carolina / Mesoscale Discussions in 2012

Mesoscale Discussion 2231

December 26, 201230 counties in North Carolina; 22 counties in South Carolina

The Storm Prediction Center issued this mesoscale discussion at Dec 26, 2012, 8:07 AM EST for 30 counties in North Carolina; 22 counties in South Carolina. It was in force for 83 min.

The area

The outline as issued.

The facts

Issued
Dec 26, 2012, 8:07 AM EST (13:07 UTC)
Expired
Dec 26, 2012, 9:30 AM EST
In force
83 min
Issued by
the Storm Prediction Center
Chance of a watch
60%
All 52 counties

Anson County, NC, Beaufort County, NC, Bladen County, NC, Brunswick County, NC, Carteret County, NC, Columbus County, NC, Craven County, NC, Cumberland County, NC, Duplin County, NC, Greene County, NC, Harnett County, NC, Hoke County, NC, Hyde County, NC, Johnston County, NC, Jones County, NC, Lee County, NC, Lenoir County, NC, Montgomery County, NC, Moore County, NC, New Hanover County, NC, Onslow County, NC, Pamlico County, NC, Pender County, NC, Richmond County, NC, Robeson County, NC, Sampson County, NC, Scotland County, NC, Stanly County, NC, Union County, NC, Wayne County, NC, Bamberg County, SC, Berkeley County, SC, Calhoun County, SC, Charleston County, SC, Chesterfield County, SC, Clarendon County, SC, Colleton County, SC, Darlington County, SC, Dillon County, SC, Dorchester County, SC, Florence County, SC, Georgetown County, SC, Horry County, SC, Kershaw County, SC, Lancaster County, SC, Lee County, SC, Marion County, SC, Marlboro County, SC, Orangeburg County, SC, Richland County, SC, Sumter County, SC, Williamsburg County, SC

The radar

The Wilmington radar (KLTX), 23 km from the middle of the area, began a volume at 13:08 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

Newport, NC (KMHX), launched 12:00Z, 1.1 hours before the alert went out and 178 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 2012-12-26Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 2012-12-26The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 540 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
438 m above ground
0-6 km bulk shear
51 kt
0-1 km storm-relative helicity
540 m²/s²
0-3 km storm-relative helicity
770 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

331 
ACUS11 KWNS 261308
SWOMCD
SPC MCD 261307
NCZ000-SCZ000-261430-

MESOSCALE DISCUSSION 2231
NWS STORM PREDICTION CENTER NORMAN OK
0707 AM CST WED DEC 26 2012

AREAS AFFECTED...CENTRAL/ERN SC...SRN NC

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 261307Z - 261430Z

PROBABILITY OF WATCH ISSUANCE...60 PERCENT

SUMMARY...TSTMS MAY INCREASE IN INTENSITY BY 16Z IN ADVANCE OF A
COLD FRONT AND DEVELOPING AREA OF LOW PRESSURE. ENVIRONMENTAL
CONDITIONS WILL FAVOR SUPERCELL AND BOWING STRUCTURES CAPABLE OF
DAMAGING WINDS AND TORNADOES. A WW MAY BE NEEDED PRIOR TO 16Z.

DISCUSSION...A WARM FRONT EXTENDED FROM JUST S OF MRH INLAND NEAR
MYR AND TO A DEVELOPING SECONDARY AREA OF LOW PRESSURE OVER NRN GA.
AS THE MORNING PROGRESSES THE WARM FRONT WILL LIFT NWD IN TANDEM
WITH THE DEVELOPING SFC LOW...RESULTING IN A MODESTLY UNSTABLE AND
STRONGLY SHEARED ATM OVER CENTRAL/ERN SC AND SRN NC. WIDESPREAD
CLOUDS AND PRECIPITATION WILL PREVENT SUBSTANTIAL
DESTABILIZATION...HOWEVER COOLING MID LEVEL TEMPERATURES AND FORCING
FOR ASCENT ASSOCIATED WITH A STRONG SHORTWAVE WILL FOSTER THE
DEVELOPMENT/INTENSIFICATION OF TSTMS DURING THE NEXT FEW HOURS OVER
THE DISCUSSION AREA. VERY STRONG LOW-LEVEL WIND FIELDS HAVE RESULTED
IN 0-1 KM SRH VALUES IN EXCESS OF 500 M2/S2...AND SUPERCELL
STRUCTURES/BOWING SEGMENTS APPEAR INCREASINGLY LIKELY WITH A RISK OF
TORNADOES AND DAMAGING WINDS. HIGH-RESOLUTION NUMERICAL GUIDANCE
DEPICTS THIS SCENARIO UNFOLDING ACROSS THE DISCUSSION AREA THROUGH
MIDDAY. CONVECTIVE TRENDS ARE BEING MONITORED FOR A WW PRIOR TO 16Z.

..BUNTING/MEAD.. 12/26/2012

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

ATTN...WFO...MHX...RAH...ILM...CHS...CAE...GSP...

LAT...LON   33048115 33738126 35288066 35587931 35547650 35397569
            35187563 34367640 34287697 34007758 33537821 32297987
            32268057 33048115

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Dec 26, 6:20 AM ESTMesoscale DiscussionSPCBrunswick, Columbus, New Hanover85 min
Dec 26, 10:08 AM ESTTornado WatchSPCBeaufort, Bladen, Brunswick, Carteret, Columbus, Craven and 23 more6 hr
Dec 26, 2:20 PM ESTMesoscale DiscussionSPCBeaufort, Bladen, Brunswick, Carteret, Columbus, Craven and 19 more85 min
Dec 26, 6:11 PM ESTMesoscale DiscussionSPCBeaufort, Bertie, Camden, Chowan, Currituck, Dare and 12 more2 hr

Nearby

Mesoscale Discussions in North Carolina, 2012Mesoscale Discussions in South Carolina, 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.