Alert archive / South Carolina / Mesoscale Discussions in 2012

Mesoscale Discussion 565

April 18, 2012Robeson County, Scotland County, North Carolina; 14 counties in South Carolina

The Storm Prediction Center issued this mesoscale discussion at Apr 18, 2012, 2:48 PM EDT for Robeson County, Scotland County, North Carolina; 14 counties in South Carolina. It was in force for 87 min.

The area

The outline as issued.

The facts

Issued: Apr 18, 2012, 2:48 PM EDT (18:48 UTC)
Expired: Apr 18, 2012, 4:15 PM EDT
In force: 87 min
Issued by: the Storm Prediction Center

Counties Robeson County, NC, Scotland County, NC, Berkeley County, SC, Chesterfield County, SC, Clarendon County, SC, Darlington County, SC, Dillon County, SC, Dorchester County, SC, Florence County, SC, Horry County, SC, Kershaw County, SC, Lee County, SC, Marion County, SC, Marlboro County, SC, Sumter County, SC, Williamsburg County, SC

The radar

The Columbia radar (KCAE), 106 km from the middle of the area, began a volume at 18:48 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

Charleston AFB, SC (KCHS), launched 12:00Z, 6.8 hours before the alert went out and 99 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 119 J/kg
Mixed-layer CIN: -9 J/kg
Mixed-layer LCL: 777 m above ground
0-6 km bulk shear: 32 kt
0-1 km storm-relative helicity: 67 m²/s²
0-3 km storm-relative helicity: 50 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.

943 
ACUS11 KWNS 181848
SWOMCD
SPC MCD 181848 
NCZ000-SCZ000-182015-

MESOSCALE DISCUSSION 0565
NWS STORM PREDICTION CENTER NORMAN OK
0148 PM CDT WED APR 18 2012

AREAS AFFECTED...PARTS OF CENTRAL AND ERN SC/ADJACENT PART OF SERN
NC

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 181848Z - 182015Z

ISOLATED STRONG TO SEVERE STORMS WILL BE POSSIBLE THIS AFTERNOON
ACROSS THE ERN HALF OF SC INTO ADJACENT COUNTIES INTO SERN NC.

18Z MESOSCALE ANALYSIS SHOWED AN AREA OF WEAK LOW PRESSURE CENTERED
OVER NRN-NERN SC /INVOF CHESTERFIELD COUNTY/ WITH A TROUGH /ALSO
DEPICTED AS A DIFFERENTIAL HEATING BOUNDARY PER VIS IMAGERY/
EXTENDING SSWWD THROUGH SRN SC TO SERN-SRN GA. SURFACE HEATING
WITHIN THE AIR MASS ALONG AND EAST OF THE TROUGH WILL ALLOW FOR
ADDITIONAL DESTABILIZATION WITH CURRENT MLCAPE AROUND 500 J/KG. 
REGIONAL RADAR IMAGERY SHOWED A BROKEN BAND OF TSTMS EXTENDING SWD
FROM NEAR THE LOW INTO COLLETON COUNTY SC.  THIS ACTIVITY WAS
LOCATED ALONG THE LEADING EDGE OF STRONGER FORCING FOR ASCENT/DPVA
SPREADING ACROSS THIS REGION AS A SHORTWAVE TROUGH LIFTS NEWD.

ALTHOUGH LOW LEVEL WINDS ARE FAIRLY WEAK...35-40 KT SWLY MIDLEVEL
WINDS ARE SUPPORTING BULK SHEAR SUFFICIENT FOR STORM ORGANIZATION. 
A FEW SUSTAINED STORMS WILL BE POSSIBLE WITH HAIL AND STRONG WIND
GUSTS THE PRIMARY THREATS...BUT LIMITED COVERAGE DUE TO THE WEAK
INSTABILITY WILL RESULT IN A LOW THREAT FOR SEVERE STORMS.

..PETERS.. 04/18/2012

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

ATTN...WFO...RAH...ILM...CHS...CAE...

LAT...LON   33488071 34438065 34988004 34797899 34447865 33947893
            33367950 32998010 32918066 32938091 33488071

Nearby

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