Alert archive / South Carolina / Mesoscale Discussions in 2012

Mesoscale Discussion 763

May 9, 2012Burke County, Richmond County, Georgia; 10 counties in North Carolina; 27 counties in South Carolina

The Storm Prediction Center issued this mesoscale discussion at May 9, 2012, 11:32 AM EDT for Burke County, Richmond County, Georgia; 10 counties in North Carolina; 27 counties in South Carolina. It was in force for 88 min.

The area

The outline as issued.

The facts

Issued: May 9, 2012, 11:32 AM EDT (15:32 UTC)
Expired: May 9, 2012, 1:00 PM EDT
In force: 88 min
Issued by: the Storm Prediction Center
Chance of a watch: 20%

All 39 counties

Burke County, GA, Richmond County, GA, Anson County, NC, Cumberland County, NC, Hoke County, NC, Montgomery County, NC, Moore County, NC, Richmond County, NC, Robeson County, NC, Scotland County, NC, Stanly County, NC, Union County, NC, Aiken County, SC, Allendale County, SC, Bamberg County, SC, Barnwell County, SC, Calhoun County, SC, Chester County, SC, Chesterfield County, SC, Clarendon County, SC, Darlington County, SC, Dillon County, SC, Edgefield County, SC, Fairfield County, SC, Florence County, SC, Kershaw County, SC, Lancaster County, SC, Lee County, SC, Lexington County, SC, Marion County, SC, Marlboro County, SC, Newberry County, SC, Orangeburg County, SC, Richland County, SC, Saluda County, SC, Sumter County, SC, Union County, SC, Williamsburg County, SC, York County, SC

The radar

The Columbia radar (KCAE), 48 km from the middle of the area, began a volume at 15:32 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.

Severe Thunderstorm Watch 269May 9, 2:00 PM EDT

The nearest sounding before it

Charleston AFB, SC (KCHS), launched 12:00Z, 3.5 hours before the alert went out and 131 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: 484 J/kg
Mixed-layer CIN: -17 J/kg
Mixed-layer LCL: 666 m above ground
0-6 km bulk shear: 18 kt
0-1 km storm-relative helicity: 39 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.

837 
ACUS11 KWNS 091532
SWOMCD
SPC MCD 091532 
NCZ000-SCZ000-GAZ000-091700-

MESOSCALE DISCUSSION 0763
NWS STORM PREDICTION CENTER NORMAN OK
1032 AM CDT WED MAY 09 2012

AREAS AFFECTED...SC/FAR ERN GA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY 

VALID 091532Z - 091700Z

PROBABILITY OF WATCH ISSUANCE...20 PERCENT

SUMMARY...CONVECTION CONTINUES TO INCREASE ACROSS WESTERN SC AND
ADJACENT AREAS...BUT ENVIRONMENT SHOULD REMAIN UNSUPPORTIVE OF
SUBSTANTIAL SEVERE POTENTIAL.

DISCUSSION...LATEST RADAR LOOP SHOWS A BAND OF THUNDERSTORMS MOVING
EWD ACROSS WRN SC AND EXTREME E CENTRAL GA ATTM...AIDED BY A BAND OF
WEAK ASCENT WHICH IS EVIDENT IN WATER VAPOR IMAGERY SHIFTING ACROSS
THIS REGION IN ADVANCE OF THE LARGER-SCALE UPPER TROUGH.  THE
CONVECTION IS ONGOING WITHIN AN ENVIRONMENT FEATURING ONLY MODEST
CAPE...WHERE POTENTIAL FOR ADDITIONAL DESTABILIZATION WILL REMAIN
LIMITED DUE TO MODEST LAPSE RATES AND SUBSTANTIAL CLOUD COVER. 
ALONG WITH THE LIMITED INSTABILITY...A MODEST KINEMATIC ENVIRONMENT
IS ALSO IN PLACE ACROSS THE AREA -- WITH UNIDIRECTIONAL WSWLY FLOW
AOB 30 KT THROUGH THE LOWER HALF OF THE TROPOSPHERE.  

AS STORMS CONTINUE SHIFTING EWD...WEAK/SLOW DESTABILIZATION INTO THE
AFTERNOON HOURS COULD PERMIT A FEW STORMS TO BECOME CAPABLE OF
PRODUCING MARGINAL HAIL/WIND.  HOWEVER...ATTM EXPECT THREAT TO
REMAIN SUFFICIENTLY LIMITED TO PRECLUDE THE NEED FOR WW ISSUANCE.

..GOSS.. 05/09/2012

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

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

LAT...LON   32808132 33008239 34778163 35438044 35327892 34397854
            33198023 32808132

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
May 9, 12:59 PM EDT	Mesoscale Discussion	SPC	Appling, Atkinson, Bacon, Baker, Ben Hill, Berrien and 49 more	2 hr
May 9, 2:00 PM EDT	Severe Thunderstorm Watch	SPC	Bryan, Bulloch, Candler, Chatham, Effingham, Evans and 4 more	5 hr
May 9, 4:54 PM EDT	Mesoscale Discussion	SPC	Bryan, Chatham, Liberty, Long, McIntosh, Wayne	96 min
May 9, 6:01 PM EDT	Mesoscale Discussion	SPC	Atkinson, Bacon, Brantley, Brooks, Camden, Charlton and 6 more	89 min
May 9, 7:04 PM EDT	Mesoscale Discussion	SPC	Bryan, Chatham, Effingham, Liberty, Long, McIntosh	26 min
May 9, 5:36 PM EDT	Mesoscale Discussion	SPC	Beaufort, Bertie, Bladen, Brunswick, Camden, Carteret and 29 more	84 min

Nearby

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