Alert archive / Georgia / Mesoscale Discussions in 2012

Mesoscale Discussion 1449

July 11, 201240 counties in Georgia; 37 counties in South Carolina

The Storm Prediction Center issued this mesoscale discussion at Jul 11, 2012, 1:30 PM EDT for 40 counties in Georgia; 37 counties in South Carolina. It was in force for 2 hr.

The area

The outline as issued.

The facts

Issued
Jul 11, 2012, 1:30 PM EDT (17:30 UTC)
Expired
Jul 11, 2012, 3:30 PM EDT
In force
2 hr
Issued by
the Storm Prediction Center
Chance of a watch
40%
All 77 counties

Baldwin County, GA, Bryan County, GA, Bulloch County, GA, Burke County, GA, Candler County, GA, Chatham County, GA, Clarke County, GA, Columbia County, GA, Effingham County, GA, Elbert County, GA, Emanuel County, GA, Evans County, GA, Franklin County, GA, Glascock County, GA, Greene County, GA, Hancock County, GA, Hart County, GA, Jasper County, GA, Jefferson County, GA, Jenkins County, GA, Johnson County, GA, Jones County, GA, Liberty County, GA, Lincoln County, GA, Madison County, GA, McDuffie County, GA, Monroe County, GA, Morgan County, GA, Oconee County, GA, Oglethorpe County, GA, Putnam County, GA, Richmond County, GA, Screven County, GA, Taliaferro County, GA, Tattnall County, GA, Treutlen County, GA, Warren County, GA, Washington County, GA, Wilkes County, GA, Wilkinson County, GA, Abbeville County, SC, Aiken County, SC, Allendale County, SC, Anderson County, SC, Bamberg County, SC, Barnwell County, SC, Beaufort 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, Edgefield County, SC, Fairfield County, SC, Florence County, SC, Georgetown County, SC, Greenwood County, SC, Hampton County, SC, Horry County, SC, Jasper County, SC, Kershaw County, SC, Laurens County, SC, Lee County, SC, Lexington County, SC, Marion County, SC, Marlboro County, SC, McCormick County, SC, Newberry County, SC, Orangeburg County, SC, Richland County, SC, Saluda County, SC, Sumter County, SC, Williamsburg County, SC

The radar

The Charleston,SC radar (KCLX), 80 km from the middle of the area, began a volume at 17:32 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 nearest sounding before it

Charleston AFB, SC (KCHS), launched 12:00Z, 5.5 hours before the alert went out and 75 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, Charleston AFB, SC at 12:00Z on 2012-07-11Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2022 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, Charleston AFB, SC at 12:00Z on 2012-07-11The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 54 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
2022 J/kg
Mixed-layer CIN
-51 J/kg
Mixed-layer LCL
802 m above ground
0-6 km bulk shear
17 kt
0-1 km storm-relative helicity
54 m²/s²
0-3 km storm-relative helicity
54 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.

414 
ACUS11 KWNS 111731
SWOMCD
SPC MCD 111730
NCZ000-SCZ000-GAZ000-111930-

MESOSCALE DISCUSSION 1449
NWS STORM PREDICTION CENTER NORMAN OK
1230 PM CDT WED JUL 11 2012

AREAS AFFECTED...NORTH/EAST GA AND SC/FAR SOUTHERN NC

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 111730Z - 111930Z

PROBABILITY OF WATCH ISSUANCE...40 PERCENT

SUMMARY...AS SCATTERED TSTMS INCREASE IN COVERAGE/INTENSITY THIS
AFTERNOON...LOCALIZED DOWNBURSTS/WIND DAMAGE AS WELL AS ISOLATED
MARGINALLY SEVERE HAIL WILL BE POSSIBLE ACROSS PORTIONS OF GA/SC AND
FAR SOUTHERN NC.

DISCUSSION...MODIFIED BY NUMEROUS CONVECTIVE OUTFLOWS FROM THE PRIOR
24-48 HR...A WEAK WSW-ENE ORIENTED FRONTAL ZONE WILL PROVIDE SOME
FOCUS FOR TSTM DEVELOPMENT THIS AFTERNOON ACROSS THE REGION...ALONG
WITH THE INLAND PROGRESSING SEA BREEZE FOR COASTAL AREAS. AS
TEMPERATURES HAVE STEADILY WARMED THROUGH THE 80S F IN CONJUNCTION
WITH NEAR 70 F SURFACE DEWPOINTS...CONVECTIVE INHIBITION IS ALREADY
ESSENTIALLY NIL EARLY THIS AFTERNOON IN MOST AREAS ALONG/SOUTH OF
THE EFFECTIVE FRONT. MODIFICATIONS TO 12Z OBSERVED SOUNDINGS FROM
ATLANTA/CHARLESTON SC SUGGEST AS MUCH AS 1000-2300 J/KG OF SBCAPE
EXISTS ACROSS THE REGION...WITH THE MOST AGGRESSIVE DESTABILIZATION
ACROSS COASTAL SC/EASTERN GA. WHILE VERTICAL SHEAR WILL REMAIN
MEAGER...THE THERMODYNAMIC ENVIRONMENT WILL SUPPORT A
PULSE/MULTICELLUAR CONVECTIVE MODE WITH LOCALIZED DOWNBURSTS/SOME
HAIL POSSIBLE THIS AFTERNOON.

..GUYER/CARBIN.. 07/11/2012

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

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

LAT...LON   34747938 34067855 33637883 33127915 32518008 32018086
            31678124 32198241 33098407 34548319 34747938

Nearby

Mesoscale Discussions in Georgia, 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.