Alert archive / South Carolina / Mesoscale Discussions in 2011

Mesoscale Discussion 2199

September 25, 201123 counties in Georgia; 17 counties in North Carolina; 31 counties in South Carolina

The Storm Prediction Center issued this mesoscale discussion at Sep 25, 2011, 6:04 PM EDT for 23 counties in Georgia; 17 counties in North Carolina; 31 counties in South Carolina. It was in force for 116 min.

The area

The outline as issued.

The facts

Issued: Sep 25, 2011, 6:04 PM EDT (22:04 UTC)
Expired: Sep 25, 2011, 8:00 PM EDT
In force: 116 min
Issued by: the Storm Prediction Center

All 71 counties

Appling County, GA, Bacon County, GA, Brantley County, GA, Bryan County, GA, Bulloch County, GA, Burke County, GA, Candler County, GA, Chatham County, GA, Effingham County, GA, Emanuel County, GA, Evans County, GA, Jeff Davis County, GA, Jenkins County, GA, Liberty County, GA, Long County, GA, Montgomery County, GA, Pierce County, GA, Richmond County, GA, Screven County, GA, Tattnall County, GA, Toombs County, GA, Ware County, GA, Wayne County, GA, Anson County, NC, Cabarrus County, NC, Catawba County, NC, Davidson County, NC, Davie County, NC, Forsyth County, NC, Gaston County, NC, Iredell County, NC, Lincoln County, NC, Mecklenburg County, NC, Montgomery County, NC, Randolph County, NC, Richmond County, NC, Rowan County, NC, Stanly County, NC, Union County, NC, Yadkin County, NC, Aiken County, SC, Allendale County, SC, Bamberg County, SC, Barnwell County, SC, Beaufort County, SC, Berkeley County, SC, Calhoun County, SC, Chester County, SC, Chesterfield County, SC, Clarendon County, SC, Colleton County, SC, Darlington County, SC, Dorchester County, SC, Edgefield County, SC, Fairfield County, SC, Florence County, SC, Hampton County, SC, Jasper County, SC, Kershaw County, SC, Lancaster County, SC, Lee County, SC, Lexington 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), 34 km from the middle of the area, began a volume at 22:07 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, 10.1 hours before the alert went out and 127 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: 1927 J/kg
Mixed-layer CIN: -2 J/kg
Mixed-layer LCL: 459 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 45 m²/s²
0-3 km storm-relative helicity: 77 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.

331 
ACUS11 KWNS 252205
SWOMCD
SPC MCD 252204
SCZ000-NCZ000-GAZ000-260000-

MESOSCALE DISCUSSION 2199
NWS STORM PREDICTION CENTER NORMAN OK
0504 PM CDT SUN SEP 25 2011

AREAS AFFECTED...PORTIONS OF CNTRL NC...SC...ERN GA

CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY

VALID 252204Z - 260000Z

AN ISOLATED SVR THREAT WILL CONTINUE INTO THE EARLY EVENING HOURS.
GIVEN THE ISOLATED NATURE OF THE THREAT...THE ISSUANCE OF A WW IS
UNLIKELY.

BROAD LOW-LEVEL CONFLUENCE BENEATH THE RIGHT-ENTRANCE REGION OF AN
UPPER-LEVEL JET STREAK AMIDST A PLUME OF SUB-TROPICAL MOISTURE -- PW
VALUES FROM 1.8 TO 2.0 INCHES PER GPS DATA -- WILL CONTINUE TO
SUSTAIN SCATTERED TO NUMEROUS CONVECTION. ALSO...CONVERGENCE ALONG
THE INLAND-PROPAGATING ATLANTIC SEA BREEZE WILL LIKELY PROVIDE AN
IMPETUS FOR STORM DEVELOPMENT/MAINTENANCE. SWLY EFFECTIVE SHEAR OF
30 TO 45 KT...OFFERED BY ENHANCED MID/UPPER-LEVEL FLOW OVER THE
OUTER CIRCULATION OF A CYCLONE CENTERED OVER THE MID MS
VALLEY...WILL SUPPORT OCCASIONALLY ORGANIZED STORM STRUCTURES. ONE
OR TWO WEAK SUPERCELLS...ALONG WITH SHORT/FORWARD-PROPAGATING LINE
SEGMENTS OWING TO WEAK ELY LOW-LEVEL FLOW PER AREA VWP DATA...WILL
BE POSSIBLE. THE STRONGEST STORMS COULD PRODUCE MARGINALLY SVR
HAIL/WIND GUSTS ON AN ISOLATED BASIS. HOWEVER...A MORE ROBUST
CONVECTIVE THREAT WILL LIKELY BE MITIGATED BY THE ABSENCE OF MORE
SALIENT SFC BOUNDARIES AND RELATIVELY WEAK MID-LEVEL LAPSE RATES.
STORMS ARE EXPECTED TO DIMINISH IN COVERAGE/INTENSITY AS NOCTURNAL
STABILIZATION ENSUES AFTER 00Z...AUGMENTED BY CONVECTIVE
OVERTURNING.

..COHEN.. 09/25/2011

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

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

LAT...LON   33318215 35198146 36338092 36358030 35607972 34777952
            34067955 32917998 32228085 31118164 30848234 31448287
            33318215

Nearby

Mesoscale Discussions in South Carolina, 2011 Mesoscale Discussions in Georgia, 2011 Mesoscale Discussions in North Carolina, 2011 Every 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.