Alert archive / Georgia / Mesoscale Discussions in 2011

Mesoscale Discussion 655

April 28, 201136 counties in Georgia; 16 counties in North Carolina; 20 counties in South Carolina

The Storm Prediction Center issued this mesoscale discussion at Apr 28, 2011, 3:30 AM EDT for 36 counties in Georgia; 16 counties in North Carolina; 20 counties in South Carolina. It was in force for 90 min.

The area

The outline as issued.

The facts

Issued
Apr 28, 2011, 3:30 AM EDT (07:30 UTC)
Expired
Apr 28, 2011, 5:00 AM EDT
In force
90 min
Issued by
the Storm Prediction Center
All 72 counties

Baldwin County, GA, Bibb County, GA, Bleckley County, GA, Burke County, GA, Chattahoochee County, GA, Columbia County, GA, Crawford County, GA, Dooly County, GA, Glascock County, GA, Hancock County, GA, Houston County, GA, Jefferson County, GA, Johnson County, GA, Jones County, GA, Laurens County, GA, Lincoln County, GA, Macon County, GA, Marion County, GA, McDuffie County, GA, Monroe County, GA, Muscogee County, GA, Peach County, GA, Pulaski County, GA, Putnam County, GA, Richmond County, GA, Schley County, GA, Stewart County, GA, Talbot County, GA, Taliaferro County, GA, Taylor County, GA, Twiggs County, GA, Upson County, GA, Warren County, GA, Washington County, GA, Wilkes County, GA, Wilkinson County, GA, Alexander County, NC, Anson County, NC, Burke County, NC, Cabarrus County, NC, Catawba County, NC, Cleveland County, NC, Gaston County, NC, Iredell County, NC, Lincoln County, NC, McDowell County, NC, Mecklenburg County, NC, Montgomery County, NC, Rowan County, NC, Rutherford County, NC, Stanly County, NC, Union County, NC, Abbeville County, SC, Aiken County, SC, Barnwell County, SC, Calhoun County, SC, Cherokee County, SC, Chester County, SC, Chesterfield County, SC, Edgefield County, SC, Fairfield County, SC, Greenwood County, SC, Kershaw County, SC, Lancaster County, SC, Laurens County, SC, Lexington County, SC, McCormick County, SC, Newberry County, SC, Richland County, SC, Saluda County, SC, Union County, SC, York County, SC

The radar

The Greer radar (KGSP), 110 km from the middle of the area, began a volume at 07:31 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

Peachtre/Fal Fld, GA (KFFC), launched 00:00Z, 7.5 hours before the alert went out and 188 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, Peachtre/Fal Fld, GA at 00:00Z on 2011-04-28Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1215 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, Peachtre/Fal Fld, GA at 00:00Z on 2011-04-28The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 244 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
1215 J/kg
Mixed-layer CIN
-15 J/kg
Mixed-layer LCL
1433 m above ground
0-6 km bulk shear
49 kt
0-1 km storm-relative helicity
244 m²/s²
0-3 km storm-relative helicity
408 m²/s²
Significant tornado parameter
1.6
Supercell composite
15.2

Open this sounding in Storm Lab

The text

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

522 
ACUS11 KWNS 280731
SWOMCD
SPC MCD 280730
NCZ000-SCZ000-GAZ000-ALZ000-280900-

MESOSCALE DISCUSSION 0655
NWS STORM PREDICTION CENTER NORMAN OK
0230 AM CDT THU APR 28 2011

AREAS AFFECTED...S CNTRL GA THROUGH CNTRL  SC AND WRN THROUGH CNTRL
NC

CONCERNING...TORNADO WATCH 248...

VALID 280730Z - 280900Z

THE SEVERE WEATHER THREAT FOR TORNADO WATCH 248 CONTINUES.

THREAT FOR ISOLATED TORNADOES...DAMAGING WIND AND LARGE HAIL WILL
PERSIST THROUGH THE EARLY MORNING FROM CNTRL-S CNTRL GA...CNTRL SC
INTO WRN AND CNTRL NC. STORMS ARE APPROACHING ERN BORDER OF NC
PORTION OF WW 248...AND THIS WW MAY BE REPLACED BY ANOTHER WW THAT
WILL EXTEND FARTHER EAST INTO NC AND SC.

PRE-FRONTAL BROKEN BAND OF STORMS WITH EMBEDDED SUPERCELLS EXTENDS
THROUGH W-CNTRL NC...WRN SC INTO CNTRL GA. ATMOSPHERE EAST OF LINE
REMAINS MARGINALLY TO MODERATELY UNSTABLE WITH MUCAPE FROM 1000 J/KG
OVER CNTRL NC TO 2000 J/KG ACROSS GA. A 50-60 KT SLY LLJ WILL
PERSIST AND SLOWLY LIFT NWD THROUGH THE CAROLINAS AND MID ATLANTIC
AS VORT MAX EJECTS THROUGH THE OH VALLEY. STRONG LOW LEVEL INFLOW
AND WEAK CAP SUGGEST STORMS WILL LIKELY CONTINUE DEVELOPING EWD.
LARGE 0-1 KM HODOGRAPHS AND STRONG EFFECTIVE SHEAR WILL SUPPORT A
THREAT OF EMBEDDED SUPERCELL AND BOWING STRUCTURES.

..DIAL.. 04/28/2011

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

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

LAT...LON   32028522 32648485 33758284 34408232 35138173 35748219
            36048099 35597963 33798052 32198294 32028522

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 27, 8:55 PM EDTMesoscale DiscussionSPCChattooga, Walker65 min
Apr 28, 12:09 AM EDTMesoscale DiscussionSPCBanks, Barrow, Bartow, Bibb, Butts, Carroll and 65 more36 min
Apr 28, 12:56 AM EDTTornado WatchSPCBaldwin, Banks, Barrow, Bibb, Bleckley, Burke and 80 more4 hr
Apr 28, 2:22 AM EDTMesoscale DiscussionSPCBaker, Calhoun, Clay, Early, Miller, Quitman and 2 more83 min
Apr 28, 4:30 AM EDTTornado WatchSPCBaldwin, Bibb, Bleckley, Bulloch, Burke, Candler and 37 more10 hr
Apr 28, 8:05 AM EDTMesoscale DiscussionSPCBurke, Candler, Dodge, Emanuel, Jefferson, Jenkins and 5 more85 min
Apr 28, 8:48 AM EDTTornado WatchSPCBryan, Bulloch, Candler, Chatham, Effingham, Evans and 6 more7 hr
Apr 28, 9:47 AM EDTSevere Thunderstorm WatchSPCAppling, Atkinson, Bacon, Brantley, Camden, Charlton and 8 more9 hr
Apr 28, 11:22 AM EDTMesoscale DiscussionSPCBulloch, Burke, Candler, Chatham, Effingham, Emanuel and 2 more53 min
Apr 28, 12:19 PM EDTMesoscale DiscussionSPCAppling, Bacon, Brantley, Camden, Charlton, Clinch and 10 more56 min
Apr 27, 10:12 PM EDTMesoscale DiscussionSPCAlleghany, Ashe, Forsyth, Rockingham, Stokes, Surry and 3 more63 min
Apr 28, 12:27 AM EDTMesoscale DiscussionSPCAlamance, Alleghany, Ashe, Caswell, Davidson, Davie and 11 more63 min
Apr 28, 12:41 AM EDTTornado WatchSPCAlamance, Alleghany, Ashe, Caswell, Davidson, Forsyth and 10 more7 hr
Apr 28, 7:38 AM EDTTornado WatchSPCBertie, Camden, Caswell, Chowan, Currituck, Gates and 9 more7 hr
Apr 28, 2:41 PM EDTTornado WatchSPCBeaufort, Bertie, Camden, Carteret, Chowan, Craven and 21 more6 hr
Apr 28, 3:19 PM EDTTornado WatchSPCBladen, Brunswick, Columbus, New Hanover, Pender4 hr
Apr 28, 6:33 PM EDTMesoscale DiscussionSPCBeaufort, Bertie, Camden, Carteret, Chowan, Craven and 20 more57 min

Nearby

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