Alert archive / Georgia / Mesoscale Discussions in 2011

Mesoscale Discussion 441

April 15, 201132 counties in Georgia

The Storm Prediction Center issued this mesoscale discussion at Apr 15, 2011, 5:30 PM EDT for 32 counties in Georgia. It was in force for 60 min.

The area

The outline as issued.

The facts

Issued
Apr 15, 2011, 5:30 PM EDT (21:30 UTC)
Expired
Apr 15, 2011, 6:30 PM EDT
In force
60 min
Issued by
the Storm Prediction Center
All 32 counties

Barrow County, GA, Bartow County, GA, Butts County, GA, Carroll County, GA, Cherokee County, GA, Clayton County, GA, Cobb County, GA, Coweta County, GA, Dawson County, GA, DeKalb County, GA, Douglas County, GA, Fayette County, GA, Forsyth County, GA, Fulton County, GA, Gilmer County, GA, Gwinnett County, GA, Hall County, GA, Heard County, GA, Henry County, GA, Jackson County, GA, Lamar County, GA, Lumpkin County, GA, Meriwether County, GA, Monroe County, GA, Newton County, GA, Paulding County, GA, Pickens County, GA, Pike County, GA, Rockdale County, GA, Spalding County, GA, Troup County, GA, Walton County, GA

The radar

The Atlanta radar (KFFC), 50 km from the middle of the area, began a volume at 21:30 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 12:00Z, 9.5 hours before the alert went out and 49 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 12:00Z on 2011-04-15Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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 12:00Z on 2011-04-15The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 106 square meters per square second.193958Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1094 m above ground
0-6 km bulk shear
44 kt
0-1 km storm-relative helicity
106 m²/s²
0-3 km storm-relative helicity
198 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.

227 
ACUS11 KWNS 152131
SWOMCD
SPC MCD 152130
GAZ000-152230-

MESOSCALE DISCUSSION 0441
NWS STORM PREDICTION CENTER NORMAN OK
0430 PM CDT FRI APR 15 2011

AREAS AFFECTED...N-CNTRL/CNTRL/W-CNTRL GA

CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE

VALID 152130Z - 152230Z

THE THREAT FOR SEVERE TSTMS IS INCREASING ACROSS
N-CNTRL/CNTRL/W-CNTRL GA...AND A WW MAY BECOME NECESSARY.

AN AREA OF MLCAPE VALUES OF 500-1000 J/KG WILL CONTINUE EXPANDING
NWD ACROSS GA DURING THE NEXT COUPLE HOURS FOLLOWING THE PASSAGE OF
A WARM FRONT. THIS WILL OCCUR IN ASSOCIATION WITH THE INFLUX OF GULF
MOISTURE AT THE ERN PERIPHERY OF THE WARM SECTOR. RECENT
SUPERCELLULAR STRUCTURE OVER WRN PICKENS COUNTY REFLECTS THE STRONG
DEEP-LAYER WIND SHEAR IN PLACE. ADDITIONAL CONVECTION WILL LIKELY
DEVELOP WITHIN THE EXPANDING WARM SECTOR AND NEAR THE WARM
FRONT...AND WIND PROFILES WILL REMAIN FAVORABLE FOR SUPERCELLS.
LARGE HAIL AND DMGG WINDS WILL BE THE PRIMARY THREATS...THOUGH
STRONG LOW-LEVEL WIND SHEAR WILL PROMOTE A THREAT FOR TORNADOES.

..COHEN.. 04/15/2011

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

ATTN...WFO...GSP...FFC...

LAT...LON   33538524 34378494 34868448 34578354 33778353 32878390
            32968506 33538524

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 15, 2:30 PM EDTMesoscale DiscussionSPCCarroll, Haralson, Heard, Polk2 hr
Apr 15, 5:46 PM EDTTornado WatchSPCBanks, Barrow, Bartow, Butts, Carroll, Chattooga and 45 more3 hr

Nearby

Mesoscale Discussions in Georgia, 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.