Alert archive / Georgia / Mesoscale Discussions in 2017

Mesoscale Discussion 302

March 21, 20175 states

The Storm Prediction Center issued this mesoscale discussion at Mar 21, 2017, 1:53 PM CDT for 5 states. It was in force for 3 hr.

The area

The outline as issued.

The facts

Issued
Mar 21, 2017, 1:53 PM CDT (18:53 UTC)
Expired
Mar 21, 2017, 4:30 PM CDT
In force
3 hr
Issued by
the Storm Prediction Center
Chance of a watch
80%
All 96 counties

Calhoun County, AL, Cherokee County, AL, Cleburne County, AL, Colbert County, AL, DeKalb County, AL, Etowah County, AL, Jackson County, AL, Lauderdale County, AL, Lawrence County, AL, Limestone County, AL, Madison County, AL, Marshall County, AL, Morgan County, AL, Banks County, GA, Barrow County, GA, Bartow County, GA, Carroll County, GA, Catoosa County, GA, Chattooga County, GA, Cherokee County, GA, Clarke County, GA, Clayton County, GA, Cobb County, GA, Coweta County, GA, Dade County, GA, Dawson County, GA, DeKalb County, GA, Douglas County, GA, Elbert County, GA, Fannin County, GA, Fayette County, GA, Floyd County, GA, Forsyth County, GA, Franklin County, GA, Fulton County, GA, Gilmer County, GA, Gordon County, GA, Gwinnett County, GA, Habersham County, GA, Hall County, GA, Haralson County, GA, Hart County, GA, Henry County, GA, Jackson County, GA, Lumpkin County, GA, Madison County, GA, Morgan County, GA, Murray County, GA, Newton County, GA, Oconee County, GA, Oglethorpe County, GA, Paulding County, GA, Pickens County, GA, Polk County, GA, Rabun County, GA, Rockdale County, GA, Stephens County, GA, Towns County, GA, Union County, GA, Walker County, GA, Walton County, GA, White County, GA, Whitfield County, GA, Cherokee County, NC, Clay County, NC, Macon County, NC, Oconee County, SC, Bedford County, TN, Bledsoe County, TN, Bradley County, TN, Cannon County, TN, Coffee County, TN, Decatur County, TN, Franklin County, TN, Giles County, TN, Grundy County, TN, Hamilton County, TN, Hardin County, TN, Henderson County, TN, Hickman County, TN, Lawrence County, TN, Lewis County, TN, Lincoln County, TN, Marion County, TN, Marshall County, TN, Maury County, TN, McMinn County, TN, Meigs County, TN, Moore County, TN, Perry County, TN, Polk County, TN, Rutherford County, TN, Sequatchie County, TN, Warren County, TN, Wayne County, TN, Williamson County, TN

The radar

The Northeast Alabama radar (KHTX), 58 km from the middle of the area, began a volume at 18:58 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, 6.9 hours before the alert went out and 178 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 2017-03-21Temperature 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 2017-03-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 125 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1219 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
125 m²/s²
0-3 km storm-relative helicity
152 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

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SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Mar 21, 2:33 PM CDTSevere Thunderstorm WatchSPCCherokee, DeKalb, Jackson, Lauderdale, Limestone, Madison and 1 more7 hr
Mar 21, 4:30 PM CDTMesoscale DiscussionSPCJackson90 min
Mar 21, 6:47 PM CDTMesoscale DiscussionSPCBurke, Clarke, Columbia, Elbert, Glascock, Greene and 17 more58 min

Nearby

Mesoscale Discussions in Georgia, 2017Mesoscale Discussions in Tennessee, 2017Mesoscale Discussions in Alabama, 2017Every mesoscale discussion in 2017

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.