Alert archive / Georgia / Mesoscale Discussions in 2021
Mesoscale Discussion 530
The Storm Prediction Center issued this mesoscale discussion at May 4, 2021, 3:07 PM EDT for 41 counties in Georgia. It was in force for 113 min.
The area
The outline as issued.
The facts
- Issued
- May 4, 2021, 3:07 PM EDT (19:07 UTC)
- Expired
- May 4, 2021, 5:00 PM EDT
- In force
- 113 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 145
All 41 counties
Banks County, GA, Barrow County, GA, Bartow County, GA, Butts County, GA, Carroll County, GA, Cherokee County, GA, Clarke County, GA, Clayton County, GA, Cobb County, GA, Coweta County, GA, Dawson County, GA, DeKalb County, GA, Douglas County, GA, Elbert County, GA, Fayette County, GA, Forsyth County, GA, Franklin County, GA, Fulton County, GA, Greene County, GA, Gwinnett County, GA, Hall County, GA, Haralson County, GA, Hart County, GA, Heard County, GA, Henry County, GA, Jackson County, GA, Jasper County, GA, Madison County, GA, Morgan County, GA, Newton County, GA, Oconee County, GA, Oglethorpe County, GA, Paulding County, GA, Pickens County, GA, Polk County, GA, Putnam County, GA, Rockdale County, GA, Spalding County, GA, Taliaferro County, GA, Walton County, GA, Wilkes County, GA
The radar
The Atlanta radar (KFFC), 69 km from the middle of the area, began a volume at 19:09 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
Peachtre/Fal Fld, GA (KFFC), launched 12:00Z, 7.1 hours before the alert went out and 64 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.
- Mixed-layer CAPE
- 590 J/kg
- Mixed-layer CIN
- -114 J/kg
- Mixed-layer LCL
- 753 m above ground
- 0-6 km bulk shear
- 39 kt
- 0-1 km storm-relative helicity
- 207 m²/s²
- 0-3 km storm-relative helicity
- 213 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 2.3
The text
As transmitted.
478
ACUS11 KWNS 041908
SWOMCD
SPC MCD 041907
SCZ000-GAZ000-ALZ000-042100-
Mesoscale Discussion 0530
NWS Storm Prediction Center Norman OK
0207 PM CDT Tue May 04 2021
Areas affected...Northern Georgia
Concerning...Severe Thunderstorm Watch 145...
Valid 041907Z - 042100Z
The severe weather threat for Severe Thunderstorm Watch 145
continues.
SUMMARY...Damaging winds remain possible across northern Georgia for
the next 1-2 hours. A gradual weakening trend is possible heading
into the late afternoon hours.
DISCUSSION...A few reports of wind damage have been noted across
northern GA associated with the ongoing MCS across the northern and
northeastern portion of the state. Recent reflectivity/velocity data
from KFFC suggests that the MCS is becoming outflow dominant across
north-central GA with a discernible outflow boundary outrunning the
higher reflectivity. GOES IR imagery also points to a gradual
weakening trend in the initial MCS as cloud tops begin to warm. A
few stronger updraft pulses remain likely within remnants of the
MCS, but will mainly be confined to northeast GA.
To the west, a bowing segment is emerging from northeast AL into
northwest GA and has a history of producing at least sporadic wind
damage and severe hail across AL. This segment is expected to move
north of the outflow boundary from the GA MCS and into a cooler,
more stable air mass. Strong velocities noted with this line (per
KFFC) suggests wind damage remains possible for northwest GA for the
next hour or so, but a gradual weakening seems likely as this
activity continues northeast.
..Moore.. 05/04/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...CAE...GSP...FFC...BMX...
LAT...LON 33148523 33678541 34448513 34538407 34548328 34278264
33968250 33638266 33118350 33138446 33148523SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 4, 8:31 AM EDT | Mesoscale Discussion | SPC | Dade | 89 min |
| May 4, 10:03 AM EDT | Mesoscale Discussion | SPC | Bartow, Carroll, Chattooga, Cherokee, Cobb, Douglas and 8 more | 117 min |
| May 4, 10:48 AM EDT | Severe Thunderstorm Watch | SPC | Banks, Barrow, Bartow, Butts, Carroll, Catoosa and 43 more | 6 hr |
| May 4, 1:21 PM EDT | Mesoscale Discussion | SPC | Banks, Barrow, Bartow, Carroll, Cherokee, Clarke and 34 more | 114 min |
| May 4, 4:56 PM EDT | Severe Thunderstorm Watch | SPC | Burke, Columbia, McDuffie, Richmond | 3 hr |
| May 4, 6:20 PM EDT | Mesoscale Discussion | SPC | Baker, Bibb, Calhoun, Chattahoochee, Clay, Colquitt and 34 more | 85 min |
| May 4, 7:26 PM EDT | Severe Thunderstorm Watch | SPC | Baker, Ben Hill, Berrien, Bibb, Bleckley, Brooks and 45 more | 6 hr |
Nearby
Mesoscale Discussions in Georgia, 2021Every mesoscale discussion in 2021
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.