Alert archive / Georgia / Mesoscale Discussions in 2021
Mesoscale Discussion 528
The Storm Prediction Center issued this mesoscale discussion at May 4, 2021, 1:21 PM EDT for 40 counties in Georgia; Clay County, Macon County, North Carolina; 4 counties in South Carolina. It was in force for 114 min.
The area
The outline as issued.
The facts
- Issued
- May 4, 2021, 1:21 PM EDT (17:21 UTC)
- Expired
- May 4, 2021, 3:15 PM EDT
- In force
- 114 min
- Issued by
- the Storm Prediction Center
- Concerning
- Severe thunderstorm watch 143...145
All 46 counties
Banks County, GA, Barrow County, GA, Bartow 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, Gwinnett County, GA, Habersham County, GA, Hall County, GA, Haralson County, GA, Hart County, GA, Heard County, GA, Henry County, GA, Jackson County, GA, Lumpkin County, GA, Madison County, GA, Morgan County, GA, Newton County, GA, Oconee County, GA, Oglethorpe County, GA, Paulding County, GA, Pickens County, GA, Rabun County, GA, Rockdale County, GA, Stephens County, GA, Towns County, GA, Union County, GA, Walton County, GA, White County, GA, Clay County, NC, Macon County, NC, Abbeville County, SC, Anderson County, SC, Oconee County, SC, Pickens County, SC
The radar
The Atlanta radar (KFFC), 109 km from the middle of the area, began a volume at 17:23 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, 5.4 hours before the alert went out and 105 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.
992
ACUS11 KWNS 041721
SWOMCD
SPC MCD 041721
SCZ000-GAZ000-NCZ000-ALZ000-041915-
Mesoscale Discussion 0528
NWS Storm Prediction Center Norman OK
1221 PM CDT Tue May 04 2021
Areas affected...Northwest Georgia
Concerning...Severe Thunderstorm Watch 143...145...
Valid 041721Z - 041915Z
The severe weather threat for Severe Thunderstorm Watch 143, 145
continues.
SUMMARY...Damaging winds remain possible across northwest Georgia as
an ongoing MCS continues to move east/southeast across the region.
DISCUSSION...An ongoing MCS continues to propagate to the
east/southeast across northwest GA. Regional VWPs and RAP
mesoanalysis suggest 0-3 km bulk shear vectors are generally between
20-35 knots and are mainly aligned along the MCS's long-axis.
However, a few meridional bulges in the line have been noted in
recent KFFC imagery, which will locally enhance the potential for
damaging winds as the outflow becomes more orthogonal to somewhat
strong low-level shear vectors. This MCS should continue to
propagate to the east/southeast over the next few hours and will
continue to pose a wind threat (particularly with any north-south
oriented bulges) as MLCAPE increases across central/eastern GA amid
partly cloudy skies and boundary-layer warming. Additional
development upstream across northern AL will likely move into
northern GA in the wake of the ongoing MCS later this afternoon and
may pose an additional risk for severe winds.
..Moore.. 05/04/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...CAE...GSP...MRX...FFC...BMX...
LAT...LON 33758533 34418482 35108375 35208318 35048261 34788228
34218236 33818282 33418385 33188483 33398547 33758533SPC 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, 3:07 PM EDT | Mesoscale Discussion | SPC | Banks, Barrow, Bartow, Butts, Carroll, Cherokee and 35 more | 113 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 |
| May 4, 9:37 AM EDT | Severe Thunderstorm Watch | SPC | Cherokee, Clay, Graham, Macon, Swain | 3 hr |
| May 4, 1:04 PM EDT | Mesoscale Discussion | SPC | Caswell, Northampton, Person, Rockingham, Stokes, Surry and 2 more | 56 min |
| May 4, 4:16 PM EDT | Mesoscale Discussion | SPC | Alamance, Anson, Bladen, Cabarrus, Caswell, Chatham and 35 more | 119 min |
| May 4, 7:59 PM EDT | Mesoscale Discussion | SPC | Berkeley, Clarendon, Dorchester, Marion, Williamsburg | 61 min |
Nearby
Mesoscale Discussions in Georgia, 2021Mesoscale Discussions in South Carolina, 2021Mesoscale Discussions in North Carolina, 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.