Alert archive / Georgia / Mesoscale Discussions in 2021
Mesoscale Discussion 268
The Storm Prediction Center issued this mesoscale discussion at Mar 25, 2021, 11:26 PM EDT for Coweta County, Fayette County, Heard County, Georgia. It was in force for 64 min.
The area
The outline as issued.
The facts
- Issued
- Mar 25, 2021, 11:26 PM EDT (03:26 UTC)
- Expired
- Mar 26, 2021, 12:30 AM EDT
- In force
- 64 min
- Issued by
- the Storm Prediction Center
- Concerning
- Tornado watch 52
Counties Coweta County, GA, Fayette County, GA, Heard County, GA
The radar
The Atlanta radar (KFFC), 35 km from the middle of the area, began a volume at 03:28 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, 3.4 hours before the alert went out and 42 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
- 344 J/kg
- Mixed-layer CIN
- -14 J/kg
- Mixed-layer LCL
- 1291 m above ground
- 0-6 km bulk shear
- 76 kt
- 0-1 km storm-relative helicity
- 328 m²/s²
- 0-3 km storm-relative helicity
- 476 m²/s²
- Significant tornado parameter
- 0.6
- Supercell composite
- 6.8
The text
As transmitted.
750 ACUS11 KWNS 260327 SWOMCD SPC MCD 260326 GAZ000-ALZ000-260430- Mesoscale Discussion 0268 NWS Storm Prediction Center Norman OK 1026 PM CDT Thu Mar 25 2021 Areas affected...parts of west-central GA Concerning...Tornado Watch 52... Valid 260326Z - 260430Z The severe weather threat for Tornado Watch 52 continues. SUMMARY...Tornado potential will maximize near the GA/AL border and eventually spread into the greater Atlanta exurbia through 1230 am EDT. It is uncertain how far east the higher probabilities for a tornado will eventually develop due to increasingly marginal low-level moisture with east extent. DISCUSSION...Surface analysis indicates mid 60s deg F dewpoints straddling the GA/AL border in west-central GA to the east of a supercell with a history of producing tornadoes (likely strong) over east-central AL. The latest RAP/NAM indicate lowest 100 mb mean mixing ratios increasing into the 13-14 g/kg range over the next hour with MLCAPE increasing from 750 J/kg to 1000-1200 J/kg. The KFFC VAD showed 500 m2/s2 0-1km SRH within the moist/sufficiently unstable airmass. Current thinking is the increasingly rich low-level moisture (dewpoints rising from 64-65 to 66) may enable a greater risk for a tornado over the next hour or so. ..Smith.. 03/26/2021 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...FFC...BMX... LAT...LON 33298539 33548489 33558440 33218430 33088530 33298539
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 26, 12:34 AM EDT | Mesoscale Discussion | SPC | Barrow, Cherokee, Clarke, Clayton, Cobb, Coweta and 11 more | 56 min |
| Mar 26, 1:55 AM EDT | Tornado Watch | SPC | Banks, Barrow, Butts, Clarke, Clayton, Coweta and 31 more | 3 hr |
| Mar 26, 4:21 AM EDT | Mesoscale Discussion | SPC | Barrow, Clarke, Clayton, Coweta, DeKalb, Elbert and 11 more | 54 min |
| Mar 26, 1:56 PM EDT | Mesoscale Discussion | SPC | Baldwin, Bibb, Bleckley, Bryan, Bulloch, Burke and 44 more | 94 min |
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.