Alert archive / Georgia / Mesoscale Discussions in 2017
Mesoscale Discussion 821
The Storm Prediction Center issued this mesoscale discussion at May 23, 2017, 8:46 PM EDT for 18 counties in Georgia; 7 counties in South Carolina. It was in force for 89 min.
The area
The outline as issued.
The facts
- Issued
- May 23, 2017, 8:46 PM EDT (00:46 UTC)
- Expired
- May 23, 2017, 10:15 PM EDT
- In force
- 89 min
- Issued by
- the Storm Prediction Center
All 25 counties
Appling County, GA, Bacon County, GA, Brantley County, GA, Bryan County, GA, Bulloch County, GA, Candler County, GA, Chatham County, GA, Effingham County, GA, Evans County, GA, Liberty County, GA, Long County, GA, McIntosh County, GA, Pierce County, GA, Screven County, GA, Tattnall County, GA, Toombs County, GA, Ware County, GA, Wayne County, GA, Allendale County, SC, Bamberg County, SC, Beaufort County, SC, Colleton County, SC, Dorchester County, SC, Hampton County, SC, Jasper County, SC
The radar
The Charleston,SC radar (KCLX), 88 km from the middle of the area, began a volume at 00:49 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
Jacksonville, FL (KJAX), launched 00:00Z, 0.8 hours before the alert went out and 182 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
- 924 J/kg
- Mixed-layer CIN
- -17 J/kg
- Mixed-layer LCL
- 1107 m above ground
- 0-6 km bulk shear
- 30 kt
- 0-1 km storm-relative helicity
- 260 m²/s²
- 0-3 km storm-relative helicity
- 303 m²/s²
- Significant tornado parameter
- 0.8
- Supercell composite
- 10.7
The text
As transmitted.
425 ACUS11 KWNS 240047 SWOMCD SPC MCD 240046 SCZ000-GAZ000-240215- Mesoscale Discussion 0821 NWS Storm Prediction Center Norman OK 0746 PM CDT Tue May 23 2017 Areas affected...Southeast GA...Southwest/central SC Concerning...Tornado Watch 258... Valid 240046Z - 240215Z The severe weather threat for Tornado Watch 258 continues. SUMMARY...Isolated damaging wind gusts and a tornado or two are still possible across portions of southeast GA and southwest SC DISCUSSION...Multiple convective lines and clusters continue to move quickly across the watch area. A few more discrete cells across southeast GA have shown low-level rotation, including a long-lived supercell now in Liberty county. Broad low-level confluence is expected to continue across the coastal portions of southeast GA and southwest SC with enough forcing for ascent and moisture convergence to support persistence of the ongoing activity. VAX VAD data continues to show an environment supportive of low-level rotation and modest storm organization. Recent data from this radar sampled 0-1 km SRH over 200 m2/s2 and 0-6 km bulk shear near 40 kt. As such, damaging wind gusts and a tornado or two are still possible across portions of far southeast AL and the coastal counties of southwest SC. The tornado threat appears to have diminished across much of the remainder of watch area over central SC. ..Mosier.. 05/24/2017 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...CHS...CAE...JAX...FFC... LAT...LON 32278246 33248127 33097989 30918181 31058258 32278246
SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 23, 8:12 PM EDT | Mesoscale Discussion | SPC | Bartow, Carroll, Cherokee, Clayton, Cobb, Coweta and 15 more | 93 min |
| May 24, 6:56 AM EDT | Tornado Watch | SPC | Brooks, Decatur, Grady, Lowndes, Seminole, Thomas | 8 hr |
| May 24, 7:41 AM EDT | Mesoscale Discussion | SPC | Bartow, Catoosa, Chattooga, Dade, Fannin, Floyd and 8 more | 3 hr |
| May 24, 8:29 AM EDT | Mesoscale Discussion | SPC | Appling, Atkinson, Bacon, Baker, Baldwin, Ben Hill and 83 more | 3 hr |
| May 24, 10:04 AM EDT | Tornado Watch | SPC | Banks, Barrow, Bartow, Carroll, Catoosa, Chattooga and 50 more | 11 hr |
| May 24, 10:26 AM EDT | Mesoscale Discussion | SPC | Decatur, Grady, Seminole | 94 min |
| May 24, 11:03 AM EDT | Tornado Watch | SPC | Appling, Atkinson, Bacon, Baker, Baldwin, Ben Hill and 96 more | 10 hr |
| May 24, 2:10 PM EDT | Mesoscale Discussion | SPC | Appling, Atkinson, Bacon, Baker, Baldwin, Ben Hill and 99 more | 95 min |
| May 24, 3:02 PM EDT | Mesoscale Discussion | SPC | Banks, Barrow, Bartow, Carroll, Cherokee, Clarke and 43 more | 88 min |
| May 24, 5:25 PM EDT | Mesoscale Discussion | SPC | Appling, Atkinson, Bacon, Baldwin, Banks, Barrow and 87 more | 65 min |
| May 24, 3:13 PM EDT | Mesoscale Discussion | SPC | Darlington, Dillon, Florence, Georgetown, Horry, Marion and 2 more | 2 hr |
| May 24, 3:46 PM EDT | Tornado Watch | SPC | Darlington, Dillon, Marlboro | 6 hr |
Nearby
Mesoscale Discussions in Georgia, 2017Mesoscale Discussions in South Carolina, 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.