Alert archive / Georgia / Mesoscale Discussions in 2021
Mesoscale Discussion 1187
The Storm Prediction Center issued this mesoscale discussion at Jul 7, 2021, 6:12 PM EDT for 12 counties in Georgia; 6 counties in South Carolina. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 7, 2021, 6:12 PM EDT (22:12 UTC)
- Expired
- Jul 7, 2021, 8:15 PM EDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...tornado watch likely
- Chance of a watch
- 95%
Counties Brantley County, GA, Bryan County, GA, Camden County, GA, Chatham County, GA, Effingham County, GA, Evans County, GA, Glynn County, GA, Liberty County, GA, Long County, GA, McIntosh County, GA, Pierce County, GA, Wayne County, GA, Beaufort County, SC, Charleston County, SC, Colleton County, SC, Dorchester County, SC, Hampton County, SC, Jasper County, SC
The radar
The Charleston,SC radar (KCLX), 86 km from the middle of the area, began a volume at 22:11 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
Charleston AFB, SC (KCHS), launched 12:00Z, 10.2 hours before the alert went out and 154 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
- 1532 J/kg
- Mixed-layer CIN
- -8 J/kg
- Mixed-layer LCL
- 725 m above ground
- 0-6 km bulk shear
- 16 kt
- 0-1 km storm-relative helicity
- 34 m²/s²
- 0-3 km storm-relative helicity
- 51 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
567
ACUS11 KWNS 072213
SWOMCD
SPC MCD 072212
SCZ000-GAZ000-FLZ000-080015-
Mesoscale Discussion 1187
NWS Storm Prediction Center Norman OK
0512 PM CDT Wed Jul 07 2021
Areas affected...Southeast Georgia and southern coastal South
Carolina
Concerning...Severe potential...Tornado Watch likely
Valid 072212Z - 080015Z
Probability of Watch Issuance...95 percent
SUMMARY...A new tornado watch will be needed by 00z across portions
of southeast Georgia and into southern areas of coastal South
Carolina and Tropical Storm Elsa continues northeastward this
evening and tonight.
DISCUSSION...Two tornadoes have been reported over the past 1-2
hours across parts of northeast FL within an pronounced convective
rain band on the east/northeastern side of Tropical Storm Elsa.
These tornadoes have largely been focused near a surface confluence
axis where near-surface winds have been nearly due easterly,
contributing to locally higher values of low-level SRH. The tornado
threat associated with this rain band/confluence axis will translate
to the northeast this evening along the southeast GA/SC coast in
tandem with the tropical storm. The easterly winds north of the
confluence axis will allow for long fetches off the coast and
support a continued influx of higher theta-e air with dewpoints in
the mid 70s. Given this potential, a downstream tornado watch will
be needed before 00z to address the evening/overnight threat.
..Moore/Thompson.. 07/07/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...CHS...CAE...JAX...
LAT...LON 30828214 31108228 31468225 32028203 32638155 33008111
33298051 33197996 32947968 32557980 32278010 31898071
31398092 31108106 30808111 30718153 30828214SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 7, 6:46 AM EDT | Tornado Watch | SPC | Brantley, Camden, Charlton, Clinch, Echols, Glynn and 3 more | 6 hr |
| Jul 7, 10:30 AM EDT | Mesoscale Discussion | SPC | Brantley, Camden, Charlton, Clinch, Echols, Glynn and 3 more | 2 hr |
| Jul 7, 12:28 PM EDT | Mesoscale Discussion | SPC | Appling, Bacon, Brantley, Bryan, Bulloch, Camden and 19 more | 2 hr |
| Jul 7, 1:04 PM EDT | Tornado Watch | SPC | Appling, Bacon, Brantley, Bryan, Bulloch, Camden and 15 more | 7 hr |
| Jul 7, 4:47 PM EDT | Mesoscale Discussion | SPC | Appling, Bacon, Brantley, Bryan, Bulloch, Camden and 22 more | 118 min |
| Jul 7, 7:25 PM EDT | Tornado Watch | SPC | Bryan, Bulloch, Burke, Candler, Chatham, Effingham and 11 more | 11 hr |
Nearby
Mesoscale Discussions in Georgia, 2021Mesoscale Discussions in South 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.