Alert archive / Georgia / Mesoscale Discussions in 2021
Mesoscale Discussion 1179
The Storm Prediction Center issued this mesoscale discussion at Jul 7, 2021, 12:28 PM EDT for 7 counties in Florida; 25 counties in Georgia. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Jul 7, 2021, 12:28 PM EDT (16:28 UTC)
- Expired
- Jul 7, 2021, 2:30 PM EDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Tornado watch 341
All 32 counties
Baker County, FL, Bradford County, FL, Clay County, FL, Columbia County, FL, Duval County, FL, Nassau County, FL, Union County, FL, Appling County, GA, Bacon County, GA, Brantley County, GA, Bryan County, GA, Bulloch County, GA, Camden County, GA, Candler County, GA, Charlton County, GA, Chatham County, GA, Clinch County, GA, Echols County, GA, Effingham County, GA, Emanuel County, GA, Evans County, GA, Glynn County, GA, Jeff Davis County, GA, Liberty County, GA, Long County, GA, McIntosh County, GA, Montgomery County, GA, Pierce County, GA, Tattnall County, GA, Toombs County, GA, Ware County, GA, Wayne County, GA
The radar
The Jacksonville radar (KJAX), 84 km from the middle of the area, began a volume at 16:28 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
Jacksonville, FL (KJAX), launched 12:00Z, 4.5 hours before the alert went out and 82 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
- 1540 J/kg
- Mixed-layer CIN
- -8 J/kg
- Mixed-layer LCL
- 838 m above ground
- 0-6 km bulk shear
- 17 kt
- 0-1 km storm-relative helicity
- 103 m²/s²
- 0-3 km storm-relative helicity
- 144 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
636
ACUS11 KWNS 071629
SWOMCD
SPC MCD 071628
SCZ000-GAZ000-FLZ000-071830-
Mesoscale Discussion 1179
NWS Storm Prediction Center Norman OK
1128 AM CDT Wed Jul 07 2021
Areas affected...North FL...southeast GA...southern SC
Concerning...Tornado Watch 341...
Valid 071628Z - 071830Z
The severe weather threat for Tornado Watch 341 continues.
SUMMARY...The risk for a few tornadoes continues in association with
Tropical Storm Elsa, and a new Tornado Watch will be coordinated
prior to the scheduled expiration of Tornado Watch 341.
DISCUSSION...A new Tornado Watch will be coordinated prior to the
17z scheduled expiration of Tornado Watch 341, and will likely be
extended north to near the SC-GA state line. Outer bands continue
to rotate northwest around the circulation of Tropical Storm Elsa,
and latest RAP forecast soundings suggest a favorable kinematic
environment for a few brief tornadoes to develop as Elsa begins to
turn to a more north-northeast motion this afternoon. In addition,
filtered heating through high-level clouds over parts of southeast
GA will contribute to an increase in buoyancy and a more favorable
thermodynamic environment.
..Bunting/Guyer.. 07/07/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...CHS...JAX...FFC...
LAT...LON 30578294 31578275 32258258 32668227 32718167 32518134
32078105 31898094 31538105 31048119 30368144 29908152
29788218 29868281 29938290 30578294SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Jul 6, 10:37 PM EDT | Tornado Watch | SPC | Alachua, Charlotte, Citrus, Collier, DeSoto, Gilchrist and 22 more | 9 hr |
| Jul 6, 11:59 PM EDT | Mesoscale Discussion | SPC | Charlotte, DeSoto, Hardee, Hillsborough | 2 hr |
| Jul 7, 3:03 AM EDT | Mesoscale Discussion | SPC | Charlotte, Citrus, DeSoto, Hardee, Hernando, Hillsborough and 5 more | 117 min |
| Jul 7, 5:42 AM EDT | Mesoscale Discussion | SPC | Alachua, Bradford, Charlotte, Citrus, Columbia, DeSoto and 19 more | 2 hr |
| Jul 7, 6:46 AM EDT | Tornado Watch | SPC | Baker, Bradford, Clay, Columbia, Duval, Hamilton and 4 more | 6 hr |
| Jul 7, 7:06 AM EDT | Mesoscale Discussion | SPC | Charlotte, Citrus, DeSoto, Hardee, Hernando, Highlands and 10 more | 54 min |
| Jul 7, 10:30 AM EDT | Mesoscale Discussion | SPC | Baker, Bradford, Clay, Columbia, Duval, Hamilton and 3 more | 2 hr |
| Jul 7, 1:04 PM EDT | Tornado Watch | SPC | Baker, Bradford, Clay, Columbia, Duval, Hamilton and 3 more | 7 hr |
| Jul 7, 4:47 PM EDT | Mesoscale Discussion | SPC | Baker, Clay, Columbia, Duval, Nassau, Saint Johns and 1 more | 118 min |
| Jul 7, 6:12 PM EDT | Mesoscale Discussion | SPC | Brantley, Bryan, Camden, Chatham, Effingham, Evans and 6 more | 2 hr |
| 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 Florida, 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.