Alert archive / Georgia / Mesoscale Discussions in 2021
Mesoscale Discussion 1542
The Storm Prediction Center issued this mesoscale discussion at Aug 17, 2021, 3:13 AM EDT for 14 counties in Georgia. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Aug 17, 2021, 3:13 AM EDT (07:13 UTC)
- Expired
- Aug 17, 2021, 5:15 AM EDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch possible
- Chance of a watch
- 60%
Counties Bibb County, GA, Butts County, GA, Crawford County, GA, Henry County, GA, Houston County, GA, Jasper County, GA, Jones County, GA, Lamar County, GA, Monroe County, GA, Newton County, GA, Peach County, GA, Rockdale County, GA, Spalding County, GA, Twiggs County, GA
The radar
The Robins AFB radar (KJGX), 52 km from the middle of the area, began a volume at 07:17 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, 7.2 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
- 288 J/kg
- Mixed-layer CIN
- 0 J/kg
- Mixed-layer LCL
- 457 m above ground
- 0-6 km bulk shear
- 13 kt
- 0-1 km storm-relative helicity
- 54 m²/s²
- 0-3 km storm-relative helicity
- 92 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
479
ACUS11 KWNS 170714
SWOMCD
SPC MCD 170713
GAZ000-170915-
Mesoscale Discussion 1542
NWS Storm Prediction Center Norman OK
0213 AM CDT Tue Aug 17 2021
Areas affected...Parts of central Georgia
Concerning...Severe potential...Watch possible
Valid 170713Z - 170915Z
Probability of Watch Issuance...60 percent
SUMMARY...The environment has become increasingly conducive to
occasional supercell structures capable of producing short-lived
tornadoes near and southwest through north of Macon, GA, and this
may continue to develop northward toward areas near and southeast of
the Greater Atlanta metropolitan area through daybreak.
DISCUSSION...As Tropical Storm Fred slowly migrates northward to the
southwest/west of the Columbus, GA area, latest observational data
and objective analysis indicate northwestward advection of moist
boundary-layer air characterized by mid/upper 70s F dew points is
ongoing across southeastern through central Georgia. This has
contributed to a substantive increase in boundary-layer CAPE during
the past few hours, and inflow of this air is contributing to
thunderstorm development within bands of convection pivoting around
the northeastern periphery of the low-level cyclonic circulation
center. This coincides with where clockwise-curved low-level
hodographs are maximized and supportive of occasional development
and strengthening of low-level mesocyclones capable of producing
tornadoes.
..Kerr/Edwards.. 08/17/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...FFC...
LAT...LON 32688414 33258436 33678415 33638366 32878319 32488337
32268371 32328397 32688414SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 17, 3:45 AM EDT | Tornado Watch | SPC | Baldwin, Banks, Barrow, Bibb, Bleckley, Butts and 49 more | 9 hr |
| Aug 17, 8:22 AM EDT | Mesoscale Discussion | SPC | Banks, Clarke, Columbia, Elbert, Franklin, Glascock and 12 more | 113 min |
| Aug 17, 10:42 AM EDT | Tornado Watch | SPC | Columbia, Lincoln, McDuffie, Rabun | 8 hr |
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.