Alert archive / Georgia / Mesoscale Discussions in 2021
Mesoscale Discussion 299
The Storm Prediction Center issued this mesoscale discussion at Mar 28, 2021, 12:38 PM EDT for 40 counties in Georgia; 25 counties in North Carolina; 29 counties in South Carolina. It was in force for 3 hr.
The area
The outline as issued.
The facts
- Issued
- Mar 28, 2021, 12:38 PM EDT (16:38 UTC)
- Expired
- Mar 28, 2021, 3:15 PM EDT
- In force
- 3 hr
- Issued by
- the Storm Prediction Center
- Concerning
- Severe potential...watch possible
- Chance of a watch
- 40%
All 94 counties
Baldwin County, GA, Bibb County, GA, Bleckley County, GA, Burke County, GA, Butts County, GA, Columbia County, GA, Crawford County, GA, Emanuel County, GA, Glascock County, GA, Greene County, GA, Hancock County, GA, Houston County, GA, Jasper County, GA, Jefferson County, GA, Jenkins County, GA, Johnson County, GA, Jones County, GA, Lamar County, GA, Laurens County, GA, Lincoln County, GA, Macon County, GA, McDuffie County, GA, Monroe County, GA, Morgan County, GA, Oglethorpe County, GA, Peach County, GA, Pike County, GA, Putnam County, GA, Richmond County, GA, Spalding County, GA, Talbot County, GA, Taliaferro County, GA, Taylor County, GA, Treutlen County, GA, Twiggs County, GA, Upson County, GA, Warren County, GA, Washington County, GA, Wilkes County, GA, Wilkinson County, GA, Alamance County, NC, Anson County, NC, Cabarrus County, NC, Caswell County, NC, Chatham County, NC, Cumberland County, NC, Davidson County, NC, Durham County, NC, Guilford County, NC, Harnett County, NC, Hoke County, NC, Lee County, NC, Mecklenburg County, NC, Montgomery County, NC, Moore County, NC, Orange County, NC, Person County, NC, Randolph County, NC, Richmond County, NC, Robeson County, NC, Rowan County, NC, Scotland County, NC, Stanly County, NC, Union County, NC, Wake County, NC, Abbeville County, SC, Aiken County, SC, Allendale County, SC, Bamberg County, SC, Barnwell County, SC, Calhoun County, SC, Chester County, SC, Chesterfield County, SC, Clarendon County, SC, Darlington County, SC, Dillon County, SC, Edgefield County, SC, Fairfield County, SC, Florence County, SC, Greenwood County, SC, Kershaw County, SC, Lancaster County, SC, Laurens County, SC, Lee County, SC, Lexington County, SC, Marlboro County, SC, McCormick County, SC, Newberry County, SC, Orangeburg County, SC, Richland County, SC, Saluda County, SC, Sumter County, SC, Union County, SC, York County, SC
The radar
The Columbia radar (KCAE), 66 km from the middle of the area, began a volume at 16:40 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
Greensboro/Hi Pt, NC (KGSO), launched 12:00Z, 4.6 hours before the alert went out and 204 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
- 139 J/kg
- Mixed-layer CIN
- -86 J/kg
- Mixed-layer LCL
- 564 m above ground
- 0-6 km bulk shear
- 70 kt
- 0-1 km storm-relative helicity
- 357 m²/s²
- 0-3 km storm-relative helicity
- 324 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.5
The text
As transmitted.
469
ACUS11 KWNS 281638
SWOMCD
SPC MCD 281638
NCZ000-SCZ000-GAZ000-281915-
Mesoscale Discussion 0299
NWS Storm Prediction Center Norman OK
1138 AM CDT Sun Mar 28 2021
Areas affected...Portions of central/eastern GA into upstate/central
SC and central NC
Concerning...Severe potential...Watch possible
Valid 281638Z - 281915Z
Probability of Watch Issuance...40 percent
SUMMARY...A gradual increase in storm coverage and intensity may
occur this afternoon, with damaging winds the main threat. Watch
issuance is possible.
DISCUSSION...Showery convection has developed as of 1630Z across
upstate SC into western NC along a composite outflow boundary from
earlier storms. Other, stronger storms are ongoing across parts of
central/eastern GA. Low-level convergence is not very strong across
these regions, with nearly unidirectional southwesterly flow in the
boundary layer. Still, there is very strong flow present in the 0-3
km layer, with multiple area VWPs showing 50-60+ kt only 1 km AGL.
Just modest diurnal heating of an already moist low-level airmass
will be needed this afternoon to support weak surface-based
instability. Even though cloud cover remains prevalent across much
of this region, surface temperatures should continue warming into at
least the upper 70s to low 80s through the afternoon ahead of the
precipitation. The development of weak but sufficient boundary-layer
instability appears probable by 18-19Z, and a corresponding increase
in storm coverage and intensity may occur. With the enhanced
low-level flow expected to only slowly veer/decrease through the
day, isolated strong to damaging winds appear possible if one or
more short bowing line segments develops. A brief tornado also
cannot be ruled out. At this point the need for a watch is
uncertain, as the overall strength and coverage of storms remains
somewhat in question this afternoon. But, convective trends will be
closely monitored.
..Gleason/Thompson.. 03/28/2021
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...RAH...ILM...RNK...CHS...CAE...GSP...FFC...
LAT...LON 36507891 36097856 35737857 34897880 34027964 33078101
32448220 32238358 32368445 32938471 33298433 33988294
34598214 34968139 35448079 36217997 36527948 36507891SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 28, 2:25 AM EDT | Mesoscale Discussion | SPC | Catoosa, Dade, Fannin, Murray, Walker, Whitfield | 2 hr |
| Mar 28, 2:57 AM EDT | Mesoscale Discussion | SPC | Chattooga, Dade, Walker | 93 min |
| Mar 28, 5:56 AM EDT | Mesoscale Discussion | SPC | Catoosa, Chattooga, Dade, Walker, Whitfield | 94 min |
| Mar 28, 6:10 AM EDT | Severe Thunderstorm Watch | SPC | Bartow, Catoosa, Chattooga, Cherokee, Dade, Dawson and 11 more | 5 hr |
| Mar 28, 8:29 AM EDT | Mesoscale Discussion | SPC | Bartow, Carroll, Cherokee, Cobb, Dawson, Forsyth and 8 more | 91 min |
| Mar 28, 10:14 AM EDT | Mesoscale Discussion | SPC | Carroll, Cherokee, Cobb, Coweta, DeKalb, Douglas and 5 more | 61 min |
| Mar 28, 5:51 PM EDT | Mesoscale Discussion | SPC | Appling, Atkinson, Bacon, Baker, Ben Hill, Berrien and 46 more | 54 min |
| Mar 28, 3:07 AM EDT | Severe Thunderstorm Watch | SPC | Cherokee, Clay, Graham, Macon, Swain | 6 hr |
| Mar 28, 3:24 PM EDT | Severe Thunderstorm Watch | SPC | Beaufort, Bertie, Camden, Chowan, Craven, Cumberland and 26 more | 4 hr |
| Mar 28, 4:53 PM EDT | Mesoscale Discussion | SPC | Beaufort, Bertie, Camden, Chowan, Craven, Currituck and 13 more | 67 min |
Nearby
Mesoscale Discussions in Georgia, 2021Mesoscale Discussions in South Carolina, 2021Mesoscale Discussions in North 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.