Alert archive / Georgia / Mesoscale Discussions in 2017
Mesoscale Discussion 285
The Storm Prediction Center issued this mesoscale discussion at Mar 10, 2017, 3:09 AM CST for 9 counties in Alabama; 31 counties in Georgia. It was in force for 96 min.
The area
The outline as issued.
The facts
- Issued
- Mar 10, 2017, 3:09 AM CST (09:09 UTC)
- Expired
- Mar 10, 2017, 4:45 AM CST
- In force
- 96 min
- Issued by
- the Storm Prediction Center
All 40 counties
Chambers County, AL, Clay County, AL, Cleburne County, AL, Coosa County, AL, Randolph County, AL, Shelby County, AL, Talladega County, AL, Tallapoosa County, AL, Tuscaloosa County, AL, Barrow County, GA, Butts County, GA, Carroll County, GA, Clarke County, GA, Clayton County, GA, Coweta County, GA, DeKalb County, GA, Douglas County, GA, Fayette County, GA, Fulton County, GA, Greene County, GA, Gwinnett County, GA, Heard County, GA, Henry County, GA, Jackson County, GA, Jasper County, GA, Jones County, GA, Lamar County, GA, Madison County, GA, Meriwether County, GA, Monroe County, GA, Morgan County, GA, Newton County, GA, Oconee County, GA, Oglethorpe County, GA, Pike County, GA, Putnam County, GA, Rockdale County, GA, Spalding County, GA, Troup County, GA, Walton County, GA
The radar
The Atlanta radar (KFFC), 56 km from the middle of the area, began a volume at 09:11 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 nearest sounding before it
Peachtre/Fal Fld, GA (KFFC), launched 00:00Z, 9.2 hours before the alert went out and 61 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
- 0 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 2857 m above ground
- 0-6 km bulk shear
- 40 kt
- 0-1 km storm-relative helicity
- 42 m²/s²
- 0-3 km storm-relative helicity
- 102 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted.
506
ACUS11 KWNS 100909
SWOMCD
SPC MCD 100909
GAZ000-ALZ000-101045-
Mesoscale Discussion 0285
NWS Storm Prediction Center Norman OK
0309 AM CST Fri Mar 10 2017
Areas affected...North-central Alabama and north/central Georgia
Concerning...Severe Thunderstorm Watch 75...
Valid 100909Z - 101045Z
The severe weather threat for Severe Thunderstorm Watch 75
continues.
SUMMARY...Fast-moving linearly organized storms may continue to pose
a localized damaging wind risk across additional portions of central
Alabama and/or north Georgia over the next hour or two, but the
overall severe-wind risk should continue to steadily diminish.
Severe thunderstorm watch 75 will be allowed to expire at/before
scheduled 10Z expiration.
DISCUSSION...A fast-moving squall line continues to steadily
progress southeastward with a 50-knot forward motion, approaching
the I-20/I-85 corridors of north-central Alabama and north Georgia
as of 09Z. A 49-knot wind gust was recently measured at Birmingham
around 234 am CST, with a 45-knot gust also noted at Dobbins Air
Force Base around 340 am EST. Recent analysis features a modest
pressure fall/rise couplet across northern Alabama, while
pre-frontal warming/moistening has been noted across central
portions of Alabama/Georgia ahead of the convective line. Even so,
cloud tops continue to gradually warm, likely related to
increasingly elevated/stable inflow in the presence of considerable
boundary layer inhibition. Near-severe-wind gusts capable of
localized wind damage may remain possible over the next 1-2 hours
mainly given the fast-forward-motion of the convection. However,
overall convective updraft/downdraft intensities are likely to
otherwise continue to diminish. No additional Watch issuances are
anticipated.
..Guyer.. 03/10/2017
...Please see www.spc.noaa.gov for graphic product...
ATTN...WFO...GSP...FFC...BMX...
LAT...LON 33438783 33518678 33738508 33958426 34398340 34218300
33768299 32988354 32678624 33438783SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Mar 9, 6:39 PM CST | Mesoscale Discussion | SPC | Fayette, Greene, Lamar, Marion, Pickens, Sumter | 96 min |
| Mar 9, 10:42 PM CST | Mesoscale Discussion | SPC | Blount, Cherokee, Colbert, Cullman, DeKalb, Etowah and 10 more | 63 min |
| Mar 9, 11:18 PM CST | Severe Thunderstorm Watch | SPC | Blount, Cherokee, Colbert, Cullman, DeKalb, Etowah and 10 more | 4 hr |
| Mar 10, 12:50 AM CST | Mesoscale Discussion | SPC | Blount, Cherokee, Colbert, Cullman, DeKalb, Etowah and 12 more | 85 min |
Nearby
Mesoscale Discussions in Georgia, 2017Mesoscale Discussions in Alabama, 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.