Alert archive / Georgia / Mesoscale Discussions in 2012
Mesoscale Discussion 1952
The Storm Prediction Center issued this mesoscale discussion at Sep 17, 2012, 5:14 PM CDT for 4 counties in Alabama; 9 counties in Florida; 48 counties in Georgia. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Sep 17, 2012, 5:14 PM CDT (22:14 UTC)
- Expired
- Sep 17, 2012, 7:15 PM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
- Chance of a watch
- 40%
All 61 counties
Barbour County, AL, Dale County, AL, Henry County, AL, Houston County, AL, Calhoun County, FL, Gadsden County, FL, Holmes County, FL, Jackson County, FL, Jefferson County, FL, Leon County, FL, Liberty County, FL, Madison County, FL, Washington County, FL, Atkinson County, GA, Baker County, GA, Ben Hill County, GA, Berrien County, GA, Bleckley County, GA, Brooks County, GA, Calhoun County, GA, Chattahoochee County, GA, Clay County, GA, Coffee County, GA, Colquitt County, GA, Cook County, GA, Crisp County, GA, Decatur County, GA, Dodge County, GA, Dooly County, GA, Dougherty County, GA, Early County, GA, Grady County, GA, Houston County, GA, Irwin County, GA, Jeff Davis County, GA, Lanier County, GA, Laurens County, GA, Lee County, GA, Lowndes County, GA, Macon County, GA, Marion County, GA, Miller County, GA, Mitchell County, GA, Peach County, GA, Pulaski County, GA, Quitman County, GA, Randolph County, GA, Schley County, GA, Seminole County, GA, Stewart County, GA, Sumter County, GA, Taylor County, GA, Telfair County, GA, Terrell County, GA, Thomas County, GA, Tift County, GA, Turner County, GA, Webster County, GA, Wheeler County, GA, Wilcox County, GA, Worth County, GA
The watches that followed
Watches SPC issued over any of the same counties within four hours of this discussion.
The nearest sounding before it
Tallahassee Rgnl, FL (KTLH), launched 12:00Z, 10.2 hours before the alert went out and 112 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
- 885 J/kg
- Mixed-layer CIN
- -14 J/kg
- Mixed-layer LCL
- 612 m above ground
- 0-6 km bulk shear
- 14 kt
- 0-1 km storm-relative helicity
- 12 m²/s²
- 0-3 km storm-relative helicity
- 37 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
336
ACUS11 KWNS 172215
SWOMCD
SPC MCD 172214
GAZ000-FLZ000-ALZ000-180015-
MESOSCALE DISCUSSION 1952
NWS STORM PREDICTION CENTER NORMAN OK
0514 PM CDT MON SEP 17 2012
AREAS AFFECTED...SRN GA...FAR SERN AL...ERN FL PANHANDLE
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE
VALID 172214Z - 180015Z
PROBABILITY OF WATCH ISSUANCE...40 PERCENT
SUMMARY...A LOW-END TORNADO AND ISOLATED DAMAGING WIND THREAT MAY
DEVELOP E/NEWD THROUGH THE EVENING.
DISCUSSION...ARC OF SEMI-ORGANIZED DEEP CONVECTION CENTERED FROM
DALE COUNTY AL TO BAY COUNTY FL SHOULD EVOLVE E/NEWD THIS EVENING
WITHIN AN AIR MASS CHARACTERIZED BY PW VALUES AROUND 2 INCHES.
ALTHOUGH MODEL GUIDANCE IS FAIRLY CONSISTENT THAT THE GREATER
INCREASE IN LOW-LEVEL SLYS WILL LARGELY REMAIN N OF THIS
ACTIVITY...A MODEST INCREASE IN LOW-LEVEL SHEAR SHOULD YIELD 0-1 KM
SRH AROUND 150 M2/S2. GIVEN THE RATHER SATURATED AIR MASS...THIS MAY
BE SUFFICIENT FOR A LOW-END TORNADO THREAT WHICH MOST LIKELY WOULD
BE BRIEF AND WEAK...ALONG WITH A RISK FOR ISOLATED DAMAGING WIND.
..GRAMS/CORFIDI.. 09/17/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...JAX...FFC...TAE...BMX...
LAT...LON 30988584 32118543 32578468 32668329 32448279 31808247
31308265 30158373 30088478 30418582 30988584SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 17, 12:58 PM CDT | Mesoscale Discussion | SPC | Baldwin, Choctaw, Clarke, Mobile, Washington | 92 min |
| Sep 17, 3:53 PM CDT | Mesoscale Discussion | SPC | Blount, Calhoun, Cherokee, Clay, Cleburne, Cullman and 13 more | 97 min |
| Sep 17, 5:39 PM CDT | Tornado Watch | SPC | Baldwin, Banks, Barrow, Bartow, Bibb, Bleckley and 84 more | 8 hr |
Nearby
Mesoscale Discussions in Georgia, 2012Mesoscale Discussions in Florida, 2012Mesoscale Discussions in Alabama, 2012Every mesoscale discussion in 2012
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.