Alert archive / Alabama / Mesoscale Discussions in 2012
Mesoscale Discussion 561
The Storm Prediction Center issued this mesoscale discussion at Apr 16, 2012, 12:56 PM CDT for 4 states. It was in force for 2 hr.
The area
The outline as issued.
The facts
- Issued
- Apr 16, 2012, 12:56 PM CDT (17:56 UTC)
- Expired
- Apr 16, 2012, 3:00 PM CDT
- In force
- 2 hr
- Issued by
- the Storm Prediction Center
All 112 counties
Autauga County, AL, Barbour County, AL, Bibb County, AL, Blount County, AL, Bullock County, AL, Butler County, AL, Calhoun County, AL, Chambers County, AL, Cherokee County, AL, Chilton County, AL, Choctaw County, AL, Clarke County, AL, Clay County, AL, Cleburne County, AL, Coffee County, AL, Conecuh County, AL, Coosa County, AL, Covington County, AL, Crenshaw County, AL, Dallas County, AL, DeKalb County, AL, Elmore County, AL, Escambia County, AL, Etowah County, AL, Hale County, AL, Jefferson County, AL, Lee County, AL, Lowndes County, AL, Macon County, AL, Marengo County, AL, Marshall County, AL, Mobile County, AL, Monroe County, AL, Montgomery County, AL, Perry County, AL, Pike County, AL, Randolph County, AL, Russell County, AL, Shelby County, AL, St. Clair County, AL, Talladega County, AL, Tallapoosa County, AL, Washington County, AL, Wilcox County, AL, Barrow County, GA, Bartow County, GA, Butts County, GA, Carroll County, GA, Chattahoochee County, GA, Chattooga County, GA, Cherokee County, GA, Clayton County, GA, Cobb County, GA, Coweta County, GA, Crawford County, GA, DeKalb County, GA, Douglas County, GA, Fayette County, GA, Floyd County, GA, Forsyth County, GA, Fulton County, GA, Gordon County, GA, Gwinnett County, GA, Haralson County, GA, Harris County, GA, Heard County, GA, Henry County, GA, Lamar County, GA, Marion County, GA, Meriwether County, GA, Monroe County, GA, Muscogee County, GA, Newton County, GA, Paulding County, GA, Pickens County, GA, Pike County, GA, Polk County, GA, Quitman County, GA, Rockdale County, GA, Spalding County, GA, Stewart County, GA, Talbot County, GA, Taylor County, GA, Troup County, GA, Upson County, GA, Walton County, GA, Ascension Parish, LA, Assumption Parish, LA, East Baton Rouge Parish, LA, Iberville Parish, LA, Lafourche Parish, LA, Livingston Parish, LA, Orleans Parish, LA, Saint Charles Parish, LA, Saint Helena Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Tammany Parish, LA, St. Mary Parish, LA, Tangipahoa Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, Forrest County, MS, George County, MS, Greene County, MS, Hancock County, MS, Harrison County, MS, Lamar County, MS, Pearl River County, MS, Perry County, MS, Stone County, MS, Wayne County, MS
The radar
The Birmingham radar (KBMX), 155 km from the middle of the area, began a volume at 18:00 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
Birmingham, AL (KBMX), launched 12:00Z, 5.9 hours before the alert went out and 155 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
- 217 J/kg
- Mixed-layer CIN
- -48 J/kg
- Mixed-layer LCL
- 691 m above ground
- 0-6 km bulk shear
- 31 kt
- 0-1 km storm-relative helicity
- 194 m²/s²
- 0-3 km storm-relative helicity
- 194 m²/s²
- Significant tornado parameter
- 0.2
- Supercell composite
- 2.7
The text
As transmitted, in the capitals the NWS used until 2016.
298
ACUS11 KWNS 161757
SWOMCD
SPC MCD 161756
GAZ000-ALZ000-FLZ000-MSZ000-LAZ000-162000-
MESOSCALE DISCUSSION 0561
NWS STORM PREDICTION CENTER NORMAN OK
1256 PM CDT MON APR 16 2012
AREAS AFFECTED...WRN GA...CNTRL/SRN AL...SERN MS...SERN LA
CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY
VALID 161756Z - 162000Z
A FEW STORMS MAY CONTAIN MARGINALLY SVR WIND GUSTS THIS AFTERNOON
ACROSS WRN GA...CNTRL/SRN AL...SERN MS...AND SERN LA. THE
SPORADIC/BRIEF/MARGINAL NATURE OF ANY SVR THREAT WILL LIKELY
PRECLUDE THE NEED FOR A WW.
SFC MESOANALYSIS DEPICTS AN OUTFLOW BOUNDARY EXTENDING FROM
CHATTANOOGA TN TO BIRMINGHAM AL TO BATON ROUGE LA TO THE S-CNTRL LA
COAST. THE EWD MOTION OF THIS FEATURE IS SLOWING AND WILL CONTINUE
TO DO SO DURING THE NEXT FEW HOURS. IT WILL ALSO SERVE AS A FOCUS
FOR SCATTERED THUNDERSTORMS INTO THE AFTERNOON...AS DIABATIC SFC
HEATING SUPPORTS THE DEVELOPMENT OF MLCAPE VALUES AROUND 1000 J/KG.
WITH 25-35 KT OF EFFECTIVE BULK SHEAR OVER THIS AREA...OCCASIONALLY
ORGANIZED STORM STRUCTURES MAY SUPPORT MARGINALLY SVR WIND
GUSTS...WITH THE THREAT AIDED BY WATER-LOADING PROCESSES GIVEN PW
VALUES AROUND 1.5 INCHES PER GPS PW DATA. FARTHER TO THE EAST...THE
LOW-LEVEL CIRCULATION ATTENDANT TO A ZONE OF DIFFERENTIAL HEATING ON
THE SERN FRINGES OF CONVECTIVE CLOUD DEBRIS OVER SERN AL INTO
W-CNTRL GA MAY ALSO SUPPORT THE DEVELOPMENT OF NEW CONVECTION INTO
THIS AFTERNOON. WITH DCAPE VALUES IN EXCESS OF 800 J/KG ON THE WARM
SIDE OF THIS ZONE OWING TO STEEPENING LOW-LEVEL LAPSE RATES...A FEW
OF THESE STORMS MAY PRODUCE MICROBURSTS WITH PERHAPS A MARGINALLY
SVR WIND GUST OR TWO.
..COHEN.. 04/16/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...FFC...TAE...BMX...HUN...MOB...JAN...LIX...LCH...
LAT...LON 34098672 34698566 34668476 34038368 32708392 31588535
31158670 30918772 30148930 29599003 29229131 29889178
30709115 31348932 32928787 34098672Nearby
Mesoscale Discussions in Alabama, 2012Mesoscale Discussions in Georgia, 2012Mesoscale Discussions in Louisiana, 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; radar from the NEXRAD Level II archive.