Alert archive / Mississippi / Mesoscale Discussions in 2011
Mesoscale Discussion 2159
The Storm Prediction Center issued this mesoscale discussion at Sep 11, 2011, 5:00 PM CDT for 4 states. It was in force for 90 min.
The area
The outline as issued.
The facts
- Issued
- Sep 11, 2011, 5:00 PM CDT (22:00 UTC)
- Expired
- Sep 11, 2011, 6:30 PM CDT
- In force
- 90 min
- Issued by
- the Storm Prediction Center
All 100 counties
Blount County, AL, Colbert County, AL, Cullman County, AL, Fayette County, AL, Franklin County, AL, Greene County, AL, Jackson County, AL, Jefferson County, AL, Lamar County, AL, Lauderdale County, AL, Lawrence County, AL, Limestone County, AL, Madison County, AL, Marion County, AL, Marshall County, AL, Morgan County, AL, Pickens County, AL, Tuscaloosa County, AL, Walker County, AL, Winston County, AL, East Carroll Parish, LA, Franklin Parish, LA, Madison Parish, LA, Tensas Parish, LA, West Carroll Parish, LA, Alcorn County, MS, Attala County, MS, Benton County, MS, Calhoun County, MS, Carroll County, MS, Chickasaw County, MS, Choctaw County, MS, Claiborne County, MS, Clay County, MS, Copiah County, MS, Grenada County, MS, Hinds County, MS, Holmes County, MS, Humphreys County, MS, Issaquena County, MS, Itawamba County, MS, Kemper County, MS, Lafayette County, MS, Leake County, MS, Lee County, MS, Leflore County, MS, Lowndes County, MS, Madison County, MS, Marshall County, MS, Monroe County, MS, Montgomery County, MS, Neshoba County, MS, Newton County, MS, Noxubee County, MS, Oktibbeha County, MS, Panola County, MS, Pontotoc County, MS, Prentiss County, MS, Rankin County, MS, Scott County, MS, Sharkey County, MS, Sunflower County, MS, Tallahatchie County, MS, Tippah County, MS, Tishomingo County, MS, Union County, MS, Warren County, MS, Washington County, MS, Webster County, MS, Winston County, MS, Yalobusha County, MS, Yazoo County, MS, Bedford County, TN, Benton County, TN, Cannon County, TN, Carroll County, TN, Chester County, TN, Coffee County, TN, Davidson County, TN, Decatur County, TN, Dickson County, TN, Franklin County, TN, Giles County, TN, Hardeman County, TN, Hardin County, TN, Henderson County, TN, Hickman County, TN, Humphreys County, TN, Lawrence County, TN, Lewis County, TN, Lincoln County, TN, Marshall County, TN, Maury County, TN, McNairy County, TN, Moore County, TN, Perry County, TN, Rutherford County, TN, Wayne County, TN, Williamson County, TN, Wilson County, TN
The radar
The Columbus AFB radar (KGWX), 28 km from the middle of the area, began a volume at 22:04 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
Little Rock, AR (KLZK), launched 12:00Z, 10.0 hours before the alert went out and 165 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
- 33 J/kg
- Mixed-layer CIN
- -149 J/kg
- Mixed-layer LCL
- 1890 m above ground
- 0-6 km bulk shear
- 8 kt
- 0-1 km storm-relative helicity
- 22 m²/s²
- 0-3 km storm-relative helicity
- 72 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
397
ACUS11 KWNS 112201
SWOMCD
SPC MCD 112200
TNZ000-ALZ000-MSZ000-LAZ000-ARZ000-112330-
MESOSCALE DISCUSSION 2159
NWS STORM PREDICTION CENTER NORMAN OK
0500 PM CDT SUN SEP 11 2011
AREAS AFFECTED...MIDDLE/WRN TN...CNTRL/NRN MS...PARTS OF CNTRL/NRN
AL...NERN LA...EXTREME SERN AR
CONCERNING...SEVERE POTENTIAL...WATCH UNLIKELY
VALID 112200Z - 112330Z
A FEW STORMS COULD PRODUCE STRONG WIND GUSTS INTO EARLY EVENING.
WITH ONLY A MINIMAL SVR THREAT...THE ISSUANCE OF A WW IS UNLIKELY.
LATE AFTERNOON MESOANALYSIS DEPICTS A SFC TROUGH AXIS EXTENDING
ACROSS THE MID-SOUTH INTO THE LOWER MS VALLEY. THIS FEATURE EXHIBITS
CHARACTERISTICS OF A DRYLINE NEAR AND SOUTH OF THE GREENVILLE MS
AREA...WHERE IT SEPARATES THE HOTTER/DEEPLY MIXED BOUNDARY LAYER TO
THE WEST FROM MODESTLY RICHER LOW-LEVEL MOISTURE TO THE EAST. THIS
MOISTURE...SUPPORTING MLCAPE VALUES OF 1000-1500 J/KG...WILL COMBINE
WITH SUFFICIENT SFC CONVERGENCE TO SUPPORT ISOLATED TO SCATTERED
THUNDERSTORMS INTO EARLY EVENING. THE GREATEST CONVECTIVE COVERAGE
IS ANTICIPATED ALONG AND NORTH OF THE HIGHWAY 82 CORRIDOR...WHERE
ASCENT OFFERED BY TWO SUBTLE MID-LEVEL IMPULSES PIVOTING AROUND THE
LARGER-SCALE PV MAX WILL AUGMENT DIURNALLY ENHANCED BOUNDARY-LAYER
CIRCULATIONS AND SFC CONVERGENCE ALONG THE TROUGH/DRYLINE. FARTHER
SOUTH...CONVECTIVE COVERAGE WILL BE MORE SUPPRESSED TOWARD
INTERSTATE 20...AS AMPLE DRY AIR ALOFT WRAPS AROUND THE SRN FRINGES
OF THE PV MAX.
ENHANCED MID/UPPER-LEVEL FLOW IN ASSOCIATION WITH A
CYCLONICALLY-CURVED UPPER-LEVEL SPEED MAX OVER THE AREA IS
SUPPORTING 25-30 KT OF EFFECTIVE BULK SHEAR SOUTH OF HIGHWAY
82...WITH WEAKER MID-LEVEL FLOW/VERTICAL SHEAR FARTHER NORTH. AS
SUCH...A FEW MULTICELLULAR CLUSTERS WILL BE POSSIBLE ACROSS PARTS OF
CNTRL/NRN MS AND CNTRL AL...WITH MORE PULSE CONVECTION ELSEWHERE.
STRONG WIND GUSTS AND SMALL HAIL WILL BE POSSIBLE WITH THE
STRONGEST/MOST PERSISTENT STORMS UNTIL AFTER 01Z...WHEN DIABATIC
COOLING COMMENCES. WHILE AN ISOLATED THREAT FOR A DMGG WIND GUST OR
MARGINALLY SVR HAIL CANNOT BE RULED OUT...THE LACK OF STRONGER
FORCING FOR ASCENT / GREATER INSTABILITY IS EXPECTED TO MITIGATE THE
OVERALL SVR THREAT.
..COHEN.. 09/11/2011
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...MRX...OHX...BMX...HUN...MEG...JAN...
LAT...LON 35138574 33148704 31659072 32219187 33549095 36018841
36418627 35138574Nearby
Mesoscale Discussions in Mississippi, 2011Mesoscale Discussions in Tennessee, 2011Mesoscale Discussions in Alabama, 2011Every mesoscale discussion in 2011
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.