Alert archive / Mississippi / Mesoscale Discussions in 2012
Mesoscale Discussion 996
The Storm Prediction Center issued this mesoscale discussion at May 31, 2012, 1:53 PM CDT for 18 parishes in Louisiana; 42 counties in Mississippi. It was in force for 67 min.
The area
The outline as issued.
The facts
- Issued
- May 31, 2012, 1:53 PM CDT (18:53 UTC)
- Expired
- May 31, 2012, 3:00 PM CDT
- In force
- 67 min
- Issued by
- the Storm Prediction Center
All 60 counties
Ascension Parish, LA, Assumption Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Iberville Parish, LA, Livingston Parish, LA, Madison 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, Tangipahoa Parish, LA, Tensas Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA, Adams County, MS, Amite County, MS, Attala County, MS, Choctaw County, MS, Claiborne County, MS, Clarke County, MS, Copiah County, MS, Covington County, MS, Forrest County, MS, Franklin County, MS, Hancock County, MS, Hinds County, MS, Holmes County, MS, Issaquena County, MS, Jasper County, MS, Jefferson County, MS, Jefferson Davis County, MS, Jones County, MS, Lamar County, MS, Lauderdale County, MS, Lawrence County, MS, Leake County, MS, Lincoln County, MS, Madison County, MS, Marion County, MS, Neshoba County, MS, Newton County, MS, Pearl River County, MS, Perry County, MS, Pike County, MS, Rankin County, MS, Scott County, MS, Sharkey County, MS, Simpson County, MS, Smith County, MS, Stone County, MS, Walthall County, MS, Warren County, MS, Wayne County, MS, Wilkinson County, MS, Winston County, MS, Yazoo County, MS
The radar
The Jackson/Brandon,MS radar (KDGX), 76 km from the middle of the area, began a volume at 18:54 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
Jackson, MS (KJAN), launched 12:00Z, 6.9 hours before the alert went out and 79 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
- 1744 J/kg
- Mixed-layer CIN
- -59 J/kg
- Mixed-layer LCL
- 674 m above ground
- 0-6 km bulk shear
- 9 kt
- 0-1 km storm-relative helicity
- 70 m²/s²
- 0-3 km storm-relative helicity
- 65 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
134
ACUS11 KWNS 311854
SWOMCD
SPC MCD 311853
MSZ000-LAZ000-312000-
MESOSCALE DISCUSSION 0996
NWS STORM PREDICTION CENTER NORMAN OK
0153 PM CDT THU MAY 31 2012
AREAS AFFECTED...ERN LA...SRN AND CNTRL MS
CONCERNING...SEVERE THUNDERSTORM WATCH 327...
VALID 311853Z - 312000Z
THE SEVERE WEATHER THREAT FOR SEVERE THUNDERSTORM WATCH 327
CONTINUES.
SUMMARY...AN ISOLATED SEVERE THREAT WILL EXIST ACROSS SRN AND CNTRL
MS THIS AFTERNOON AS CELLS APPROACH FROM THE WEST. WIND DAMAGE AND
HAIL WILL BE THE PRIMARY THREATS. WW ISSUANCE REMAINS POSSIBLE TO
THE EAST OF WW 327 LATER THIS AFTERNOON.
DISCUSSION...A CLUSTER OF STRONG THUNDERSTORMS IS ONGOING ACROSS ERN
LA JUST AHEAD OF A BAND OF STRONG LARGE-SCALE ASCENT ASSOCIATED WITH
A WELL-DEFINED SHORTWAVE TROUGH EVIDENT ON WATER VAPOR IMAGERY.
AHEAD OF THE CONVECTION...THE AIRMASS IS MODERATELY UNSTABLE WITH
MLCAPE VALUES ESTIMATED TO BE FROM AROUND 1000 J/KG IN SRN MS TO
ALMOST 2000 J/KG IN NCNTRL MS. THIS SUGGESTS THE GREATER SEVERE
THREAT SHOULD EXIST ACROSS CNTRL MS WHERE WW ISSUANCE WILL BE
POSSIBLE. MESOANALYSIS CURRENTLY SHOWS STEEPENING LOW-LEVEL LAPSE
RATES ACROSS WRN AND CNTRL MS WITH 0-3 KM LAPSE RATES ESTIMATED AT
JUST ABOVE 8.0 C/KM. THIS SHOULD HELP ENHANCE DOWNDRAFTS WITH WIND
DAMAGE A POSSIBILITY WITH THE STRONGER MULTICELLS. HAIL MAY ALSO
ACCOMPANY THE CELLS THAT PULSE UP AND MATURE IN INTENSITY.
..BROYLES/WEISS.. 05/31/2012
...PLEASE SEE WWW.SPC.NOAA.GOV FOR GRAPHIC PRODUCT...
ATTN...WFO...MOB...JAN...LIX...LCH...
LAT...LON 30038986 30458912 30928862 31718866 32648866 33408894
33548918 33408981 33119045 32959080 32509132 31789168
31189154 30259142 29759117 29679076 30038986SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 31, 9:47 AM CDT | Mesoscale Discussion | SPC | Acadia, Allen, Beauregard, Calcasieu, Cameron, Evangeline and 7 more | 58 min |
| May 31, 10:41 AM CDT | Severe Thunderstorm Watch | SPC | Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 37 more | 6 hr |
| May 31, 2:53 PM CDT | Severe Thunderstorm Watch | SPC | Jefferson, Lafourche, Orleans, Plaquemines, Saint Bernard, Saint Charles and 4 more | 5 hr |
| May 31, 11:59 AM CDT | Mesoscale Discussion | SPC | Alcorn, Attala, Benton, Bolivar, Calhoun, Carroll and 32 more | 61 min |
| May 31, 12:59 PM CDT | Severe Thunderstorm Watch | SPC | Alcorn, Attala, Benton, Bolivar, Calhoun, Carroll and 41 more | 6 hr |
| May 31, 2:38 PM CDT | Mesoscale Discussion | SPC | Alcorn, Attala, Benton, Bolivar, Calhoun, Carroll and 38 more | 67 min |
| May 31, 5:30 PM CDT | Mesoscale Discussion | SPC | Prentiss, Tishomingo | 2 hr |
Nearby
Mesoscale Discussions in Mississippi, 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.