Alert archive / Mississippi / Severe Thunderstorm Watches in 2012
Severe Thunderstorm Watch 330
The Storm Prediction Center issued this severe thunderstorm watch at May 31, 2012, 2:53 PM CDT for 10 parishes in Louisiana; 24 counties in Mississippi. It was in force for 5 hr.
The area
The outline as issued.
The facts
- Issued
- May 31, 2012, 2:53 PM CDT (19:53 UTC)
- Expired
- May 31, 2012, 7:28 PM CDT
- In force
- 5 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1.5 in
- Strongest gust expected
- 60 kt
All 34 counties
Jefferson Parish, LA, Lafourche Parish, LA, Orleans Parish, LA, Plaquemines Parish, LA, Saint Bernard Parish, LA, Saint Charles Parish, LA, Saint John the Baptist Parish, LA, Saint Tammany Parish, LA, Tangipahoa Parish, LA, Washington Parish, LA, Clarke County, MS, Covington County, MS, Forrest County, MS, George County, MS, Greene County, MS, Hancock County, MS, Harrison County, MS, Jackson County, MS, Jasper County, MS, Jefferson Davis County, MS, Jones County, MS, Lamar County, MS, Lauderdale County, MS, Lawrence County, MS, Marion County, MS, Newton County, MS, Pearl River County, MS, Perry County, MS, Scott County, MS, Simpson County, MS, Smith County, MS, Stone County, MS, Walthall County, MS, Wayne County, MS
What SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 10%
- One or more EF2 to EF5 tornadoes
- 5%
- Ten or more severe wind reports
- 40%
- One or more gusts of 65 knots or more
- 10%
- Ten or more severe hail reports
- 30%
- One or more hailstones of 2 inches or more
- 5%
- Six or more combined severe hail and wind reports
- 70%
Warnings issued inside it
21 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| May 31, 2:55 PM CDT | Tornado Warning | LIX | Livingston, Saint Helena, Tangipahoa | 35 min |
| May 31, 3:06 PM CDT | Severe Thunderstorm Warning | LIX | Walthall | 24 min |
| May 31, 3:12 PM CDT | Severe Thunderstorm Warning | JAN | Attala, Carroll, Holmes, Leake, Madison, Scott | 63 min |
| May 31, 3:17 PM CDT | Severe Thunderstorm Warning | LIX | Walthall | 28 min |
| May 31, 3:23 PM CDT | Severe Thunderstorm Warning | JAN | Copiah, Hinds, Leake, Madison, Rankin, Simpson | 67 min |
| May 31, 3:31 PM CDT | Severe Thunderstorm Warning | LIX | Washington | 29 min |
| May 31, 3:35 PM CDT | Severe Thunderstorm Warning | JAN | Jefferson Davis, Lawrence, Marion | 55 min |
| May 31, 3:49 PM CDT | Severe Thunderstorm Warning | LIX | Washington | 26 min |
| May 31, 3:56 PM CDT | Severe Thunderstorm Warning | JAN | Leake, Madison, Scott | 64 min |
| May 31, 4:09 PM CDT | Severe Thunderstorm Warning | JAN | Covington, Jefferson Davis, Smith | 66 min |
| May 31, 4:16 PM CDT | Severe Thunderstorm Warning | JAN | Lamar | 59 min |
| May 31, 4:28 PM CDT | Severe Thunderstorm Warning | JAN | Forrest, Jones | 62 min |
| May 31, 4:30 PM CDT | Severe Thunderstorm Warning | JAN | Neshoba, Newton, Winston | 60 min |
| May 31, 4:35 PM CDT | Severe Thunderstorm Warning | JAN | Jasper, Lauderdale | 55 min |
| May 31, 4:40 PM CDT | Severe Thunderstorm Warning | MOB | Wayne | 50 min |
| May 31, 4:49 PM CDT | Flash Flood Warning | JAN | Scott | 116 min |
| May 31, 4:57 PM CDT | Severe Thunderstorm Warning | JAN | Scott | 33 min |
| May 31, 5:01 PM CDT | Tornado Warning | JAN | Jasper, Newton | 34 min |
| May 31, 5:04 PM CDT | Tornado Warning | JAN | Newton | 34 min |
| May 31, 5:24 PM CDT | Severe Thunderstorm Warning | JAN | Clarke, Jones, Lauderdale | 81 min |
| May 31, 5:38 PM CDT | Severe Thunderstorm Warning | JAN | Jasper, Newton | 23 min |
Discussions around it
SPC mesoscale discussions over the same counties from four hours before the watch to its end.
The nearest sounding before it
Slidell Radar S, LA (KSIL), launched 12:00Z, 7.9 hours before the alert went out and 47 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
- 1878 J/kg
- Mixed-layer CIN
- -13 J/kg
- Mixed-layer LCL
- 652 m above ground
- 0-6 km bulk shear
- 13 kt
- 0-1 km storm-relative helicity
- -18 m²/s²
- 0-3 km storm-relative helicity
- -31 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
573
WWUS20 KWNS 311954
SEL0
SPC WW 311954
LAZ000-MSZ000-CWZ000-010200-
URGENT - IMMEDIATE BROADCAST REQUESTED
SEVERE THUNDERSTORM WATCH NUMBER 330
NWS STORM PREDICTION CENTER NORMAN OK
255 PM CDT THU MAY 31 2012
THE NWS STORM PREDICTION CENTER HAS ISSUED A
SEVERE THUNDERSTORM WATCH FOR PORTIONS OF
SOUTHEAST LOUISIANA
SOUTHEAST AND EAST CENTRAL MISSISSIPPI
COASTAL WATERS
EFFECTIVE THIS THURSDAY AFTERNOON AND EVENING FROM 255 PM UNTIL
900 PM CDT.
HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70
MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.
THE SEVERE THUNDERSTORM WATCH AREA IS APPROXIMATELY ALONG AND 55
STATUTE MILES EAST AND WEST OF A LINE FROM 55 MILES SOUTHEAST OF
NEW ORLEANS LOUISIANA TO 35 MILES WEST NORTHWEST OF MERIDIAN
MISSISSIPPI. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU0).
REMEMBER...A SEVERE THUNDERSTORM WATCH MEANS CONDITIONS ARE
FAVORABLE FOR SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS. SEVERE THUNDERSTORMS CAN AND OCCASIONALLY
DO PRODUCE TORNADOES.
OTHER WATCH INFORMATION...CONTINUE...WW 327...WW 328...WW 329...
DISCUSSION...SEVERAL ORGANIZED BANDS OF STRONG/SEVERE STORMS ARE
PROGRESSING EWD ACROSS SOUTH CENTRAL MS AND SRN LA. THESE STORMS
WILL MOVE INTO A MODERATELY UNSTABLE DOWNSTREAM ENVIRONMENT WITH
MLCAPE OF 1500-2000 J/KG. DEEP LAYER SHEAR IN THE LOWEST 8 KM IS
SUFFICIENT TO MAINTAIN MULTICELL STRUCTURES WITH STRONGER CELLS
CAPABLE OF PRODUCING LOCALIZED DAMAGING WIND GUSTS AND OCCASIONAL
HAIL.
AVIATION...A FEW SEVERE THUNDERSTORMS WITH HAIL SURFACE AND ALOFT
TO 1.5 INCHES. EXTREME TURBULENCE AND SURFACE WIND GUSTS TO 60
KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 550. MEAN STORM
MOTION VECTOR 24020.
...WEISSSPC 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, 1:53 PM CDT | Mesoscale Discussion | SPC | Ascension, Assumption, East Baton Rouge, East Feliciana, Iberville, Livingston and 12 more | 67 min |
| 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
Severe Thunderstorm Watches in Mississippi, 2012Severe Thunderstorm Watches in Louisiana, 2012Every severe thunderstorm watch 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.