Alert archive / Mississippi / Tornado Watches in 2012
Tornado Watch 656
The Storm Prediction Center issued this tornado watch at Sep 30, 2012, 2:36 PM CDT for 12 parishes in Louisiana; 27 counties in Mississippi. It was in force for 3 hr.
The area
The outline as issued.
The facts
- Issued
- Sep 30, 2012, 2:36 PM CDT (19:36 UTC)
- Expired
- Sep 30, 2012, 5:56 PM CDT
- In force
- 3 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1 in
- Strongest gust expected
- 60 kt
All 39 counties
Ascension Parish, LA, East Baton Rouge Parish, LA, East Feliciana Parish, LA, Iberville Parish, LA, Livingston Parish, LA, Pointe Coupee Parish, LA, Saint Helena Parish, LA, Saint Tammany Parish, LA, Tangipahoa Parish, LA, Washington Parish, LA, West Baton Rouge Parish, LA, West Feliciana Parish, LA, Amite County, MS, Clarke County, MS, Copiah County, MS, Covington County, MS, Forrest County, MS, Franklin 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, Lawrence County, MS, Lincoln County, MS, Marion County, MS, Pearl River County, MS, Perry County, MS, Pike County, MS, Simpson County, MS, Smith County, MS, Stone County, MS, Walthall County, MS, Wayne County, MS, Wilkinson County, MS
The radar
The Jackson/Brandon,MS radar (KDGX), 109 km from the middle of the area, began a volume at 19:38 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.
What SPC expected
The probabilities SPC published with the watch, for the watch area over its life.
- Two or more tornadoes
- 30%
- One or more EF2 to EF5 tornadoes
- 10%
- Ten or more severe wind reports
- 30%
- One or more gusts of 65 knots or more
- 20%
- Ten or more severe hail reports
- 10%
- One or more hailstones of 2 inches or more
- 5%
- Six or more combined severe hail and wind reports
- 50%
Warnings issued inside it
8 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 30, 2:48 PM CDT | Tornado Warning | LIX | Hancock, Pearl River | 27 min |
| Sep 30, 3:15 PM CDT | Tornado Warning | LIX | Hancock, Pearl River | 30 min |
| Sep 30, 3:26 PM CDT | Tornado Warning | LIX | Hancock, Harrison | 22 min |
| Sep 30, 3:36 PM CDT | Severe Thunderstorm Warning | MOB | George, Perry, Stone | 54 min |
| Sep 30, 4:09 PM CDT | Tornado Warning | MOB | Stone | 51 min |
| Sep 30, 4:33 PM CDT | Tornado Warning | MOB | Perry, Stone | 42 min |
| Sep 30, 5:04 PM CDT | Tornado Warning | MOB | George, Greene, Perry, Stone | 41 min |
| Sep 30, 5:37 PM CDT | Tornado Warning | LIX | Orleans, Saint Tammany | 38 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
Jackson, MS (KJAN), launched 12:00Z, 7.6 hours before the alert went out and 116 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
- 1 J/kg
- Mixed-layer CIN
- No buoyant parcel
- Mixed-layer LCL
- 617 m above ground
- 0-6 km bulk shear
- 27 kt
- 0-1 km storm-relative helicity
- 127 m²/s²
- 0-3 km storm-relative helicity
- 288 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
605
WWUS20 KWNS 301937
SEL6
SPC WW 301937
LAZ000-MSZ000-CWZ000-010100-
URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 656
NWS STORM PREDICTION CENTER NORMAN OK
135 PM CST SUN SEP 30 2012
THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF
SOUTHEAST LOUISIANA
SOUTHERN MISSISSIPPI
COASTAL WATERS
EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 135 PM UNTIL 700
PM CST.
TORNADOES...HAIL TO 1 INCH IN DIAMETER...THUNDERSTORM WIND GUSTS
TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.
THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 80 STATUTE
MILES EAST AND WEST OF A LINE FROM 50 MILES NORTH NORTHWEST OF
PINE BELT MISSISSIPPI TO 30 MILES WEST SOUTHWEST OF SLIDELL
LOUISIANA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU6).
REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND 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.
DISCUSSION...STORMS DEVELOPING AHEAD OF COLD FRONT AND EAST OF NEWD
ADVANCING MESOLOW CIRCULATION MAY BECOME CAPABLE OF PRODUCING
ISOLATED TORNADOES AND DAMAGING WIND GUSTS. MLCAPE FROM 1000-1500
J/KG AND 0-1 KM STORM RELATIVE HELICITY FROM 150-200 M2/S2 WILL
SUPPORT THE POTENTIAL FOR ORGANIZED STORMS INCLUDING LOW LEVEL
MESOCYCLONES AND BOWING SEGMENTS AS ACTIVITY CONTINUES THROUGH THE
WARM SECTOR.
AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 1 INCH. EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 400.
MEAN STORM MOTION VECTOR 22030.
...DIALSPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 30, 10:33 AM CDT | Mesoscale Discussion | SPC | Ascension, Assumption, East Baton Rouge, East Feliciana, Iberville, Lafayette and 13 more | 117 min |
| Sep 30, 5:09 PM CDT | Mesoscale Discussion | SPC | Saint Tammany, Washington | 96 min |
| Sep 30, 5:50 PM CDT | Tornado Watch | SPC | Concordia, Madison, Orleans, Plaquemines, Saint Bernard, Saint Tammany and 3 more | 8 hr |
Nearby
Tornado Watches in Mississippi, 2012Tornado Watches in Louisiana, 2012Every tornado 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; radar from the NEXRAD Level II archive.