Alert archive / Louisiana / Tornado Watches in 2012
Tornado Watch 591
The Storm Prediction Center issued this tornado watch at Aug 28, 2012, 9:46 AM CDT for 4 states. It was in force for 9 hr.
The area
The outline as issued.
The facts
- Issued
- Aug 28, 2012, 9:46 AM CDT (14:46 UTC)
- Expired
- Aug 28, 2012, 6:48 PM CDT
- In force
- 9 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 0.5 in
- Strongest gust expected
- 60 kt
All 37 counties
Baldwin County, AL, Choctaw County, AL, Clarke County, AL, Conecuh County, AL, Escambia County, AL, Mobile County, AL, Monroe County, AL, Washington County, AL, Bay County, FL, Escambia County, FL, Holmes County, FL, Okaloosa County, FL, Santa Rosa County, FL, Walton County, FL, Washington County, FL, 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, Terrebonne Parish, LA, Washington Parish, LA, George County, MS, Greene County, MS, Hancock County, MS, Harrison County, MS, Jackson County, MS, Pearl River County, MS, Perry County, MS, Pike County, MS, Stone County, MS, Walthall County, MS, Wayne County, MS
The radar
The Mobile radar (KMOB), 52 km from the middle of the area, began a volume at 14:46 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
- 40%
- One or more EF2 to EF5 tornadoes
- 20%
- Ten or more severe wind reports
- 5%
- One or more gusts of 65 knots or more
- 5%
- Ten or more severe hail reports
- 5%
- One or more hailstones of 2 inches or more
- 5%
- Six or more combined severe hail and wind reports
- 20%
Warnings issued inside it
3 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 28, 11:52 AM CDT | Tornado Warning | LIX | Orleans, Saint Tammany | 23 min |
| Aug 28, 4:45 PM CDT | Tornado Warning | MOB | Baldwin | 30 min |
| Aug 28, 5:09 PM CDT | Tornado Warning | MOB | Santa Rosa | 51 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, 2.8 hours before the alert went out and 121 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
- 41 J/kg
- Mixed-layer CIN
- -110 J/kg
- Mixed-layer LCL
- 650 m above ground
- 0-6 km bulk shear
- 28 kt
- 0-1 km storm-relative helicity
- 272 m²/s²
- 0-3 km storm-relative helicity
- 266 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.0
The text
As transmitted, in the capitals the NWS used until 2016.
079
WWUS20 KWNS 281448
SEL1
SPC WW 281448
ALZ000-FLZ000-LAZ000-MSZ000-CWZ000-290000-
URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 591
NWS STORM PREDICTION CENTER NORMAN OK
945 AM CDT TUE AUG 28 2012
THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF
SOUTHWEST ALABAMA
WESTERN FLORIDA PANHANDLE
SOUTHEAST LOUISIANA
FAR SOUTHEAST MISSISSIPPI
COASTAL WATERS
EFFECTIVE THIS TUESDAY MORNING AND EVENING FROM 945 AM UNTIL 700
PM CDT.
TORNADOES...HAIL TO 0.5 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 55 STATUTE
MILES NORTH AND SOUTH OF A LINE FROM 15 MILES WEST OF NEW ORLEANS
LOUISIANA TO 20 MILES EAST OF PANAMA CITY FLORIDA. FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU1).
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...A SLOW INCREASE IN CONVECTION HAS BEEN NOTED THIS
MORNING ON OUTER PERIPHERY OF ISAAC WHERE BREAKS IN THE CLOUDS ARE
SUPPORTING AIR MASS DESTABILIZATION. THIS TREND SHOULD CONTINUE
THROUGH THE REMAINDER OF THE MORNING AND THIS AFTERNOON WITH AN
INCREASED RISK FOR MINI SUPERCELLS AND AN ASSOCIATED TORNADO THREAT.
AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 0.5 INCH. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
450. MEAN STORM MOTION VECTOR 11040.
...MEADSPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Aug 28, 7:01 AM CDT | Mesoscale Discussion | SPC | Baldwin, Clarke, Coffee, Conecuh, Covington, Escambia and 4 more | 2 hr |
| Aug 28, 12:37 PM CDT | Mesoscale Discussion | SPC | Baldwin, Escambia, Mobile, Washington | 83 min |
| Aug 28, 3:46 PM CDT | Mesoscale Discussion | SPC | Baldwin, Clarke, Escambia, Mobile, Monroe, Washington | 89 min |
| Aug 28, 5:48 PM CDT | Mesoscale Discussion | SPC | Baldwin, Conecuh, Covington, Escambia, Mobile, Monroe and 1 more | 87 min |
| Aug 28, 6:47 PM CDT | Tornado Watch | SPC | Baldwin, Choctaw, Clarke, Conecuh, Escambia, Mobile and 2 more | 21 hr |
| Aug 28, 12:56 PM CDT | Tornado Watch | SPC | Covington, Forrest, Jefferson Davis, Jones, Lamar, Lawrence and 2 more | 6 hr |
Nearby
Tornado Watches in Louisiana, 2012Tornado Watches in Mississippi, 2012Tornado Watches in Alabama, 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.