Alert archive / Louisiana / Tornado Watches in 2008
Tornado Watch 69
The Storm Prediction Center issued this tornado watch at Feb 21, 2008, 3:23 AM CST for 21 parishes in Louisiana; Jefferson County, Orange County, Texas. It was in force for 6 hr.
The area
The outline as issued.
The facts
- Issued
- Feb 21, 2008, 3:23 AM CST (09:23 UTC)
- Expired
- Feb 21, 2008, 9:23 AM CST
- In force
- 6 hr
- Issued by
- the Storm Prediction Center
- Largest hail expected
- 1 in
- Strongest gust expected
- 60 kt
All 23 counties
Acadia Parish, LA, Ascension Parish, LA, Assumption Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, Iberia Parish, LA, Iberville Parish, LA, Jefferson Davis Parish, LA, Jefferson Parish, LA, Lafayette Parish, LA, Lafourche Parish, LA, Orleans Parish, LA, Plaquemines Parish, LA, Saint Bernard Parish, LA, Saint Charles Parish, LA, Saint James Parish, LA, Saint John the Baptist Parish, LA, Saint Martin Parish, LA, St. Mary Parish, LA, Terrebonne Parish, LA, Vermilion Parish, LA, Jefferson County, TX, Orange County, TX
The radar
The Lake Charles radar (KLCH), 124 km from the middle of the area, began a volume at 09:27 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
- 30%
- One or more gusts of 65 knots or more
- 10%
- Ten or more severe hail reports
- 20%
- One or more hailstones of 2 inches or more
- 5%
- Six or more combined severe hail and wind reports
- 70%
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 |
|---|---|---|---|---|
| Feb 21, 4:18 AM CST | Severe Thunderstorm Warning | LIX | Lafourche, Terrebonne | 42 min |
| Feb 21, 4:25 AM CST | Severe Thunderstorm Warning | LIX | Lafourche, Terrebonne | 35 min |
| Feb 21, 4:51 AM CST | Severe Thunderstorm Warning | LIX | Jefferson | 24 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
Lake Charles Mun, LA (KLCH), launched 00:00Z, 9.4 hours before the alert went out and 123 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
- 116 J/kg
- Mixed-layer CIN
- -43 J/kg
- Mixed-layer LCL
- 604 m above ground
- 0-6 km bulk shear
- 56 kt
- 0-1 km storm-relative helicity
- 193 m²/s²
- 0-3 km storm-relative helicity
- 295 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 1.7
The text
As transmitted, in the capitals the NWS used until 2016.
000
WWUS20 KWNS 210930
SEL9
SPC WW 210930
LAZ000-TXZ000-CWZ000-211700-
URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 69
NWS STORM PREDICTION CENTER NORMAN OK
325 AM CST THU FEB 21 2008
THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF
SOUTHERN LOUISIANA
SOUTHEAST TEXAS
COASTAL WATERS
EFFECTIVE THIS THURSDAY MORNING FROM 325 AM UNTIL 1100 AM 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 45 STATUTE
MILES NORTH AND SOUTH OF A LINE FROM 50 MILES WEST SOUTHWEST OF
LAKE CHARLES LOUISIANA TO 30 MILES EAST NORTHEAST OF BOOTHVILLE
LOUISIANA. FOR A COMPLETE DEPICTION OF THE WATCH SEE THE
ASSOCIATED WATCH OUTLINE UPDATE (WOUS64 KWNS WOU9).
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...SUSTAINED TSTMS/SUPERCELLS FORMING ALONG WARM FRONT
EXTENDING ESE OVER THE NWRN GULF FROM JUST S OF BPT EXPECTED
INCREASE IN COVERAGE THROUGH MIDDAY AS LOW-LEVEL WAA SLOWLY
STRENGTHENS DOWNSTREAM FROM APPROACHING SRN RCKYS TROUGH. WARM
FRONT SHOULD CONTINUE SLOWLY NEWD THROUGH THE PERIOD...RESULTING IN
A GRADUAL NEWD SHIFT OF SVR THREAT ASSOCIATED WITH THE STORMS.
COMBINATION OF INCREASING WIND FIELD/MOISTURE INFLOW SUGGESTS A
POTENTIAL FOR TORNADOES...IN ADDITION TO LOCALLY DMGG
WIND/MARGINALLY SVR HAIL...AS DEEP WSWLY SHEAR REMAINS AROUND 50
KTS.
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 500.
MEAN STORM MOTION VECTOR 26030.
...CORFIDISPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Feb 21, 1:48 AM CST | Mesoscale Discussion | SPC | Assumption, Cameron, Iberia, Jefferson, Lafourche, Plaquemines and 3 more | 57 min |
| Feb 21, 2:51 AM CST | Mesoscale Discussion | SPC | Bienville, Bossier, Caddo, Caldwell, Claiborne, De Soto and 14 more | 24 min |
| Feb 21, 6:47 AM CST | Mesoscale Discussion | SPC | Acadia, Ascension, Assumption, Calcasieu, Cameron, Iberia and 15 more | 58 min |
| Feb 21, 12:56 PM CST | Mesoscale Discussion | SPC | Acadia, Allen, Beauregard, Calcasieu, Cameron, Evangeline and 8 more | 64 min |
| Feb 21, 1:41 PM CST | Tornado Watch | SPC | Acadia, Allen, Ascension, Avoyelles, Beauregard, Calcasieu and 20 more | 7 hr |
| Feb 21, 4:55 PM CST | Mesoscale Discussion | SPC | Acadia, Ascension, Assumption, Calcasieu, Cameron, Iberia and 15 more | 95 min |
Nearby
Tornado Watches in Louisiana, 2008Tornado Watches in Texas, 2008Every tornado watch in 2008
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.