Alert archive / Louisiana / Tornado Watches in 2007

Tornado Watch 186

April 25, 200716 parishes in Louisiana; 14 counties in Texas

The Storm Prediction Center issued this tornado watch at Apr 25, 2007, 9:13 AM CDT for 16 parishes in Louisiana; 14 counties in Texas. It was in force for 8 hr.

The area

The outline as issued.

The facts

Issued
Apr 25, 2007, 9:13 AM CDT (14:13 UTC)
Expired
Apr 25, 2007, 5:00 PM CDT
In force
8 hr
Issued by
the Storm Prediction Center
Largest hail expected
1.5 in
Strongest gust expected
60 kt
All 30 counties

Acadia Parish, LA, Allen Parish, LA, Avoyelles Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, Evangeline Parish, LA, Iberia Parish, LA, Jefferson Davis Parish, LA, Lafayette Parish, LA, Rapides Parish, LA, Saint Landry Parish, LA, Saint Martin Parish, LA, St. Mary Parish, LA, Vermilion Parish, LA, Vernon Parish, LA, Aransas County, TX, Brazoria County, TX, Calhoun County, TX, Chambers County, TX, Fort Bend County, TX, Galveston County, TX, Hardin County, TX, Harris County, TX, Jasper County, TX, Jefferson County, TX, Liberty County, TX, Matagorda County, TX, Newton County, TX, Orange County, TX

The radar

The Houston radar (KHGX), 91 km from the middle of the area, began a volume at 14:17 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
20%
Ten or more severe wind reports
40%
One or more gusts of 65 knots or more
20%
Ten or more severe hail reports
40%
One or more hailstones of 2 inches or more
20%
Six or more combined severe hail and wind reports
80%

Warnings issued inside it

3 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Apr 25, 10:25 AM CDTTornado WarningHGXBrazoria, Matagorda50 min
Apr 25, 1:52 PM CDTFlash Flood WarningLCHBeauregard, Vernon3 hr
Apr 25, 1:52 PM CDTFlash Flood WarningLCHBeauregard, Rapides, Vernon3 hr

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 12:00Z, 2.2 hours before the alert went out and 105 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.

Skew-T log-pSkew-T log-p diagram, Lake Charles Mun, LA at 12:00Z on 2007-04-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 835 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Lake Charles Mun, LA at 12:00Z on 2007-04-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 63 square meters per square second.19395878Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.
Mixed-layer CAPE
835 J/kg
Mixed-layer CIN
-10 J/kg
Mixed-layer LCL
644 m above ground
0-6 km bulk shear
26 kt
0-1 km storm-relative helicity
63 m²/s²
0-3 km storm-relative helicity
76 m²/s²
Significant tornado parameter
0.2
Supercell composite
1.4

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

000
WWUS20 KWNS 251414
SEL6  
SPC WW 251414
LAZ000-TXZ000-CWZ000-252200-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 186
NWS STORM PREDICTION CENTER NORMAN OK
915 AM CDT WED APR 25 2007

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF 

       SOUTHWEST AND SOUTH CENTRAL LOUISIANA
       SOUTHEAST TEXAS
       COASTAL WATERS

EFFECTIVE THIS WEDNESDAY MORNING AND AFTERNOON FROM 915 AM UNTIL
500 PM CDT.

TORNADOES...HAIL TO 1.5 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 100 STATUTE
MILES EAST AND WEST OF A LINE FROM 65 MILES NORTH NORTHEAST OF
LAKE CHARLES LOUISIANA TO 60 MILES SOUTHEAST OF PALACIOS TEXAS. 
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.

OTHER WATCH INFORMATION...THIS TORNADO WATCH REPLACES TORNADO
WATCH NUMBER 185. WATCH NUMBER 185 WILL NOT BE IN EFFECT AFTER
915 AM CDT. 

DISCUSSION...SEMI-DISCRETE STORMS/POSSIBLE SUPERCELLS EXPECTED TO
PERSIST ALONG SLOWLY-PROGRESSIVE SQLN OVER SE TX.  WHILE LOW LEVEL
WINDS ARE WEAK...SLIGHTLY BACKED NEAR-SFC WINDS...RICH MOISTURE
SUPPLY...50+ KT MID LEVEL SWLY FLOW PARALLEL TO LINE...AND BROKEN
NATURE OF LINE SUGGEST ISOLATED TORNADO POTENTIAL AS STORMS RIDE NE
ALONG EXISTING STORM OUTFLOW INTO LA.

AVIATION...TORNADOES AND 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
500. MEAN STORM MOTION VECTOR 24035.


...CORFIDI

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 25, 2:10 AM CDTMesoscale DiscussionSPCBienville, Bossier, Caddo, Claiborne, De Soto, Jackson and 6 more65 min
Apr 25, 9:00 AM CDTMesoscale DiscussionSPCAcadia, Allen, Avoyelles, Beauregard, Calcasieu, Cameron and 7 more60 min
Apr 25, 1:23 PM CDTMesoscale DiscussionSPCCatahoula, Concordia, East Feliciana, Franklin, Madison, Tensas and 1 more67 min
Apr 25, 1:46 PM CDTTornado WatchSPCCatahoula, Concordia, East Baton Rouge, East Carroll, East Feliciana, Franklin and 9 more5 hr
Apr 25, 3:05 PM CDTMesoscale DiscussionSPCAcadia, Allen, Beauregard, Calcasieu, Cameron, Evangeline and 6 more55 min
Apr 25, 6:15 PM CDTMesoscale DiscussionSPCBossier, Caddo, Claiborne, De Soto, Webster90 min
Apr 24, 7:33 PM CDTMesoscale DiscussionSPCBowie, Camp, Cass, Collin, Dallas, Delta and 25 more117 min
Apr 24, 10:07 PM CDTMesoscale DiscussionSPCAnderson, Atascosa, Bandera, Bastrop, Bell, Bexar and 65 more83 min
Apr 24, 10:35 PM CDTTornado WatchSPCAnderson, Bell, Bosque, Bowie, Camp, Cass and 37 more5 hr
Apr 24, 10:53 PM CDTTornado WatchSPCAtascosa, Bandera, Bastrop, Bexar, Blanco, Burnet and 28 more7 hr
Apr 24, 11:58 PM CDTMesoscale DiscussionSPCAnderson, Bell, Bowie, Camp, Cass, Cherokee and 20 more92 min
Apr 25, 1:14 AM CDTMesoscale DiscussionSPCAtascosa, Bandera, Bastrop, Bee, Bexar, Blanco and 35 more91 min
Apr 25, 1:40 AM CDTTornado WatchSPCAransas, Austin, Bee, Brazoria, Brazos, Burleson and 30 more7 hr
Apr 25, 4:29 AM CDTMesoscale DiscussionSPCAngelina, Aransas, Austin, Bee, Brazoria, Brazos and 35 more91 min
Apr 25, 7:36 AM CDTMesoscale DiscussionSPCAransas, Austin, Bee, Brazoria, Calhoun, Chambers and 28 more84 min

Nearby

Tornado Watches in Louisiana, 2007Tornado Watches in Texas, 2007Every tornado watch in 2007

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.