Alert archive / Louisiana / Tornado Watches in 2003
Tornado Watch 954
The Storm Prediction Center issued this tornado watch at Nov 17, 2003, 9:25 PM CST for 18 parishes in Louisiana; Sabine County, San Augustine County, Shelby County, Texas. It was in force for 7 hr.
The area
The outline as issued.
The facts
- Issued
- Nov 17, 2003, 9:25 PM CST (03:25 UTC)
- Expired
- Nov 18, 2003, 4:00 AM CST
- In force
- 7 hr
- Issued by
- the Storm Prediction Center
All 21 counties
Bienville Parish, LA, Bossier Parish, LA, Caddo Parish, LA, Caldwell Parish, LA, Claiborne Parish, LA, De Soto Parish, LA, Grant Parish, LA, Jackson Parish, LA, LaSalle Parish, LA, Lincoln Parish, LA, Natchitoches Parish, LA, Ouachita Parish, LA, Rapides Parish, LA, Red River Parish, LA, Sabine Parish, LA, Union Parish, LA, Webster Parish, LA, Winn Parish, LA, Sabine County, TX, San Augustine County, TX, Shelby County, TX
The radar
The Shreveport radar (KSHV), 73 km from the middle of the area, began a volume at 03:24 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.
Warnings issued inside it
5 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Nov 17, 9:57 PM CST | Tornado Warning | SHV | Natchitoches, Winn | 48 min |
| Nov 17, 10:34 PM CST | Tornado Warning | SHV | Sabine | 41 min |
| Nov 18, 12:24 AM CST | Severe Thunderstorm Warning | SHV | Bienville | 51 min |
| Nov 18, 1:01 AM CST | Severe Thunderstorm Warning | SHV | Natchitoches | 29 min |
| Nov 18, 3:05 AM CST | Severe Thunderstorm Warning | SHV | LaSalle | 40 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
Shreveport, LA (KSHV), launched 00:00Z, 3.4 hours before the alert went out and 71 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
- 512 J/kg
- Mixed-layer CIN
- -7 J/kg
- Mixed-layer LCL
- 515 m above ground
- 0-6 km bulk shear
- 41 kt
- 0-1 km storm-relative helicity
- 231 m²/s²
- 0-3 km storm-relative helicity
- 284 m²/s²
- Significant tornado parameter
- 0.6
- Supercell composite
- 3.6
The text
As transmitted, in the capitals the NWS used until 2016.
000
WWUS20 KWNS 180328
SEL4
SPC WW 180325
LAZ000-TXZ000-181000-
URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 954
NWS STORM PREDICTION CENTER NORMAN OK
925 PM CST MON NOV 17 2003
THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF
NORTH AND NORTHWEST LOUISIANA
EXTREME EAST CENTRAL AND NORTHEAST TEXAS
EFFECTIVE THIS MONDAY NIGHT AND TUESDAY MORNING FROM 925 PM UNTIL
400 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 ALONG AND 65 STATUTE MILES EAST AND WEST
OF A LINE FROM 55 MILES NORTHEAST OF SHREVEPORT LOUISIANA TO 95
MILES SOUTH SOUTHEAST OF SHREVEPORT LOUISIANA.
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...CONTINUE...WW 952...WW 953...
DISCUSSION...ENE-WSW BAND OF THUNDERSTORMS WITH EMBEDDED SUPERCELLS
IS LIFTING NWD ACROSS W CENTRAL LA...WHILE ADDITIONAL STORMS SHOULD
INTENSIFY GRADUALLY ALONG A PRE-FRONTAL TROUGH IN E TX. THE LOW
LEVELS APPEAR TO BE DESTABILIZING NWD ACROSS WRN LA...WHILE STORMS
CONTINUE TO INITIATE AND FEED INTO THIS AREA FROM E/SE TX. A 50-60
KT LLJ /IN ADVANCE OF AN EJECTING MID LEVEL TROUGH OVER TX/ IS
CONTRIBUTING TO 0-1 KM SRH OF 300-400 M2/S2 OVER E TX AND WRN LA.
EXPECT THE THREAT FOR A FEW TORNADOES TO SPREAD NWD INTO NW LA INTO
THE EARLY MORNING HOURS.
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 450.
MEAN STORM MOTION VECTOR 22035.
...THOMPSON
330,0920 311,0920 311,0941 330,0941SPC that day
Everything else SPC issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Nov 17, 7:48 PM CST | Mesoscale Discussion | SPC | Bossier, Caddo, Claiborne, Webster | 87 min |
| Nov 17, 8:10 PM CST | Mesoscale Discussion | SPC | Beauregard, Calcasieu, Natchitoches, Sabine, Vernon | 95 min |
| Nov 17, 10:53 PM CST | Mesoscale Discussion | SPC | Beauregard, Calcasieu | 97 min |
| Nov 17, 11:44 PM CST | Mesoscale Discussion | SPC | Bienville, Bossier, Caldwell, Claiborne, De Soto, Grant and 11 more | 91 min |
| Nov 17, 11:50 PM CST | Tornado Watch | SPC | Acadia, Allen, Beauregard, Calcasieu, Cameron, Evangeline and 2 more | 5 hr |
| Nov 18, 2:08 AM CST | Mesoscale Discussion | SPC | Ascension, Assumption, Avoyelles, Catahoula, Concordia, East Baton Rouge and 25 more | 97 min |
| Nov 18, 2:25 AM CST | Tornado Watch | SPC | Acadia, Allen, Ascension, Assumption, Avoyelles, Beauregard and 32 more | 6 hr |
| Nov 18, 4:48 AM CST | Mesoscale Discussion | SPC | Ascension, Assumption, Concordia, East Baton Rouge, East Feliciana, Iberville and 17 more | 117 min |
| Nov 18, 6:08 AM CST | Mesoscale Discussion | SPC | Ascension, Jefferson, Lafourche, Livingston, Orleans, Plaquemines and 8 more | 2 hr |
| Nov 18, 6:55 AM CST | Tornado Watch | SPC | Ascension, Assumption, East Baton Rouge, Jefferson, Lafourche, Livingston and 11 more | 5 hr |
| Nov 18, 10:30 AM CST | Mesoscale Discussion | SPC | Saint Bernard | 90 min |
| Nov 17, 6:55 PM CST | Severe Thunderstorm Watch | SPC | Austin, Brazoria, Colorado, Fort Bend, Grimes, Harris and 12 more | 5 hr |
Nearby
Tornado Watches in Louisiana, 2003Tornado Watches in Texas, 2003Every tornado watch in 2003
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.