Alert archive / Texas / Tornado Watches in 2003

Tornado Watch 51

March 18, 20038 parishes in Louisiana; 19 counties in Texas

The Storm Prediction Center issued this tornado watch at Mar 18, 2003, 11:40 AM CST for 8 parishes in Louisiana; 19 counties in Texas. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued: Mar 18, 2003, 11:40 AM CST (17:40 UTC)
Expired: Mar 18, 2003, 5:00 PM CST
In force: 5 hr
Issued by: the Storm Prediction Center

All 27 counties

Allen Parish, LA, Beauregard Parish, LA, Calcasieu Parish, LA, Cameron Parish, LA, Grant Parish, LA, Natchitoches Parish, LA, Sabine Parish, LA, Vernon Parish, LA, Angelina County, TX, Brazoria County, TX, Chambers County, TX, Galveston County, TX, Hardin County, TX, Harris County, TX, Jasper County, TX, Jefferson County, TX, Liberty County, TX, Nacogdoches County, TX, Newton County, TX, Orange County, TX, Polk County, TX, Sabine County, TX, San Augustine County, TX, San Jacinto County, TX, Shelby County, TX, Trinity County, TX, Tyler County, TX

The radar

The Houston radar (KHGX), 77 km from the middle of the area, began a volume at 17:41 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

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

Issued	Product	Office	Counties	Lasted
Mar 18, 12:34 PM CST	Tornado Warning	LCH	Hardin	26 min
Mar 18, 12:39 PM CST	Severe Thunderstorm Warning	LCH	Jasper, Tyler	66 min
Mar 18, 12:47 PM CST	Severe Thunderstorm Warning	HGX	Chambers, Harris	43 min
Mar 18, 1:27 PM CST	Severe Thunderstorm Warning	LCH	Newton	63 min
Mar 18, 2:06 PM CST	Severe Thunderstorm Warning	SHV	Sabine	39 min
Mar 18, 3:08 PM CST	Severe Thunderstorm Warning	LCH	Vernon	67 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 12:00Z, 5.7 hours before the alert went out and 129 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 0 J/kg
Mixed-layer CIN: No buoyant parcel
Mixed-layer LCL: 787 m above ground
0-6 km bulk shear: 52 kt
0-1 km storm-relative helicity: 129 m²/s²
0-3 km storm-relative helicity: 147 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

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

000 
WWUS20 KWNS 181737
SEL1
SPC WW 181740
LAZ000-TXZ000-CWZ000-182300-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 51
STORM PREDICTION CENTER NORMAN OK
1140 AM CST TUE MAR 18 2003

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

   SOUTHWEST AND WEST CENTRAL LOUISIANA                          
   EAST CENTRAL AND SOUTHEAST TEXAS                              
   COASTAL WATERS                     

EFFECTIVE THIS TUESDAY MORNING AND AFTERNOON FROM 1140 AM UNTIL 500
PM CST.

TORNADOES...HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS
TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE TORNADO WATCH AREA IS ALONG AND 75 STATUTE MILES EAST AND WEST
OF A LINE FROM 45 MILES SOUTH OF GALVESTON TEXAS TO 65 MILES NORTH
NORTHWEST OF FORT POLK 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.


DISCUSSION...LINE OF STRONG/SEVERE STORMS CONTINUE TO MOVE EWD INTO
AREA OF VERY UNSTABLE AIR MASS.  SURFACE LIS ARE -6 TO -9 ACROSS
THE AREA WITH SBCAPE AROUND 1500 J/KG.  EXPECT DEEP LAYER SHEAR TO
INCREASE NEXT SEVERAL HOURS ENHANCING POTENTIAL FOR
SUPERCELL/TORNADIC STORMS.


AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2 INCHES.  EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 60 KNOTS.  A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500. 
MEAN STORM MOTION VECTOR 23035.


...MCCARTHY

315,0921 284,0933 284,0955 315,0945

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Mar 18, 9:36 AM CST	Mesoscale Discussion	SPC	Bossier, Caddo, De Soto, Red River, Sabine, Webster	3 hr
Mar 18, 1:12 PM CST	Mesoscale Discussion	SPC	Bienville, Caldwell, Catahoula, De Soto, Franklin, Grant and 13 more	2 hr
Mar 18, 2:15 PM CST	Tornado Watch	SPC	Acadia, Allen, Avoyelles, Beauregard, Bienville, Calcasieu and 28 more	7 hr
Mar 18, 3:33 PM CST	Mesoscale Discussion	SPC	Bienville, Caldwell, Catahoula, De Soto, Franklin, Grant and 13 more	57 min
Mar 18, 4:30 PM CST	Mesoscale Discussion	SPC	Ascension, East Baton Rouge, East Carroll, East Feliciana, Livingston, Madison and 8 more	2 hr
Mar 18, 5:05 PM CST	Tornado Watch	SPC	Ascension, East Baton Rouge, East Feliciana, Iberville, Livingston, Saint Helena and 4 more	6 hr
Mar 17, 8:19 PM CST	Mesoscale Discussion	SPC	Archer, Bosque, Clay, Cooke, Denton, Eastland and 13 more	86 min
Mar 17, 10:27 PM CST	Mesoscale Discussion	SPC	Archer, Brown, Callahan, Coleman, Comanche, Concho and 20 more	3 hr
Mar 18, 2:03 AM CST	Mesoscale Discussion	SPC	Bell, Bosque, Burnet, Collin, Coryell, Dallas and 23 more	3 hr

Nearby

Tornado Watches in Texas, 2003 Tornado Watches in Louisiana, 2003 Every 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.