Alert archive / Texas / Tornado Watches in 2002

Tornado Watch 673

September 6, 200216 counties in Texas

The Storm Prediction Center issued this tornado watch at Sep 6, 2002, 11:35 PM CDT for 16 counties in Texas. It was in force for 8 hr.

The area

The outline as issued.

The facts

Issued
Sep 6, 2002, 11:35 PM CDT (04:35 UTC)
Expired
Sep 7, 2002, 8:00 AM CDT
In force
8 hr
Issued by
the Storm Prediction Center

Counties Austin County, TX, Brazoria County, TX, Chambers County, TX, Colorado County, TX, Fayette County, TX, Fort Bend County, TX, Galveston County, TX, Harris County, TX, Jackson County, TX, Lavaca County, TX, Liberty County, TX, Matagorda County, TX, Montgomery County, TX, Victoria County, TX, Waller County, TX, Wharton County, TX

The radar

The Houston radar (KHGX), 94 km from the middle of the area, began a volume at 04:38 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

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

IssuedProductOfficeCountiesLasted
Sep 7, 12:01 AM CDTTornado WarningHGXBrazoria44 min
Sep 7, 12:17 AM CDTFlash Flood WarningHGXMatagorda3 hr
Sep 7, 12:34 AM CDTTornado WarningHGXMatagorda41 min
Sep 7, 12:45 AM CDTTornado WarningHGXBrazoria45 min
Sep 7, 1:39 AM CDTTornado WarningHGXBrazoria, Matagorda, Wharton51 min
Sep 7, 2:13 AM CDTFlash Flood WarningHGXFort Bend, Wharton3 hr
Sep 7, 2:47 AM CDTTornado WarningHGXBrazoria, Fort Bend43 min
Sep 7, 2:56 AM CDTFlash Flood WarningHGXBrazoria2 hr
Sep 7, 3:39 AM CDTTornado WarningHGXWharton36 min
Sep 7, 4:37 AM CDTFlash Flood WarningHGXColorado3 hr

The nearest sounding before it

Corpus Christi, TX (KCRP), launched 00:00Z, 4.6 hours before the alert went out and 244 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, Corpus Christi, TX at 00:00Z on 2002-09-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 408 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Corpus Christi, TX at 00:00Z on 2002-09-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -26 square meters per square second.1939Sfc1 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
408 J/kg
Mixed-layer CIN
-15 J/kg
Mixed-layer LCL
1317 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
-26 m²/s²
0-3 km storm-relative helicity
-11 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

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

000 
WWUS20 KWNS 070442
SEL3  
SPC WW 070435
TXZ000-071300-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 673
STORM PREDICTION CENTER NORMAN OK
1140 PM CDT FRI SEP 6 2002

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

   SOUTHEAST TEXAS                              
   COASTAL WATERS                     

EFFECTIVE THIS FRIDAY NIGHT AND SATURDAY MORNING FROM 1140 PM UNTIL
800 AM CDT.

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

THE TORNADO WATCH AREA IS ALONG AND 50 STATUTE MILES NORTH AND
SOUTH OF A LINE FROM 25 MILES NORTH NORTHWEST OF VICTORIA TEXAS TO
40 MILES NORTH NORTHEAST OF GALVESTON TEXAS.

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 672.  WATCH NUMBER 672 WILL NOT BE IN EFFECT AFTER 1135 PM
CDT.

DISCUSSION...DEEP CONVECTION WITH ABUNDANT LIGHTNING CONTINUES
ALONG THE UPPER TX COAST...WELL NORTH OF T.S. FAY/S CENTER. 
VERTICAL WIND PROFILE FROM HOUSTON YIELDS VERY IMPRESSIVE LOW LEVEL
SHEAR...WITH 0-3 KM HELICITIES IN EXCESS OF 500 M2/S2.  THIS WILL
MAINTAIN A FAVORABLE ENVIRONMENT FOR TORNADOES ALONG AND JUST
INLAND.  AS THE CONVECTION MOVES/DEVELOPS SLOWLY WWD OVERNIGHT
ASSOCIATED WITH THE SLOW WWD DRIFT FROM FAY...THE TORNADO THREAT
MAY SPREAD FARTHER INLAND ACROSS THE COASTAL PLAIN.


AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH EXTREME
TURBULENCE AND SURFACE WIND GUSTS TO 60 KNOTS.  A FEW CUMULONIMBI
WITH MAXIMUM TOPS TO 450.  MEAN STORM MOTION VECTOR 10020.


...EVANS

295,0970 303,0942 290,0942 282,0970

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 6, 7:15 PM CDTTornado WatchSPCAustin, Brazoria, Chambers, Colorado, Fort Bend, Galveston and 9 more5 hr
Sep 7, 6:15 AM CDTTornado WatchSPCAtascosa, Austin, Bexar, Brazoria, Colorado, DeWitt and 11 more6 hr
Sep 7, 10:40 AM CDTTornado WatchSPCAustin, Brazos, Burleson, Chambers, Colorado, Fayette and 16 more5 hr

Nearby

Tornado Watches in Texas, 2002Every tornado watch in 2002

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.