Alert archive / Texas / Tornado Watches in 2002

Tornado Watch 672

September 6, 200215 counties in Texas

The Storm Prediction Center issued this tornado watch at Sep 6, 2002, 7:15 PM CDT for 15 counties in Texas. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Sep 6, 2002, 7:15 PM CDT (00:15 UTC)
Expired
Sep 7, 2002, 12:00 AM CDT
In force
5 hr
Issued by
the Storm Prediction Center

Counties Austin County, TX, Brazoria County, TX, Chambers County, TX, Colorado County, TX, Fort Bend County, TX, Galveston County, TX, Hardin County, TX, Harris County, TX, Jackson County, TX, Jefferson County, TX, Liberty County, TX, Matagorda County, TX, Orange County, TX, Waller County, TX, Wharton County, TX

The radar

The Houston radar (KHGX), 44 km from the middle of the area, began a volume at 00:18 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

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

IssuedProductOfficeCountiesLasted
Sep 6, 7:53 PM CDTFlash Flood WarningHGXBrazoria3 hr
Sep 6, 8:51 PM CDTFlash Flood WarningHGXGalveston3 hr
Sep 6, 10:35 PM CDTFlash Flood WarningHGXBrazoria, Matagorda3 hr
Sep 6, 11:17 PM CDTTornado WarningHGXBrazoria43 min

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 00:00Z, 0.3 hours before the alert went out and 229 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 00:00Z on 2002-09-07Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 150 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, Lake Charles Mun, LA at 00:00Z on 2002-09-07The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -30 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
150 J/kg
Mixed-layer CIN
-53 J/kg
Mixed-layer LCL
815 m above ground
0-6 km bulk shear
14 kt
0-1 km storm-relative helicity
-30 m²/s²
0-3 km storm-relative helicity
-33 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 070018
SEL2  
SPC WW 070015
TXZ000-070500-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 672
STORM PREDICTION CENTER NORMAN OK
715 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 715 PM UNTIL
MIDNIGHT 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 40 MILES NORTHWEST OF PALACIOS TEXAS TO 20
MILES EAST OF PORT ARTHUR 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...  CONTINUE...WW 671...

DISCUSSION...WIND PROFILE AT HOUSTON IS INCREASING AS LOW LEVEL
SHEAR HAS SHOWN MORE TURNING IN THE PAST HOUR OR SO.  HELICITIES
ARE NOW OVER 200 M2/S2 WITH 20+ KT OF 0-1 KM SHEAR.  THEREFORE...
SOUTHEAST TX COASTAL COUNTIES WILL HAVE AN INCREASED THREAT OF A
FEW TORNADOES THROUGH THE EVENING AS H85 WINDS STRENGTHEN.


AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH EXTREME
TURBULENCE AND SURFACE WIND GUSTS TO 60 KNOTS.  A FEW CUMULONIMBI
WITH MAXIMUM TOPS TO 300.  MEAN STORM MOTION VECTOR 10030.


...EVANS

295,0964 304,0934 291,0934 282,0964

NNNN

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 6, 11:35 PM CDTTornado WatchSPCAustin, Brazoria, Chambers, Colorado, Fayette, Fort Bend and 10 more8 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.