Alert archive / Texas / Severe Thunderstorm Warnings in 2001

Severe Thunderstorm Warning 134, NWS Houston/Galveston, TX

September 21, 2001Brazoria County, Galveston County, Harris County, Texas

NWS Houston/Galveston, TX issued this severe thunderstorm warning at Sep 21, 2001, 6:15 PM CDT for Brazoria County, Galveston County, Harris County, Texas. It was in force for 45 min. No storm report in the archive falls inside the area while it was in force.

The area

The counties it named.

The facts

Issued
Sep 21, 2001, 6:15 PM CDT (23:15 UTC)
Expired
Sep 21, 2001, 7:00 PM CDT
In force
45 min
Issued by
NWS Houston/Galveston, TX
Area
Whole counties; the outline is the Mesonet’s reconstruction

Counties Brazoria County, TX, Galveston County, TX, Harris County, TX

The radar

The Houston radar (KHGX), 13 km from the middle of the area, began a volume at 23:14 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.

The nearest sounding before it

Lake Charles Mun, LA (KLCH), launched 12:00Z, 11.3 hours before the alert went out and 208 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 2001-09-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2390 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 2001-09-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -5 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
2390 J/kg
Mixed-layer CIN
-25 J/kg
Mixed-layer LCL
749 m above ground
0-6 km bulk shear
11 kt
0-1 km storm-relative helicity
-5 m²/s²
0-3 km storm-relative helicity
22 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

The text of this product is not in the archive. The NWS text archive before 2002 is incomplete.

What forecasters said that day

The local office's own words before this severe thunderstorm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Houston/Galveston, TX wrote its last area forecast discussion before this severe thunderstorm warning went out at Sep 21, 2:57 PM CDT, 3 hours 18 minutes earlier.

Area forecast discussion, Sep 21, 2:57 PM CDT, 3 hours 18 minutes before
SOUTHEAST TEXAS FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
257 PM CDT FRI SEP 21 2001

SO FAR...ISOLATED SHOWERS AND THUNDERSTORMS HAVE DEVELOPED ACROSS
SOUTHEAST TEXAS. EXPECT MORE ACTIVITY TO FORM DURING THE REMAINDER
OF THE AFTERNOON AND EVENING HOURS. SLOW STORM MOTION FAVORS LOCALLY
HEAVY RAINFALL (2 TO 4 INCHES IN THE STRONGER STORMS) AND DYNAMICS
ARE STILL STRONG ENOUGH FOR SOME SEVERE THUNDERSTORMS (DAMAGING
WINDS STILL GREATEST RISK). AFTER THIS EVENING...OUR BIG PROBLEM IS
TRYING TO TIME IMPULSES AND ASSOCIATED RAINS. SHORTWAVE ENERGY
LINGERS ACROSS EAST TEXAS THIS WEEKEND...AND THIS SHOULD ALLOW MORE
SHOWERS AND THUNDERSTORMS TO DEVELOP THROUGH THE PERIOD. WILL
GENERALLY CALL FOR 40% POPS THROUGH SUNDAY NIGHT. WILL NEED TO
EVALUATE SITUATION THROUGH THE WEEKEND FOR POSSIBLE CONTINUATION OF
SEVERE THUNDERSTORM RISK AND LOCALLY HEAVY RAINFALL THREAT.

STRONG COLD FRONT WILL SWEEP THROUGH SOUTHEAST TEXAS LATE SUNDAY
NIGHT AND EARLY MONDAY MORNING. MUCH DRIER AND COOLER FALL AIR WILL
SWEEP INTO SOUTHEAST TEXAS BEHIND THE FRONT ON MONDAY AS A GREAT
LAKES TROF DEEPENS SHARPLY AND EVENTUALLY BECOMES A CUTOFF LOW.
EXPECT SUNNY MILD DAYS AND CLEAR COOL NIGHTS FOR TUESDAY THROUGH
FRIDAY WITH LOWS GENERALLY IN THE 50S TO AROUND 60 AND HIGHS AROUND
80. FMR DATA IS FLIRTING WITH RECORD LOWS ON TUESDAY AND WEDNESDAY
MORNING. FOR NOW...WILL NOT GO THAT COLD (RECORD LOW AT IAH FOR
TUESDAY THE 25TH IS 50 AND FOR WEDNESDAY THE 26TH IS 49). THE COOL
AIR IS COMING

42/47/DO/30/38

.HGX...NONE.

PRELIMS...
CLL EE 071/089 071/085 063 444
IAH EE 071/089 071/085 065 444
GLS EE 079/088 078/086 070 344

In the hours before

Special weather statement, Sep 21, 3:30 PM CDT, 2 hours 45 minutes before
GMZ330-335-350-355-370-375-TXZ163-164-176>179-195>200-210>214-226-227-
235>238-220400-

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE HOUSTON/GALVESTON TX
330 PM CDT FRI SEP 21 2001

...SEVERE THUNDERSTORMS AND LOCALLY HEAVY RAINFALL POSSIBLE ACROSS
SOUTHEAST TEXAS THIS AFTERNOON AND THIS EVENING...

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHEAST
TEXAS FOR THE REMAINDER OF THIS AFTERNOON AND ON INTO THE EVENING
HOURS. SHOWERS AND THUNDERSTORMS ARE EXPECTED TO CONTINUE TO DEVELOP
AS THE ATMOSPHERE DESTABILIZES AND DEVELOPING STORMS INTERACT WITH
OUTFLOW BOUNDARIES.

DAMAGING DOWNBURST WINDS AND LARGE HAIL ARE THE GREATEST RISK WITH
THE SEVERE THUNDERSTORMS. IN ADDITION...ISOLATED TORNADOES CANNOT BE
RULED OUT.

IN ADDITION TO THE SEVERE THUNDERSTORM THREAT...THERE IS ALSO THE
THREAT FOR LOCALLY HEAVY RAINFALL. THROUGH THIS EVENING...RAINFALL
AMOUNTS WILL AVERAGE 1/2 TO 1 INCH WITH ISOLATED 2 TO 4 INCH TOTALS
LIKELY IN THE STRONGER AND SLOWER MOVING STORMS. RESIDENTS ACROSS
ALL OF SOUTHEAST TEXAS ARE URGED TO MONITOR THE WEATHER THROUGH THE
REMAINING AFTERNOON HOURS AND ON INTO THE EVENING HOURS IN CASE
WATCHES OR WARNINGS ARE ISSUED.

STAY TUNED TO NOAA WEATHER RADIO OR OTHER WEATHER NEWS SOURCES FOR
FURTHER UPDATES ON THIS SEVERE WEATHER THREAT.

The office that day

Everything else NWS Houston/Galveston, TX issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 20, 7:20 PM CDTTornado WarningHGXHarris40 min
Sep 21, 2:26 PM CDTSevere Thunderstorm WarningHGXChambers, Harris, Liberty34 min
Sep 21, 3:02 PM CDTSevere Thunderstorm WarningHGXLiberty28 min
Sep 21, 3:51 PM CDTSevere Thunderstorm WarningHGXHouston24 min
Sep 21, 4:26 PM CDTSevere Thunderstorm WarningHGXAustin49 min
Sep 21, 4:29 PM CDTSevere Thunderstorm WarningHGXMontgomery46 min
Sep 21, 4:45 PM CDTSevere Thunderstorm WarningHGXHarris30 min
Sep 21, 5:46 PM CDTSevere Thunderstorm WarningHGXGalveston, Harris29 min
Sep 21, 5:50 PM CDTSevere Thunderstorm WarningHGXBrazoria, Fort Bend25 min
Sep 21, 6:19 PM CDTSevere Thunderstorm WarningHGXChambers, Liberty41 min

Nearby

Severe Thunderstorm Warnings in Texas, 2001Every severe thunderstorm warning in 2001

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.