Alert archive / Texas / Severe Thunderstorm Warnings in 2011

Severe Thunderstorm Warning 521, NWS Fort Worth, TX

September 29, 2011Denton County, Texas

NWS Fort Worth, TX issued this severe thunderstorm warning at Sep 29, 2011, 8:34 PM CDT for Denton County, Texas. It was in force for 41 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
Sep 29, 2011, 8:34 PM CDT (01:34 UTC)
Expired
Sep 29, 2011, 9:15 PM CDT
In force
41 min
Issued by
NWS Fort Worth, TX
Area
Storm-based polygon

County Denton County, TX

The radar

The Dallas/Ft Worth radar (KFWS), 59 km from the middle of the area, began a volume at 01:37 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

Fort Worth, TX (KFWD), launched 00:00Z, 1.6 hours before the alert went out and 31 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, Fort Worth, TX at 00:00Z on 2011-09-30Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1124 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, Fort Worth, TX at 00:00Z on 2011-09-30The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 19 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
1124 J/kg
Mixed-layer CIN
-29 J/kg
Mixed-layer LCL
2883 m above ground
0-6 km bulk shear
21 kt
0-1 km storm-relative helicity
19 m²/s²
0-3 km storm-relative helicity
112 m²/s²
Significant tornado parameter
0.0
Supercell composite
1.5

Open this sounding in Storm Lab

The text

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

868 
WUUS54 KFWD 300134
SVRFWD
TXC121-300215-
/O.NEW.KFWD.SV.W.0521.110930T0134Z-110930T0215Z/

BULLETIN - EAS ACTIVATION REQUESTED
SEVERE THUNDERSTORM WARNING
NATIONAL WEATHER SERVICE FORT WORTH TX
834 PM CDT THU SEP 29 2011

THE NATIONAL WEATHER SERVICE IN FORT WORTH HAS ISSUED A

* SEVERE THUNDERSTORM WARNING FOR...
  SOUTHERN DENTON COUNTY IN NORTH CENTRAL TEXAS...

* UNTIL 915 PM CDT

* AT 835 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
  LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING QUARTER SIZE
  HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH.  THESE STORMS WERE
  LOCATED ALONG A LINE EXTENDING FROM 4 MILES NORTHEAST OF LITTLE ELM
  TO 4 MILES NORTHEAST OF ARGYLE TO JUSTIN...AND MOVING SOUTH AT 20
  MPH.

* SEVERE THUNDERSTORMS WILL BE NEAR...
  LITTLE ELM...CORINTH AND ARGYLE AROUND 840 PM...
  LAKE DALLAS...HACKBERRY AND BARTONVILLE AROUND 845 PM...
  LAKE LEWISVILLE...HIGHLAND VILLAGE...HICKORY CREEK AND COPPER
  CANYON AROUND 850 PM...

THIS WILL IMPACT THE FOLLOWING INTERSTATES...
I-35 BETWEEN MILE MARKERS 468 AND 470...
I-35W BETWEEN MILE MARKERS 71 AND 85...
I-35E BETWEEN MILE MARKERS 80 AND 96.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

FOR YOUR PROTECTION MOVE TO A STURDY SHELTER UNTIL THE STORM HAS
PASSED.

IF YOU ARE CAUGHT OUTSIDE...SEEK SHELTER IN A STRONG BUILDING AND
STAY INSIDE...AWAY FROM WINDOWS UNTIL THE STORM HAS PASSED.

&&

LAT...LON 3326 9685 3299 9685 3298 9718 3299 9740
      3300 9741 3300 9739 3309 9740 3313 9730
      3321 9717
TIME...MOT...LOC 0135Z 002DEG 16KT 3320 9689 3315 9714
          3306 9729

$$


85/NH
2 follow-up statements
053 
WWUS54 KFWD 300200
SVSFWD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE FORT WORTH TX
900 PM CDT THU SEP 29 2011

TXC121-300215-
/O.CON.KFWD.SV.W.0521.000000T0000Z-110930T0215Z/
DENTON TX-
900 PM CDT THU SEP 29 2011

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 915 PM CDT
FOR SOUTHERN DENTON COUNTY...

AT 900 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
LINE OF SEVERE THUNDERSTORMS CAPABLE OF PRODUCING QUARTER SIZE
HAIL...AND DAMAGING WINDS IN EXCESS OF 60 MPH.  THESE STORMS WERE
LOCATED ALONG A LINE EXTENDING FROM LEWISVILLE TO DOUBLE OAK TO 4
MILES SOUTHWEST OF ROANOKE...MOVING SOUTH AT 20 MPH.

SEVERE THUNDERSTORMS WILL BE NEAR...
  HEBRON...TROPHY CLUB...LEWISVILLE AND FLOWER MOUND AROUND 905 PM
  CDT...

THIS WILL IMPACT THE FOLLOWING INTERSTATES...
I-35W BETWEEN MILE MARKERS 71 AND 81...
I-35E BETWEEN MILE MARKERS 81 AND 91.

LAT...LON 3314 9685 3313 9685 3299 9685 3298 9718
      3299 9718 3299 9726 3300 9738 3313 9714
      3315 9685
TIME...MOT...LOC 0200Z 002DEG 16KT 3306 9698 3304 9714
          3295 9729

$$
116 
WWUS54 KFWD 300214
SVSFWD

SEVERE WEATHER STATEMENT
NATIONAL WEATHER SERVICE FORT WORTH TX
914 PM CDT THU SEP 29 2011

TXC121-300224-
/O.EXP.KFWD.SV.W.0521.000000T0000Z-110930T0215Z/
DENTON TX-
914 PM CDT THU SEP 29 2011

...THE SEVERE THUNDERSTORM WARNING FOR SOUTHERN DENTON COUNTY EXPIRES
AT 915 PM CDT...

AT 914 PM CDT THE SEVERE THUNDERSTORM THAT PROMPTED THE WARNING 
WEAKENED AND WAS NO LONGER SEVERE.

RADAR INDICATED THAT HEAVY RAIN...SMALL HAIL...AND GUSTY WINDS WERE
STILL POSSIBLE FROM THE THUNDERSTORM.

LAT...LON 3314 9685 3313 9685 3299 9685 3298 9718
      3299 9718 3299 9726 3300 9738 3313 9714
      3315 9685
TIME...MOT...LOC 0214Z 002DEG 16KT 3300 9698 3298 9714
          3289 9729

$$

The office that day

Everything else NWS Fort Worth, TX issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Sep 29, 8:22 PM CDTSpecial Weather StatementFWDCollin, Denton38 min
Sep 29, 8:52 PM CDTSevere Thunderstorm WarningFWDTarrant53 min
Sep 29, 9:12 PM CDTSevere Thunderstorm WarningFWDDallas63 min
Sep 29, 9:22 PM CDTSpecial Weather StatementFWDParker38 min
Sep 29, 9:39 PM CDTSevere Thunderstorm WarningFWDDallas, Ellis, Johnson, Tarrant66 min
Sep 29, 10:14 PM CDTSpecial Weather StatementFWDComanche, Mills31 min
Sep 29, 10:31 PM CDTSpecial Weather StatementFWDEllis, Hill, Navarro59 min
Sep 29, 10:34 PM CDTSpecial Weather StatementFWDHood, Somervell26 min
Sep 29, 10:41 PM CDTSpecial Weather StatementFWDMills34 min
Sep 29, 11:27 PM CDTSpecial Weather StatementFWDCoryell, Hamilton, McLennan63 min
Sep 29, 11:44 PM CDTSevere Thunderstorm WarningFWDHamilton37 min
Sep 30, 12:25 AM CDTSpecial Weather StatementFWDCoryell35 min
Sep 30, 12:42 AM CDTSpecial Weather StatementFWDBell63 min
Sep 30, 2:56 AM CDTRed Flag WarningFWDAnderson, Bell, Coryell, Falls, Freestone, Henderson and 7 more16 hr

Nearby

Severe Thunderstorm Warnings in Texas, 2011Every severe thunderstorm warning in 2011

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.