Alert archive / Texas / Flash Flood Warnings in 2009

Flash Flood Warning 82, NWS Fort Worth, TX

September 21, 2009Johnson County, Texas

NWS Fort Worth, TX issued this flash flood warning at Sep 21, 2009, 8:55 PM CDT for Johnson County, Texas. It was in force for 3 hr. 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, 2009, 8:55 PM CDT (01:55 UTC)
Expired
Sep 22, 2009, 12:00 AM CDT
In force
3 hr
Issued by
NWS Fort Worth, TX
Area
Storm-based polygon
Flood severity
None

County Johnson County, TX

The radar

The Dallas/Ft Worth radar (KFWS), 22 km from the middle of the area, began a volume at 01:58 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, 1.9 hours before the alert went out and 51 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 2009-09-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2664 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 2009-09-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 102 square meters per square second.193958Sfc1 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
2664 J/kg
Mixed-layer CIN
-12 J/kg
Mixed-layer LCL
1499 m above ground
0-6 km bulk shear
28 kt
0-1 km storm-relative helicity
102 m²/s²
0-3 km storm-relative helicity
190 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

What forecasters said that day

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

NWS Fort Worth, TX wrote its last area forecast discussion before this flash flood warning went out at Sep 21, 7:23 PM CDT, 1 hour 32 minutes earlier.

Area forecast discussion, Sep 21, 7:23 PM CDT, 1 hour 32 minutes before
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE FORT WORTH TX
723 PM CDT MON SEP 21 2009

.AVIATION...
/00Z TAFS/

AN AIRPORT WEATHER WARNING IS IN EFFECT FROM 730-1100PM...
PRIMARILY FOR LIGHTNING...THOUGH GUSTY WEST WINDS AND SMALL HAIL
MAY ALSO ACCOMPANY THE STORMS IN THE METROPLEX THIS EVENING. THE
BROKEN LINE OF STORMS WILL MAKE SLOW EASTWARD PROGRESS...LINGERING
AT METRO TAF SITES MUCH OF THE EVENING.

CONVECTIVE WIND SHIFT MAY BE TEMPORARY AS EASTERLY OUTFLOW WINDS
ALREADY OBSERVED OUT THE BACK OF THE LINE. COLD FRONT IS NEAR SPS
AT 7 PM...AND WILL ARRIVE AT METRO TAF SITES AROUND MIDNIGHT.

MVFR CIGS WILL PREVAIL THEREAFTER...SHOULD STAY ABOVE ABOVE 1KFT.
SHOULD LIFT ABOVE ALTERNATE CATEGORY EARLY TUESDAY AFTERNOON...VFR
BY TUESDAY EVENING.

THE ORIENTATION OF THE SQUALL LINE WILL MEAN A MUCH LATER ARRIVAL
AT WACO. (A SIMILAR DELAY IN FROPA AND LIFTING OF CIGS ABOVE 2KFT.)

25

&&

.PREV DISCUSSION... /ISSUED 259 PM CDT MON SEP 21 2009/
OVERALL...LITTLE HAS CHANGED IN FORECAST THINKING FOR OUR EVENT
TONIGHT. CONVECTION ACROSS EASTERN OKLAHOMA CONTINUES TO BUILD
SOUTHWESTWARD INTO CENTRAL...AND EVENTUALLY SOUTHERN OKLAHOMA.

FRONTAL BOUNDARY IS CURRENTLY ACROSS NORTHWEST OKLAHOMA...WITH A
PREFRONTAL TROUGH DRAPED OVER MUCH OF CENTRAL OKLAHOMA. HERE IN
NORTH TEXAS...BREEZY SOUTH WINDS CONTINUE THE FLOW OF MOISTURE...
WITH SURFACE DEWPOINTS IN THE LOW 70S. DEEP MOISTURE WILL YIELD
AMPLE INSTABILITY...WITH 2000 J/KG OF ML CAPE STILL ACROSS NORTH
TEXAS AT 06Z TONIGHT. BULK SHEAR VALUES FROM 25-30 KTS WILL BE
SUFFICIENT FOR A STRONGLY FORCED LINE OF CONVECTION ALONG THE
FRONT THIS EVENING/TONIGHT. LARGE HAIL AND WINDS TO 70 MPH WILL BE
THE PRIMARY HAZARDS.

MODEL DATA IS FAIRLY CONSISTENT WITH DEVELOPING A SECONDARY AREA
OF CONVECTION BEHIND THE FRONT...MAINLY ACROSS THE DFW METRO AND
POINTS TO THE NORTHEAST. IF THIS COMES TO FRUITION...ADDITIONAL
HEAVY RAINFALL CAN BE EXPECTED. WITH SEVERAL ROUNDS OF HEAVY
RAINFALL POSSIBLE...AND THE ALREADY SATURATED GROUNDS...WE WILL
CONTINUE THE FLASH FLOOD WATCH AS IS THROUGH 6 AM.

THE PRECIP FORECAST REMAINS MESSY FOR THE REMAINDER OF THIS
WEEK...AS THE UPPER LEVEL LOW MEANDERS ACROSS THE ROCKIES. SUBTLE
UPPER LEVEL WAVES RIDING ALONG THE SOUTHERN PORTION OF THE UPPER
LOW...ALONG WITH A LINGERING SURFACE BOUNDARY IN OUR AREA AND
AMPLE MOISTURE...WILL KEEP THUNDERSTORMS IN THE FORECAST THROUGH
FRIDAY EVENING. HOWEVER...THE BEST CHANCE /ASIDE FROM TONIGHT/
APPEARS TO BE ON THURSDAY.

GIVEN THE PRECIP CHANCES AND ASSOCIATED CLOUD COVER...HAVE OPTED
TO STAY RATHER CLOSE TO GUIDANCE ON TEMPERATURES THIS WEEK.
GENERALLY EXPECT HIGHS IN THE MID 70S TO LOWER 80S FOR THE REST OF
THE WORK WEEK...WITH READINGS CLIMBING INTO THE UPPER 80S THIS WEEKEND.

SCHULTZ

&&

.PRELIMINARY POINT TEMPS/POPS...
DALLAS-FT. WORTH, TX  68  74  61  79  64 /  90  50  10  10  20
WACO, TX              71  78  61  79  65 /  70  70  20  20  30
PARIS, TX             68  76  61  79  63 /  90  50  20  20  20
DENTON, TX            66  75  58  79  61 /  90  50  10  10  20
MCKINNEY, TX          67  76  58  80  61 /  90  50  10  10  20
DALLAS, TX            69  76  62  80  67 /  90  60  10  10  20
TERRELL, TX           69  78  62  79  66 /  90  70  20  20  20
CORSICANA, TX         70  77  62  79  65 /  70  70  20  20  30
TEMPLE, TX            71  76  61  78  64 /  50  70  20  20  30

&&

.FWD WATCHES/WARNINGS/ADVISORIES...
FLASH FLOOD WATCH UNTIL 6 AM CDT TUESDAY FOR TXZ093>095-103>107-
118>123-131>135-144>146.

&&

25/58
Hazardous weather outlook, Sep 21, 3:18 PM CDT, 5 hours 37 minutes before
HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE FORT WORTH TX
318 PM CDT MON SEP 21 2009

TXZ091>095-100>107-115>123-129>135-141>148-156>162-174-175-221145-
MONTAGUE-COOKE-GRAYSON-FANNIN-LAMAR-YOUNG-JACK-WISE-DENTON-COLLIN-
HUNT-DELTA-HOPKINS-STEPHENS-PALO PINTO-PARKER-TARRANT-DALLAS-
ROCKWALL-KAUFMAN-VAN ZANDT-RAINS-EASTLAND-ERATH-HOOD-SOMERVELL-
JOHNSON-ELLIS-HENDERSON-COMANCHE-MILLS-HAMILTON-BOSQUE-HILL-NAVARRO-
FREESTONE-ANDERSON-LAMPASAS-CORYELL-BELL-MCLENNAN-FALLS-LIMESTONE-
LEON-MILAM-ROBERTSON-
318 PM CDT MON SEP 21 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH TEXAS.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

THUNDERSTORMS ARE EXPECTED TO DEVELOP NEAR A BOWIE TO BRECKENRIDGE
LINE LATE THIS AFTERNOON...AND THEN BECOME MORE NUMEROUS WHILE
MOVING SOUTHEAST DURING THE EVENING AND OVERNIGHT HOURS AS A COLD
FRONT MOVES THROUGH THE OUTLOOK AREA. ANY STORMS THAT DEVELOP THIS
AFTERNOON THROUGH THE OVERNIGHT HOURS WILL BE CAPABLE OF PRODUCING
DAMAGING WINDS IN EXCESS OF 60 MPH AND LARGE HAIL.

IN ADDITION TO ANY SEVERE WEATHER...HEAVY RAINFALL WILL BE
POSSIBLE AS THE FRONT MOVES THROUGH LEADING TO FLASH FLOODING. A
FLASH FLOOD WATCH IS IN EFFECT FOR AREAS NORTH AND EAST OF A
GAINESVILLE TO MERIDIAN TO ATHENS LINE THROUGH TONIGHT.

.DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY.

SHOWERS AND THUNDERSTORMS WILL CONTINUE MAINLY ACROSS THE
SOUTHEAST HALF OF NORTH TEXAS INTO TUESDAY. HEAVY RAINFALL WILL BE
THE MAIN THREAT DURING THIS TIME.

THE CHANCE FOR THUNDERSTORMS WILL CONTINUE FOR ALL OF NORTH TEXAS
THURSDAY AND FRIDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION IS LIKELY LATE THIS AFTERNOON AND INTO THE
EVENING HOURS FOR AREAS GENERALLY ALONG AND NORTH OF INTERSTATE
20. SPOTTER ACTIVATION MAY BE NEEDED ACROSS ALL OF NORTH TEXAS
DURING THE OVERNIGHT HOURS.

CAVANAUGH

In the hours before

Local storm report, Sep 21, 8:20 PM CDT, 35 minutes before
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Local storm report, Sep 21, 8:22 PM CDT, 33 minutes before
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Special weather statement, Sep 21, 8:24 PM CDT, 31 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE FORT WORTH TX
824 PM CDT MON SEP 21 2009

TXZ103-104-220200-
DENTON TX-COLLIN TX-
824 PM CDT MON SEP 21 2009

...SIGNIFICANT WEATHER ADVISORY FOR...
  NORTHWESTERN COLLIN COUNTY
  NORTHEASTERN DENTON COUNTY

AT 824 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
STRONG THUNDERSTORM 13 MILES NORTHEAST OF DENTON...MOVING EAST AT 20
MPH.

CITIES IN THE PATH OF THIS STORM INCLUDE ANNA...AUBREY...CELINA...
CROSS ROADS...KRUGERVILLE...LITTLE ELM...MCKINNEY...PILOT POINT...
PROSPER AND RAY ROBERTS PARK ISLE DU BOIS.

PEA-SIZED HAIL AND WIND GUSTS TO 50 MPH CAN BE EXPECTED FROM THIS
STORM.

IF THIS STORM INTENSIFIES...A SEVERE WEATHER WARNING MAY BE NEEDED.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 1100 PM CDT
MONDAY EVENING FOR NORTHEASTERN TEXAS.

LAT...LON 3342 9683 3340 9683 3340 9679 3340 9654
      3341 9652 3341 9651 3321 9650 3315 9698
      3337 9708 3343 9697
TIME...MOT...LOC 0124Z 251DEG 17KT 3331 9694
Special weather statement, Sep 21, 8:29 PM CDT, 26 minutes before
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE FORT WORTH TX
829 PM CDT MON SEP 21 2009

TXZ142-220200-
MILLS TX-
829 PM CDT MON SEP 21 2009

...SIGNIFICANT WEATHER ADVISORY FOR...
  WESTERN MILLS COUNTY

AT 829 PM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
STRONG THUNDERSTORM 10 MILES SOUTHEAST OF BROWNWOOD...MOVING EAST AT
20 MPH.

CITIES IN THE PATH OF THIS STORM INCLUDE GOLDTHWAITE AND MULLIN.

FREQUENT CLOUD TO GROUND LIGHTNING...VERY HEAVY RAINFALL...PEA-SIZED
HAIL...AND WIND GUSTS TO 50 MPH CAN BE EXPECTED FROM THIS STORM.

IF THIS STORM INTENSIFIES...A SEVERE WEATHER WARNING MAY BE NEEDED.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 1100 PM CDT
MONDAY EVENING FOR NORTHEASTERN TEXAS.

LAT...LON 3150 9897 3161 9879 3170 9876 3172 9849
      3171 9848 3132 9861 3133 9866 3136 9866
      3135 9872 3140 9871 3141 9874 3137 9878
      3141 9880 3141 9884 3144 9888 3143 9893
      3146 9900
TIME...MOT...LOC 0129Z 288DEG 16KT 3162 9886
Local storm report, Sep 21, 8:35 PM CDT, 20 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FORT WORTH TX
835 PM CDT MON SEP 21 2009

..TIME..    ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE..    ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0745 PM     TSTM WND DMG     6 W BURLESON            32.53N  97.42W
09/21/2009                   JOHNSON            TX   AMATEUR RADIO

            MULTIPLE TREES DOWN AND STRUCTURE DAMAGE OF UNKNOWN
            SEVERITY
Local storm report, Sep 21, 8:41 PM CDT, 14 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE FORT WORTH TX
841 PM CDT MON SEP 21 2009

..TIME..    ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE..    ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0813 PM     TSTM WND DMG     CLEBURNE                32.35N  97.40W
09/21/2009                   JOHNSON            TX   AMATEUR RADIO

            POWER LINES DOWN IN CLEBURNE

The office that day

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

IssuedProductOfficeCountiesLasted
Sep 21, 7:03 PM CDTSpecial Weather StatementFWDErath27 min
Sep 21, 7:15 PM CDTSpecial Weather StatementFWDHood30 min
Sep 21, 7:18 PM CDTSevere Thunderstorm WarningFWDHood, Johnson, Parker, Tarrant57 min
Sep 21, 7:20 PM CDTSevere Thunderstorm WarningFWDComanche, Erath70 min
Sep 21, 7:38 PM CDTSpecial Weather StatementFWDPalo Pinto37 min
Sep 21, 8:05 PM CDTAreal Flood AdvisoryFWDJohnson, Tarrant3 hr
Sep 21, 8:09 PM CDTSpecial Weather StatementFWDHill36 min
Sep 21, 8:12 PM CDTSpecial Weather StatementFWDDallas33 min
Sep 21, 8:16 PM CDTSevere Thunderstorm WarningFWDDallas, Ellis, Johnson, Tarrant59 min
Sep 21, 8:23 PM CDTAreal Flood AdvisoryFWDErath3 hr
Sep 21, 8:24 PM CDTSpecial Weather StatementFWDCollin36 min
Sep 21, 8:28 PM CDTSevere Thunderstorm WarningFWDErath62 min
Sep 21, 8:29 PM CDTSpecial Weather StatementFWDMills31 min
Sep 21, 8:33 PM CDTAreal Flood AdvisoryFWDHood, Somervell2 hr
Sep 21, 8:54 PM CDTSevere Thunderstorm WarningFWDHamilton, Mills66 min
Sep 21, 8:56 PM CDTSpecial Weather StatementFWDDallas, Rockwall34 min
Sep 21, 8:59 PM CDTAreal Flood AdvisoryFWDDallas, Ellis2 hr
Sep 21, 8:59 PM CDTFlash Flood WarningFWDErath3 hr
Sep 21, 9:03 PM CDTSpecial Weather StatementFWDHill27 min
Sep 21, 9:13 PM CDTSevere Thunderstorm WarningFWDBosque, Hamilton62 min
Sep 21, 9:15 PM CDTSpecial Weather StatementFWDEllis, Hill, Kaufman, Rockwall30 min
Sep 21, 9:21 PM CDTSevere Thunderstorm WarningFWDEllis, Hill, Johnson, Navarro54 min
Sep 21, 9:34 PM CDTAreal Flood AdvisoryFWDBosque, Hill3 hr
Sep 21, 9:53 PM CDTSevere Thunderstorm WarningFWDBosque, Coryell, Hamilton, McLennan67 min
Sep 21, 9:59 PM CDTSpecial Weather StatementFWDHenderson, Kaufman, Rains, Van Zandt31 min
Sep 21, 10:02 PM CDTSpecial Weather StatementFWDLampasas28 min
Sep 21, 10:20 PM CDTSpecial Weather StatementFWDHill, McLennan25 min
Sep 21, 10:27 PM CDTSpecial Weather StatementFWDFannin, Lamar33 min
Sep 21, 10:32 PM CDTAreal Flood AdvisoryFWDMills3 hr
Sep 21, 11:12 PM CDTSpecial Weather StatementFWDLamar33 min
Sep 22, 12:10 AM CDTAreal Flood AdvisoryFWDCoryell, Lampasas2 hr
Sep 22, 1:08 AM CDTSpecial Weather StatementFWDBell37 min

Nearby

Flash Flood Warnings in Texas, 2009Every flash flood warning in 2009

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.