Alert archive / Texas / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 422, NWS Fort Worth, TX

August 20, 2009Lamar County, Texas

NWS Fort Worth, TX issued this severe thunderstorm warning at Aug 20, 2009, 9:34 PM CDT for Lamar 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 counties it named.

The facts

Issued
Aug 20, 2009, 9:34 PM CDT (02:34 UTC)
Expired
Aug 20, 2009, 10:15 PM CDT
In force
41 min
Issued by
NWS Fort Worth, TX
Area
Storm-based polygon

County Lamar County, TX

The radar

The Dallas/Ft Worth radar (KFWS), 202 km from the middle of the area, began a volume at 02:34 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 watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
Aug 20, 3:08 PM CDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Fort Worth, TX (KFWD), launched 00:00Z, 2.6 hours before the alert went out and 185 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 2009-08-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 2085 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 2009-08-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 44 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
2085 J/kg
Mixed-layer CIN
-48 J/kg
Mixed-layer LCL
2065 m above ground
0-6 km bulk shear
25 kt
0-1 km storm-relative helicity
44 m²/s²
0-3 km storm-relative helicity
120 m²/s²
Significant tornado parameter
0.0
Supercell composite
3.6

Open this sounding in Storm Lab

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 Fort Worth, TX wrote its last area forecast discussion before this severe thunderstorm warning went out at Aug 20, 8:30 PM CDT, 1 hour 4 minutes earlier.

Area forecast discussion, Aug 20, 8:30 PM CDT, 1 hour 4 minutes before
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Hazardous weather outlook, Aug 20, 8:38 PM CDT, 56 minutes before
HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE FORT WORTH TX
838 PM CDT THU AUG 20 2009

TXZ091>095-100>107-115>123-129>135-141>148-156>162-174-175-211200-
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-
838 PM CDT THU AUG 20 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH TEXAS.

.DAY ONE...TONIGHT.
THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS EAST OF A SHERMAN...
DALLAS...HILLSBORO...FAIRFIELD AND PALESTINE LINE OVERNIGHT. DAMAGING
WINDS...LARGE HAIL...BRIEF HEAVY RAINFALL...AND POSSIBLY A BRIEF TORNADO
WILL BE THE MAIN THREATS...AS SCATTERED STORMS MOVE THROUGH THE SLIGHT
RISK AREA.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.
THUNDERSTORMS REMAIN POSSIBLE FRIDAY SOUTHEAST OF A TEMPLE...CORSICANA...
SULPHUR SPRINGS LINE. CLOUD TO GROUND LIGHTNING AND BRIEF HEAVY RAIN
MAY ACCOMPANY THE STORMS.

.SPOTTER INFORMATION STATEMENT...
LIMITED SPOTTER ACTIVATION MAY BE REQUESTED ACROSS EASTERN NORTH TEXAS.

05/

The office that day

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

IssuedProductOfficeCountiesLasted
Aug 20, 10:29 PM CDTSpecial Weather StatementFWDLamar31 min
Aug 20, 10:37 PM CDTAreal Flood AdvisoryFWDLamar113 min
Aug 20, 10:49 PM CDTSevere Thunderstorm WarningFWDLamar56 min
Aug 20, 10:51 PM CDTFlash Flood WarningFWDLamar114 min
Aug 20, 11:35 PM CDTAreal Flood AdvisoryFWDFannin115 min
Aug 20, 11:48 PM CDTSpecial Weather StatementFWDDelta, Fannin, Lamar27 min
Aug 21, 12:47 AM CDTFlash Flood WarningFWDFannin, Lamar4 hr
Aug 21, 12:57 AM CDTSevere Thunderstorm WarningFWDFannin36 min
Aug 21, 2:36 AM CDTSpecial Weather StatementFWDDallas24 min
Aug 21, 2:55 AM CDTSevere Thunderstorm WarningFWDHopkins, Hunt, Rains36 min
Aug 21, 3:46 AM CDTSpecial Weather StatementFWDVan Zandt29 min
Aug 21, 5:07 AM CDTSpecial Weather StatementFWDHenderson23 min
Aug 21, 5:46 AM CDTSpecial Weather StatementFWDNavarro29 min
Aug 21, 5:59 AM CDTSevere Thunderstorm WarningFWDHenderson, Navarro42 min
Aug 21, 6:16 AM CDTSpecial Weather StatementFWDEllis29 min
Aug 21, 6:41 AM CDTAreal Flood AdvisoryFWDDallas, Tarrant109 min
Aug 21, 6:42 AM CDTSpecial Weather StatementFWDEllis33 min
Aug 21, 6:44 AM CDTSpecial Weather StatementFWDTarrant31 min
Aug 21, 6:59 AM CDTSpecial Weather StatementFWDNavarro31 min
Aug 21, 7:11 AM CDTSpecial Weather StatementFWDDallas34 min
Aug 21, 7:29 AM CDTSpecial Weather StatementFWDNavarro31 min
Aug 21, 7:37 AM CDTRiver Flood WarningFWDDallas3 hr
Aug 21, 8:32 AM CDTSpecial Weather StatementFWDPalo Pinto28 min
Aug 21, 8:45 AM CDTSevere Thunderstorm WarningFWDPalo Pinto45 min
Aug 21, 8:54 AM CDTSpecial Weather StatementFWDParker36 min
Aug 21, 8:58 AM CDTSevere Thunderstorm WarningFWDHood, Johnson, Parker47 min
Aug 21, 9:26 AM CDTSevere Thunderstorm WarningFWDErath, Palo Pinto64 min
Aug 21, 10:49 AM CDTSpecial Weather StatementFWDEastland26 min

Nearby

Severe Thunderstorm Warnings in Texas, 2009Every severe thunderstorm 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.