Alert archive / Texas / Severe Thunderstorm Warnings in 2009

Severe Thunderstorm Warning 170, NWS Fort Worth, TX

May 6, 2009Grayson County, Texas

NWS Fort Worth, TX issued this severe thunderstorm warning at May 6, 2009, 4:48 AM CDT for Grayson County, Texas. It was in force for 57 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: May 6, 2009, 4:48 AM CDT (09:48 UTC)
Expired: May 6, 2009, 5:45 AM CDT
In force: 57 min
Issued by: NWS Fort Worth, TX
Area: Storm-based polygon

County Grayson County, TX

The radar

The Dallas/Ft Worth radar (KFWS), 131 km from the middle of the area, began a volume at 09:49 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.

Issued	Product	Office	Lasted
May 5, 11:26 PM CDT	Severe Thunderstorm Watch	SPC	6 hr

The nearest sounding before it

Fort Worth, TX (KFWD), launched 00:00Z, 9.8 hours before the alert went out and 105 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 2348 J/kg
Mixed-layer CIN: -24 J/kg
Mixed-layer LCL: 779 m above ground
0-6 km bulk shear: 56 kt
0-1 km storm-relative helicity: 217 m²/s²
0-3 km storm-relative helicity: 367 m²/s²
Significant tornado parameter: 5.0
Supercell composite: 16.1

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 May 6, 4:17 AM CDT, 31 minutes earlier.

Area forecast discussion, May 6, 4:17 AM CDT, 31 minutes before

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Hazardous weather outlook, May 6, 4:36 AM CDT, 12 minutes before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE FORT WORTH TX
436 AM CDT WED MAY 6 2009

TXZ091>095-100>107-115>123-129>135-141>148-156>162-174-175-071100-
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-
436 AM CDT WED MAY 6 2009

THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTH TEXAS.

.DAY ONE...TODAY AND TONIGHT.
THUNDERSTORMS ARE POSSIBLE NORTHWEST OF A GRAHAM TO HEARNE LINE
TODAY. LARGE HAIL...HEAVY RAINFALL...AND DAMAGING WINDS ARE
POSSIBLE. THE SEVERE WEATHER AND FLASH FLOODING POTENTIAL WILL BE
GREATEST NORTHWEST OF A BOWIE TO KAUFMAN LINE THROUGH EARLY
AFTERNOON.

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY.
THERE IS A CHANCE FOR THUNDERSTORMS NORTH OF A BRECKENRIDGE TO
PALESTINE LINE FRIDAY NIGHT THROUGH SATURDAY AND ACROSS ALL OF
NORTH TEXAS SATURDAY NIGHT. STORMS WILL BE POSSIBLE NORTH OF AN
EASTLAND TO PALESTINE LINE SUNDAY AND SUNDAY NIGHT.

.SPOTTER INFORMATION STATEMENT...
SPOTTER ACTIVATION IS LIKELY NORTHWEST OF A BOWIE TO KAUFMAN LINE
THROUGH EARLY AFTERNOON.

13

In the hours before

Local storm report, May 5, 11:09 PM CDT, 5 hours 39 minutes before

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Local storm report, May 5, 11:24 PM CDT, 5 hours 24 minutes before

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Local storm report, May 5, 11:31 PM CDT, 5 hours 17 minutes before

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Special weather statement, May 6, 4:33 AM CDT, 15 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE FORT WORTH TX
433 AM CDT WED MAY 6 2009

TXZ092-093-061000-
GRAYSON TX-COOKE TX-
433 AM CDT WED MAY 6 2009

...SIGNIFICANT WEATHER ADVISORY FOR...
  EASTERN COOKE COUNTY
  NORTHERN GRAYSON COUNTY

AT 432 AM CDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED A
STRONG THUNDERSTORM 23 MILES NORTH OF WHITESBORO...MOVING SOUTHEAST
AT 35 MPH.

THESE THUNDERSTORMS ARE CURRENTLY CAPABLE OF PRODUCING HAIL GREATER
THAN 2 INCHES IN DIAMETER AND WINDS IN EXCESS OF 60 MPH.

IF THIS STORM CONTINUES ON ITS PRESENT COURSE...A SEVERE WEATHER
WARNING MAY BE NEEDED.

A SEVERE THUNDERSTORM WATCH REMAINS IN EFFECT UNTIL 700 AM CDT
WEDNESDAY MORNING FOR NORTHEASTERN TEXAS.

LAT...LON 3386 9685 3384 9671 3392 9667 3391 9659
      3384 9659 3378 9648 3379 9642 3374 9636
      3361 9637 3348 9710 3374 9718 3373 9710
      3380 9710 3382 9706 3386 9712 3383 9721
      3390 9723 3385 9702 3394 9700 3397 9692
TIME...MOT...LOC 0932Z 327DEG 29KT 3399 9696

85/NH

The office that day

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

Issued	Product	Office	Counties	Lasted
May 5, 7:06 PM CDT	Severe Thunderstorm Warning	FWD	Palo Pinto, Stephens	54 min
May 5, 7:58 PM CDT	Severe Thunderstorm Warning	FWD	Eastland, Erath, Palo Pinto, Stephens	62 min
May 5, 9:03 PM CDT	Special Weather Statement	FWD	Erath	27 min
May 5, 10:20 PM CDT	Special Weather Statement	FWD	Wise	25 min
May 5, 10:34 PM CDT	Severe Thunderstorm Warning	FWD	Jack, Parker, Tarrant, Wise	56 min
May 5, 11:20 PM CDT	Severe Thunderstorm Warning	FWD	Tarrant	22 min
May 6, 4:33 AM CDT	Special Weather Statement	FWD	Grayson	27 min
May 6, 4:55 AM CDT	Special Weather Statement	FWD	Fannin	35 min
May 6, 5:04 AM CDT	Severe Thunderstorm Warning	FWD	Cooke	43 min
May 6, 5:24 AM CDT	Severe Thunderstorm Warning	FWD	Fannin	66 min
May 6, 5:33 AM CDT	Severe Thunderstorm Warning	FWD	Collin, Grayson	57 min
May 6, 5:43 AM CDT	Severe Thunderstorm Warning	FWD	Lamar	62 min
May 6, 5:52 AM CDT	Severe Thunderstorm Warning	FWD	Delta, Hopkins, Hunt	53 min
May 6, 6:15 AM CDT	Severe Thunderstorm Warning	FWD	Collin, Dallas, Rockwall	60 min
May 6, 6:42 AM CDT	Severe Thunderstorm Warning	FWD	Hopkins, Hunt, Kaufman, Rains, Van Zandt	63 min
May 6, 6:52 AM CDT	Flash Flood Warning	FWD	Fannin, Grayson	3 hr
May 6, 7:50 AM CDT	Flash Flood Warning	FWD	Collin, Grayson, Hunt	3 hr
May 6, 8:26 AM CDT	Areal Flood Advisory	FWD	Delta, Hopkins	2 hr
May 6, 9:16 AM CDT	Special Weather Statement	FWD	Fannin	29 min
May 6, 9:45 AM CDT	Areal Flood Advisory	FWD	Fannin	90 min
May 6, 9:50 AM CDT	River Flood Warning	FWD	Hunt	35 hr
May 6, 9:50 AM CDT	River Flood Warning	FWD	Hunt, Rockwall	11 hr
May 6, 10:11 AM CDT	River Flood Warning	FWD	Delta, Hopkins	4 days
May 6, 10:16 AM CDT	River Flood Warning	FWD	Collin	23 hr
May 6, 11:40 AM CDT	River Flood Warning	FWD	Collin	21 hr

Nearby

Severe Thunderstorm Warnings in Texas, 2009 Every 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.