Alert archive / Oklahoma / Tornado Watches in 2007

Tornado Watch 415

June 18, 200716 counties in Oklahoma; 5 counties in Texas

The Storm Prediction Center issued this tornado watch at Jun 18, 2007, 4:49 AM CDT for 16 counties in Oklahoma; 5 counties in Texas. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued: Jun 18, 2007, 4:49 AM CDT (09:49 UTC)
Expired: Jun 18, 2007, 12:00 PM CDT
In force: 7 hr
Issued by: the Storm Prediction Center
Largest hail expected: 1 in
Strongest gust expected: 60 kt

All 21 counties

Atoka County, OK, Bryan County, OK, Carter County, OK, Choctaw County, OK, Coal County, OK, Garvin County, OK, Hughes County, OK, Johnston County, OK, Latimer County, OK, Love County, OK, Marshall County, OK, Murray County, OK, Pittsburg County, OK, Pontotoc County, OK, Pushmataha County, OK, Seminole County, OK, Cooke County, TX, Delta County, TX, Fannin County, TX, Grayson County, TX, Lamar County, TX

The radar

The Norman radar (KTLX), 123 km from the middle of the area, began a volume at 09:51 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.

What SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes: 30%
One or more EF2 to EF5 tornadoes: 10%
Ten or more severe wind reports: 30%
One or more gusts of 65 knots or more: 10%
Ten or more severe hail reports: 20%
One or more hailstones of 2 inches or more: 5%
Six or more combined severe hail and wind reports: 60%

Warnings issued inside it

7 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

Issued	Product	Office	Counties	Lasted
Jun 18, 4:53 AM CDT	Severe Thunderstorm Warning	FWD	Cooke, Grayson	67 min
Jun 18, 5:20 AM CDT	Flash Flood Warning	FWD	Cooke, Grayson	4 hr
Jun 18, 5:34 AM CDT	Severe Thunderstorm Warning	OUN	Bryan	41 min
Jun 18, 6:23 AM CDT	Severe Thunderstorm Warning	FWD	Cooke	67 min
Jun 18, 7:24 AM CDT	Severe Thunderstorm Warning	FWD	Collin, Denton, Grayson	66 min
Jun 18, 9:00 AM CDT	Flash Flood Warning	FWD	Cooke, Grayson	3 hr
Jun 18, 9:24 AM CDT	Flash Flood Warning	FWD	Fannin, Hunt	3 hr

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

Norman, OK (KOUN), launched 00:00Z, 9.8 hours before the alert went out and 120 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: 204 J/kg
Mixed-layer CIN: -19 J/kg
Mixed-layer LCL: 748 m above ground
0-6 km bulk shear: 11 kt
0-1 km storm-relative helicity: 55 m²/s²
0-3 km storm-relative helicity: 85 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.0

Open this sounding in Storm Lab

The text

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

000
WWUS20 KWNS 180952
SEL5  
SPC WW 180952
OKZ000-TXZ000-181700-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 415
NWS STORM PREDICTION CENTER NORMAN OK
450 AM CDT MON JUN 18 2007

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF 

       SOUTH CENTRAL AND SOUTHEAST OKLAHOMA
       NORTH TEXAS

EFFECTIVE THIS MONDAY MORNING FROM 450 AM UNTIL NOON CDT.

TORNADOES...HAIL TO 1 INCH IN DIAMETER...THUNDERSTORM WIND GUSTS
TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 60 STATUTE
MILES EAST AND WEST OF A LINE FROM 30 MILES WEST NORTHWEST OF
MCALESTER OKLAHOMA TO 25 MILES SOUTH SOUTHEAST OF SHERMAN TEXAS. 
FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU5).

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.

DISCUSSION...SMALL MCS ASSOCIATED WITH EJECTING UPR VORT EXPECTED TO
CONTINUE SLOWLY ENE THIS MORNING.  AS DEEP SHEAR INCREASES...
POTENTIAL MAY INCREASE FOR EMBEDDED SEMI-DISCRETE STRUCTURES. 
SLIGHTLY BACKED AND VERY MOIST LLJ ASSOCIATED WITH SYSTEM WILL
CONTINUE TO SUPPORT OCCASIONAL AREAS OF ENHANCED LOW LEVEL
ROTATION...AND A THREAT FOR BRIEF TORNADOES/STRONG WET MICROBURSTS.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 1 INCH. EXTREME TURBULENCE AND SURFACE WIND
GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO 500.
MEAN STORM MOTION VECTOR 24020.


...CORFIDI

SPC that day

Everything else SPC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jun 18, 1:58 AM CDT	Mesoscale Discussion	SPC	Atoka, Bryan, Choctaw, Coal, Haskell, Hughes and 11 more	92 min
Jun 18, 6:39 AM CDT	Mesoscale Discussion	SPC	Bryan	96 min

Nearby

Tornado Watches in Oklahoma, 2007 Tornado Watches in Texas, 2007 Every tornado watch in 2007

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.