Alert archive / Oklahoma / Tornado Watches in 2009

Tornado Watch 609

July 20, 200925 counties in Oklahoma

The Storm Prediction Center issued this tornado watch at Jul 20, 2009, 8:43 PM CDT for 25 counties in Oklahoma. It was in force for 7 hr.

The area

The outline as issued.

The facts

Issued
Jul 20, 2009, 8:43 PM CDT (01:43 UTC)
Expired
Jul 21, 2009, 4:00 AM CDT
In force
7 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt
All 25 counties

Adair County, OK, Alfalfa County, OK, Cherokee County, OK, Craig County, OK, Creek County, OK, Delaware County, OK, Garfield County, OK, Grant County, OK, Kay County, OK, Mayes County, OK, McIntosh County, OK, Muskogee County, OK, Noble County, OK, Nowata County, OK, Okfuskee County, OK, Okmulgee County, OK, Osage County, OK, Ottawa County, OK, Pawnee County, OK, Payne County, OK, Rogers County, OK, Sequoyah County, OK, Tulsa County, OK, Wagoner County, OK, Washington County, OK

The radar

The Tulsa radar (KINX), 109 km from the middle of the area, began a volume at 01:43 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
20%
Ten or more severe wind reports
30%
One or more gusts of 65 knots or more
20%
Ten or more severe hail reports
40%
One or more hailstones of 2 inches or more
30%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Jul 20, 8:44 PM CDTSevere Thunderstorm WarningOUNGrant76 min
Jul 20, 9:20 PM CDTSevere Thunderstorm WarningTSADelaware40 min
Jul 20, 9:48 PM CDTSevere Thunderstorm WarningOUNGarfield, Noble72 min
Jul 20, 10:02 PM CDTSevere Thunderstorm WarningOUNAlfalfa, Grant58 min
Jul 20, 10:26 PM CDTSevere Thunderstorm WarningOUNGarfield, Major79 min
Jul 20, 11:11 PM CDTSevere Thunderstorm WarningOUNAlfalfa, Grant64 min
Jul 21, 12:25 AM CDTSevere Thunderstorm WarningTSAOsage95 min
Jul 21, 12:38 AM CDTSevere Thunderstorm WarningOUNGrant, Kay67 min
Jul 21, 12:55 AM CDTSevere Thunderstorm WarningTSAOsage65 min
Jul 21, 1:23 AM CDTSevere Thunderstorm WarningOUNGarfield, Grant, Kay, Noble67 min
Jul 21, 1:27 AM CDTSevere Thunderstorm WarningTSAOsage, Pawnee, Washington63 min
Jul 21, 2:20 AM CDTSevere Thunderstorm WarningTSACreek, Nowata, Osage, Pawnee, Rogers, Tulsa and 2 more74 min

Discussions around it

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

The nearest sounding before it

Lamont, OK (KLMN), launched 00:00Z, 1.7 hours before the alert went out and 69 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, Lamont, OK at 00:00Z on 2009-07-21Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, Lamont, OK at 00:00Z on 2009-07-21The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 19 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
3054 m above ground
0-6 km bulk shear
42 kt
0-1 km storm-relative helicity
19 m²/s²
0-3 km storm-relative helicity
100 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 20, 8:26 PM CDTMesoscale DiscussionSPCCraig, Delaware, Kay, Mayes, Nowata, Osage and 6 more94 min
Jul 20, 10:03 PM CDTMesoscale DiscussionSPCBeaver, Beckham, Blaine, Canadian, Custer, Dewey and 8 more57 min
Jul 20, 10:27 PM CDTSevere Thunderstorm WatchSPCBeaver, Blaine, Canadian, Cleveland, Custer, Dewey and 15 more8 hr
Jul 21, 1:10 AM CDTSevere Thunderstorm WatchSPCBeckham, Caddo, Carter, Comanche, Cotton, Garvin and 11 more5 hr
Jul 21, 1:34 AM CDTMesoscale DiscussionSPCAdair, Cherokee, Craig, Creek, Delaware, Garfield and 20 more86 min
Jul 21, 3:21 AM CDTMesoscale DiscussionSPCBeckham, Blaine, Caddo, Canadian, Carter, Cleveland and 25 more114 min
Jul 21, 5:40 AM CDTMesoscale DiscussionSPCCarter, Cleveland, Comanche, Cotton, Garvin, Grady and 12 more35 min
Jul 21, 11:58 AM CDTMesoscale DiscussionSPCBryan, Choctaw, McCurtain92 min
Jul 21, 5:59 PM CDTMesoscale DiscussionSPCCimarron91 min

Nearby

Tornado Watches in Oklahoma, 2009Every tornado watch 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.