Alert archive / Oklahoma / Tornado Watches in 2018

Tornado Watch 402

October 9, 201837 counties in Oklahoma

The Storm Prediction Center issued this tornado watch at Oct 9, 2018, 8:48 AM CDT for 37 counties in Oklahoma. It was in force for 5 hr.

The area

The outline as issued.

The facts

Issued
Oct 9, 2018, 8:48 AM CDT (13:48 UTC)
Expired
Oct 9, 2018, 2:00 PM CDT
In force
5 hr
Issued by
the Storm Prediction Center
Largest hail expected
1 in
Strongest gust expected
55 kt
All 37 counties

Adair County, OK, Atoka County, OK, Bryan County, OK, Cherokee County, OK, Choctaw County, OK, Coal County, OK, Craig County, OK, Creek County, OK, Delaware County, OK, Haskell County, OK, Hughes County, OK, Johnston County, OK, Kay County, OK, Latimer County, OK, LeFlore County, OK, Lincoln 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, Pittsburg County, OK, Pontotoc County, OK, Pottawatomie County, OK, Pushmataha County, OK, Rogers County, OK, Seminole County, OK, Sequoyah County, OK, Tulsa County, OK, Wagoner County, OK, Washington County, OK

The radar

The Tulsa radar (KINX), 118 km from the middle of the area, began a volume at 13:52 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
40%
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
5%
One or more hailstones of 2 inches or more
5%
Six or more combined severe hail and wind reports
40%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Oct 9, 8:57 AM CDTTornado WarningOUNLincoln, Pottawatomie, Seminole48 min
Oct 9, 9:01 AM CDTSevere Thunderstorm WarningOUNAtoka, Bryan, Coal, Hughes, Johnston, Marshall and 2 more74 min
Oct 9, 9:29 AM CDTSevere Thunderstorm WarningOUNHughes, Kay, Lincoln, Noble, Payne, Pottawatomie and 1 more46 min
Oct 9, 9:29 AM CDTSevere Thunderstorm WarningTSACreek, Okfuskee46 min
Oct 9, 9:49 AM CDTTornado WarningTSACreek, Okfuskee41 min
Oct 9, 10:23 AM CDTSevere Thunderstorm WarningTSACreek, Osage, Pawnee, Tulsa52 min
Oct 9, 10:31 AM CDTSevere Thunderstorm WarningTSACreek, McIntosh, Muskogee, Okfuskee, Okmulgee, Osage and 1 more44 min
Oct 9, 10:55 AM CDTSevere Thunderstorm WarningTSAOsage50 min
Oct 9, 11:04 AM CDTSevere Thunderstorm WarningTSANowata, Osage, Rogers, Tulsa, Washington41 min
Oct 9, 11:10 AM CDTSevere Thunderstorm WarningTSAMcIntosh, Muskogee, Okmulgee, Rogers, Tulsa, Wagoner50 min
Oct 9, 11:27 AM CDTTornado WarningTSARogers, Tulsa, Wagoner18 min
Oct 9, 11:37 AM CDTSevere Thunderstorm WarningTSANowata, Osage, Rogers, Tulsa, Washington38 min
Oct 9, 11:54 AM CDTSevere Thunderstorm WarningTSAMayes, Rogers, Wagoner36 min
Oct 9, 12:11 PM CDTSevere Thunderstorm WarningTSACraig, Mayes, Nowata, Rogers, Washington49 min
Oct 9, 12:16 PM CDTSevere Thunderstorm WarningTSACherokee, Craig, Delaware, Mayes, Rogers, Wagoner44 min
Oct 9, 12:54 PM CDTSevere Thunderstorm WarningTSACraig, Delaware, Mayes, Ottawa66 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

Norman, OK (KOUN), launched 12:00Z, 1.8 hours before the alert went out and 138 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, Norman, OK at 12:00Z on 2018-10-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 211 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, Norman, OK at 12:00Z on 2018-10-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 268 square meters per square second.19395878Sfc1 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
211 J/kg
Mixed-layer CIN
-11 J/kg
Mixed-layer LCL
555 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
268 m²/s²
0-3 km storm-relative helicity
282 m²/s²
Significant tornado parameter
0.2
Supercell composite
2.2

Open this sounding in Storm Lab

The text

As transmitted.

736 
WWUS20 KWNS 091346
SEL2  
SPC WW 091346
OKZ000-091900-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 402
NWS Storm Prediction Center Norman OK
850 AM CDT Tue Oct 9 2018

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Eastern Oklahoma

* Effective this Tuesday morning and afternoon from 850 AM until
  200 PM CDT.

* Primary threats include...
  A couple tornadoes possible
  Isolated damaging wind gusts to 65 mph possible

SUMMARY...Line of strong storms with embedded low-level circulations
will continue to pose a risk for brief tornadoes through midday as
the line progresses across eastern Oklahoma.

The tornado watch area is approximately along and 65 statute miles
east and west of a line from 55 miles east of Durant OK to 15 miles
north of Bartlesville OK. For a complete depiction of the watch see
the associated watch outline update (WOUS64 KWNS WOU2).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

&&

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 1 inch. Extreme turbulence and surface wind
gusts to 55 knots. A few cumulonimbi with maximum tops to 450. Mean
storm motion vector 24035.

...Grams

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Oct 9, 9:09 AM CDTMesoscale DiscussionSPCAdair, Atoka, Bryan, Cherokee, Choctaw, Coal and 27 more2 hr
Oct 9, 11:31 AM CDTMesoscale DiscussionSPCAdair, Cherokee, Craig, Delaware, Haskell, Mayes and 7 more89 min

Nearby

Tornado Watches in Oklahoma, 2018Every tornado watch in 2018

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.