Alert archive / Oklahoma / Tornado Warnings in 2017

Tornado Warning 96, NWS Norman, OK

October 21, 2017Pottawatomie County, Seminole County, Oklahoma

NWS Norman, OK issued this tornado warning at Oct 21, 2017, 9:38 PM CDT for Pottawatomie County, Seminole County, Oklahoma. It was in force for 37 min. 3 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued
Oct 21, 2017, 9:38 PM CDT (02:38 UTC)
Expired
Oct 21, 2017, 10:15 PM CDT
In force
37 min
Issued by
NWS Norman, OK
Area
Storm-based polygon
Tornado
Radar indicated
Hail
1.0 in

Counties Pottawatomie County, OK, Seminole County, OK

The radar

The Norman radar (KTLX), 48 km from the middle of the area, began a volume at 02:40 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 was reported inside it

TimeReportWhereRemark
Oct 21, 9:52 PM CDTTORNADOSeminole, OKAN EF1 TORNADO DEVELOPED IN NORTHWEST SEMINOLE AND MOVED SOUTHEAST THROUGH TOWN. A FEW RESIDENIAL AND BUSINESS BUILDINGS HAD SOME DAMAGE, INCLUDING AT LEAST TWO HOMES PARTIALLY UNROOFED. TREE AND POWER LINE DAMAGE OCCURRED ALONG THE PATH. THE TORNADO HAD A PAT
Oct 21, 9:52 PM CDTTORNADOSeminole, OKAN EF1 TORNADO DEVELOPED IN NORTHWEST SEMINOLE AND MOVED SOUTHEAST THROUGH TOWN. A FEW RESIDENIAL AND BUSINESS BUILDINGS HAD SOME DAMAGE, INCLUDING AT LEAST TWO HOMES PARTIALLY UNROOFED. TREE AND POWER LINE DAMAGE OCCURRED ALONG THE PATH. THE TORNADO HAD A PAT
Oct 21, 9:53 PM CDTTSTM WND DMGSeminole, OKTREE AND POWERLINE DAMAGE IN SEMINOLE. POSSIBLE TORNADO.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The watch it was issued in

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

IssuedProductOfficeLasted
Oct 21, 7:24 PM CDTTornado WatchSPC7 hr

The nearest sounding before it

Norman, OK (KOUN), launched 00:00Z, 2.6 hours before the alert went out and 58 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 00:00Z on 2017-10-22Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1764 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Norman, OK at 00:00Z on 2017-10-22The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 207 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
1764 J/kg
Mixed-layer CIN
-20 J/kg
Mixed-layer LCL
974 m above ground
0-6 km bulk shear
48 kt
0-1 km storm-relative helicity
207 m²/s²
0-3 km storm-relative helicity
226 m²/s²
Significant tornado parameter
1.9
Supercell composite
10.8

Open this sounding in Storm Lab

The text

As transmitted.

238 
WFUS54 KOUN 220238
TOROUN
OKC125-133-220315-
/O.NEW.KOUN.TO.W.0096.171022T0238Z-171022T0315Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Norman OK
938 PM CDT SAT OCT 21 2017

The National Weather Service in Norman has issued a

* Tornado Warning for...
  Central Seminole County in east central Oklahoma...
  Central Pottawatomie County in central Oklahoma...

* Until 1015 PM CDT
    
* At 938 PM CDT, a severe thunderstorm capable of producing a tornado
  was located 4 miles southeast of Tecumseh, moving east at 40 mph.

  HAZARD...Tornado and quarter size hail. 

  SOURCE...Radar indicated rotation. 

  IMPACT...Flying debris will be dangerous to those caught without 
           shelter. Mobile homes will be damaged or destroyed. 
           Damage to roofs, windows, and vehicles will occur.  Tree 
           damage is likely. 

* Locations impacted include...
  Seminole, Tecumseh, Earlsboro and Harjo. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a storm shelter, safe room or an interior
room on the lowest floor of a sturdy building. Avoid windows. If you
are outdoors, in a mobile home, or in a vehicle, move to the closest
substantial shelter and protect yourself from flying debris.

Tornadoes are extremely difficult to see and confirm at night. Do not
wait to see or hear the tornado. TAKE COVER NOW!

&&

LAT...LON 3516 9692 3521 9693 3525 9692 3536 9659
      3529 9653 3519 9651
TIME...MOT...LOC 0238Z 260DEG 33KT 3522 9688 

TORNADO...RADAR INDICATED
HAIL...1.00IN

$$

KURTZ
4 follow-up statements
933 
WWUS54 KOUN 220246
SVSOUN

Severe Weather Statement
National Weather Service Norman OK
946 PM CDT SAT OCT 21 2017

OKC125-133-220315-
/O.CON.KOUN.TO.W.0096.000000T0000Z-171022T0315Z/
Seminole OK-Pottawatomie OK-
946 PM CDT SAT OCT 21 2017

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 1015 PM CDT FOR
NORTHWESTERN SEMINOLE AND CENTRAL POTTAWATOMIE COUNTIES...
    
At 946 PM CDT, a severe thunderstorm capable of producing a tornado
was located near Earlsboro, moving east at 40 mph.

HAZARD...Tornado and quarter size hail. 

SOURCE...Radar indicated rotation. 

IMPACT...Flying debris will be dangerous to those caught without 
         shelter. Mobile homes will be damaged or destroyed. Damage 
         to roofs, windows, and vehicles will occur.  Tree damage is 
         likely. 

Locations impacted include...
Seminole, Earlsboro and Harjo. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a storm shelter, safe room, or an interior
room on the lowest floor of a sturdy building. Avoid windows. If you
are outdoors, in a mobile home, or in a vehicle, move to the closest
substantial shelter and protect yourself from flying debris.

Tornadoes are extremely difficult to see and confirm at night. Do not
wait to see or hear the tornado. TAKE COVER NOW!

&&

LAT...LON 3519 9682 3523 9684 3528 9684 3536 9659
      3529 9653 3524 9652
TIME...MOT...LOC 0246Z 252DEG 36KT 3524 9678 

TORNADO...RADAR INDICATED
HAIL...1.00IN

$$

KURTZ
322 
WWUS54 KOUN 220254
SVSOUN

Severe Weather Statement
National Weather Service Norman OK
954 PM CDT SAT OCT 21 2017

OKC125-220304-
/O.CAN.KOUN.TO.W.0096.000000T0000Z-171022T0315Z/
Pottawatomie OK-
954 PM CDT SAT OCT 21 2017

...THE TORNADO WARNING FOR CENTRAL POTTAWATOMIE COUNTY IS
CANCELLED...
    
The tornadic thunderstorm which prompted the warning has moved out 
of the warned area. Therefore, the warning has been cancelled.

LAT...LON 3521 9671 3525 9674 3530 9674 3536 9659
      3529 9653 3524 9652
TIME...MOT...LOC 0254Z 265DEG 34KT 3525 9669 

$$

OKC133-220315-
/O.CON.KOUN.TO.W.0096.000000T0000Z-171022T0315Z/
Seminole OK-
954 PM CDT SAT OCT 21 2017

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 1015 PM CDT FOR
NORTHWESTERN SEMINOLE COUNTY...
    
At 954 PM CDT, a severe thunderstorm capable of producing a tornado
was located near Seminole, moving east at 40 mph.

HAZARD...Tornado and quarter size hail. 

SOURCE...Radar indicated rotation. 

IMPACT...Flying debris will be dangerous to those caught without 
         shelter. Mobile homes will be damaged or destroyed. Damage 
         to roofs, windows, and vehicles will occur.  Tree damage is 
         likely. 

Locations impacted include...
Seminole.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a storm shelter, safe room, or an interior
room on the lowest floor of a sturdy building. Avoid windows. If you
are outdoors, in a mobile home, or in a vehicle, move to the closest
substantial shelter and protect yourself from flying debris.

Tornadoes are extremely difficult to see and confirm at night. Do not
wait to see or hear the tornado. TAKE COVER NOW!

&&

LAT...LON 3521 9671 3525 9674 3530 9674 3536 9659
      3529 9653 3524 9652
TIME...MOT...LOC 0254Z 265DEG 34KT 3525 9669 

TORNADO...RADAR INDICATED
HAIL...1.00IN

$$

KURTZ
177 
WWUS54 KOUN 220300
SVSOUN

Severe Weather Statement
National Weather Service Norman OK
1000 PM CDT SAT OCT 21 2017

OKC133-220315-
/O.CON.KOUN.TO.W.0096.000000T0000Z-171022T0315Z/
Seminole OK-
1000 PM CDT SAT OCT 21 2017

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 1015 PM CDT FOR NORTH
CENTRAL SEMINOLE COUNTY...
    
At 1000 PM CDT, a severe thunderstorm capable of producing a tornado
was located 4 miles northeast of Seminole, moving east at 40 mph.

HAZARD...Tornado. 

SOURCE...Radar indicated rotation. 

IMPACT...Flying debris will be dangerous to those caught without 
         shelter. Mobile homes will be damaged or destroyed. Damage 
         to roofs, windows, and vehicles will occur.  Tree damage is 
         likely. 

This tornadic thunderstorm will remain over mainly rural areas of
north central Seminole County.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

TAKE COVER NOW! Move to a storm shelter, safe room, or an interior
room on the lowest floor of a sturdy building. Avoid windows. If you
are outdoors, in a mobile home, or in a vehicle, move to the closest
substantial shelter and protect yourself from flying debris.

Tornadoes are extremely difficult to see and confirm at night. Do not
wait to see or hear the tornado. TAKE COVER NOW!

&&

LAT...LON 3522 9662 3525 9664 3528 9665 3533 9657
      3529 9653 3524 9652
TIME...MOT...LOC 0300Z 259DEG 35KT 3526 9661 

TORNADO...RADAR INDICATED
HAIL...<.75IN

$$

KURTZ
531 
WWUS54 KOUN 220308
SVSOUN

Severe Weather Statement
National Weather Service Norman OK
1008 PM CDT SAT OCT 21 2017

OKC133-220318-
/O.EXP.KOUN.TO.W.0096.000000T0000Z-171022T0315Z/
Seminole OK-
1008 PM CDT SAT OCT 21 2017

...THE TORNADO WARNING FOR NORTH CENTRAL SEMINOLE COUNTY WILL EXPIRE
AT 1015 PM CDT...
        
The storm which prompted the warning has weakened below severe
limits, and has exited the warned area. Therefore, the warning will
be allowed to expire.  However gusty winds are still possible with
this thunderstorm.

LAT...LON 3522 9662 3525 9664 3528 9665 3533 9657
      3529 9653 3524 9652
TIME...MOT...LOC 0308Z 260DEG 33KT 3527 9654 

$$

KURTZ

The office that day

Everything else NWS Norman, OK issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Oct 21, 7:09 PM CDTSevere Thunderstorm WarningOUNJackson, Tillman36 min
Oct 21, 7:10 PM CDTTornado WarningOUNCaddo35 min
Oct 21, 7:13 PM CDTSevere Thunderstorm WarningOUNComanche, Tillman47 min
Oct 21, 7:22 PM CDTSevere Thunderstorm WarningOUNCaddo, Canadian, Grady38 min
Oct 21, 7:24 PM CDTSevere Thunderstorm WarningOUNCaddo, Comanche, Grady51 min
Oct 21, 7:27 PM CDTTornado WarningOUNCaddo, Grady33 min
Oct 21, 7:34 PM CDTFlash Flood WarningOUNCaddo116 min
Oct 21, 7:39 PM CDTAreal Flood AdvisoryOUNCaddo, Comanche2 hr
Oct 21, 7:40 PM CDTSpecial Weather StatementOUNKay, Kingfisher, Logan, Noble35 min
Oct 21, 7:53 PM CDTAreal Flood AdvisoryOUNCaddo, Canadian, Grady, Kingfisher, Logan, Oklahoma and 1 more3 hr
Oct 21, 7:55 PM CDTTornado WarningOUNGrady, McClain35 min
Oct 21, 7:56 PM CDTSevere Thunderstorm WarningOUNCanadian, Cleveland, Grady, Oklahoma49 min
Oct 21, 7:59 PM CDTSevere Thunderstorm WarningOUNComanche, Cotton, Tillman46 min
Oct 21, 8:07 PM CDTSpecial Weather StatementOUNPayne23 min
Oct 21, 8:10 PM CDTSevere Thunderstorm WarningOUNCleveland, Grady, McClain50 min
Oct 21, 8:17 PM CDTAreal Flood WarningOUNCaddo, Canadian, Grady118 min
Oct 21, 8:20 PM CDTAreal Flood WarningOUNCaddo, Canadian, Grady115 min
Oct 21, 8:33 PM CDTSpecial Weather StatementOUNLincoln, Oklahoma, Payne27 min
Oct 21, 8:33 PM CDTSevere Thunderstorm WarningOUNGrady, Jefferson, Stephens42 min
Oct 21, 8:36 PM CDTAreal Flood AdvisoryOUNLincoln, Logan, Noble, Payne114 min
Oct 21, 8:37 PM CDTTornado WarningOUNCleveland, McClain23 min
Oct 21, 8:47 PM CDTAreal Flood WarningOUNCanadian, Cleveland, Grady, McClain, Oklahoma3 hr
Oct 21, 8:48 PM CDTSevere Thunderstorm WarningOUNCleveland, McClain, Oklahoma42 min
Oct 21, 8:49 PM CDTFlash Flood WarningOUNCanadian, Cleveland, Grady, McClain, Oklahoma116 min
Oct 21, 8:57 PM CDTSevere Thunderstorm WarningOUNCotton, Tillman48 min
Oct 21, 9:02 PM CDTFlash Flood WarningOUNCleveland, Lincoln, Logan, Oklahoma118 min
Oct 21, 9:04 PM CDTSpecial Weather StatementOUNLincoln, Payne41 min
Oct 21, 9:10 PM CDTSevere Thunderstorm WarningOUNCarter, Garvin, Grady, Stephens50 min
Oct 21, 9:17 PM CDTAreal Flood AdvisoryOUNCarter, Cleveland, Comanche, Cotton, Garvin, Grady and 10 more118 min
Oct 21, 9:19 PM CDTSevere Thunderstorm WarningOUNCleveland, Lincoln, Oklahoma, Pottawatomie, Seminole41 min
Oct 21, 9:34 PM CDTSpecial Weather StatementOUNJefferson26 min
Oct 21, 9:52 PM CDTSevere Thunderstorm WarningOUNHughes, Lincoln, Pottawatomie, Seminole38 min
Oct 21, 9:55 PM CDTSevere Thunderstorm WarningOUNGarvin, Pontotoc, Seminole50 min
Oct 21, 10:10 PM CDTTornado WarningOUNPontotoc22 min
Oct 21, 10:39 PM CDTSpecial Weather StatementOUNCarter, Johnston, Love, Marshall, Murray36 min
Oct 21, 10:47 PM CDTSpecial Weather StatementOUNCoal, Hughes28 min
Oct 21, 10:52 PM CDTAreal Flood AdvisoryOUNCoal, Garvin, Hughes, Murray, Pontotoc, Seminole53 min
Oct 21, 11:47 PM CDTSpecial Weather StatementOUNBryan28 min
Oct 21, 11:48 PM CDTSpecial Weather StatementOUNAtoka27 min
Oct 22, 9:53 AM CDTRiver Flood WarningOUNComanche, Cotton56 hr

Nearby

Tornado Warnings in Oklahoma, 2017Every tornado warning in 2017Tornadoes in 2017

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.