Alert archive / Oklahoma / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 73, NWS Norman, OK

April 9, 2021Pottawatomie County, Seminole County, Oklahoma

NWS Norman, OK issued this severe thunderstorm warning at Apr 9, 2021, 6:22 PM CDT for Pottawatomie County, Seminole County, Oklahoma. It was in force for 27 min. 1 report 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
Apr 9, 2021, 6:22 PM CDT (23:22 UTC)
Expired
Apr 9, 2021, 6:49 PM CDT
In force
27 min
Issued by
NWS Norman, OK
Area
Storm-based polygon
Hail
2.0 in
Wind
60.0 mph

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 23:25 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
Apr 9, 6:29 PM CDTHAIL 15 S Tecumseh, OK

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
Apr 9, 3:55 PM CDTSevere Thunderstorm WatchSPC7 hr

The nearest sounding before it

Norman, OK (KOUN), launched 12:00Z, 11.4 hours before the alert went out and 56 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 2021-04-09Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 1068 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 2021-04-09The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 28 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
1068 J/kg
Mixed-layer CIN
-311 J/kg
Mixed-layer LCL
1414 m above ground
0-6 km bulk shear
37 kt
0-1 km storm-relative helicity
28 m²/s²
0-3 km storm-relative helicity
137 m²/s²
Significant tornado parameter
0.0
Supercell composite
-0.6

Open this sounding in Storm Lab

The text

As transmitted.

804 
WUUS54 KOUN 092322
SVROUN
OKC125-133-100015-
/O.NEW.KOUN.SV.W.0073.210409T2322Z-210410T0015Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Norman OK
622 PM CDT Fri Apr 9 2021

The National Weather Service in Norman has issued a

* Severe Thunderstorm Warning for...
  West central Seminole County in east central Oklahoma...
  Central Pottawatomie County in central Oklahoma...

* Until 715 PM CDT.

* At 622 PM CDT, a severe thunderstorm was located near Brooksville,
  moving east at 20 mph.

  HAZARD...Two inch hail and 60 mph wind gusts.

  SOURCE...Radar indicated.

  IMPACT...People and animals outdoors will be injured. Expect hail 
           damage to roofs, siding, windows, and vehicles. Expect 
           wind damage to roofs, siding, and trees.

* Locations impacted include...
  Seminole, Tecumseh, Maud, Bowlegs, St. Louis, Brooksville, Macomb,
  Lima and Harjo.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm is producing large hail. SEEK SHELTER NOW inside a sturdy
structure and stay away from windows!

&&

LAT...LON 3514 9704 3526 9694 3526 9653 3511 9656
      3505 9662
TIME...MOT...LOC 2322Z 283DEG 19KT 3518 9691 

HAIL...2.00IN
WIND...60MPH
 
$$

Mahale
4 follow-up statements
231 
WWUS54 KOUN 092333
SVSOUN

Severe Weather Statement
National Weather Service Norman OK
633 PM CDT Fri Apr 9 2021

OKC125-133-100015-
/O.CON.KOUN.SV.W.0073.000000T0000Z-210410T0015Z/
Seminole OK-Pottawatomie OK-
633 PM CDT Fri Apr 9 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 715 PM CDT
FOR WEST CENTRAL SEMINOLE AND CENTRAL POTTAWATOMIE COUNTIES...

At 633 PM CDT, a severe thunderstorm was located 4 miles northwest of
Maud, moving east at 20 mph.

HAZARD...Golf ball size hail and 60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...People and animals outdoors will be injured. Expect hail 
         damage to roofs, siding, windows, and vehicles. Expect wind 
         damage to roofs, siding, and trees.

Locations impacted include...
Seminole, Tecumseh, Maud, Bowlegs, St. Louis, Lima and Harjo. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

This storm is producing large hail. SEEK SHELTER NOW inside a sturdy
structure and stay away from windows.

&&

LAT...LON 3513 9698 3526 9689 3526 9653 3511 9656
      3505 9662
TIME...MOT...LOC 2333Z 283DEG 19KT 3517 9684 

HAIL...1.75IN
WIND...60MPH
 
$$

Mahale
315 
WWUS54 KOUN 092339
SVSOUN

Severe Weather Statement
National Weather Service Norman OK
639 PM CDT Fri Apr 9 2021

OKC125-133-100015-
/O.CON.KOUN.SV.W.0073.000000T0000Z-210410T0015Z/
Seminole OK-Pottawatomie OK-
639 PM CDT Fri Apr 9 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 715 PM CDT
FOR WEST CENTRAL SEMINOLE AND CENTRAL POTTAWATOMIE COUNTIES...

At 639 PM CDT, a severe thunderstorm was located near Maud, moving
east at 20 mph.

HAZARD...Ping pong ball size hail and 60 mph wind gusts.

SOURCE...Radar indicated.

IMPACT...People and animals outdoors will be injured. Expect hail 
         damage to roofs, siding, windows, and vehicles. Expect wind 
         damage to roofs, siding, and trees.

Locations impacted include...
Seminole, Maud, Bowlegs, St. Louis, Lima and Harjo. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

This storm is producing large hail. SEEK SHELTER NOW inside a sturdy
structure and stay away from windows.

&&

LAT...LON 3512 9693 3526 9682 3526 9653 3511 9656
      3505 9662
TIME...MOT...LOC 2339Z 283DEG 19KT 3516 9680 

HAIL...1.50IN
WIND...60MPH
 
$$

Mahale
475 
WWUS54 KOUN 092342
SVSOUN

Severe Weather Statement
National Weather Service Norman OK
642 PM CDT Fri Apr 9 2021

OKC125-133-100015-
/O.CON.KOUN.SV.W.0073.000000T0000Z-210410T0015Z/
Seminole OK-Pottawatomie OK-
642 PM CDT Fri Apr 9 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 715 PM CDT
FOR WEST CENTRAL SEMINOLE AND CENTRAL POTTAWATOMIE COUNTIES...

At 642 PM CDT, a severe thunderstorm was located near Maud, moving
east at 20 mph.

HAZARD...Quarter size hail.

SOURCE...Radar indicated.

IMPACT...Damage to vehicles is expected.

Locations impacted include...
Seminole, Maud, Bowlegs, St. Louis, Lima and Harjo. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

For your protection move to an interior room on the lowest floor of a
building.

&&

LAT...LON 3511 9690 3523 9681 3521 9654 3511 9656
      3505 9662
TIME...MOT...LOC 2342Z 283DEG 19KT 3516 9678 

HAIL...1.00IN
WIND...<50MPH
 
$$

Mahale
558 
WWUS54 KOUN 092349
SVSOUN

Severe Weather Statement
National Weather Service Norman OK
649 PM CDT Fri Apr 9 2021

OKC125-133-092359-
/O.CAN.KOUN.SV.W.0073.000000T0000Z-210410T0015Z/
Seminole OK-Pottawatomie OK-
649 PM CDT Fri Apr 9 2021

...THE SEVERE THUNDERSTORM WARNING FOR WEST CENTRAL SEMINOLE AND
CENTRAL POTTAWATOMIE COUNTIES IS CANCELLED...
                 
The storm which prompted the warning has weakened below severe
limits, therefore the warning has been cancelled.  However small hail
and heavy rain are still possible with this thunderstorm.

LAT...LON 3511 9690 3523 9681 3521 9654 3511 9656
      3505 9662
TIME...MOT...LOC 2348Z 283DEG 19KT 3515 9673 

$$

Mahale

The office that day

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

IssuedProductOfficeCountiesLasted
Apr 9, 2:57 AM CDTWind AdvisoryOUNAlfalfa, Beckham, Blaine, Caddo, Canadian, Cleveland and 31 more20 hr
Apr 9, 10:21 AM CDTSpecial Weather StatementOUNBryan24 min
Apr 9, 10:32 AM CDTSpecial Weather StatementOUNBryan28 min
Apr 9, 3:21 PM CDTSpecial Weather StatementOUNGreer24 min
Apr 9, 3:28 PM CDTSevere Thunderstorm WarningOUNGreer23 min
Apr 9, 3:35 PM CDTSpecial Weather StatementOUNWashita40 min
Apr 9, 3:39 PM CDTSpecial Weather StatementOUNKingfisher36 min
Apr 9, 3:49 PM CDTSpecial Weather StatementOUNCanadian26 min
Apr 9, 3:52 PM CDTSpecial Weather StatementOUNGreer23 min
Apr 9, 3:57 PM CDTSevere Thunderstorm WarningOUNCaddo, Canadian, Grady48 min
Apr 9, 4:12 PM CDTSpecial Weather StatementOUNLogan33 min
Apr 9, 4:13 PM CDTSpecial Weather StatementOUNWashita32 min
Apr 9, 4:23 PM CDTSpecial Weather StatementOUNGrant37 min
Apr 9, 4:25 PM CDTSevere Thunderstorm WarningOUNLogan, Payne50 min
Apr 9, 4:29 PM CDTSevere Thunderstorm WarningOUNKiowa, Washita16 min
Apr 9, 4:36 PM CDTSevere Thunderstorm WarningOUNCaddo, Canadian, Grady39 min
Apr 9, 4:52 PM CDTSpecial Weather StatementOUNKingfisher23 min
Apr 9, 4:53 PM CDTSevere Thunderstorm WarningOUNKingfisher52 min
Apr 9, 5:06 PM CDTSevere Thunderstorm WarningOUNGrady39 min
Apr 9, 5:17 PM CDTSevere Thunderstorm WarningOUNLogan, Noble, Payne43 min
Apr 9, 5:18 PM CDTSevere Thunderstorm WarningOUNKingfisher, Logan, Oklahoma42 min
Apr 9, 5:25 PM CDTSevere Thunderstorm WarningOUNLincoln, Logan, Payne50 min
Apr 9, 5:31 PM CDTSevere Thunderstorm WarningOUNGrady, McClain44 min
Apr 9, 5:36 PM CDTSpecial Weather StatementOUNPottawatomie24 min
Apr 9, 5:39 PM CDTSpecial Weather StatementOUNLincoln36 min
Apr 9, 5:48 PM CDTSpecial Weather StatementOUNLincoln27 min
Apr 9, 5:51 PM CDTSevere Thunderstorm WarningOUNPottawatomie, Seminole39 min
Apr 9, 5:57 PM CDTSevere Thunderstorm WarningOUNLincoln, Logan, Oklahoma48 min
Apr 9, 6:05 PM CDTSevere Thunderstorm WarningOUNGarvin, Grady, McClain, Stephens40 min
Apr 9, 6:09 PM CDTSpecial Weather StatementOUNLincoln36 min
Apr 9, 6:34 PM CDTSevere Thunderstorm WarningOUNLincoln56 min
Apr 9, 6:38 PM CDTSpecial Weather StatementOUNPottawatomie52 min
Apr 9, 6:58 PM CDTSpecial Weather StatementOUNPottawatomie, Seminole47 min

Nearby

Severe Thunderstorm Warnings in Oklahoma, 2021Every severe thunderstorm warning in 2021

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.