Alert archive / Oklahoma / Severe Thunderstorm Warnings in 2021
Severe Thunderstorm Warning 486, NWS Norman, OK
NWS Norman, OK issued this severe thunderstorm warning at Sep 17, 2021, 6:53 PM CDT for Harper County, Oklahoma. It was in force for 52 min. 5 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
- Sep 17, 2021, 6:53 PM CDT (23:53 UTC)
- Expired
- Sep 17, 2021, 7:45 PM CDT
- In force
- 52 min
- Issued by
- NWS Norman, OK
- Area
- Storm-based polygon
- Hail
- 0.75 in
- Wind
- 60.0 mph
County Harper County, OK
What was reported inside it
| Time | Report | Where | Remark |
|---|---|---|---|
| Sep 17, 7:00 PM CDT | TSTM WND DMG | 3 N Rosston, OK | BACK WINDOW BLOWN OUT OF VEHICLE BLOWN OUT AND MULTIPLE POWER LINES DOWNED. |
| Sep 17, 7:00 PM CDT | TSTM WND GST 80 | 4 N Rosston, OK | |
| Sep 17, 7:00 PM CDT | TSTM WND GST 86 | 3 N Rosston, OK | |
| Sep 17, 7:00 PM CDT | HAIL 1 | 3 N Rosston, OK | |
| Sep 17, 7:40 PM CDT | TSTM WND GST 72 | 1 N Laverne, OK |
Local storm reports filed while the alert was in force, from inside its polygon or its counties.
The nearest sounding before it
Dodge City, (KDDC), launched 12:00Z, 11.9 hours before the alert went out and 103 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.
- Mixed-layer CAPE
- 326 J/kg
- Mixed-layer CIN
- -373 J/kg
- Mixed-layer LCL
- 1512 m above ground
- 0-6 km bulk shear
- 12 kt
- 0-1 km storm-relative helicity
- 119 m²/s²
- 0-3 km storm-relative helicity
- 372 m²/s²
- Significant tornado parameter
- 0.0
- Supercell composite
- 0.3
The text
As transmitted.
038
WUUS54 KOUN 172353
SVROUN
OKC059-180045-
/O.NEW.KOUN.SV.W.0486.210917T2353Z-210918T0045Z/
BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Norman OK
653 PM CDT Fri Sep 17 2021
The National Weather Service in Norman has issued a
* Severe Thunderstorm Warning for...
Northwestern Harper County in northwestern Oklahoma...
* Until 745 PM CDT.
* At 653 PM CDT, a severe thunderstorm was located 4 miles northeast
of Rosston, moving southeast at 15 mph.
HAZARD...60 mph wind gusts and penny size hail.
SOURCE...Radar indicated.
IMPACT...Expect damage to roofs, siding, and trees.
* Locations impacted include...
Laverne, Buffalo and Rosston.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 3690 9957 3675 9968 3669 9996 3679 10001
3686 10001 3692 9999 3698 9988
TIME...MOT...LOC 2353Z 303DEG 15KT 3685 9988
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...0.75 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...60 MPH
$$
JP2 follow-up statements
570
WWUS54 KOUN 180014
SVSOUN
Severe Weather Statement
National Weather Service Norman OK
714 PM CDT Fri Sep 17 2021
OKC059-180045-
/O.CON.KOUN.SV.W.0486.000000T0000Z-210918T0045Z/
Harper OK-
714 PM CDT Fri Sep 17 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 745 PM CDT
FOR NORTHWESTERN HARPER COUNTY...
At 713 PM CDT, a severe thunderstorm was located 4 miles east of
Rosston, moving southeast at 15 mph.
THIS IS A DESTRUCTIVE STORM FOR LAVERNE.
HAZARD...80 mph wind gusts and quarter size hail.
SOURCE...Broadcast media.
IMPACT...Flying debris will be dangerous to those caught without
shelter. Mobile homes will be heavily damaged. Expect
considerable damage to roofs, windows, and vehicles.
Extensive tree damage and power outages are likely.
Locations impacted include...
Laverne, Buffalo and Rosston.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 3685 9961 3675 9968 3669 9996 3679 10001
3686 10001 3692 9999 3695 9988
TIME...MOT...LOC 0013Z 309DEG 12KT 3681 9985
THUNDERSTORM DAMAGE THREAT...DESTRUCTIVE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...80 MPH
$$
JP047
WWUS54 KOUN 180020 CCA
SVSOUN
Severe Weather Statement
National Weather Service Norman OK
720 PM CDT Fri Sep 17 2021
OKC059-180045-
/O.COR.KOUN.SV.W.0486.000000T0000Z-210918T0045Z/
Harper OK-
720 PM CDT Fri Sep 17 2021
...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 745 PM CDT
FOR NORTHWESTERN HARPER COUNTY...
At 719 PM CDT, a severe thunderstorm was located near Rosston, moving
south at 10 mph.
THIS IS A DESTRUCTIVE STORM FOR Rosston and Laverne.
HAZARD...80 mph wind gusts and quarter size hail.
SOURCE...Broadcast media.
IMPACT...Flying debris will be dangerous to those caught without
shelter. Mobile homes will be heavily damaged. Expect
considerable damage to roofs, windows, and vehicles.
Extensive tree damage and power outages are likely.
Locations impacted include...
Laverne, Buffalo and Rosston.
PRECAUTIONARY/PREPAREDNESS ACTIONS...
For your protection move to an interior room on the lowest floor of a
building.
&&
LAT...LON 3685 9961 3675 9968 3669 9996 3679 10001
3686 10001 3692 9999 3695 9988
TIME...MOT...LOC 0014Z 338DEG 8KT 3681 9985
THUNDERSTORM DAMAGE THREAT...DESTRUCTIVE
HAIL THREAT...OBSERVED
MAX HAIL SIZE...1.00 IN
WIND THREAT...OBSERVED
MAX WIND GUST...80 MPH
$$
TLThe office that day
Everything else NWS Norman, OK issued on the same UTC day.
| Issued | Product | Office | Counties | Lasted |
|---|---|---|---|---|
| Sep 17, 5:54 PM CDT | Special Weather Statement | OUN | Harper | 36 min |
| Sep 17, 6:30 PM CDT | Special Weather Statement | OUN | Harper | 30 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.