Alert archive / Oklahoma / Severe Thunderstorm Warnings in 2021

Severe Thunderstorm Warning 489, NWS Norman, OK

September 17, 2021Ellis County, Harper County, Woodward County, Oklahoma

NWS Norman, OK issued this severe thunderstorm warning at Sep 17, 2021, 8:04 PM CDT for Ellis County, Harper County, Woodward County, Oklahoma. It was in force for 41 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Sep 17, 2021, 8:04 PM CDT (01:04 UTC)
Expired: Sep 17, 2021, 8:45 PM CDT
In force: 41 min
Issued by: NWS Norman, OK
Area: Storm-based polygon
Damage threat: Destructive
Hail: 1.0 in
Wind: 80.0 mph

Counties Ellis County, OK, Harper County, OK, Woodward County, OK

The radar

The Vance AFB radar (KVNX), 141 km from the middle of the area, began a volume at 01:06 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.

The nearest sounding before it

Dodge City, (KDDC), launched 00:00Z, 1.1 hours before the alert went out and 144 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-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

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: 1092 J/kg
Mixed-layer CIN: -21 J/kg
Mixed-layer LCL: 1639 m above ground
0-6 km bulk shear: 30 kt
0-1 km storm-relative helicity: 25 m²/s²
0-3 km storm-relative helicity: 142 m²/s²
Significant tornado parameter: 0.1
Supercell composite: 1.4

Open this sounding in Storm Lab

The text

As transmitted.

990 
WUUS54 KOUN 180104
SVROUN
OKC045-059-153-180145-
/O.NEW.KOUN.SV.W.0489.210918T0104Z-210918T0145Z/

BULLETIN - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Warning
National Weather Service Norman OK
804 PM CDT Fri Sep 17 2021

The National Weather Service in Norman has issued a

* Severe Thunderstorm Warning for...
  North central Ellis County in northwestern Oklahoma...
  South central Harper County in northwestern Oklahoma...
  West central Woodward County in northwestern Oklahoma...

* Until 845 PM CDT.

* At 803 PM CDT, a severe thunderstorm was located 4 miles southeast
  of May, moving southeast at 35 mph.

  THIS IS A DESTRUCTIVE STORM FOR NORTHEAST ELLIS COUNTY.

  HAZARD...80 mph wind gusts and quarter size hail.

  SOURCE...Radar indicated.

  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...
  Woodward, Fargo, Fort Supply, May and Tangier. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3659 9987 3667 9968 3644 9940 3634 9949
      3630 9971
TIME...MOT...LOC 0103Z 319DEG 29KT 3656 9972 

THUNDERSTORM DAMAGE THREAT...DESTRUCTIVE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...80 MPH

$$

JP

1 follow-up statement

713 
WWUS54 KOUN 180125
SVSOUN

Severe Weather Statement
National Weather Service Norman OK
825 PM CDT Fri Sep 17 2021

OKC059-180133-
/O.CAN.KOUN.SV.W.0489.000000T0000Z-210918T0145Z/
Harper OK-
825 PM CDT Fri Sep 17 2021

...THE SEVERE THUNDERSTORM WARNING FOR SOUTH CENTRAL HARPER COUNTY IS
CANCELLED...
    
The severe thunderstorm which prompted the warning has moved out of 
the warned area. Therefore, the warning has been cancelled.

LAT...LON 3659 9967 3659 9959 3644 9940 3634 9949
      3630 9971 3652 9983
TIME...MOT...LOC 0123Z 327DEG 19KT 3650 9969 

$$

OKC045-153-180145-
/O.CON.KOUN.SV.W.0489.000000T0000Z-210918T0145Z/
Ellis OK-Woodward OK-
825 PM CDT Fri Sep 17 2021

...A SEVERE THUNDERSTORM WARNING REMAINS IN EFFECT UNTIL 845 PM CDT
FOR NORTH CENTRAL ELLIS AND WEST CENTRAL WOODWARD COUNTIES...

At 823 PM CDT, a severe thunderstorm was located 8 miles southwest of
Fort Supply, moving southeast at 20 mph.

HAZARD...70 mph wind gusts and quarter size hail.

SOURCE...Radar indicated.

IMPACT...Hail damage to vehicles is expected. Expect considerable 
         tree damage. Wind damage is also likely to mobile homes, 
         roofs, and outbuildings.

Locations impacted include...
Woodward, Fargo, Fort Supply and Tangier. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

&&

LAT...LON 3659 9967 3659 9959 3644 9940 3634 9949
      3630 9971 3652 9983
TIME...MOT...LOC 0123Z 327DEG 19KT 3650 9969 

THUNDERSTORM DAMAGE THREAT...CONSIDERABLE
HAIL THREAT...RADAR INDICATED
MAX HAIL SIZE...1.00 IN
WIND THREAT...RADAR INDICATED
MAX WIND GUST...70 MPH

$$

JP

The office that day

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

Issued	Product	Office	Counties	Lasted
Sep 17, 7:28 PM CDT	Severe Thunderstorm Warning Considerable damage threat	OUN	Harper	47 min
Sep 17, 7:34 PM CDT	Areal Flood Advisory	OUN	Harper	3 hr
Sep 17, 7:48 PM CDT	Severe Thunderstorm Warning Considerable damage threat	OUN	Ellis, Harper	42 min
Sep 17, 8:46 PM CDT	Special Weather Statement	OUN	Ellis	29 min
Sep 17, 8:48 PM CDT	Special Weather Statement	OUN	Ellis	27 min
Sep 17, 9:21 PM CDT	Special Weather Statement	OUN	Ellis	24 min
Sep 17, 9:54 PM CDT	Special Weather Statement	OUN	Roger Mills	36 min

Nearby

Severe Thunderstorm Warnings in Oklahoma, 2021 Every 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.