Alert archive / Oklahoma / Tornado Warnings in 2018

Tornado Warning 2, NWS Norman, OK

May 1, 2018Harper County, Oklahoma

NWS Norman, OK issued this tornado warning at May 1, 2018, 6:28 PM CDT for Harper County, Oklahoma. It was in force for 17 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: May 1, 2018, 6:28 PM CDT (23:28 UTC)
Expired: May 1, 2018, 6:45 PM CDT
In force: 17 min
Issued by: NWS Norman, OK
Area: Storm-based polygon
Tornado: Radar indicated
Hail: 1.25 in

County Harper County, OK

The radar

The Dodge City radar (KDDC), 96 km from the middle of the area, began a volume at 23:31 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

Time	Report	Where	Remark
May 1, 6:29 PM CDT	TORNADO	9 Nne Buffalo, OK	POSSIBLE TORNADO

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, 11.5 hours before the alert went out and 94 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: 1353 J/kg
Mixed-layer CIN: -253 J/kg
Mixed-layer LCL: 970 m above ground
0-6 km bulk shear: 43 kt
0-1 km storm-relative helicity: 376 m²/s²
0-3 km storm-relative helicity: 354 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.8

Open this sounding in Storm Lab

The text

As transmitted.

841 
WFUS54 KOUN 012328
TOROUN
OKC059-012345-
/O.NEW.KOUN.TO.W.0002.180501T2328Z-180501T2345Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Norman OK
628 PM CDT TUE MAY 1 2018

The National Weather Service in Norman has issued a

* Tornado Warning for...
  Northeastern Harper County in northwestern Oklahoma...

* Until 645 PM CDT
    
* At 628 PM CDT, a severe thunderstorm capable of producing a tornado
  was located 10 miles north of Buffalo, moving northeast at 40 mph.

  HAZARD...Tornado and half dollar 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. 

* This tornadic thunderstorm will remain over mainly rural areas of
  northeastern Harper 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.

&&

LAT...LON 3700 9946 3699 9944 3698 9944 3693 9955
      3694 9962 3700 9964
TIME...MOT...LOC 2328Z 227DEG 36KT 3698 9956 

TORNADO...RADAR INDICATED
HAIL...1.25IN

$$

MAHALE

1 follow-up statement

479 
WWUS54 KOUN 012340
SVSOUN

Severe Weather Statement
National Weather Service Norman OK
640 PM CDT TUE MAY 1 2018

OKC059-012350-
/O.EXP.KOUN.TO.W.0002.000000T0000Z-180501T2345Z/
Harper OK-
640 PM CDT TUE MAY 1 2018

...THE TORNADO WARNING FOR NORTHEASTERN HARPER COUNTY WILL EXPIRE AT
645 PM CDT...
        
The storm which prompted the warning has moved out of the area.
Therefore the warning will be allowed to expire.

LAT...LON 3700 9946 3699 9944 3698 9944 3693 9955
      3694 9962 3700 9964
TIME...MOT...LOC 2340Z 227DEG 36KT 3705 9947 

$$

MAHALE

The office that day

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

Issued	Product	Office	Counties	Lasted
Apr 30, 9:14 PM CDT	Special Weather Statement	OUN	Ellis	31 min
May 1, 1:48 AM CDT	Special Weather Statement	OUN	Alfalfa	57 min
May 1, 5:31 PM CDT	Special Weather Statement	OUN	Harper	29 min
May 1, 5:58 PM CDT	Special Weather Statement	OUN	Harper	32 min
May 1, 6:00 PM CDT	Severe Thunderstorm Warning	OUN	Harper	30 min

Nearby

Tornado Warnings in Oklahoma, 2018 Every tornado warning in 2018 Tornadoes 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.