Alert archive / Nebraska / Tornado Warnings in 2017

Tornado Warning 31, NWS Cheyenne, WY

August 15, 2017Cheyenne County, Nebraska

NWS Cheyenne, WY issued this tornado warning at Aug 15, 2017, 6:20 PM MDT for Cheyenne County, Nebraska. It was in force for 40 min. 2 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: Aug 15, 2017, 6:20 PM MDT (00:20 UTC)
Expired: Aug 15, 2017, 7:00 PM MDT
In force: 40 min
Issued by: NWS Cheyenne, WY
Area: Storm-based polygon
Tornado: Observed
Hail: 2.75 in

County Cheyenne County, NE

The radar

The Cheyenne radar (KCYS), 137 km from the middle of the area, began a volume at 00:21 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
Aug 15, 6:23 PM MDT	TORNADO	10 Ne Potter, NE	TORNADO ON GROUND.
Aug 15, 6:25 PM MDT	HAIL 1	9 Ne Potter, NE

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.

Issued	Product	Office	Lasted
Aug 15, 4:03 PM MDT	Severe Thunderstorm Watch	SPC	7 hr

The nearest sounding before it

Denver, CO (KDEN), launched 00:00Z, 0.3 hours before the alert went out and 156 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: 467 J/kg
Mixed-layer CIN: -27 J/kg
Mixed-layer LCL: 2755 m above ground
0-6 km bulk shear: 29 kt
0-1 km storm-relative helicity: -37 m²/s²
0-3 km storm-relative helicity: 77 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.2

Open this sounding in Storm Lab

The text

As transmitted.

291 
WFUS55 KCYS 160020
TORCYS
NEC033-160100-
/O.NEW.KCYS.TO.W.0031.170816T0020Z-170816T0100Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Cheyenne WY
620 PM MDT TUE AUG 15 2017

The National Weather Service in Cheyenne has issued a

* Tornado Warning for...
  Northwestern Cheyenne County in the Panhandle of Nebraska...

* Until 700 PM MDT

* At 620 PM MDT, a confirmed tornado was located 9 miles northeast of
  Potter, or 15 miles northwest of Sidney, moving east at 25 mph.

  HAZARD...Damaging tornado and baseball size hail. 

  SOURCE...Weather spotters confirmed tornado. 

  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. 

* The tornado will be near...
  Gurley around 645 PM MDT. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

To repeat, a tornado is on the ground. TAKE COVER NOW! Move to a
basement 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.

Heavy rainfall may hide this tornado. Do not wait to see or hear the
tornado. TAKE COVER NOW!

&&

LAT...LON 4123 10337 4136 10336 4135 10287 4117 10292
TIME...MOT...LOC 0020Z 274DEG 22KT 4130 10317 

TORNADO...OBSERVED
HAIL...2.75IN

$$

Cox

2 follow-up statements

710 
WWUS55 KCYS 160034
SVSCYS

Severe Weather Statement
National Weather Service Cheyenne WY
634 PM MDT TUE AUG 15 2017

NEC033-160100-
/O.CON.KCYS.TO.W.0031.000000T0000Z-170816T0100Z/
Cheyenne NE-
634 PM MDT TUE AUG 15 2017

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 700 PM MDT FOR CENTRAL
CHEYENNE COUNTY...
    
At 633 PM MDT, a confirmed tornado was located 7 miles north of
Brownson, or 12 miles northwest of Sidney, moving east at 40 mph.

HAZARD...Damaging tornado and golf ball size hail. 

SOURCE...Weather spotters confirmed tornado. 

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 tornado will be near...
  Gurley around 640 PM MDT. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

To repeat, a tornado is on the ground. TAKE COVER NOW! Move to a
basement 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.

Heavy rainfall may hide this tornado. Do not wait to see or hear the
tornado. TAKE COVER NOW!

&&

LAT...LON 4121 10320 4136 10320 4135 10287 4117 10292
TIME...MOT...LOC 0033Z 290DEG 37KT 4127 10311 

TORNADO...OBSERVED
HAIL...1.75IN

$$

Rubin

529 
WWUS55 KCYS 160054
SVSCYS

Severe Weather Statement
National Weather Service Cheyenne WY
654 PM MDT TUE AUG 15 2017

NEC033-160103-
/O.EXP.KCYS.TO.W.0031.000000T0000Z-170816T0100Z/
Cheyenne NE-
654 PM MDT TUE AUG 15 2017

...THE TORNADO WARNING FOR CENTRAL CHEYENNE COUNTY WILL EXPIRE AT 700
PM MDT...
    
The tornado threat has diminished and the Tornado Warning has been
cancelled. However, large hail and damaging winds remain likely and 
a Severe Thunderstorm Warning remains in effect for northeastern 
Cheyenne County and southeastern Morrill County until 800 pm MDT.

A severe thunderstorm watch remains in effect until 1100 PM MDT for
the Panhandle of Nebraska.

LAT...LON 4121 10320 4136 10320 4135 10287 4117 10292
TIME...MOT...LOC 0053Z 274DEG 22KT 4126 10297 

$$

Rubin

The office that day

Everything else NWS Cheyenne, WY issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Aug 15, 6:20 PM MDT	Special Weather Statement	CYS	Cheyenne	25 min
Aug 15, 6:38 PM MDT	Special Weather Statement	CYS	Box Butte	52 min
Aug 15, 6:52 PM MDT	Severe Thunderstorm Warning	CYS	Cheyenne, Morrill	34 min
Aug 15, 7:20 PM MDT	Areal Flood Advisory	CYS	Banner, Cheyenne, Kimball	3 hr

Nearby

Tornado Warnings in Nebraska, 2017 Every tornado warning in 2017 Tornadoes 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.