Alert archive / Nebraska / Tornado Watches in 2015

Tornado Watch 75

April 18, 20157 counties in Colorado; 13 counties in Kansas; 17 counties in Nebraska

The Storm Prediction Center issued this tornado watch at Apr 18, 2015, 2:08 PM MDT for 7 counties in Colorado; 13 counties in Kansas; 17 counties in Nebraska. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
Apr 18, 2015, 2:08 PM MDT (20:08 UTC)
Expired
Apr 18, 2015, 8:00 PM MDT
In force
6 hr
Issued by
the Storm Prediction Center
Largest hail expected
2 in
Strongest gust expected
60 kt
All 37 counties

Cheyenne County, CO, Kit Carson County, CO, Logan County, CO, Phillips County, CO, Sedgwick County, CO, Washington County, CO, Yuma County, CO, Cheyenne County, KS, Decatur County, KS, Gove County, KS, Graham County, KS, Greeley County, KS, Logan County, KS, Norton County, KS, Rawlins County, KS, Sheridan County, KS, Sherman County, KS, Thomas County, KS, Wallace County, KS, Wichita County, KS, Arthur County, NE, Chase County, NE, Cheyenne County, NE, Custer County, NE, Deuel County, NE, Dundy County, NE, Frontier County, NE, Garden County, NE, Hayes County, NE, Hitchcock County, NE, Keith County, NE, Lincoln County, NE, Logan County, NE, McPherson County, NE, Morrill County, NE, Perkins County, NE, Red Willow County, NE

The radar

The Goodland radar (KGLD), 132 km from the middle of the area, began a volume at 20:09 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 SPC expected

The probabilities SPC published with the watch, for the watch area over its life.

Two or more tornadoes
60%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
30%
One or more gusts of 65 knots or more
10%
Ten or more severe hail reports
50%
One or more hailstones of 2 inches or more
30%
Six or more combined severe hail and wind reports
70%

Warnings issued inside it

6 tornado, severe thunderstorm and flash flood warnings for its counties while it was in force.

IssuedProductOfficeCountiesLasted
Apr 18, 2:44 PM MDTSevere Thunderstorm WarningGLDSherman31 min
Apr 18, 3:02 PM MDTSevere Thunderstorm WarningCYSCheyenne28 min
Apr 18, 4:40 PM MDTSevere Thunderstorm WarningGLDGraham35 min
Apr 18, 5:01 PM MDTSevere Thunderstorm WarningGLDNorton29 min
Apr 18, 5:03 PM MDTSevere Thunderstorm WarningGLDGraham, Norton42 min
Apr 18, 5:26 PM MDTSevere Thunderstorm WarningGLDNorton29 min

Discussions around it

SPC mesoscale discussions over the same counties from four hours before the watch to its end.

The nearest sounding before it

N. Platte/Lee Bi, NE (KLBF), launched 12:00Z, 8.1 hours before the alert went out and 130 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, N. Platte/Lee Bi, NE at 12:00Z on 2015-04-18Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 0 joules per kilogram.LCL10008507005003002001001 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, N. Platte/Lee Bi, NE at 12:00Z on 2015-04-18The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity -48 square meters per square second.193958Sfc1 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
0 J/kg
Mixed-layer CIN
No buoyant parcel
Mixed-layer LCL
1223 m above ground
0-6 km bulk shear
46 kt
0-1 km storm-relative helicity
-48 m²/s²
0-3 km storm-relative helicity
-125 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

392 
WWUS20 KWNS 182005
SEL5  
SPC WW 182005
COZ000-KSZ000-NEZ000-190200-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 75
NWS STORM PREDICTION CENTER NORMAN OK
210 PM MDT SAT APR 18 2015

THE NWS STORM PREDICTION CENTER HAS ISSUED A

* TORNADO WATCH FOR PORTIONS OF 
  NORTHEAST COLORADO
  NORTHWEST KANSAS
  SOUTHWEST NEBRASKA

* EFFECTIVE THIS SATURDAY AFTERNOON AND EVENING FROM 210 PM UNTIL
  800 PM MDT.

* PRIMARY THREATS INCLUDE...
  A FEW TORNADOES LIKELY
  SCATTERED LARGE HAIL AND ISOLATED VERY LARGE HAIL EVENTS TO 2
    INCHES IN DIAMETER POSSIBLE
  ISOLATED DAMAGING WIND GUSTS TO 70 MPH POSSIBLE

SUMMARY...ISOLATED THUNDERSTORMS WILL CONTINUE TO DEVELOP BENEATH AN
UPPER LOW OVER NORTHEAST CO.  A FEW OF THE STORMS MAY DEVELOP
TORNADOES...ALONG WITH SOME RISK OF HAIL AND DAMAGING WINDS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 80 STATUTE
MILES EAST AND WEST OF A LINE FROM 65 MILES NORTHWEST OF NORTH
PLATTE NEBRASKA TO 50 MILES SOUTH OF GOODLAND KANSAS.  FOR A
COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINE
UPDATE (WOUS64 KWNS WOU5).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FOR
TORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCH
AREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FOR
THREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTS
AND POSSIBLE WARNINGS.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 72...WW 73...WW 74...

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 2 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 18025.


...HART

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Apr 17, 6:06 PM MDTMesoscale DiscussionSPCCheyenne, Kit Carson, Logan, Morgan, Phillips, Sedgwick and 2 more84 min
Apr 17, 7:56 PM MDTMesoscale DiscussionSPCCheyenne, Kit Carson, Logan, Phillips, Sedgwick, Washington and 1 more94 min
Apr 18, 5:07 PM MDTMesoscale DiscussionSPCCheyenne, Kit Carson, Logan, Phillips, Sedgwick, Yuma53 min
Apr 17, 6:26 PM MDTMesoscale DiscussionSPCGrant, Morton, Stevens2 hr
Apr 17, 7:24 PM MDTMesoscale DiscussionSPCEllsworth, Lincoln, Mitchell, Osborne, Phillips, Russell and 1 more2 hr
Apr 18, 11:45 AM MDTMesoscale DiscussionSPCBarber, Harper, Kingman, Pratt60 min
Apr 18, 12:52 PM MDTMesoscale DiscussionSPCBarber, Clark, Comanche, Edwards, Ford, Kiowa and 1 more113 min
Apr 18, 1:43 PM MDTSevere Thunderstorm WatchSPCBarber, Barton, Butler, Clark, Comanche, Cowley and 27 more8 hr
Apr 18, 1:49 PM MDTMesoscale DiscussionSPCCheyenne, Decatur, Graham, Norton, Phillips, Rawlins and 3 more116 min
Apr 18, 3:07 PM MDTMesoscale DiscussionSPCButler, Chase, Chautauqua, Clay, Cowley, Dickinson and 9 more2 hr
Apr 18, 4:31 PM MDTMesoscale DiscussionSPCBarber, Barton, Clark, Comanche, Edwards, Ellis and 24 more59 min
Apr 17, 10:48 PM MDTMesoscale DiscussionSPCFrontier, Hayes, Lincoln57 min

Nearby

Tornado Watches in Nebraska, 2015Tornado Watches in Kansas, 2015Tornado Watches in Colorado, 2015Every tornado watch in 2015

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.