Alert archive / Nebraska / Tornado Watches in 2008

Tornado Watch 340

May 23, 20087 counties in Colorado; 8 counties in Nebraska; 6 counties in Wyoming

The Storm Prediction Center issued this tornado watch at May 23, 2008, 12:41 PM MDT for 7 counties in Colorado; 8 counties in Nebraska; 6 counties in Wyoming. It was in force for 6 hr.

The area

The outline as issued.

The facts

Issued
May 23, 2008, 12:41 PM MDT (18:41 UTC)
Expired
May 23, 2008, 6:15 PM MDT
In force
6 hr
Issued by
the Storm Prediction Center
Largest hail expected
3 in
Strongest gust expected
60 kt
All 21 counties

Larimer County, CO, Logan County, CO, Morgan County, CO, Phillips County, CO, Sedgwick County, CO, Washington County, CO, Weld County, CO, Banner County, NE, Box Butte County, NE, Cheyenne County, NE, Dawes County, NE, Kimball County, NE, Morrill County, NE, Scotts Bluff County, NE, Sioux County, NE, Albany County, WY, Converse County, WY, Goshen County, WY, Laramie County, WY, Niobrara County, WY, Platte County, WY

The radar

The Cheyenne radar (KCYS), 97 km from the middle of the area, began a volume at 18:44 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
40%
One or more EF2 to EF5 tornadoes
20%
Ten or more severe wind reports
50%
One or more gusts of 65 knots or more
30%
Ten or more severe hail reports
70%
One or more hailstones of 2 inches or more
50%
Six or more combined severe hail and wind reports
90%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
May 23, 1:28 PM MDTSevere Thunderstorm WarningCYSLaramie47 min
May 23, 2:00 PM MDTTornado WarningCYSLaramie45 min
May 23, 2:34 PM MDTSevere Thunderstorm WarningCYSLaramie26 min
May 23, 2:39 PM MDTSevere Thunderstorm WarningCYSLaramie37 min
May 23, 3:14 PM MDTTornado WarningCYSLaramie28 min
May 23, 3:22 PM MDTSevere Thunderstorm WarningCYSPlatte53 min
May 23, 3:35 PM MDTTornado WarningBOUWeld25 min
May 23, 3:40 PM MDTTornado WarningCYSLaramie, Platte50 min
May 23, 3:49 PM MDTTornado WarningBOUMorgan41 min
May 23, 3:54 PM MDTTornado WarningBOUWeld21 min
May 23, 4:01 PM MDTSevere Thunderstorm WarningBOULarimer42 min
May 23, 4:05 PM MDTTornado WarningCYSPlatte25 min
May 23, 4:22 PM MDTTornado WarningBOUWeld38 min
May 23, 4:23 PM MDTTornado WarningCYSLaramie52 min
May 23, 4:25 PM MDTSevere Thunderstorm WarningCYSPlatte65 min
May 23, 4:30 PM MDTSevere Thunderstorm WarningCYSPlatte45 min
May 23, 4:31 PM MDTTornado WarningBOUMorgan44 min
May 23, 5:07 PM MDTSevere Thunderstorm WarningCYSNiobrara53 min
May 23, 5:21 PM MDTTornado WarningCYSPlatte24 min
May 23, 5:40 PM MDTTornado WarningCYSGoshen19 min
May 23, 5:45 PM MDTSevere Thunderstorm WarningCYSPlatte13 min
May 23, 5:47 PM MDTSevere Thunderstorm WarningBOUWeld16 min
May 23, 5:53 PM MDTTornado WarningCYSPlatte13 min
May 23, 6:02 PM MDTSevere Thunderstorm WarningCYSNiobrara58 min
May 23, 6:07 PM MDTTornado WarningCYSGoshen26 min
May 23, 6:10 PM MDTTornado WarningCYSKimball28 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

Denver, CO (KDNR), launched 12:00Z, 6.7 hours before the alert went out and 274 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, Denver, CO at 12:00Z on 2008-05-23Temperature 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 km-30°-20°-10°0°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Denver, CO at 12:00Z on 2008-05-23The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 96 square meters per square second.1939587897117Sfc1 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
974 m above ground
0-6 km bulk shear
87 kt
0-1 km storm-relative helicity
96 m²/s²
0-3 km storm-relative helicity
149 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.

000
WWUS20 KWNS 231839
SEL0  
SPC WW 231839
COZ000-NEZ000-WYZ000-240100-

URGENT - IMMEDIATE BROADCAST REQUESTED
TORNADO WATCH NUMBER 340
NWS STORM PREDICTION CENTER NORMAN OK
1240 PM MDT FRI MAY 23 2008

THE NWS STORM PREDICTION CENTER HAS ISSUED A
TORNADO WATCH FOR PORTIONS OF 

       PARTS OF NORTHEAST COLORADO
       MUCH OF NEBRASKA PANHANDLE
       PARTS OF EASTERN WYOMING

EFFECTIVE THIS FRIDAY AFTERNOON AND EVENING FROM 1240 PM UNTIL
700 PM MDT.

TORNADOES...HAIL TO 3 INCHES IN DIAMETER...THUNDERSTORM WIND
GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE
AREAS.

THE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 85 STATUTE
MILES EAST AND WEST OF A LINE FROM 45 MILES NORTH NORTHEAST OF
DOUGLAS WYOMING TO 25 MILES WEST SOUTHWEST OF AKRON COLORADO. 
FOR A COMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH
OUTLINE UPDATE (WOUS64 KWNS WOU0).

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.

DISCUSSION...VERY STRONG VEERING SHEAR PROFILES E OF HIGHER TERRAIN
IN SERN WY/NERN CO WITH INCREASINGLY MOIST SELY FLOW.  WITH LITTLE
REMAINING CINH...THUNDERSTORMS EXPECTED TO INCREASE RAPIDLY IN
NUMBER/INTENSITY.  SUPERCELLS WILL DEVELOP WITH ASSOCIATED VERY
LARGE HAIL AND POSSIBLE TORNADOES AS THEY MOVE QUICKLY N ACROSS
WATCH AREA.

AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAIL
SURFACE AND ALOFT TO 3 INCHES. EXTREME TURBULENCE AND SURFACE
WIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO
500. MEAN STORM MOTION VECTOR 18040.


...HALES

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
May 23, 8:53 AM MDTMesoscale DiscussionSPCLogan, Phillips, Sedgwick, Yuma67 min
May 23, 12:13 PM MDTMesoscale DiscussionSPCLarimer, Morgan, Weld92 min
May 23, 1:15 PM MDTTornado Watch PDSSPCKit Carson, Yuma7 hr
May 23, 5:02 PM MDTMesoscale DiscussionSPCAdams, Broomfield, Denver, Larimer, Logan, Morgan and 5 more58 min
May 23, 5:18 PM MDTMesoscale DiscussionSPCKit Carson, Yuma57 min
May 23, 5:37 PM MDTMesoscale DiscussionSPCLogan, Morgan, Phillips, Sedgwick, Washington, Weld and 1 more23 min
May 22, 7:16 PM MDTMesoscale DiscussionSPCAdams, Buffalo, Chase, Clay, Dawson, Deuel and 25 more29 min
May 22, 8:11 PM MDTTornado WatchSPCAdams, Buffalo, Clay, Dawson, Fillmore, Franklin and 11 more8 hr
May 22, 8:24 PM MDTMesoscale DiscussionSPCArthur, Banner, Blaine, Box Butte, Brown, Cherry and 15 more66 min
May 22, 9:34 PM MDTMesoscale DiscussionSPCBoone, Butler, Cass, Colfax, Dodge, Douglas and 16 more56 min
May 22, 10:43 PM MDTMesoscale DiscussionSPCAdams, Buffalo, Clay, Dawson, Fillmore, Franklin and 14 more62 min
May 23, 1:01 AM MDTMesoscale DiscussionSPCJefferson, Nuckolls, Saline, Thayer89 min
May 23, 4:26 PM MDTMesoscale DiscussionSPCAdams, Boone, Buffalo, Butler, Clay, Colfax and 23 more64 min

Nearby

Tornado Watches in Nebraska, 2008Tornado Watches in Colorado, 2008Tornado Watches in Wyoming, 2008Every tornado watch in 2008

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.