Alert archive / Wyoming / Tornado Watches in 2019

Tornado Watch 484

July 4, 20195 counties in Nebraska; 6 counties in Wyoming

The Storm Prediction Center issued this tornado watch at Jul 4, 2019, 2:37 PM MDT for 5 counties in Nebraska; 6 counties in Wyoming. It was in force for 9 hr.

The area

The outline as issued.

The facts

Issued
Jul 4, 2019, 2:37 PM MDT (20:37 UTC)
Expired
Jul 4, 2019, 11:53 PM MDT
In force
9 hr
Issued by
the Storm Prediction Center
Largest hail expected
2.5 in
Strongest gust expected
65 kt

Counties Banner County, NE, Box Butte County, NE, Dawes 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), 148 km from the middle of the area, began a volume at 20:39 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
10%
Ten or more severe wind reports
40%
One or more gusts of 65 knots or more
30%
Ten or more severe hail reports
60%
One or more hailstones of 2 inches or more
60%
Six or more combined severe hail and wind reports
90%

Warnings issued inside it

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

IssuedProductOfficeCountiesLasted
Jul 4, 3:21 PM MDTSevere Thunderstorm WarningCYSAlbany, Platte24 min
Jul 4, 3:37 PM MDTSevere Thunderstorm WarningCYSAlbany, Platte23 min
Jul 4, 3:54 PM MDTSevere Thunderstorm WarningCYSAlbany, Platte66 min
Jul 4, 4:32 PM MDTTornado WarningCYSLaramie, Platte28 min
Jul 4, 4:57 PM MDTTornado WarningCYSPlatte48 min
Jul 4, 5:45 PM MDTSevere Thunderstorm WarningCYSConverse, Platte45 min
Jul 4, 5:53 PM MDTSevere Thunderstorm WarningCYSGoshen, Laramie, Platte28 min
Jul 4, 6:18 PM MDTSevere Thunderstorm WarningCYSConverse24 min
Jul 4, 6:41 PM MDTSevere Thunderstorm WarningCYSAlbany, Converse, Platte34 min
Jul 4, 7:28 PM MDTSevere Thunderstorm WarningCYSAlbany, Converse, Platte32 min
Jul 4, 7:31 PM MDTFlash Flood WarningCYSAlbany, Converse, Platte3 hr
Jul 4, 7:56 PM MDTSevere Thunderstorm WarningCYSConverse, Platte49 min
Jul 4, 7:59 PM MDTSevere Thunderstorm WarningCYSNiobrara46 min
Jul 4, 8:17 PM MDTSevere Thunderstorm WarningCYSAlbany, Converse43 min
Jul 4, 8:33 PM MDTSevere Thunderstorm WarningCYSConverse, Goshen, Niobrara, Platte42 min
Jul 4, 8:44 PM MDTSevere Thunderstorm WarningCYSNiobrara31 min
Jul 4, 8:54 PM MDTSevere Thunderstorm WarningCYSLaramie36 min
Jul 4, 8:56 PM MDTSevere Thunderstorm WarningCYSAlbany, Converse, Platte34 min
Jul 4, 9:09 PM MDTSevere Thunderstorm WarningCYSAlbany, Converse36 min
Jul 4, 9:26 PM MDTSevere Thunderstorm WarningCYSPlatte49 min
Jul 4, 9:39 PM MDTSevere Thunderstorm WarningCYSAlbany, Converse, Platte51 min
Jul 4, 10:11 PM MDTSevere Thunderstorm WarningCYSGoshen, Platte64 min
Jul 4, 10:30 PM MDTSevere Thunderstorm WarningCYSPlatte60 min
Jul 4, 10:59 PM MDTSevere Thunderstorm WarningCYSGoshen61 min
Jul 4, 11:38 PM MDTSevere Thunderstorm WarningCYSSioux52 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

Rapid City, SD (KUNR), launched 12:00Z, 8.6 hours before the alert went out and 225 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, Rapid City, SD at 12:00Z on 2019-07-04Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 111 joules per kilogram.LCLLFCEL10008507005003002001001 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, Rapid City, SD at 12:00Z on 2019-07-04The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 63 square meters per square second.19395878Sfc1 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
111 J/kg
Mixed-layer CIN
-196 J/kg
Mixed-layer LCL
760 m above ground
0-6 km bulk shear
47 kt
0-1 km storm-relative helicity
63 m²/s²
0-3 km storm-relative helicity
62 m²/s²
Significant tornado parameter
-0.0
Supercell composite
-0.0

Open this sounding in Storm Lab

The text

As transmitted.

926 
WWUS20 KWNS 042033
SEL4  
SPC WW 042033
NEZ000-WYZ000-050400-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 484
NWS Storm Prediction Center Norman OK
235 PM MDT Thu Jul 4 2019

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Northwest Nebraska Panhandle
  Southeast Wyoming

* Effective this Thursday afternoon and evening from 235 PM until
  1000 PM MDT.

* Primary threats include...
  A couple tornadoes possible
  Scattered large hail and isolated very large hail events to 2.5
    inches in diameter likely
  Scattered damaging winds and isolated significant gusts to 75
    mph possible

SUMMARY...Multiple supercells should develop across southeast
Wyoming this evening and may eventually evolve into a cluster across
parts of the Nebraska Panhandle.

The tornado watch area is approximately along and 75 statute miles
north and south of a line from 45 miles south southwest of Douglas
WY to 30 miles south southeast of Chadron NE. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU4).

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 483...

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 2.5 inches. Extreme turbulence and surface wind
gusts to 65 knots. A few cumulonimbi with maximum tops to 500. Mean
storm motion vector 24030.

...Grams

SPC that day

Everything else SPC issued on the same UTC day.

IssuedProductOfficeCountiesLasted
Jul 3, 6:06 PM MDTMesoscale DiscussionSPCBlaine, Brown, Cherry, Grant, Hooker, Keya Paha and 3 more114 min
Jul 3, 7:03 PM MDTSevere Thunderstorm WatchSPCBlaine, Brown, Cherry, Grant, Hooker, Keya Paha and 3 more3 hr
Jul 3, 9:13 PM MDTMesoscale DiscussionSPCBlaine, Brown, Hooker, Keya Paha, Loup, Rock and 1 more92 min
Jul 4, 1:56 PM MDTMesoscale DiscussionSPCBanner, Box Butte, Dawes, Morrill, Scotts Bluff, Sioux2 hr
Jul 4, 2:36 PM MDTMesoscale DiscussionSPCBlaine, Brown, Cherry, Dawes, Grant, Hooker and 6 more114 min
Jul 4, 3:32 PM MDTSevere Thunderstorm WatchSPCBlaine, Brown, Cherry, Sheridan, Thomas5 hr
Jul 4, 4:53 PM MDTMesoscale DiscussionSPCBanner, Box Butte, Dawes, Morrill, Scotts Bluff, Sioux2 hr
Jul 4, 5:30 PM MDTMesoscale DiscussionSPCCherry, Hooker2 hr
Jul 3, 6:09 PM MDTSevere Thunderstorm WatchSPCAurora, Beadle, Brown, Brule, Buffalo, Campbell and 21 more7 hr
Jul 3, 9:26 PM MDTMesoscale DiscussionSPCButte, Custer, Fall River, Lawrence, Meade, Pennington64 min
Jul 4, 2:31 PM MDTSevere Thunderstorm WatchSPCBennett, Butte, Custer, Fall River, Haakon, Jackson and 4 more8 hr
Jul 4, 3:58 PM MDTMesoscale DiscussionSPCCampbell, Crook, Hot Springs, Johnson, Washakie, Weston62 min

Nearby

Tornado Watches in Wyoming, 2019Tornado Watches in Nebraska, 2019Every tornado watch in 2019

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.