Alert archive / Wyoming / Tornado Warnings in 2018

Tornado Warning 2, NWS Riverton, WY

May 27, 2018Fremont County, Wyoming

NWS Riverton, WY issued this tornado warning at May 27, 2018, 12:45 PM MDT for Fremont County, Wyoming. It was in force for 30 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued
May 27, 2018, 12:45 PM MDT (18:45 UTC)
Expired
May 27, 2018, 1:15 PM MDT
In force
30 min
Issued by
NWS Riverton, WY
Area
Storm-based polygon
Tornado
Radar indicated
Hail
1.25 in

County Fremont County, WY

The radar

The Riverton/Lander radar (KRIW), 66 km from the middle of the area, began a volume at 18:45 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.

The watch it was issued in

The SPC watch in force over the same counties when this warning went out.

IssuedProductOfficeLasted
May 27, 12:05 PM MDTSevere Thunderstorm WatchSPC9 hr

The nearest sounding before it

Riverton, WY (KRIW), launched 12:00Z, 6.8 hours before the alert went out and 68 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, Riverton, WY at 12:00Z on 2018-05-27Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 52 joules per kilogram.LCLLFCEL10008507005003002001001 km2 km3 km6 km9 km12 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed.
HodographHodograph, Riverton, WY at 12:00Z on 2018-05-27The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 58 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
52 J/kg
Mixed-layer CIN
-196 J/kg
Mixed-layer LCL
1809 m above ground
0-6 km bulk shear
47 kt
0-1 km storm-relative helicity
58 m²/s²
0-3 km storm-relative helicity
145 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.1

Open this sounding in Storm Lab

The text

As transmitted.

444 
WFUS55 KRIW 271845
TORRIW
WYC013-271915-
/O.NEW.KRIW.TO.W.0002.180527T1845Z-180527T1915Z/

BULLETIN - EAS ACTIVATION REQUESTED
Tornado Warning
National Weather Service Riverton WY
1245 PM MDT SUN MAY 27 2018

The National Weather Service in Riverton has issued a

* Tornado Warning for...
  South central Fremont County in central Wyoming...

* Until 115 PM MDT
    
* At 1245 PM MDT, a severe thunderstorm capable of producing a
  tornado was located near South Pass City, which is 26 miles south
  of Lander, moving north at 15 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 dangerous storm will be near...
  South Pass City and Atlantic City around 1255 PM MDT.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

&&

LAT...LON 4243 10853 4236 10879 4258 10892 4265 10858
TIME...MOT...LOC 1845Z 161DEG 13KT 4245 10874 

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

$$

Jones
2 follow-up statements
851 
WWUS55 KRIW 271857
SVSRIW

Severe Weather Statement
National Weather Service Riverton WY
1257 PM MDT SUN MAY 27 2018

WYC013-271915-
/O.CON.KRIW.TO.W.0002.000000T0000Z-180527T1915Z/
Fremont-
1257 PM MDT SUN MAY 27 2018

...A TORNADO WARNING REMAINS IN EFFECT UNTIL 115 PM MDT FOR SOUTH
CENTRAL FREMONT COUNTY...
    
At 1256 PM MDT, a severe thunderstorm capable of producing a tornado
was located over South Pass City, which is 23 miles south of Lander,
moving north at 10 to 15 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 dangerous storm will cross State Highway 28 near the old US 
Steel mine.

Other locations impacted by this tornadic thunderstorm include
Atlantic City and South Pass City.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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.

&&

LAT...LON 4246 10854 4243 10882 4258 10892 4265 10858
TIME...MOT...LOC 1856Z 161DEG 13KT 4249 10876 

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

$$

CNJ
901 
WWUS55 KRIW 271909
SVSRIW

Severe Weather Statement
National Weather Service Riverton WY
109 PM MDT SUN MAY 27 2018

WYC013-271918-
/O.EXP.KRIW.TO.W.0002.000000T0000Z-180527T1915Z/
Fremont-
109 PM MDT SUN MAY 27 2018

...THE TORNADO WARNING FOR SOUTH CENTRAL FREMONT COUNTY WILL EXPIRE
AT 115 PM MDT...
                
The storm which prompted the warning has weakened and no longer 
appears capable of producing a tornado. Therefore the tornado 
warning will be allowed to expire.

However, heavy rain is still possible with thunderstorms across 
Fremont County this afternoon

A severe thunderstorm watch remains in effect until 800 PM MDT for
central Wyoming.

LAT...LON 4246 10854 4243 10882 4258 10892 4265 10858
TIME...MOT...LOC 1908Z 161DEG 13KT 4253 10878 

$$

CNJ

The office that day

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

IssuedProductOfficeCountiesLasted
May 26, 6:49 PM MDTSpecial Weather StatementRIWPark41 min
May 26, 11:00 PM MDTAreal Flood WarningRIWBig Horn12 hr
May 26, 11:21 PM MDTAreal Flood WarningRIWWashakie12 hr
May 27, 1:46 AM MDTFlash Flood WatchRIWJohnson, Natrona25 hr
May 27, 9:40 AM MDTAreal Flood WarningRIWFremont47 hr
May 27, 10:24 AM MDTSpecial Weather StatementRIWFremont36 min
May 27, 11:03 AM MDTSpecial Weather StatementRIWFremont42 min
May 27, 11:19 AM MDTFlash Flood WarningRIWFremont3 hr
May 27, 11:42 AM MDTSpecial Weather StatementRIW33 min
May 27, 11:50 AM MDTSpecial Weather StatementRIW40 min
May 27, 11:58 AM MDTSpecial Weather StatementRIWFremont47 min
May 27, 12:01 PM MDTFlash Flood WarningRIWFremont3 hr
May 27, 12:15 PM MDTSpecial Weather StatementRIW45 min
May 27, 12:18 PM MDTTornado WarningRIWFremont27 min
May 27, 12:39 PM MDTSpecial Weather StatementRIW51 min
May 27, 12:52 PM MDTSevere Thunderstorm WarningRIWFremont38 min
May 27, 12:54 PM MDTFlash Flood WarningRIWSweetwater3 hr
May 27, 1:01 PM MDTFlash Flood WarningRIWFremont3 hr
May 27, 1:07 PM MDTSpecial Weather StatementRIWFremont38 min
May 27, 1:13 PM MDTSevere Thunderstorm WarningRIWFremont62 min
May 27, 1:25 PM MDTSpecial Weather StatementRIW50 min
May 27, 1:27 PM MDTSevere Thunderstorm WarningRIWSweetwater63 min
May 27, 1:38 PM MDTTornado WarningRIWSweetwater37 min
May 27, 2:03 PM MDTSpecial Weather StatementRIWFremont42 min
May 27, 2:12 PM MDTSpecial Weather StatementRIW33 min
May 27, 2:13 PM MDTTornado WarningRIWFremont, Sweetwater47 min
May 27, 2:14 PM MDTSpecial Weather StatementRIWTeton46 min
May 27, 2:24 PM MDTSevere Thunderstorm WarningRIWNatrona51 min
May 27, 2:52 PM MDTSpecial Weather StatementRIWFremont38 min
May 27, 3:05 PM MDTSpecial Weather StatementRIW40 min
May 27, 3:13 PM MDTSpecial Weather StatementRIWNatrona47 min
May 27, 3:22 PM MDTSpecial Weather StatementRIWHot Springs53 min
May 27, 3:42 PM MDTSevere Thunderstorm WarningRIWNatrona48 min
May 27, 3:44 PM MDTSevere Thunderstorm WarningRIWNatrona46 min
May 27, 4:13 PM MDTTornado WarningRIWNatrona32 min
May 27, 4:18 PM MDTSpecial Weather StatementRIWHot Springs42 min
May 27, 4:29 PM MDTSevere Thunderstorm WarningRIWNatrona46 min
May 27, 4:38 PM MDTSevere Thunderstorm WarningRIWBig Horn, Hot Springs, Park, Washakie37 min
May 27, 4:46 PM MDTAreal Flood AdvisoryRIWNatrona119 min
May 27, 5:21 PM MDTSpecial Weather StatementRIWBig Horn39 min
May 27, 5:43 PM MDTSevere Thunderstorm WarningRIWBig Horn, Park47 min

Nearby

Tornado Warnings in Wyoming, 2018Every tornado warning in 2018Tornadoes 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; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.