Alert archive / Wyoming / Winter Storm Warnings in 2018

Winter Storm Warning 7, NWS Riverton, WY

March 25, 2018Johnson County, Wyoming

NWS Riverton, WY issued this winter storm warning at Mar 25, 2018, 2:04 AM MDT for Johnson County, Wyoming. It took effect at Mar 25, 2018, 12:00 PM MDT. It was in force for 27 hr. 7 reports came from inside the area while it was in force.

The area

The counties it named, with what was reported inside it.

The facts

Issued
Mar 25, 2018, 2:04 AM MDT (08:04 UTC)
In effect from
Mar 25, 2018, 12:00 PM MDT
Expired
Mar 26, 2018, 3:16 PM MDT
In force
27 hr
Issued by
NWS Riverton, WY

County Johnson County, WY

The radar

The Riverton/Lander radar (KRIW), 187 km from the middle of the area, began a volume at 08:10 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

TimeReportWhereRemark
Mar 26, 5:28 AM MDTHEAVY SNOW 914 Wnw Mayoworth, WYBEAR TRAP MEADOW SNOTEL
Mar 26, 7:21 AM MDTHEAVY SNOW 613 Sse Buffalo, WY
Mar 26, 9:37 AM MDTSNOW 3.37 Ne Buffalo, WY
Mar 26, 9:37 AM MDTSNOW 44 Ssw Buffalo, WY
Mar 26, 9:37 AM MDTHEAVY SNOW 817 Nnw Kaycee, WY
Mar 26, 9:56 AM MDTSNOW 317 W Buffalo, WYCLOUD PEAK RESERVOIR SNOTEL
Mar 26, 9:56 AM MDTSNOW 514 Wsw Buffalo, WYHANSEN SAWMILL SNOTEL

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Riverton, WY (KRIW), launched 00:00Z, 8.1 hours before the alert went out and 182 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 00:00Z on 2018-03-25Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel. CAPE 18 joules per kilogram.LCLLFCEL10008507005003002001001 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, Riverton, WY at 00:00Z on 2018-03-25The wind through the lowest 10 kilometers. Zero to 1 km storm-relative helicity 9 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
18 J/kg
Mixed-layer CIN
-69 J/kg
Mixed-layer LCL
2331 m above ground
0-6 km bulk shear
49 kt
0-1 km storm-relative helicity
9 m²/s²
0-3 km storm-relative helicity
159 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0

Open this sounding in Storm Lab

The text

As transmitted.

001 
WWUS45 KRIW 250804
WSWRIW

URGENT - WINTER WEATHER MESSAGE
National Weather Service Riverton WY
204 AM MDT Sun Mar 25 2018

...Light to moderate snowfall for Central Wyoming and Moderate to
heavy snowfall for Johnson County and the Bighorn Mountains 
tonight and Monday...

.Slow moving storm system will bring periods of snow to the area 
tonight into Monday.

WYZ010-011-252200-
/O.UPG.KRIW.WS.A.0005.180326T0000Z-180327T0000Z/
/O.NEW.KRIW.WS.W.0007.180326T0000Z-180327T0000Z/
Northeast Johnson County-Southeast Johnson County-
Including the cities of Buffalo and Kaycee
204 AM MDT Sun Mar 25 2018

...WINTER STORM WARNING IN EFFECT FROM 6 PM THIS EVENING TO 6 PM
MDT MONDAY...

* WHAT...Heavy snow expected. Total snow accumulations of 6 to 8
  inches, with localized higher amounts possible. 

* WHERE...Johnson County.

* WHEN...From 6 PM this evening to 6 PM MDT Monday.

* ADDITIONAL DETAILS...Plan on difficult travel conditions,
  including during the morning commute on Monday. Expect
  significant reductions in visibility at times. Interstates 25
  and 90 will be impacted considerably.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Storm Warning for snow means severe winter weather
conditions will make travel very hazardous or impossible. If you
must travel, keep an extra flashlight, food and water in your
vehicle in case of an emergency. The latest road conditions for
the state you are calling from can be obtained by calling 5 1 1.

&&

$$

WYZ008-009-252200-
/O.UPG.KRIW.WS.A.0005.180326T0000Z-180327T0000Z/
/O.NEW.KRIW.WW.Y.0016.180326T0000Z-180327T0000Z/
Bighorn Mountains West-Bighorn Mountains Southeast-
204 AM MDT Sun Mar 25 2018

...WINTER WEATHER ADVISORY IN EFFECT FROM 6 PM THIS EVENING TO
6 PM MDT MONDAY...

* WHAT...Snow expected. Total snow accumulations of 6 to 12 
  inches, with localized higher amounts possible.

* WHERE...Bighorn Mountains.

* WHEN...From 6 PM this evening to 6 PM MDT Monday.

* ADDITIONAL DETAILS...Plan on difficult travel conditions. Expect
  reduced visibilities at times. This includes Powder River and 
  Granite Passes.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

WYZ015-252200-
/O.NEW.KRIW.WW.Y.0016.180326T0000Z-180327T0000Z/
Wind River Mountains East-
204 AM MDT Sun Mar 25 2018

...WINTER WEATHER ADVISORY IN EFFECT FROM 6 PM THIS EVENING TO
6 PM MDT MONDAY...

* WHAT...Snow expected. Total snow accumulations of 6 to 12
  inches, with localized higher amounts possible.

* WHERE...Wind River Mountains East Slopes.

* WHEN...From 6 PM this evening to 6 PM MDT Monday.

* ADDITIONAL DETAILS...Plan on difficult travel conditions, 
  including during the morning commute on Monday. Expect reduced 
  visibilities at times. This includes South Pass.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

WYZ017-018-252200-
/O.NEW.KRIW.WW.Y.0016.180326T0000Z-180326T1800Z/
Wind River Basin-Lander Foothills-
Including the cities of Riverton, Shoshoni, and Lander
204 AM MDT Sun Mar 25 2018

...WINTER WEATHER ADVISORY IN EFFECT FROM 6 PM THIS EVENING TO
NOON MDT MONDAY...

* WHAT...Snow expected. Total snow accumulations of 3 to 5 inches,
  with localized higher amounts possible.

* WHERE...Wind River Basin and Lander Foothills.

* WHEN...From 6 PM this evening to noon MDT Monday.

* ADDITIONAL DETAILS...Plan on slippery road conditions, 
  including during the morning commute on Monday. Expect reduced 
  visibilities at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

WYZ019-252200-
/O.NEW.KRIW.WW.Y.0016.180326T0000Z-180326T1800Z/
Green Mountains and Rattlesnake Range-
Including the city of Jeffrey City
204 AM MDT Sun Mar 25 2018

...WINTER WEATHER ADVISORY IN EFFECT FROM 6 PM THIS EVENING TO
NOON MDT MONDAY...

* WHAT...Snow expected. Total snow accumulations of 3 to 6 inches,
  with localized higher amounts possible.

* WHERE...This includes Highway 789 from Sweetwater Station to
  Muddy Gap, as well as, the Green Mountains and Rattlesnake 
  Range.

* WHEN...From 6 PM this evening to noon MDT Monday.

* ADDITIONAL DETAILS...Plan on slippery road conditions, 
  including during the morning commute on Monday. Expect reduced 
  visibilities at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

WYZ020-252200-
/O.NEW.KRIW.WW.Y.0016.180326T0000Z-180326T1800Z/
Natrona County Lower Elevations-
Including the city of Casper
204 AM MDT Sun Mar 25 2018

...WINTER WEATHER ADVISORY IN EFFECT FROM 6 PM THIS EVENING TO
NOON MDT MONDAY...

* WHAT...Snow expected. Total snow accumulations of 3 to 6 inches,
  mainly Western and Northern Natrona County. For the Casper area,
  snow accumulations 1 to 3 inches are expected.
 
* WHERE...Natrona County Lower Elevations.

* WHEN...From 6 PM this evening to noon MDT Monday.

* ADDITIONAL DETAILS...Plan on slippery road conditions, including
  during the morning commute on Monday. Expect reduced
  visibilities at times. Interstate 25 north of Casper and Highway
  20 26 west of Casper may see hazardous driving conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

For more information from the National Weather Service visit
http://weather.gov/riw
5 follow-up statements
796 
WWUS45 KRIW 251540
WSWRIW

URGENT - WINTER WEATHER MESSAGE
National Weather Service Riverton WY
940 AM MDT Sun Mar 25 2018

...Light to moderate snowfall for Central Wyoming and Moderate to
heavy snowfall for Johnson County and the Bighorn Mountains
tonight and Monday...

.Slow moving storm system will bring periods of snow to the area
tonight into Monday.

WYZ010-011-260600-
/O.EXT.KRIW.WS.W.0007.180325T1800Z-180327T0000Z/
Northeast Johnson County-Southeast Johnson County-
Including the cities of Buffalo and Kaycee
940 AM MDT Sun Mar 25 2018

...WINTER STORM WARNING NOW IN EFFECT UNTIL 6 PM MDT MONDAY...

* WHAT...Heavy snow expected. Total snow accumulations of 4 to 7 
  inches, with localized amounts up to 9 inches, are expected.

* WHERE...Northeast Johnson County and Southeast Johnson County.

* WHEN...Until 6 PM MDT Monday.

* ADDITIONAL DETAILS...Plan on difficult travel conditions, 
  including during the morning commute on Monday. Expect 
  significant reductions in visibility at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Storm Warning for snow means severe winter weather
conditions will make travel very hazardous or impossible. If you
must travel, keep an extra flashlight, food and water in your
vehicle in case of an emergency. The latest road conditions for
the state you are calling from can be obtained by calling 5 1 1.

&&

$$

WYZ008-009-260600-
/O.EXT.KRIW.WW.Y.0016.180325T1800Z-180327T0000Z/
Bighorn Mountains West-Bighorn Mountains Southeast-
940 AM MDT Sun Mar 25 2018

...WINTER WEATHER ADVISORY NOW IN EFFECT UNTIL 6 PM MDT MONDAY...

* WHAT...Snow expected. Total snow accumulations of 8 to 12
  inches, with localized amounts up to 18 inches, are expected.

* WHERE...Bighorn Mountains West and Bighorn Mountains Southeast.

* WHEN...Until 6 PM MDT Monday.

* ADDITIONAL DETAILS...Plan on difficult travel conditions. 
  Expect reduced visibilities at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

WYZ015-260600-
/O.CON.KRIW.WW.Y.0016.180326T0000Z-180327T0000Z/
Wind River Mountains East-
940 AM MDT Sun Mar 25 2018

...WINTER WEATHER ADVISORY REMAINS IN EFFECT FROM 6 PM THIS
EVENING TO 6 PM MDT MONDAY...

* WHAT...Snow expected. Total snow accumulations of 4 to 7 
  inches, with localized amounts up to 12 inches, are expected.

* WHERE...Wind River Mountains East.

* WHEN...From 6 PM this evening to 6 PM MDT Monday.

* ADDITIONAL DETAILS...Plan on slippery road conditions, 
  including during the evening commute on Monday. Expect reduced 
  visibilities at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

WYZ017-018-260600-
/O.CON.KRIW.WW.Y.0016.180326T0000Z-180326T1800Z/
Wind River Basin-Lander Foothills-
Including the cities of Riverton, Shoshoni, and Lander
940 AM MDT Sun Mar 25 2018

...WINTER WEATHER ADVISORY REMAINS IN EFFECT FROM 6 PM THIS
EVENING TO NOON MDT MONDAY...

* WHAT...Snow expected. Total snow accumulations of 3 to 5 
  inches, with localized amounts up to 8 inches, are expected.

* WHERE...Wind River Basin and Lander Foothills.

* WHEN...From 6 PM this evening to noon MDT Monday.

* ADDITIONAL DETAILS...Plan on slippery road conditions, 
  including during the morning commute on Monday. Expect reduced 
  visibilities at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

WYZ019-260600-
/O.CON.KRIW.WW.Y.0016.180326T0000Z-180326T1800Z/
Green Mountains and Rattlesnake Range-
Including the city of Jeffrey City
940 AM MDT Sun Mar 25 2018

...WINTER WEATHER ADVISORY REMAINS IN EFFECT FROM 6 PM THIS
EVENING TO NOON MDT MONDAY...

* WHAT...Snow expected. Total snow accumulations of 3 to 5 
  inches, with localized amounts up to 8 inches, are expected.

* WHERE...Green Mountains and Rattlesnake Range.

* WHEN...From 6 PM this evening to noon MDT Monday.

* ADDITIONAL DETAILS...Plan on slippery road conditions, 
  including during the morning commute on Monday. Expect reduced 
  visibilities at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

WYZ020-260600-
/O.CON.KRIW.WW.Y.0016.180326T0000Z-180326T1800Z/
Natrona County Lower Elevations-
Including the city of Casper
940 AM MDT Sun Mar 25 2018

...WINTER WEATHER ADVISORY REMAINS IN EFFECT FROM 6 PM THIS
EVENING TO NOON MDT MONDAY...

* WHAT...Snow expected. Total snow accumulations of 3 to 5 
  inches, with localized amounts up to 7 inches, are expected.

* WHERE...Natrona County Lower Elevations.

* WHEN...From 6 PM this evening to noon MDT Monday.

* ADDITIONAL DETAILS...Plan on slippery road conditions, 
  including during the morning commute on Monday. Expect reduced 
  visibilities at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

For more information from the National Weather Service visit
http://weather.gov/riw
000 
WWUS45 KRIW 260008
WSWRIW

URGENT - WINTER WEATHER MESSAGE
National Weather Service Riverton WY
608 PM MDT Sun Mar 25 2018

...Light to moderate snowfall for Central Wyoming and Moderate to
heavy snowfall for Johnson County and the Bighorn Mountains
tonight and Monday...

.Slow moving storm system will bring periods of snow to the area
tonight into Monday.

WYZ010-011-260930-
/O.CON.KRIW.WS.W.0007.000000T0000Z-180327T0000Z/
Northeast Johnson County-Southeast Johnson County-
Including the cities of Buffalo and Kaycee
608 PM MDT Sun Mar 25 2018

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 6 PM MDT MONDAY...

* WHAT...Heavy snow. Additional snow accumulations of 5 to 8 
  inches, with localized amounts up to 10 inches, are expected.

* WHERE...Northeast Johnson County and Southeast Johnson County.

* WHEN...Until 6 PM MDT Monday.

* ADDITIONAL DETAILS...Plan on difficult travel conditions, 
  including during the morning commute on Monday. Expect 
  significant reductions in visibility at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Storm Warning for snow means severe winter weather
conditions will make travel very hazardous or impossible. If you
must travel, keep an extra flashlight, food and water in your
vehicle in case of an emergency. The latest road conditions for
the state you are calling from can be obtained by calling 5 1 1.

&&

$$

WYZ005>007-260930-
/O.EXB.KRIW.WW.Y.0016.180326T0300Z-180326T1800Z/
Southwest Big Horn Basin-Southeast Big Horn Basin-
Owl Creek and Bridger Mountains-
Including the cities of Thermopolis and Worland
608 PM MDT Sun Mar 25 2018

...WINTER WEATHER ADVISORY IN EFFECT FROM 9 PM THIS EVENING TO
NOON MDT MONDAY...

* WHAT...Snow expected. Total snow accumulations of 3 to 6 inches
  south and east of Worland and Thermopolis with 1 to 2 inches
  expected from a Worland to Thermopolis line and north and west.
  5 to 10 inches of snow are expected in the Owl Creek Mountains
  and Wind River Canyon.  

* WHERE...Southwest Big Horn Basin, Southeast Big Horn Basin and 
  Owl Creek and Bridger Mountains.

* WHEN...From 9 PM this evening to noon MDT Monday.

* ADDITIONAL DETAILS...Plan on slippery road conditions, 
  including during the morning commute on Monday. Expect reduced 
  visibilities at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

WYZ008-009-260930-
/O.CON.KRIW.WW.Y.0016.000000T0000Z-180327T0000Z/
Bighorn Mountains West-Bighorn Mountains Southeast-
608 PM MDT Sun Mar 25 2018

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 6 PM MDT
MONDAY...

* WHAT...Snow. Additional snow accumulations of 8 to 12 inches,
  with localized amounts up to 16 inches, are expected.

* WHERE...Bighorn Mountains West and Bighorn Mountains Southeast.

* WHEN...Until 6 PM MDT Monday.

* ADDITIONAL DETAILS...Plan on difficult travel conditions. 
  Expect reduced visibilities at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

WYZ015-260930-
/O.CON.KRIW.WW.Y.0016.000000T0000Z-180327T0000Z/
Wind River Mountains East-
608 PM MDT Sun Mar 25 2018

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 6 PM MDT
MONDAY...

* WHAT...Snow expected. Total snow accumulations of 5 to 8 inches,
  with localized amounts up to 12 inches, are expected.

* WHERE...Wind River Mountains East.

* WHEN...Until 6 PM MDT Monday.

* ADDITIONAL DETAILS...Plan on difficult travel conditions, 
  including during the morning commute on Monday. Expect reduced 
  visibilities at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

WYZ017-018-260930-
/O.CON.KRIW.WW.Y.0016.000000T0000Z-180326T1800Z/
Wind River Basin-Lander Foothills-
Including the cities of Riverton, Shoshoni, and Lander
608 PM MDT Sun Mar 25 2018

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL NOON MDT
MONDAY...

* WHAT...Snow expected. Total snow accumulations of 3 to 5 inches.

* WHERE...Wind River Basin and Lander Foothills.

* WHEN...Until noon MDT Monday.

* ADDITIONAL DETAILS...Plan on slippery road conditions, 
  including during the morning commute on Monday. Expect reduced 
  visibilities at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

WYZ019-260930-
/O.CON.KRIW.WW.Y.0016.000000T0000Z-180326T1800Z/
Green Mountains and Rattlesnake Range-
Including the city of Jeffrey City
608 PM MDT Sun Mar 25 2018

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL NOON MDT
MONDAY...

* WHAT...Snow expected. Total snow accumulations of 3 to 5 inches,
  with localized amounts up to 9 inches, are expected.

* WHERE...Green Mountains and Rattlesnake Range.

* WHEN...Until noon MDT Monday.

* ADDITIONAL DETAILS...Plan on slippery road conditions, 
  including during the morning commute on Monday. Expect reduced 
  visibilities at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

WYZ020-260930-
/O.CON.KRIW.WW.Y.0016.000000T0000Z-180326T1800Z/
Natrona County Lower Elevations-
Including the city of Casper
608 PM MDT Sun Mar 25 2018

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL NOON MDT
MONDAY...

* WHAT...Snow expected. Total snow accumulations of 3 to 7 inches
  north of U.S. Highway 20 with 1 to 3 inches south of U.S. 
  Highway 20 and the Casper area. 

* WHERE...Natrona County Lower Elevations.

* WHEN...Until noon MDT Monday.

* ADDITIONAL DETAILS...Plan on slippery road conditions, 
  including during the morning commute on Monday. Expect reduced 
  visibilities at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

For more information from the National Weather Service visit
http://weather.gov/riw
103 
WWUS45 KRIW 260739
WSWRIW

URGENT - WINTER WEATHER MESSAGE
National Weather Service Riverton WY
139 AM MDT Mon Mar 26 2018

...Light to moderate snowfall for Central Wyoming through noon and
Moderate to heavy snowfall for Johnson County and the Bighorn 
Mountains through this afternoon...

WYZ010-011-261830-
/O.CON.KRIW.WS.W.0007.000000T0000Z-180327T0000Z/
Northeast Johnson County-Southeast Johnson County-
Including the cities of Buffalo and Kaycee
139 AM MDT Mon Mar 26 2018

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 6 PM MDT THIS
EVENING...

* WHAT...Heavy snow. Additional snow accumulations of 3 to 6 
  inches are expected.

* WHERE...Johnson County.

* WHEN...Until 6 PM MDT this evening.

* ADDITIONAL DETAILS...Plan on difficult travel conditions,
  including during the morning commute. Expect significant
  reductions in visibility at times. This includes interstates 25
  and 90.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Storm Warning for snow means severe winter weather
conditions will make travel very hazardous or impossible. If you
must travel, keep an extra flashlight, food and water in your
vehicle in case of an emergency. The latest road conditions for
the state you are calling from can be obtained by calling 5 1 1.

&&

$$

WYZ008-009-261830-
/O.CON.KRIW.WW.Y.0016.000000T0000Z-180327T0000Z/
Bighorn Mountains West-Bighorn Mountains Southeast-
139 AM MDT Mon Mar 26 2018

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 6 PM MDT THIS
EVENING...

* WHAT...Snow. Additional snow accumulations of 4 to 7 inches,
  with localized amounts up to 9 inches, are expected.

* WHERE...Bighorn Mountains.

* WHEN...Until 6 PM MDT this evening.

* ADDITIONAL DETAILS...Plan on slippery road conditions, 
  including during the morning commute. Expect reduced 
  visibilities at times. This includes Powder River and 
  Granite Passes.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

WYZ015-261830-
/O.CON.KRIW.WW.Y.0016.000000T0000Z-180327T0000Z/
Wind River Mountains East-
139 AM MDT Mon Mar 26 2018

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 6 PM MDT THIS
EVENING...

* WHAT...Snow. Additional snow accumulations of 3 to 6 inches,
  with localized amounts up to 8 inches, are expected.

* WHERE...Wind River Mountains East.

* WHEN...Until 6 PM MDT this evening.

* ADDITIONAL DETAILS...Plan on slippery road conditions, including
  during the morning commute. In addition, some reductions to
  visibility are likely. This includes South Pass. Winds gusting 
  as high as 30 mph will cause patchy blowing and drifting snow.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

WYZ017-018-261800-
/O.CON.KRIW.WW.Y.0016.000000T0000Z-180326T1800Z/
Wind River Basin-Lander Foothills-
Including the cities of Riverton, Shoshoni, and Lander
139 AM MDT Mon Mar 26 2018

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL NOON MDT
TODAY...

* WHAT...Snow. Total snow accumulations of 3 to 5 inches are 
  expected.

* WHERE...Wind River Basin and Lander Foothills.

* WHEN...Until noon MDT today.

* ADDITIONAL DETAILS...Plan on slippery road conditions, 
  including during the morning commute. Expect reduced 
  visibilities at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

WYZ019-261800-
/O.CON.KRIW.WW.Y.0016.000000T0000Z-180326T1800Z/
Green Mountains and Rattlesnake Range-
Including the city of Jeffrey City
139 AM MDT Mon Mar 26 2018

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL NOON MDT
TODAY...

* WHAT...Snow. Additional snow accumulations of 2 to 4 inches are
  expected.

* WHERE...This includes Highway 789 from Sweetwater Station to 
  Muddy Gap, as well as, the Green Mountains and Rattlesnake 
  Range.

* WHEN...Until noon MDT today.

* ADDITIONAL DETAILS...Plan on slippery road conditions, 
  including during the morning commute. Expect reduced 
  visibilities at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

WYZ020-261800-
/O.CON.KRIW.WW.Y.0016.000000T0000Z-180326T1800Z/
Natrona County Lower Elevations-
Including the city of Casper
139 AM MDT Mon Mar 26 2018

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL NOON MDT
TODAY...

* WHAT...Snow. Additional snow accumulations of 2 to 4 inches,
  with localized amounts up to 6 inches for Western and Northern
  Natrona County. For the Casper area, total snow accumulations 
  of 1 to 3 inches are expected.

* WHERE...Natrona County Lower Elevations.

* WHEN...Until noon MDT today.

* ADDITIONAL DETAILS...Plan on slippery road conditions, including
  during the morning commute. Expect reduced visibilities at
  times. Interstate 25 north of Casper and Highway 20 26 west of
  Casper may see hazardous driving conditions.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

WYZ005>007-261800-
/O.CON.KRIW.WW.Y.0016.000000T0000Z-180326T1800Z/
Southwest Big Horn Basin-Southeast Big Horn Basin-
Owl Creek and Bridger Mountains-
Including the cities of Thermopolis and Worland
139 AM MDT Mon Mar 26 2018

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL NOON MDT
TODAY...

* WHAT...Snow. Total snow accumulations of 3 to 6 inches
  south and east of Worland and Thermopolis with 1 to 2 inches
  expected from a Worland to Thermopolis line and north and west.
  5 to 10 inches of snow are expected in the Owl Creek Mountains
  and Wind River Canyon.

* WHERE...Southwest Big Horn Basin, Southeast Big Horn Basin and 
  Owl Creek and Bridger Mountains.

* WHEN...Until noon MDT today.

* ADDITIONAL DETAILS...Plan on slippery road conditions, 
  including during the morning commute. Expect reduced 
  visibilities at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

For more information from the National Weather Service visit
http://weather.gov/riw
257 
WWUS45 KRIW 261755
WSWRIW

URGENT - WINTER WEATHER MESSAGE
National Weather Service Riverton WY
1155 AM MDT Mon Mar 26 2018

...Light snow with little to no additional accumulation expected
for Johnson County and the Bighorn Mountains this afternoon...

WYZ017-018-261900-
/O.EXP.KRIW.WW.Y.0016.000000T0000Z-180326T1800Z/
Wind River Basin-Lander Foothills-
Including the cities of Riverton, Shoshoni, and Lander
1155 AM MDT Mon Mar 26 2018

...WINTER WEATHER ADVISORY WILL EXPIRE AT NOON MDT TODAY...

Snow has ended across the area. Any additional showers will fall 
as rain, as temperatures rise above freezing this afternoon.

$$

WYZ019-261900-
/O.EXP.KRIW.WW.Y.0016.000000T0000Z-180326T1800Z/
Green Mountains and Rattlesnake Range-
Including the city of Jeffrey City
1155 AM MDT Mon Mar 26 2018

...WINTER WEATHER ADVISORY WILL EXPIRE AT NOON MDT TODAY...

Snow has ended across the area. Any additional showers will fall 
as rain, as temperatures rise above freezing this afternoon..

$$

WYZ020-261900-
/O.EXP.KRIW.WW.Y.0016.000000T0000Z-180326T1800Z/
Natrona County Lower Elevations-
Including the city of Casper
1155 AM MDT Mon Mar 26 2018

...WINTER WEATHER ADVISORY WILL EXPIRE AT NOON MDT TODAY...

Snow has ended across the area. Any additional showers will fall 
as rain, as temperatures rise above freezing this afternoon..

$$

WYZ005>007-261900-
/O.EXP.KRIW.WW.Y.0016.000000T0000Z-180326T1800Z/
Southwest Big Horn Basin-Southeast Big Horn Basin-
Owl Creek and Bridger Mountains-
Including the cities of Thermopolis and Worland
1155 AM MDT Mon Mar 26 2018

...WINTER WEATHER ADVISORY WILL EXPIRE AT NOON MDT TODAY...

Snow has ended across the area. Any additional showers will fall 
as rain, as temperatures rise above freezing this afternoon.

$$

WYZ010-011-270000-
/O.CON.KRIW.WS.W.0007.000000T0000Z-180327T0000Z/
Northeast Johnson County-Southeast Johnson County-
Including the cities of Buffalo and Kaycee
1155 AM MDT Mon Mar 26 2018

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL 6 PM MDT THIS
EVENING...

* WHAT...Light snow. Additional snow accumulations of up to 1 inch 
  are expected.

* WHERE...Northeast Johnson County and Southeast Johnson County.

* WHEN...Until 6 PM MDT this evening.

* ADDITIONAL DETAILS...Plan on difficult travel conditions. 
  Expect significant reductions in visibility at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Storm Warning for snow means severe winter weather
conditions will make travel very hazardous or impossible. If you
must travel, keep an extra flashlight, food and water in your
vehicle in case of an emergency. The latest road conditions for
the state you are calling from can be obtained by calling 5 1 1.

&&

$$

WYZ008-009-270000-
/O.CON.KRIW.WW.Y.0016.000000T0000Z-180327T0000Z/
Bighorn Mountains West-Bighorn Mountains Southeast-
1155 AM MDT Mon Mar 26 2018

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 6 PM MDT THIS
EVENING...

* WHAT...Snow. Additional snow accumulations of 1 to 3 inches 
  are expected.

* WHERE...Bighorn Mountains West and Bighorn Mountains Southeast.

* WHEN...Until 6 PM MDT this evening.

* ADDITIONAL DETAILS...Plan on slippery road conditions. Expect 
  reduced visibilities at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

WYZ015-270000-
/O.CON.KRIW.WW.Y.0016.000000T0000Z-180327T0000Z/
Wind River Mountains East-
1155 AM MDT Mon Mar 26 2018

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL 6 PM MDT THIS
EVENING...

* WHAT...Snow. Additional snow accumulations of 1 to 3 inches 
  are expected.

* WHERE...Wind River Mountains East.

* WHEN...Until 6 PM MDT this evening.

* ADDITIONAL DETAILS...Plan on slippery road conditions. Expect 
  reduced visibilities at times.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A Winter Weather Advisory for snow means periods of snow will
cause primarily travel difficulties. Expect snow covered roads
and limited visibilities, and use caution while driving. The
latest road conditions for the state you are calling from can be
obtained by calling 5 1 1.

&&

$$

For more information from the National Weather Service visit
http://weather.gov/riw
856 
WWUS45 KRIW 262116
WSWRIW

URGENT - WINTER WEATHER MESSAGE
National Weather Service Riverton WY
316 PM MDT Mon Mar 26 2018


WYZ010-011-262230-
/O.CAN.KRIW.WS.W.0007.000000T0000Z-180327T0000Z/
Northeast Johnson County-Southeast Johnson County-
Including the cities of Buffalo and Kaycee
316 PM MDT Mon Mar 26 2018

...WINTER STORM WARNING IS CANCELLED...

Snow has ended across the area. Any additional snow will have
little to no accumulation.

$$

WYZ008-009-015-262230-
/O.CAN.KRIW.WW.Y.0016.000000T0000Z-180327T0000Z/
Bighorn Mountains West-Bighorn Mountains Southeast-
Wind River Mountains East-
316 PM MDT Mon Mar 26 2018

...WINTER WEATHER ADVISORY IS CANCELLED...

Snow has ended across the area. Any additional snow will have
little to no accumulation..

$$

For more information from the National Weather Service visit
http://weather.gov/riw

What forecasters said that day

The local office's own words before this winter storm warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Riverton, WY wrote its last area forecast discussion before this winter storm warning went out at Mar 24, 11:58 PM MDT, 2 hours 6 minutes earlier.

Area forecast discussion, Mar 24, 11:58 PM MDT, 2 hours 6 minutes before
Area Forecast Discussion
National Weather Service Riverton WY
1158 PM MDT Sat Mar 24 2018

.SHORT TERM...This evening through Tuesday
Issued at 210 PM MDT Sat Mar 24 2018

A large Pacific low pressure trough moving inland along the
Pacific northwest coast will move rapidly east tonight and Sunday
moving across western Wyoming Sunday afternoon. Moisture in the
southwest flow aloft is becoming limited as colder dry air moves
through the trough. This is expected to limit snowfall through
Sunday in the west while the snow shifts to areas east of the
Continental Divide. Behind the trough colder air will move in
Sunday night and Monday with snow and areas of rain in the lower
elevations . At this time it looks like Johnson County and the
Bighorn mountains will get hit the hardest where and Winter Storm
Watch is in effect. Areas of the northern Bighorns could see 12
to 15 inches while 5 to 8 inches may hit the Buffalo area.
Snowfall is expected to be lower to the west in the Bighorn Basin
and to the South in Natrona and Fremont counties where Snowfall of
2 to 4 inches below 7000 feet with 4 to 8 inches above 7000 feet
is expected by Monday afternoon. Temperatures will fall
significantly. Monday night and Tuesday will see clearing with
some showers lingering over the mountains. Some areas of fog will
likely form in the lower elevations but this is will depend on the
distribution of the precipitation and the amount of clearing and
is not the focus of the forecast at this time.

.LONG TERM...Tuesday night through Saturday night
Issued at 210 PM MDT Sat Mar 24 2018

The period will be dominated by NW flow aloft, with a ridge of
high pressure over the EPAC through Thursday. This will allow for
a more progressive, zonal flow toward the end of the period. A
cold front will approach northern WY Tuesday night into Wednesday,
spreading rain and snow chances southward across much of the area
by Wednesday afternoon. Any cold air associated with this front
will stay over E WY, keeping precipitation as rain for areas east
of the Divide. This activity will continue Wednesday night, as a
second shortwave quickly reinforces the first system. Rain will
change over to snow, as temperatures drop through the night.
Precipitation will then recede back to the northern and western
mountains by Thursday morning and remain confined there through
the rest of the period. Isolated to scattered (at best) rain and
snow showers will occur over these areas. Temperatures will be
seasonal, with highs in the 40s to lower 50s and lows mainly in
the 20s.

&&

.AVIATION...(For the 06Z TAFS through 06Z Sunday night)
Issued at 1156 PM MDT Sat Mar 24 2018

West of the Divide...KBPI/KJAC/KPNA/KRKS Routes

An upper level low pressure system will move east into the
northern Great Basin on Sunday and across western Wyoming Sunday
night. Scattered MVFR, isolated IFR snow showers with occasional
mountain obscurations occur Sunday morning, most of this activity
vicinity KBPI-KPNA. Snow showers, MVFR/IFR conditions, mountain
obscurations will become more widespread after 21z Sunday vicinity
and south of a vicinity KJAC-KDUB line and continue through early
Monday morning.

East of the Divide...KCOD/KCPR/KLND/KRIW/KWRL Routes

Scattered MVFR, isolated IFR snow showers will occur mainly vicinity
and north of a KTHP-50SM north KCPR line through Sunday morning.
Snow showers are expected to become more numerous and push
southward Sunday evening with more widespread MVFR, areas of IFR
conditions expected vicinity and north of a KLND-KCPR line after
03z Monday.

&&

.FIRE WEATHER...
Issued AT 210 PM MDT Sat Mar 24 2018

A large Pacific low pressure trough moving inland along the
Pacific northwest coast will move rapidly east tonight and Sunday
moving across western Wyoming Sunday afternoon. Moisture in the
southwest flow aloft is becoming limited as colder dry air moves
through the trough. This is expected to limit snowfall through
Sunday in the west while the snow shifts to areas east of the
Continental Divide. Behind the trough colder air will move in
Sunday night and Monday with snow and areas of rain in the lower
elevations . At this time it looks like Johnson County and the
Bighorn mountains will get hit the hardest where and Winter Storm
Watch is in effect. Areas of the northern Bighorns could see 12
to 15 inches while 5 to 8 inches may hit the Buffalo area.
Snowfall is expected to be lower to the west in the Bighorn Basin
and to the South in Natrona and Fremont counties where Snowfall of
2 to 4 inches below 7000 feet with 4 to 8 inches above 7000 feet
is expected by Monday afternoon. Temperatures will fall
significantly. Monday night and Tuesday will see clearing with
some showers lingering over the mountains. Some areas of fog will
likely form in the lower elevations but this is will depend on the
distribution of the precipitation and the amount of clearing and
is not the focus of the forecast at this time. The west will have
poor smoke dispersal Sunday while the east will have good or
better smoke dispersal. Most of the area will have poor smoke
dispersal on Monday.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
Winter Storm Watch from Sunday evening through Monday afternoon
for WYZ008>011.

&&

SHORT TERM...Baker
LONG TERM...LaVoie
AVIATION...Meunier
FIRE WEATHER...Baker
Hazardous weather outlook, Mar 24, 3:25 AM MDT, 22 hours 39 minutes before
Hazardous Weather Outlook
National Weather Service Riverton WY
325 AM MDT Sat Mar 24 2018

WYZ001>020-022>030-251200-
Yellowstone National Park-Absaroka Mountains-Cody Foothills-
North Big Horn Basin-Southwest Big Horn Basin-
Southeast Big Horn Basin-Owl Creek and Bridger Mountains-
Bighorn Mountains West-Bighorn Mountains Southeast-
Northeast Johnson County-Southeast Johnson County-
Teton and Gros Ventre Mountains-Jackson Hole-
Wind River Mountains West-Wind River Mountains East-
Upper Wind River Basin-Wind River Basin-Lander Foothills-
Green Mountains and Rattlesnake Range-
Natrona County Lower Elevations-Casper Mountain-Star Valley-
Salt River and Wyoming Ranges-Upper Green River Basin Foothills-
Upper Green River Basin-South Lincoln County-
Rock Springs and Green River-Flaming Gorge-East Sweetwater County-
325 AM MDT Sat Mar 24 2018

This Hazardous Weather Outlook is for Western and Central Wyoming.

.DAY ONE...Today and Tonight

Light to moderate snow in the western mountains.

.DAYS TWO THROUGH SEVEN...Sunday through Friday

Sunday...A cold front will likely bring periods of snow across
the west. Rain will begin east of the divide later in the
afternoon the change to snow in the evening.

Sunday Night and Monday...A good chance of snow for much of
Central Wyoming. Moderate to heavy snow is possible over Johnson
County and the Bighorn Mountains.

Wednesday...A chance of snow in the north. A chance of rain and
snow in the central and south.

.SPOTTER INFORMATION STATEMENT...

Spotters are encouraged to report snow amounts.

The office that day

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

IssuedProductOfficeCountiesLasted
Mar 25, 2:04 AM MDTWinter Weather AdvisoryRIWBig Horn, Fremont, Hot Springs, Johnson, Natrona, Sublette and 2 more37 hr

Nearby

Winter Storm Warnings in Wyoming, 2018Every winter storm warning 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; local storm reports from the same archive; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.