Winter Storm Warning 16, NWS Riverton, WY

602 
WWUS45 KRIW 200357
WSWRIW

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE RIVERTON WY
857 PM MST MON DEC 19 2016

...SNOW AND STRONG WINDS HEADED FOR WESTERN WYOMING MIDNIGHT
TONIGHT THROUGH MIDNIGHT TUESDAY NIGHT...

.A VERY STRONG AND MOIST PACIFIC STORM SYSTEM WILL BRING
INCREASING SNOWFALL AND STRONG WINDS TO THE WEST LATER TONIGHT
THROUGH TUESDAY EVENING. WIND WILL GUSTS TO 55 MPH OVER THE
MOUNTAIN PASSES AND HIGHER RIDGES LATER TONIGHT AND TUESDAY. SNOW
AND STRONG WIND WILL CONTINUE THROUGH TUESDAY AND TUESDAY EVENING
THEN RAPIDLY DECREASE AROUND MIDNIGHT TUESDAY NIGHT AS THE MAIN
TROUGH PASSES EAST OF THE AREA. SNOWFALL OF 10 TO 20 INCHES IS
EXPECTED IN THE TETONS WITH 8 TO 12 INCHES IN THE OTHER WESTERN
MOUNTAIN RANGES. SIGNIFICANT BLOWING AND DRIFTING SNOW IS EXPECTED
WITH NEAR ZERO VISIBILITY AT TIMES.

WYZ012-013-201200-
/O.CON.KRIW.WS.W.0016.161220T0700Z-161221T0700Z/
TETON AND GROS VENTRE MOUNTAINS-JACKSON HOLE-
INCLUDING THE CITY OF...JACKSON
857 PM MST MON DEC 19 2016

...WINTER STORM WARNING REMAINS IN EFFECT FROM MIDNIGHT TONIGHT
TO MIDNIGHT MST TUESDAY NIGHT...

* TIMING...INCREASING SNOWFALL AND STRONG WINDS WILL DEVELOP LATER
  TONIGHT WITH MODERATE TO HEAVY SNOW BECOMING MORE WIDESPREAD. SIGNIFICANT
  BLOWING AND DRIFTING SNOW WILL REDUCE VISIBILITY TO NEAR ZERO AT
  TIMES. THE SNOW AND WIND IS EXPECTED TO CONTINUE THROUGH TUESDAY
  EVENING THEN TAPER OFF AROUND MIDNIGHT.

* SNOWFALL...10 TO 20 INCHES OF SNOW IS EXPECTED IN THE TETON 
  MOUNTAINS WITH 5 TO 10 INCHES IN JACKSON HOLE. 

* WIND AND VISIBILITY...WEST WINDS OF 20 TO 30 MPH WITH GUSTS AS
  HIGH AS 55 MPH WILL CAUSE BLOWING AND DRIFTING SNOW WITH NEAR
  ZERO VISIBILITY AT TIMES...ESPECIALLY AT PASS LEVEL AND OVER
  EXPOSED RIDGES. THE JACKSON VALLEY CAN EXPECT SOUTHWEST WINDS 15
  TO 25 MPH WITH GUSTS TO 35 MPH OVER OPEN AREAS NORTH OF JACKSON.

* MAIN IMPACT...ROADS WILL BECOME SLICK AND SNOW PACKED AND LOW 
  VISIBILITY WILL MAKE DRIVING DIFFICULT WITH NEAR ZERO 
  VISIBILITY. 

* OTHER IMPACTS...OUTDOOR ACTIVITY WILL BECOME VERY DIFFICULT 
  WITH THE STRONG WIND INCREASING THE CHANCES FOR HYPOTHERMIA. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER STORM WARNING MEANS SIGNIFICANT AMOUNTS OF SNOW... AND
OR BLOWING SNOW ARE EXPECTED OR OCCURRING. THIS COULD MAKE TRAVEL
VERY HAZARDOUS OR IMPOSSIBLE. IF YOU MUST TRAVEL KEEP SOME FOOD...
WATER... AND AN EXTRA FLASHLIGHT IN YOUR VEHICLE IN CASE OF AN
EMERGENCY. CHECK THE LATEST ROAD CONDITIONS AT WYOROAD.INFO OR BY
DIALING 5 1 1.

&&

$$

WYZ001-002-201200-
/O.CON.KRIW.WW.Y.0040.161220T0700Z-161221T0700Z/
YELLOWSTONE NATIONAL PARK-ABSAROKA MOUNTAINS-
INCLUDING THE CITIES OF...LAKE...MAMMOTH...OLD FAITHFUL
857 PM MST MON DEC 19 2016

...WINTER WEATHER ADVISORY REMAINS IN EFFECT FROM MIDNIGHT
TONIGHT TO MIDNIGHT MST TUESDAY NIGHT...

* TIMING...INCREASING SNOWFALL AND STRONG WINDS WILL DEVELOP LATER
  TONIGHT WITH MODERATE TO HEAVY SNOW BECOMING MORE WIDESPREAD.
  SIGNIFICANT BLOWING AND DRIFTING SNOW WILL REDUCE VISIBILITY TO
  NEAR ZERO AT TIMES. THE SNOW AND WIND IS EXPECTED TO CONTINUE
  THROUGH TUESDAY EVENING THEN TAPER OFF AROUND MIDNIGHT.

* SNOWFALL...6 TO 12 INCHES OF SNOW IS EXPECTED IN THE ABSAROKA 
  MOUNTAINS WITH 3 TO 6 INCHES AROUND MAMMOTH. 

* WIND AND VISIBILITY...WEST WINDS OF 20 TO 30 MPH WITH GUSTS AS 
  HIGH AS 55 MPH WILL CAUSE BLOWING AND DRIFTING SNOW WITH NEAR 
  ZERO VISIBILITY AT TIMES. 

* MAIN IMPACT...ROADS WILL BECOME SLICK AND SNOW PACKED AND LOW 
  VISIBILITY WILL MAKE DRIVING DIFFICULT WITH NEAR ZERO 
  VISIBILITY. 

* OTHER IMPACTS...OUTDOOR ACTIVITY WILL BECOME VERY DIFFICULT 
  WITH THE STRONG WIND INCREASING THE CHANCES FOR HYPOTHERMIA. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER WEATHER ADVISORY FOR SNOW AND BLOWING SNOW MEANS PERIODS
OF SNOW WILL CAUSE PRIMARILY TRAVEL DIFFICULTIES. BE PREPARED FOR
SNOW COVERED AND SLICK ROADS WITH LIMITED VISIBILITIES. SLOW
DOWN... AND ALLOW EXTRA TIME TO REACH YOUR DESTINATION. CHECK THE
LATEST ROAD CONDITIONS AT WYOROAD.INFO OR BY DIALING 5 1 1.

&&

$$

WYZ023-024-201200-
/O.CON.KRIW.WW.Y.0040.161220T0700Z-161221T0700Z/
STAR VALLEY-SALT RIVER AND WYOMING RANGES-
INCLUDING THE CITIES OF...AFTON...ALPINE...STAR VALLEY RANCH...
THAYNE
857 PM MST MON DEC 19 2016

...WINTER WEATHER ADVISORY REMAINS IN EFFECT FROM MIDNIGHT
TONIGHT TO MIDNIGHT MST TUESDAY NIGHT...

* TIMING...INCREASING SNOWFALL AND STRONG WINDS WILL DEVELOP LATER
  TONIGHT WITH MODERATE TO HEAVY SNOW BECOMING MORE WIDESPREAD.
  SIGNIFICANT BLOWING AND DRIFTING SNOW WILL REDUCE VISIBILITY TO
  NEAR ZERO AT TIMES. THE SNOW AND WIND IS EXPECTED TO CONTINUE
  THROUGH TUESDAY EVENING THEN TAPER OFF AROUND MIDNIGHT.

* SNOWFALL...6 TO 12 INCHES OF SNOW IS EXPECTED IN THE WYOMING 
  AND SALT RIVER RANGES WITH 3 TO 6 INCHES IN THE STAR VALLEY. 

* WIND AND VISIBILITY...WEST WINDS OF 20 TO 30 MPH WITH GUSTS AS
  HIGH AS 55 MPH WILL CAUSE BLOWING AND DRIFTING SNOW WITH NEAR
  ZERO VISIBILITY AT TIMES ON SALT RIVER PASS. THE STAR VALLEY CAN
  EXPECT SOUTHWEST WINDS GENERALLY IN THE 15 TO 25 MPH RANGE.

* MAIN IMPACT...ROADS WILL BECOME SLICK AND SNOW PACKED AND LOW
  VISIBILITY WILL MAKE DRIVING DIFFICULT WITH NEAR ZERO VISIBILITY
  IN THE MOUNTAINS AND UNDER ONE HALF MILE AT TIMES IN THE LOWER
  ELEVATIONS.

* OTHER IMPACTS...OUTDOOR ACTIVITY WILL BECOME VERY DIFFICULT 
  WITH THE STRONG WIND INCREASING THE CHANCES FOR HYPOTHERMIA. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER WEATHER ADVISORY FOR SNOW AND BLOWING SNOW MEANS PERIODS
OF SNOW WILL CAUSE PRIMARILY TRAVEL DIFFICULTIES. BE PREPARED FOR
SNOW COVERED AND SLICK ROADS WITH LIMITED VISIBILITIES. SLOW
DOWN... AND ALLOW EXTRA TIME TO REACH YOUR DESTINATION. CHECK THE
LATEST ROAD CONDITIONS AT WYOROAD.INFO OR BY DIALING 5 1 1.

&&

$$

WYZ014-015-201200-
/O.CON.KRIW.WW.Y.0040.161220T0700Z-161221T0700Z/
WIND RIVER MOUNTAINS WEST-WIND RIVER MOUNTAINS EAST-
857 PM MST MON DEC 19 2016

...WINTER WEATHER ADVISORY REMAINS IN EFFECT FROM MIDNIGHT
TONIGHT TO MIDNIGHT MST TUESDAY NIGHT...

* TIMING...SNOWFALL WILL GRADUALLY INCREASE OVERNIGHT INTO
  TUESDAY MORNING ALONG WITH INCREASING SOUTHWEST WIND. THE
  SNOWFALL WILL CONTINUE INTO TUESDAY EVENING ALONG WITH
  SIGNIFICANT BLOWING AND DRIFTING SNOW.

* SNOWFALL...6 TO 12 INCHES OF SNOW IS EXPECTED IN THE WIND 
  RIVER MOUNTAINS. 

* WIND AND VISIBILITY...WEST WINDS OF 20 TO 30 MPH WITH GUSTS AS 
  HIGH AS 55 MPH WILL CAUSE BLOWING AND DRIFTING SNOW WITH NEAR 
  ZERO VISIBILITY AT TIMES ON SOUTH PASS. 

* MAIN IMPACT...ROADS WILL BECOME SLICK AND SNOW PACKED AND LOW 
  VISIBILITY WILL MAKE DRIVING DIFFICULT WITH NEAR ZERO 
  VISIBILITY. 

* OTHER IMPACTS...OUTDOOR ACTIVITY WILL BECOME VERY DIFFICULT 
  WITH THE STRONG WIND INCREASING THE CHANCES FOR HYPOTHERMIA. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER WEATHER ADVISORY FOR SNOW AND BLOWING SNOW MEANS PERIODS
OF SNOW WILL CAUSE PRIMARILY TRAVEL DIFFICULTIES. BE PREPARED FOR
SNOW COVERED AND SLICK ROADS WITH LIMITED VISIBILITIES. SLOW
DOWN... AND ALLOW EXTRA TIME TO REACH YOUR DESTINATION. CHECK THE
LATEST ROAD CONDITIONS AT WYOROAD.INFO OR BY DIALING 5 1 1.

&&

$$

759 
WWUS45 KRIW 200854
WSWRIW

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE RIVERTON WY
154 AM MST TUE DEC 20 2016

...SNOW AND STRONG WINDS FOR WESTERN WYOMING THROUGH TONIGHT...

.A VERY STRONG AND MOIST PACIFIC STORM SYSTEM WILL BRING
INCREASING SNOWFALL AND STRONG WINDS TO THE WEST THROUGH THIS
EVENING.

WYZ012-013-202300-
/O.CON.KRIW.WS.W.0016.000000T0000Z-161221T0700Z/
TETON AND GROS VENTRE MOUNTAINS-JACKSON HOLE-
INCLUDING THE CITY OF...JACKSON
154 AM MST TUE DEC 20 2016

...WINTER STORM WARNING REMAINS IN EFFECT UNTIL MIDNIGHT MST
TONIGHT...

* TIMING...LIGHT SNOW THIS MORNING WILL BECOME STEADIER AND
  HEAVIER WITH THE HEAVIEST SNOW EXPECTED THIS AFTERNOON AND EARLY
  THIS EVENING BEFORE TAPERING OFF AROUND MIDNIGHT.

* SNOWFALL...10 TO 16 INCHES IN THE MOUNTAINS...4 TO 8 INCHES IN
  THE JACKSON VALLEY.

* WIND AND VISIBILITY...WEST WINDS 20 TO 30 MPH WITH GUSTS AS HIGH
  AS 55 MPH WILL CAUSE BLOWING AND DRIFTING SNOW WITH NEAR ZERO
  VISIBILITY AT TIMES...ESPECIALLY AT PASS LEVEL AND OVER EXPOSED
  RIDGES. THE JACKSON VALLEY WILL HAVE SOUTHWEST WINDS 15 TO 25
  MPH WITH GUSTS TO 35 MPH OVER OPEN AREAS NORTH OF JACKSON.

* MAIN IMPACT...ROADS WILL BECOME SLICK AND SNOW PACKED AND LOW 
  VISIBILITY WILL MAKE DRIVING DIFFICULT WITH NEAR ZERO 
  VISIBILITY. 

* OTHER IMPACTS...OUTDOOR ACTIVITY WILL BECOME VERY DIFFICULT 
  WITH THE STRONG WIND INCREASING THE CHANCES FOR HYPOTHERMIA. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER STORM WARNING MEANS SIGNIFICANT AMOUNTS OF SNOW... AND
OR BLOWING SNOW ARE EXPECTED OR OCCURRING. THIS COULD MAKE TRAVEL
VERY HAZARDOUS OR IMPOSSIBLE. IF YOU MUST TRAVEL KEEP SOME FOOD...
WATER... AND AN EXTRA FLASHLIGHT IN YOUR VEHICLE IN CASE OF AN
EMERGENCY. CHECK THE LATEST ROAD CONDITIONS AT WYOROAD.INFO OR BY
DIALING 5 1 1.

&&

$$

WYZ001-002-202300-
/O.CON.KRIW.WW.Y.0040.000000T0000Z-161221T0700Z/
YELLOWSTONE NATIONAL PARK-ABSAROKA MOUNTAINS-
INCLUDING THE CITIES OF...LAKE...MAMMOTH...OLD FAITHFUL
154 AM MST TUE DEC 20 2016

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL MIDNIGHT MST
TONIGHT...

* TIMING...LIGHT SNOW THIS MORNING WILL BECOME STEADIER AND
  HEAVIER WITH THE HEAVIEST SNOW EXPECTED THIS AFTERNOON AND EARLY
  THIS EVENING BEFORE TAPERING OFF AROUND MIDNIGHT.

* SNOWFALL...5 TO 10 INCHES OF SNOW IS EXPECTED IN THE ABSAROKA
  MOUNTAINS WITH 3 TO 6 INCHES AROUND MAMMOTH.

* WIND AND VISIBILITY...WEST WINDS OF 20 TO 30 MPH WITH GUSTS AS
  HIGH AS 50 MPH WILL CAUSE BLOWING AND DRIFTING SNOW WITH NEAR
  ZERO VISIBILITY AT TIMES.

* MAIN IMPACT...ROADS WILL BECOME SLICK AND SNOW PACKED AND LOW
  VISIBILITY WILL MAKE DRIVING DIFFICULT.

* OTHER IMPACTS...OUTDOOR ACTIVITY WILL BECOME VERY DIFFICULT 
  WITH THE STRONG WIND INCREASING THE CHANCES FOR HYPOTHERMIA. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER WEATHER ADVISORY FOR SNOW AND BLOWING SNOW MEANS PERIODS
OF SNOW WILL CAUSE PRIMARILY TRAVEL DIFFICULTIES. BE PREPARED FOR
SNOW COVERED AND SLICK ROADS WITH LIMITED VISIBILITIES. SLOW
DOWN... AND ALLOW EXTRA TIME TO REACH YOUR DESTINATION. CHECK THE
LATEST ROAD CONDITIONS AT WYOROAD.INFO OR BY DIALING 5 1 1.

&&

$$

WYZ023-024-202300-
/O.CON.KRIW.WW.Y.0040.000000T0000Z-161221T0700Z/
STAR VALLEY-SALT RIVER AND WYOMING RANGES-
INCLUDING THE CITIES OF...AFTON...ALPINE...STAR VALLEY RANCH...
THAYNE
154 AM MST TUE DEC 20 2016

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL MIDNIGHT MST
TONIGHT...

* TIMING...LIGHT SNOW THIS MORNING WILL BECOME STEADIER AND
  HEAVIER WITH THE HEAVIEST SNOW EXPECTED THIS AFTERNOON AND EARLY
  THIS EVENING BEFORE TAPERING OFF AROUND MIDNIGHT.

* SNOWFALL...6 TO 12 INCHES OF SNOW IS EXPECTED IN THE WYOMING 
  AND SALT RIVER RANGES WITH 3 TO 6 INCHES IN THE STAR VALLEY. 

* WIND AND VISIBILITY...WEST WINDS OF 20 TO 30 MPH WITH GUSTS AS
  HIGH AS 55 MPH WILL CAUSE BLOWING AND DRIFTING SNOW WITH NEAR
  ZERO VISIBILITY AT TIMES ON SALT RIVER PASS. THE STAR VALLEY CAN
  EXPECT SOUTHWEST WINDS 15 TO 25 MPH.

* MAIN IMPACT...ROADS WILL BECOME SLICK AND SNOW PACKED AND LOW
  VISIBILITY WILL MAKE DRIVING DIFFICULT.

* OTHER IMPACTS...OUTDOOR ACTIVITY WILL BECOME VERY DIFFICULT 
  WITH THE STRONG WIND INCREASING THE CHANCES FOR HYPOTHERMIA. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER WEATHER ADVISORY FOR SNOW AND BLOWING SNOW MEANS PERIODS
OF SNOW WILL CAUSE PRIMARILY TRAVEL DIFFICULTIES. BE PREPARED FOR
SNOW COVERED AND SLICK ROADS WITH LIMITED VISIBILITIES. SLOW
DOWN... AND ALLOW EXTRA TIME TO REACH YOUR DESTINATION. CHECK THE
LATEST ROAD CONDITIONS AT WYOROAD.INFO OR BY DIALING 5 1 1.

&&

$$

WYZ014-015-202300-
/O.CON.KRIW.WW.Y.0040.000000T0000Z-161221T0700Z/
WIND RIVER MOUNTAINS WEST-WIND RIVER MOUNTAINS EAST-
154 AM MST TUE DEC 20 2016

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL MIDNIGHT MST
TONIGHT...

* TIMING...LIGHT SNOW THIS MORNING WILL BECOME STEADIER AND
  HEAVIER WITH THE HEAVIEST SNOW EXPECTED THIS AFTERNOON AND EARLY
  THIS EVENING BEFORE TAPERING OFF AROUND MIDNIGHT.

* SNOWFALL...5 TO 10 INCHES.

* WIND AND VISIBILITY...WEST WINDS OF 20 TO 30 MPH WITH GUSTS AS 
  HIGH AS 55 MPH WILL CAUSE BLOWING AND DRIFTING SNOW WITH NEAR 
  ZERO VISIBILITY AT TIMES ON SOUTH PASS. 

* MAIN IMPACT...ROADS WILL BECOME SLICK AND SNOW PACKED AND LOW
  VISIBILITY WILL MAKE DRIVING DIFFICULT.

* OTHER IMPACTS...OUTDOOR ACTIVITY WILL BECOME VERY DIFFICULT 
  WITH THE STRONG WIND INCREASING THE CHANCES FOR HYPOTHERMIA. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER WEATHER ADVISORY FOR SNOW AND BLOWING SNOW MEANS PERIODS
OF SNOW WILL CAUSE PRIMARILY TRAVEL DIFFICULTIES. BE PREPARED FOR
SNOW COVERED AND SLICK ROADS WITH LIMITED VISIBILITIES. SLOW
DOWN... AND ALLOW EXTRA TIME TO REACH YOUR DESTINATION. CHECK THE
LATEST ROAD CONDITIONS AT WYOROAD.INFO OR BY DIALING 5 1 1.

&&

$$

156 
WWUS45 KRIW 202029
WSWRIW

URGENT - WINTER WEATHER MESSAGE
NATIONAL WEATHER SERVICE RIVERTON WY
129 PM MST TUE DEC 20 2016

...SNOW AND STRONG WINDS FOR WESTERN WYOMING THIS EVENING...

.A STRONG AND MOIST PACIFIC STORM SYSTEM WILL BRING INCREASING
SNOWFALL AND STRONG WINDS TO THE WEST THROUGH THIS EVENING.

WYZ012-013-210700-
/O.CAN.KRIW.WS.W.0016.000000T0000Z-161221T0700Z/
/O.EXA.KRIW.WW.Y.0040.000000T0000Z-161221T0700Z/
TETON AND GROS VENTRE MOUNTAINS-JACKSON HOLE-
INCLUDING THE CITY OF...JACKSON
129 PM MST TUE DEC 20 2016

...WINTER WEATHER ADVISORY IN EFFECT UNTIL MIDNIGHT MST TONIGHT...
...WINTER STORM WARNING IS CANCELLED...

THE NATIONAL WEATHER SERVICE IN RIVERTON HAS ISSUED A WINTER
WEATHER ADVISORY FOR SNOW AND BLOWING SNOW...WHICH IS IN EFFECT
UNTIL MIDNIGHT MST TONIGHT. THE WINTER STORM WARNING HAS BEEN
CANCELLED.

* TIMING...SNOW WILL BE MODERATE TO HEAVY THIS AFTERNOON AND
  EVENING IN THE TETON MOUNTAINS WITH LIGHT SNOW IN JACKSON HOLE.
  THE SNOW WILL TAPER OFF AROUND MIDNIGHT.

* SNOWFALL...6 TO 12 INCHES OF SNOW IS EXPECTED IN THE TETONS WITH
  WITH 3 TO 5 INCHES IN JACKSON HOLE WITH AROUND 2 INCHES IN
  JACKSON. 

* WIND AND VISIBILITY...WEST WINDS OF 20 TO 30 MPH WITH GUSTS AS
  HIGH AS 35 MPH WILL CAUSE BLOWING AND DRIFTING SNOW WITH LOW
  VISIBILITY ON TETON AND TOGWOTEE PASSES. 

* MAIN IMPACT...ROADS WILL BECOME SLICK AND SNOW PACKED AND LOW 
  VISIBILITY WILL MAKE DRIVING DIFFICULT. 

* OTHER IMPACTS...OUTDOOR ACTIVITY WILL BECOME VERY DIFFICULT 
  WITH THE STRONG WIND INCREASING THE CHANCES FOR HYPOTHERMIA. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER WEATHER ADVISORY FOR SNOW AND BLOWING SNOW MEANS PERIODS
OF SNOW WILL CAUSE PRIMARILY TRAVEL DIFFICULTIES. BE PREPARED FOR
SNOW COVERED AND SLICK ROADS WITH LIMITED VISIBILITIES. SLOW
DOWN... AND ALLOW EXTRA TIME TO REACH YOUR DESTINATION. CHECK THE
LATEST ROAD CONDITIONS AT WYOROAD.INFO OR BY DIALING 5 1 1.

&&

$$

WYZ023-202130-
/O.CAN.KRIW.WW.Y.0040.000000T0000Z-161221T0700Z/
STAR VALLEY-
INCLUDING THE CITIES OF...AFTON...ALPINE...STAR VALLEY RANCH...
THAYNE
129 PM MST TUE DEC 20 2016

...WINTER WEATHER ADVISORY IS CANCELLED...

THE NATIONAL WEATHER SERVICE IN RIVERTON HAS CANCELLED THE WINTER
WEATHER ADVISORY. 

SNOWFALL OF 1 TO 2 INCHES HAS FALLEN IN THE STAR VALLEY.  ONLY
LIGHT SNOW IS EXPECTED THIS EVENING WITH LOCAL 3 INCH
ACCUMULATIONS POSSIBLE.

$$

WYZ001-002-210700-
/O.CON.KRIW.WW.Y.0040.000000T0000Z-161221T0700Z/
YELLOWSTONE NATIONAL PARK-ABSAROKA MOUNTAINS-
INCLUDING THE CITIES OF...LAKE...MAMMOTH...OLD FAITHFUL
129 PM MST TUE DEC 20 2016

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL MIDNIGHT MST
TONIGHT...

* TIMING...SNOW WILL BE HEAVIER WITH THE HEAVIEST SNOW EXPECTED EARLY
  THIS EVENING BEFORE TAPERING OFF AROUND MIDNIGHT.

* SNOWFALL...5 TO 10 INCHES OF SNOW IS EXPECTED IN THE ABSAROKA 
  MOUNTAINS WITH 3 TO 6 INCHES AROUND MAMMOTH. 

* WIND AND VISIBILITY...WEST WINDS OF 20 TO 30 MPH WITH GUSTS AS
  HIGH AS 40 MPH WILL CAUSE BLOWING AND DRIFTING SNOW WITH NEAR
  ZERO VISIBILITY AT TIMES.

* MAIN IMPACT...ROADS WILL BECOME SLICK AND SNOW PACKED AND LOW 
  VISIBILITY WILL MAKE DRIVING DIFFICULT. 

* OTHER IMPACTS...OUTDOOR ACTIVITY WILL BECOME VERY DIFFICULT 
  WITH THE STRONG WIND INCREASING THE CHANCES FOR HYPOTHERMIA. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER WEATHER ADVISORY FOR SNOW AND BLOWING SNOW MEANS PERIODS
OF SNOW WILL CAUSE PRIMARILY TRAVEL DIFFICULTIES. BE PREPARED FOR
SNOW COVERED AND SLICK ROADS WITH LIMITED VISIBILITIES. SLOW
DOWN... AND ALLOW EXTRA TIME TO REACH YOUR DESTINATION. CHECK THE
LATEST ROAD CONDITIONS AT WYOROAD.INFO OR BY DIALING 5 1 1.

&&

$$

WYZ024-210700-
/O.CON.KRIW.WW.Y.0040.000000T0000Z-161221T0700Z/
SALT RIVER AND WYOMING RANGES-
129 PM MST TUE DEC 20 2016

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL MIDNIGHT MST
TONIGHT...

* TIMING...SNOW WILL BECOME STEADIER AND HEAVIER WITH THE HEAVIEST
  SNOW EXPECTED EARLY THIS EVENING BEFORE TAPERING OFF AROUND
  MIDNIGHT.

* SNOWFALL...5 TO 10 INCHES OF SNOW IS EXPECTED IN THE WYOMING AND
  SALT RIVER RANGES.

* WIND AND VISIBILITY...WEST WINDS OF 20 TO 30 MPH WITH GUSTS AS
  HIGH AS 45 MPH WILL CAUSE BLOWING AND DRIFTING SNOW WITH NEAR
  ZERO VISIBILITY AT TIMES ON SALT RIVER PASS. 

* MAIN IMPACT...ROADS WILL BECOME SLICK AND SNOW PACKED AND LOW 
  VISIBILITY WILL MAKE DRIVING DIFFICULT. 

* OTHER IMPACTS...OUTDOOR ACTIVITY WILL BECOME VERY DIFFICULT 
  WITH THE STRONG WIND INCREASING THE CHANCES FOR HYPOTHERMIA. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER WEATHER ADVISORY FOR SNOW AND BLOWING SNOW MEANS PERIODS
OF SNOW WILL CAUSE PRIMARILY TRAVEL DIFFICULTIES. BE PREPARED FOR
SNOW COVERED AND SLICK ROADS WITH LIMITED VISIBILITIES. SLOW
DOWN... AND ALLOW EXTRA TIME TO REACH YOUR DESTINATION. CHECK THE
LATEST ROAD CONDITIONS AT WYOROAD.INFO OR BY DIALING 5 1 1.

&&

$$

WYZ014-015-210700-
/O.CON.KRIW.WW.Y.0040.000000T0000Z-161221T0700Z/
WIND RIVER MOUNTAINS WEST-WIND RIVER MOUNTAINS EAST-
129 PM MST TUE DEC 20 2016

...WINTER WEATHER ADVISORY REMAINS IN EFFECT UNTIL MIDNIGHT MST
TONIGHT...

* TIMING...SNOW WILL BECOME STEADIER AND HEAVIER WITH THE HEAVIEST
  SNOW EXPECTED EARLY THIS EVENING BEFORE TAPERING OFF AROUND
  MIDNIGHT.

* SNOWFALL...4 TO 9 INCHES.

* WIND AND VISIBILITY...WEST WINDS OF 20 TO 30 MPH WITH GUSTS AS
  HIGH AS 50 MPH WILL CAUSE BLOWING AND DRIFTING SNOW WITH NEAR
  ZERO VISIBILITY AT TIMES ON SOUTH PASS.

* MAIN IMPACT...ROADS WILL BECOME SLICK AND SNOW PACKED AND LOW 
  VISIBILITY WILL MAKE DRIVING DIFFICULT. 

* OTHER IMPACTS...OUTDOOR ACTIVITY WILL BECOME VERY DIFFICULT 
  WITH THE STRONG WIND INCREASING THE CHANCES FOR HYPOTHERMIA. 

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER WEATHER ADVISORY FOR SNOW AND BLOWING SNOW MEANS PERIODS
OF SNOW WILL CAUSE PRIMARILY TRAVEL DIFFICULTIES. BE PREPARED FOR
SNOW COVERED AND SLICK ROADS WITH LIMITED VISIBILITIES. SLOW
DOWN... AND ALLOW EXTRA TIME TO REACH YOUR DESTINATION. CHECK THE
LATEST ROAD CONDITIONS AT WYOROAD.INFO OR BY DIALING 5 1 1.

&&

$$

Area Forecast Discussion
National Weather Service Riverton WY
1031 AM MST Mon Dec 19 2016

.SHORT TERM...Monday through Wednesday night

With the contrast in conditions we will split the discussion into
West and East of the Divide this morning.

West of the Divide...The concern here is for snow. For today there
will be a little warm advection / upglide that will begin this
afternoon and continue into tonight. There is not a lot of upper
level support with this system through tonight so only light amounts
of snow are expected. Temperatures will continue moderating but
remain below normal.

This will change Tuesday as another system, this one of Pacific
origin approaches the area. It has a decent amount of moisture to
work with. However, this system looks to be a fairly quick hitter.
Steady snow will fall during the day Tuesday. However, the moderate
to heavy snow looks to hold off until Tuesday afternoon when we get
additional lift from an approaching front and right rear quadrant of
an 130 knot jet passing along the Wyoming-Montana border. It could
snow fairly hard, but the period of heavy snow would not be long
enough for most areas to receiving warning levels of snow. The
exceptions would be higher in the mountains but this would be above
pass level for the most part and impacts would be minimal. At this
point, it looks more like an advisory level situation. There will be
some gusty winds though so travel could get difficult at times. The
snow should end fairly quickly later Tuesday evening with most areas
dry by Wednesday morning.

Dry weather will return on Wednesday as high pressure builds into
the area. It will cool off again. However, since the origin of the
air behind the front is Pacific and not Arctic, it will not get
extremely cold.

East of the Divide...Here get turn off the snow machine and turn on
the wind machine. We have already had some strong wind gusts in the
normally wind prone areas, like Casper and of course, Clark, the
most important crossroad in the universe. The usual suspects are the
causes, strong 700 millibar winds, up to 60 to 70 knots near Clark
and up to 55 knots around the southwestern Wind Corridor. The high
wind warning will be continued in the Cody Foothills although there
will likely be a lull in the wind in the afternoon before increasing
again at night as the system from the west approaches and we get an
assist from the jet max passing near the area. In the southwestern
wind corridor, it will be a more consistent threat with maybe a
slight drop in wind tonight and then increasing again on Tuesday as
the front approaches. We will upgrade the high wind watch for Zones
19 and 20 to warnings. The other problem will be blowing snow that
could restrict visibilities. This was also included in the grids.

The good part of the wind is that it will get rid of the Arctic air.
And again, this leads to the temperature problem for today. The
inversions are beginning to shrink, as shown here in Riverton. We are
reading around 7 above on our ASOS at around 1 am as the cold air
in the inversion sloshes back and forth. Meanwhile, a weather
station in town down by the river, not in a van though, is
currently minus 13. This the problem in the basins where
forecasting high temperatures is rather difficult. If the
inversion can mix out it could get much warmer than the forecast
high temperatures. For now, we kept them cold, with a simple
reasoning. If it gets warmer than forecast, most people will be
happy.

The best chance of mixing out would be Tuesday, especially as the
front approaches late in the day and at night. Again, with the
uncertainty we went conservative and kept the high temperatures in
the basins below guidance. As for the chance of snow with the
frontal passage, at this point, it looks fairly minimal except for
the mountains due to the strong downsloping flow.

High pressure will build back over the area on Wednesday with dry
weather returning. Temperatures will cool off behind the front, but
was stated in the West of the Divide discussion, with the Pacific
origin of the air mass, temperatures should not be nearly as cold as
they were last week.

.LONG TERM...Thursday through Monday

Thursday looks dry with seasonal temps. The moisture moves into
the west Thursday night through Friday as a weather system moves
through the area. Friday will be mostly dry east of the divide
except for some snow in the Bighorn mountains. The long range
models are having issues with the next weather system that moves
into the western U.S. Friday night and then into the four corners
Saturday. The GFS model is progressive and swings this storm
through the Rockies Saturday night and Sunday. The ECMWF model
slows this storm down and develops a potent system for the
Christmas weekend. Neither model has much consistency with their
respective solutions, so this leads to major uncertainty for the
Christmas weekend forecast. For now will have a chance of snow for
much of the region Saturday and Sunday. This storm will have to be
watched over the coming days. Next Monday looks dry as the storm
is supposed to be out of the area. Temps will be near normal
through Friday and then colder temps are expected Saturday through
Monday.

&&

.AVIATION.../18Z ISSUANCE/

West of the divide...KBPI/KJAC/KPNA/KRKS Terminals

VFR conditions are expected through the forecast period for most of
the forecast terminal sites except KJAC later this afternoon. Clouds
will increase NW-SSE across the area this afternoon with MVFR
ceilings spreading south to a vicinity KJAC-KDUB line by 00z Tuesday
with areas of light snow and mountain obscurations. MVFR conditions
are expected to deteriorate to IFR over this area with snowfall
increasing after 08z Tuesday. MVFR/IFR CIGS will move further south
across the Wyoming and Salt Mountain Ranges by this evening.
Otherwise, mountain top winds will increase this afternoon and
tonight with along with widespread areas of LLWS.

East of the divide...KCOD/KCPR/KLND/KRIW/KWRL Terminals

VFR conditions will prevail through the period. Gusty west to
southwest winds along the east slopes of the Continental Divide and
along the wind corridor from the South Pass area to vicinity KCPR
will cause areas of blowing snow and some terrain obscurations
through the period. Stronger west to northwest wind aloft will also
continue areas of LLWS over the shallow Arctic air trapped in the
lower central basins. Snow showers will increase from NW-SE along
and west of the Continental Divide this afternoon and evening with
mountains above 9kft becoming obscured.

&&

.FIRE WEATHER...

It will be another cold day across the Basins although temperatures
will slowly moderate. It the lee of the Absarokas and from the Red
Desert through Casper will be warmer but with high winds at times.
Across the western mountains, some light snow will fall today with
more cloud cover. Smoke dispersal will remain poor in most locations
but a bit better across the windy areas. A more substantial system
will move into the west Tuesday with another chance of several
inches of snow.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...

High Wind Warning until 8 PM MST Tuesday for WYZ019-020.

High Wind Warning until 11 AM MST Tuesday for WYZ003.

&&

SHORT TERM...Hattings
LONG TERM...AR
AVIATION...Braun
FIRE WEATHER...Hattings

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE RIVERTON WY
300 AM MST MON DEC 19 2016

WYZ001>020-022>030-201200-
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-
300 AM MST MON DEC 19 2016

...HIGH WIND WARNING FOR THE CODY FOOTHILLS TODAY THROUGH TUESDAY
MORNING...

...HIGH WIND WARNING FROM THE RATTLESNAKE RANGE TO NATRONA COUNTY
TODAY THROUGH TUESDAY EVENING...

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL WYOMING.

.DAY ONE...TODAY AND TONIGHT

STRONG WIND AND WIND GUSTS ARE FORECAST FOR THE CODY FOOTHILLS
AND FROM THE RED DESERT TO NATRONA COUNTY.

.DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY

TUESDAY...STRONG GUSTY WIND TO CONTINUE FOR THE CODY FOOTHILLS
AND FROM THE RED DESERT TO NATRONA COUNTY.

TUESDAY AND TUESDAY NIGHT...SNOW LIKELY IN THE WESTERN MOUNTAINS
AND FAR WEST VALLEYS.

THURSDAY NIGHT AND FRIDAY...A CHANCE OF SNOW IN THE WESTERN
MOUNTAINS AND VALLEYS.

.SPOTTER INFORMATION STATEMENT...

SPOTTERS ARE URGED TO REPORT WIND GUSTS PAST 45 MPH. THANK YOU.