High Wind Warning 20, NWS Riverton, WY

000 
WWUS75 KRIW 100419
NPWRIW

URGENT - WEATHER MESSAGE
NATIONAL WEATHER SERVICE RIVERTON WY
919 PM MST TUE DEC 9 2008

...STRONG WINDS EXPECTED OVER THE ABSAROKA MOUNTAINS THROUGH
EARLY WEDNESDAY MORNING...

.A STRONG WEST TO EAST SURFACE PRESSURE GRADIENT ACROSS THE
ABSAROKA MOUNTAINS WILL CAUSE WEST WINDS TO INCREASE THIS EVENING.
THE WINDS ARE EXPECTED TO CONTINUE THROUGH WEDNESDAY MORNING.

WYZ002-101030-
/O.CON.KRIW.HW.W.0020.000000T0000Z-081210T1500Z/
ABSAROKA MOUNTAINS-
919 PM MST TUE DEC 9 2008

...HIGH WIND WARNING REMAINS IN EFFECT UNTIL 8 AM MST WEDNESDAY...

A HIGH WIND WARNING REMAINS IN EFFECT UNTIL 8 AM MST WEDNESDAY. 

WEST TO NORTHWEST WINDS WILL CONTINUE ACROSS THE ABSAROKA
MOUNTAINS OVERNIGHT. THE WINDS WILL BE ESPECIALLY STRONG ALONG
THE CHIEF JOSEPH HIGHWAY...WITH NORTHWEST WINDS OF 40 TO 60 MPH
SUSTAINED WITH GUSTS AS HIGH AS 80 TO 90 MPH ARE EXPECTED AT THE
PASS. THE STRONGEST OF THESE WINDS WILL LIKELY OCCUR BETWEEN 2
AND 5 AM. ELSEWHERE...SUCH AS ALONG THE NORTH FORK OF THE SHOSHONE
RIVER INCLUDING HIGHWAY 14...WEST WINDS ARE EXPECTED TO BLOW AT 30
TO 40 MPH WITH GUSTS OF 50 TO 70 MPH. AT 620 PM...A SUSTAINED WIND
OF 67 MPH WAS RECORDED AT CHIEF JOSEPH PASS.

IN ADDITION...WITH FRESH SNOW COVER IN PLACE...THESE WINDS WILL
CAUSE CONSIDERABLE BLOWING AND DRIFTING SNOW LOCALLY REDUCING THE
VISIBILITY TO NEAR ZERO AT TIMES.

REMEMBER...A HIGH WIND WARNING MEANS HAZARDOUS WEATHER CONDITIONS
ARE IMMINENT OR HIGHLY LIKELY.

$$

000 
WWUS75 KRIW 100944
NPWRIW

URGENT - WEATHER MESSAGE
NATIONAL WEATHER SERVICE RIVERTON WY
244 AM MST WED DEC 10 2008


WYZ002-101045-
/O.CAN.KRIW.HW.W.0020.000000T0000Z-081210T1500Z/
ABSAROKA MOUNTAINS-
244 AM MST WED DEC 10 2008

...HIGH WIND WARNING IS CANCELLED...

THE NATIONAL WEATHER SERVICE IN RIVERTON HAS CANCELLED THE HIGH
WIND WARNING. 

WIND SPEEDS HAVE DECREASED OVER THE ABSAROKA MOUNTAINS THIS
MORNING. THEREFORE THE HIGH WIND WARNING HAS BEEN CANCELLED. WEST
TO NORTHWEST WINDS OF 20 TO 35 MPH WITH GUSTS TO 60 MPH ARE STILL
POSSIBLE THROUGH 8 AM...ESPECIALLY ON CHIEF JOSEPH PASS.

$$

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
319 AM MST TUE DEC 9 2008

.SHORT TERM...TODAY THROUGH THURSDAY NIGHT
TRAILING EDGE OF TROUGH MOVING SOUTHEAST ACROSS WYOMING THIS MORNING
WITH RIDGE BUILDING IN BEHIND IT.  HIGH CLOUDS SPILLING OVER
RIDGE...ACROSS WESTERN MONTANA AND IDAHO.  THE HIGH CLOUDS WILL WORK
THEIR WAY ACROSS WYOMING THIS MORNING AND AFTERNOON.  SOME WEAK WARM
AIR ADVECTION AND ISENTROPIC LIFT ALONG WITH LIMITED MID LEVEL
MOISTURE...WILL BRING A SLIGHT CHANCE OF LIGHT SNOW TO THE HIGH
PEAKS OF THE NORTHERN MOUNTAINS THIS AFTERNOON.  LEE TROUGH DEVELOPS
THIS MORNING WITH THE TYPICAL WIND CORRIDORS GETTING BREEZY TODAY.
H7 TEMPS STAY COLD TODAY...AROUND -10C OVER THE SOUTH AND
EAST...WITH -7C OVER THE NORTHWEST.  TEMPERATURES TO STRUGGLE
TODAY...WITH MAXS MAINLY IN THE MID 20S TO LOWER 30S.  WEAK CLIPPER
SHORTWAVE TRACKS ESE ACROSS MONTANA TONIGHT.  IT WILL TIGHTEN THE
GRADIENT ACROSS THE AREA...WITH WINDY AREAS...SUCH AS THE
ABSAROKAS...BIGHORNS AS WELL AS NATRONA COUNTY.  WITH THE NORTHWEST
FLOW...UPPER GREEN BASIN SHOULD KEEP A BREEZE THROUGH THE NIGHT
TONIGHT.  THEREFORE...HAVE WARMED UP MIN TEMPS THERE.  ALSO...MID
LEVEL MOISTURE INCREASES A BIT ACROSS THE NORTH...BRINGING A CHANCE
OF SNOW THERE.  MOISTURE IN THE NORTHWEST FLOW LINGERS WEDNESDAY
WITH WARMER TEMPERATURES EXPECTED...MAX TEMPS IN THE UPPER 30S TO
MID 40S.  WILL KEEP THE CHANCE OF LIGHT SNOW GOING FOR THE NORTHERN
MOUNTAINS.  AGAIN...SHOULD BE MAINLY OVER HIGHER ELEVATIONS WITH
LITTLE IF ANY ACCUMULATIONS.  ANOTHER SHORTWAVE MOVES THROUGH
THURSDAY MORNING...WITH MORE WIND AS WELL AS THE CHANCE OF SNOW
ACROSS THE NORTH.  THE NORTHWEST FLOW DRIES OUT THURSDAY WITH THE
CHANCE OF SNOW DIMINISHING THROUGH THE DAY.  ANOTHER CLIPPER MOVES
ACROSS NORTHERN MONTANA THURS NIGHT. WILL KEEP A SLIGHT CHANCE OF
SNOW OVER THE FAR NORTHERN MOUNTAINS. OTHERWISE HAVE REMOVED MOST
POPS THERE WITH BEST MOISTURE AND DYNAMICS OVER MONTANA.
ALSO...HAVE INCREASED THE WINDS WITH TIGHTENING GRADIENT.

.LONG TERM...FRIDAY THROUGH TUESDAY
GFS AND ECMWF HAVE BACKED OFF WITH THE COLD FRONT PUSH INTO WY
FRIDAY. THUS A MILD DAY ALONG WITH DRY CONDITIONS AT THE LOWER
ELEVATIONS. WILL KEEP A CHANCE OF SNOW IN THE WESTERN MTS AS
MOISTURE DOES INCREASE IN THE AFTERNOON IN A WEST FLOW ALOFT. THE
COLD FRONT INVADES NORTHERN AND WESTERN WY LATE FRI NIGHT. HAVE
INCREASED THE SNOW CHANCE IN THE WESTERN MTS FRI NIGHT AS THE
FIRST SHORTWAVE SWINGS TOWARD WESTERN WY. CENTRAL AND EAST ZONES
STILL LOOK MOSTLY DRY ASIDE FROM LIGHT SNOW DEVELOPING IN THE FAR
NORTH LATE FRI NIGHT BEHIND THE FRONTAL PUSH. WILL SEE HOW THINGS
LOOK IN UPCOMING MODEL RUNS. THE COLD FRONT SURGES SOUTH ON
SATURDAY BRINGING MUCH COLDER TEMPERATURES AND THE CHANCE FOR SNOW
BEHIND THE FRONTAL PASSAGE. AGAIN HAVE RAISED PRECIP CHANCES
ESPECIALLY IN THE WEST WHERE A MOIST WEST SOUTHWEST FLOW IS
FORECAST. SATURDAY NIGHT THROUGH SUNDAY NIGHT LOOK QUITE COLD WITH
PERIODS OF LIGHT SNOW MOST PLACES. THE GFS AND ECMWF HAVE SOME
DIFFERENCES WITH THE WESTERN TROUGH AND SHORTWAVE TIMING AS PIECES
OF ENERGY SWING THROUGH THE TROUGH. HAVE INCREASED THE PRECIP
CHANCE MOST AREAS SAT NIGHT THROUGH SUN NIGHT. MONDAY AND TUESDAY
LOOK TO BE QUITE COLD WITH SOME LIGHT SNOW AT TIMES PER THE GFS
AND ECMWF DESPITE THEIR DIFFERENCES IN TROUGH ORIENTATION BY THAT
TIME. STILL A LOT OF UNCERTAINTY ON HOW THIS TROUGH WILL SET UP
THIS WEEKEND INTO NEXT WEEK FOR SNOW PRODUCTION. THE MAIN AGREEMENT
IS THE FRIGID TEMPS FROM SUNDAY THROUGH TUESDAY.

&&

.AVIATION...
SOME LOW STRATUS AND LIGHT SNOW AND FOG WILL PRODUCE LOCAL MVFR TO
IFR CEILINGS AND VISIBILITIES ACROSS THE SOUTH...CENTRAL AND EAST
THIS MORNING...THEN CLEARING WILL BRING PREVAILING VFR CONDITIONS
ACROSS WESTERN AND CENTRAL WYOMING.  LOCAL LOW STRATUS AND FOG CAN
BE EXPECTED TO FORM OVER FRESH SNOWFALL LATE TONIGHT AND EARLY
WEDNESDAY MORNING ALONG THE RIVER VALLEYS.

&&

.FIRE WEATHER...
HIGH PRESSURE BUILDS IN TODAY WITH WINDS SHIFTING TO THE SOUTHWEST
TO WEST BECOMING BREEZY IN THE TYPICAL SPOTS. TEMPERATURES WILL
REMAIN COOL TODAY WITH RHS NOT GETTING MUCH BELOW 40 PERCENT.
SOME MOISTURE IN THE FLOW MAY BRING THE NORTHERN MOUNTAINS SOME
LIGHT SNOW OVER THE NEXT FEW DAYS. IT GETS MUCH WARMER WEDNESDAY
WITH HIGHS IN THE UPPER 30S TO MID 40S. SOME RHS MAY DIP INTO THE
30 PERCENT RANGE.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...NONE.

&&

SHORT TERM...TWB
LONG TERM...AR
AVIATION...C.BAKER
FIRE WEATHER...TWB

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE RIVERTON WY
500 AM MST TUE DEC 9 2008

WYZ001>020-022>030-101300-
ABSAROKA MOUNTAINS-BIGHORN MOUNTAINS SOUTHEAST-
BIGHORN MOUNTAINS WEST-CASPER MOUNTAIN-CODY FOOTHILLS-
EAST SWEETWATER COUNTY-FLAMING GORGE-
GREEN MOUNTAINS AND RATTLESNAKE RANGE-JACKSON HOLE-LANDER FOOTHILLS-
NATRONA COUNTY LOWER ELEVATIONS-NORTH BIG HORN BASIN-
NORTHEAST JOHNSON COUNTY-OWL CREEK AND BRIDGER MOUNTAINS-
ROCK SPRINGS AND GREEN RIVER-SALT RIVER AND WYOMING RANGES-
SOUTH LINCOLN COUNTY-SOUTHEAST BIG HORN BASIN-
SOUTHEAST JOHNSON COUNTY-SOUTHWEST BIG HORN BASIN-STAR VALLEY-
TETON AND GROS VENTRE MOUNTAINS-UPPER GREEN RIVER BASIN-
UPPER GREEN RIVER BASIN FOOTHILLS-UPPER WIND RIVER BASIN-
WIND RIVER BASIN-WIND RIVER MOUNTAINS EAST-WIND RIVER MOUNTAINS WEST-
YELLOWSTONE NATIONAL PARK-
500 AM MST TUE DEC 9 2008

THIS HAZARDOUS WEATHER OUTLOOK IS FOR WESTERN AND CENTRAL WYOMING.

.DAY ONE...TODAY AND TONIGHT

NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

A WINTER STORM MAY BRING SIGNIFICANT SNOWFALL AND MUCH COLDER WEATHER
ACROSS WEST AND CENTRAL WYOMING SATURDAY THROUGH MONDAY. THIS WINTER
STORM SYSTEM WILL LIKELY HAVE SIGNIFICANT IMPACTS ON TRAVEL AND
OUTDOOR ACTIVITIES. STAY TUNED FOR UPDATES ALL WEEK ON THIS WEATHER
SITUATION.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY AND TONIGHT.

TEAM RIVERTON