Area Forecast Discussion
Issued by NWS Riverton, WY

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000
FXUS65 KRIW 142012
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
112 PM MST SUN FEB 14 2016

.SHORT TERM...TONIGHT THROUGH MONDAY

A MOIST WEST NORTHWEST FLOW WILL BRING WIDESPREAD SNOW TO THE WEST
AND NORTH THROUGH MONDAY.  MOUNTAIN AREAS MAY SEE UP TO 20 INCHES
OF SNOW IN THE TETONS...WITH OTHER MOUNTAIN AREAS RECEIVING A
FOOT OF SNOW. VALLEY AREAS SHOULD SEE UP TO 6 INCHES AND MAY SEE
RAIN MIXED WITH THE SNOW ON MONDAY. BREEZY TO WINDY AREAS WILL
CONTINUE WITH AREAS OF BLOWING SNOW IN THE MOUNTAINS. CLOUD COVER
AND PRECIPITATION WILL MODERATE TEMPERATURES ELEVATING OVERNIGHT
LOWS AND HOLDING DOWN DAYTIME HIGHS. A WINTER STORM WARNING
CONTINUES THROUGH 5 PM MST MONDAY FOR THE TETON AND GROS VENTRE
MOUNTAINS. MUCH OF THE WEST AND NORTH MOUNTAINS REMAIN IN WINTER
WEATHER ADVISORIES FOR SNOW AND BLOWING SNOW. JACKSON HOLE...STAR
VALLEY AND PINEDALE FOOTHILLS ALSO REMAIN IN WINTER WEATHER
ADVISORIES THROUGH 5 PM MST MONDAY.

.LONG TERM...MONDAY NIGHT THROUGH SUNDAY

MOISTURE WILL CONTINUE TO MOVE ALONG THE FAST NORTHWEST FLOW INTO
MONDAY EVENING WITH OCCASIONALLY LIGHT TO MODERATE SNOW EXPECTED
ACROSS THE WEST AND IN THE BIGHORNS BUT MOST OF THE SNOW
ACCUMULATION WILL BE OVER BY MONDAY NIGHT. MILD AIR REMAINS IN THE
VALLEYS WITH A RAIN/SNOW MIX EXPECTED IN THE LOWER ELEVATIONS...BUT
NOT MUCH IS EXPECTED TO MAKE IT OFF THE MOUNTAINS. WIND WILL ALSO
CONTINUE TO BE AN ISSUE WITH A TIGHT GRADIENT REMAINING AT THE
SURFACE...50KT PLUS WIND BARBS AT H7 AND STRONG FORCING FOR DESCENT
BEHIND THE UPPER TROUGH MONDAY EVENING...EXPECT SIGNIFICANT BLOWING
SNOW AT PASS LEVEL. THE DOWNWARD FORCING WILL ALSO FLOOD THE
FOOTHILLS AND LOWER ELEVATIONS WITH GUSTY WINDS...ESPECIALLY FOR
THOSE PRONE TO WESTNORTHWEST FLOW LIKE THE UPPER WIND RIVER BASIN
INTO PAVILLION AND THE MISSOURI VALLEY AREA...CODY FOOTHILLS AND
PORTIONS OF THE UPPER GREEN RIVER BASIN...WIND GUSTS OVER 45 MPH
WILL BE COMMON IN THESE AREAS MONDAY EVENING WITH OCCASIONAL GUSTS
APPROACHING 60 MPH EARLY IN THE PERIOD...ESPECIALLY AROUND CROWHEART
AND AREAS NORTH...WILL HAVE TO CONTINUE TO WATCH THIS AREA FOR
POTENTIAL WIND HIGHLIGHTS AS THE BACK SIDE OF THE TROUGH MOVES
THROUGH.

RIDGING BUILDS IN FROM THE WEST TUESDAY INTO WEDNESDAY WITH MILDER
TEMPERATURES AND WEATHER EXPECTED FOR MID WEEK. A SYSTEM BEGINS TO
MOVE INTO THE WEST AS EARLY AS THURSDAY MORNING AND THEN MOVING EAST
ACROSS THE REST OF THE AREA LATER THURSDAY INTO THURSDAY NIGHT...THE
TIMING OF THIS SYSTEM LOOKS IDENTICAL IN THE MODELS TODAY AS IT DID
YESTERDAY SO THAT INCREASES CONFIDENCE A BIT EVEN THOUGH THE
EUROPEAN IS SLIGHTLY COLDER THAN THE GFS. ONE NOTABLE CHANGE IS THE
AMOUNT OF PRECIPITATION THAT MAKES IT EAST OF THE DIVIDE IN THE
NEWER RUNS...SO ADDED AT LEAST SOME SLIGHT CHANCE POPS ACROSS THE
BOARD THURSDAY EVENING. PERIODS OF STRONG WIND WILL AGAIN BE
POSSIBLE WITH THE FRONT AND WILL PROBABLY BE THE MAIN STORY EAST OF
THE DIVIDE WITH ANY RAIN AND SNOW IN THE LOW ELEVATIONS AS AN
AFTERTHOUGHT.

A RIDGE BUILDS IN BEHIND THE THURSDAY SYSTEM...THE GFS KEEPS A FLAT
RIDGE WHILE THE EUROPEAN POPS UP A MORE AMPLIFIED RIDGE AHEAD OF THE
NEXT TROUGH MOVING INTO THE WEST COAST. THERE IS STILL DISAGREEMENT
ON THE TIMING AND THE SOUTHERN EXTENT OF THE TROUGH BETWEEN
MODELS...WITH THE EUROPEAN BRINGING THROUGH A MORE ORGANIZED FRONT
AND PRECIPITATION SHIELD FOR SATURDAY NIGHT INTO SUNDAY WHILE THE
GFS KEEPS MUCH OF THE IMPACT AND THE COLDER TEMPERATURES WELL TO THE
NORTH.

&&

.AVIATION.../00Z ISSUANCE/

WEST OF THE CONTINENTAL DIVIDE...KJAC/KRKS/KPNA/KBPI ROUTES

A LARGE FETCH OF PACIFIC MOISTURE WILL SPREAD WIDESPREAD MVFR/IFR
CEILINGS WITH VISIBILITY REDUCED IN SNOW AND BLOWING SNOW
OBSCURING TERRAIN OVER THE WESTERN MOUNTAINS AND VALLEYS INCLUDING
KJAC...KAFO AND AT TIMES KPNA...KEMM AND KBPI. MVFR CONDITIONS MAY
MOVE INTO KRKS OCCASIONALLY.

EAST OF THE CONTINENTAL DIVIDE...KCPR/KCOD/KRIW/KWRL/KLND ROUTES

VFR CONDITIONS WILL PREVAIL AT THE AIRPORTS THROUGH 00Z TUESDAY.
AREAS OF LLWS WILL BE ENCOUNTERED VCNTY AND WEST OF KLND-KCOD
UNTIL 18Z MONDAY WITH RIDGE TOP WINDS FROM 290 AT 40KT. MOIST
NORTHWEST FLOW WILL PRODUCE MVFR TO IFR CEILINGS WITH SNOW AND
BLOWING SNOW REDUCING VISIBILITY OVER THE MOUNTAINS DOWN TO 7500
FEET WITH WIDESPREAD MOUNTAIN OBSCURATIONS. LOCAL MVFR CEILINGS
AND VISIBILITIES MAY BE ENCOUNTERED IN THE LOWER ELEVATIONS OF THE
BIGHORN BASIN VICINITY KPOY...KU68...KCOD...KGEY AND IN NORTHERN
JOHNSON COUNTY VICINITY KBYG.

&&

.FIRE WEATHER...

A MOIST WEST NORTHWEST FLOW WILL BRING WIDESPREAD SNOW TO THE WEST
AND NORTH THROUGH MONDAY.  MOUNTAIN AREAS MAY SEE UP TO 20 INCHES
OF SNOW IN THE TETONS...WITH OTHER MOUNTAIN AREAS RECEIVING A
FOOT OF SNOW. VALLEY AREAS SHOULD SEE UP TO 6 INCHES AND MAY SEE
RAIN MIXED WITH THE SNOW ON MONDAY. BREEZY TO WINDY AREAS WILL
CONTINUE WITH AREAS OF BLOWING SNOW IN THE MOUNTAINS. RELATIVE
HUMIDITY WILL BE HIGH. CLOUD COVER AND PRECIPITATION WILL
MODERATE TEMPERATURES ELEVATING OVERNIGHT LOWS AND HOLDING DOWN
DAYTIME HIGHS. MIXING HEIGHTS WILL BE LOW WITH POOR SMOKE
DISPERSAL.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 5 PM MST MONDAY FOR WYZ001-002-008-
009-013-014-023>025.

WINTER STORM WARNING UNTIL 5 PM MST MONDAY FOR WYZ012.

&&

$$

SHORT TERM...C.BAKER
LONG TERM...ALLEN
AVIATION...C.BAKER
FIRE WEATHER...C.BAKER


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