901 FXUS65 KRIW 122227 AFDRIW AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RIVERTON WY 327 PM MST MON NOV 12 2012 .SHORT TERM...TONIGHT THROUGH THURSDAY WESTERLY FLOW WILL INCREASE ACROSS WESTERN AND CENTRAL WYOMING TUESDAY AND WEDNESDAY WITH PACIFIC MOISTURE IN THE FLOW PRODUCING INCREASED AREAS OF LIGHT SNOW IN THE WESTERN AND NORTHERN MOUNTAINS. SNOWFALL UP TO 8 INCHES MAY OCCUR OVER THE WESTERN MOUNTAINS OVER THE NEXT FEW DAYS...WHILE THE VALLEYS ARE EXPECTED TO RECEIVE LESS THAN 2 INCHES OVER THE PERIOD. INCREASED DOWNSLOPE WINDS ALONG AND EAST OF THE CONTINENTAL DIVIDE WILL PRODUCE WARMING ALONG AND NEAR THE EAST SLOPES OF THE MOUNTAINS. AWAY FROM THE MOUNTAINS IN THE BASINS TEMPERATURES WILL REMAIN COOL UNDER INVERSIONS OVER SNOW COVER. OVERALL TEMPERATURES WILL WARM. HIGH PRESSURE WILL BUILD OVER THE AREA WEDNESDAY NIGHT AND THURSDAY WITH DRY AND WARMER CONDITIONS EXPECTED. .LONG TERM...THURSDAY NIGHT THROUGH MONDAY A WEAK SHORT WAVE MOVES THROUGH THURSDAY NIGHT...IT WILL BE LARGELY DRY BUT THERE COULD BE SOME GUSTY WINDS ACROSS THE ABSAROKAS DURING THE EVENING HOURS. A TRANSITORY RIDGE BUILDS IN THEREAFTER LEADING TO MOSTLY SUNNY SKIES AND TEMPERATURES NEAR TO SLIGHTLY ABOVE NORMAL FOR AREAS EAST OF THE DIVIDE WHILE ANOTHER PUSH OF PACIFIC MOISTURE ASSOCIATED WITH A WEAK SHORTWAVE MOVES INTO THE WEST. IT DOESN'T LOOK LIKE THERE WILL BE ENOUGH MOISTURE FOR SIGNIFICANT SNOWS...JUST A COUPLE OF INCHES IN THE WESTERN MOUNTAINS AT BEST ON FRIDAY AND SATURDAY. DRY WEST/SOUTHWEST FLOW IS EXPECTED SUNDAY IN WAKE OF THE WEAK SHORTWAVE TROUGH SATURDAY...AND AHEAD OF A DIGGING TROUGH OFF THE WEST COAST. THIS TROUGH IS EXPECTED TO PUSH INTO THE WEST ON MONDAY WITH SOME ACTIVITY POSSIBLY AFFECTING THE FAR WESTERN ZONES EARLY MONDAY MORNING. THE MAIN IMPACTS WITH THIS TROUGH SHOULD OCCUR BEYOND MONDAY...WITH MEDIUM RANGE MODELS STILL HAVING SIGNIFICANT DIFFERENCES ON THE EVOLUTION OF THIS TROUGH EARLY NEXT WEEK...THE GFS DIGS A SIGNIFICANT TROUGH ACROSS THE WEST WHILE THE EUROPEAN PLACES WYOMING IN ZONAL FLOW AS MOST OF THE ENERGY FROM THIS WAVE REMAINS WELL TO OUR NORTH. && .AVIATION.../00Z ISSUANCE/ A WEAK SHORT WAVE WILL BRING MORE -SHSN TO THE WESTERN MOUNTAINS BETWEEN 00Z AND 10Z TUE WITH OCCNL MVFR AND IFR CIGS AND VSBYS IN -SN...AS WELL AS WIDESPREAD MOUNTAIN OBSCURATIONS VCNTY KJAC. CIGS WILL LOWER ACROSS THE REGION...BUT SHOULD STILL REMAIN IN THE VFR CATEGORY EAST OF THE DIVIDE AND ACROSS THE SOUTH. WITH HIGHER MOUNTAINS OBSCURED INCL THE WIND RIVER AND TETON PEAKS. A LEE SURFACE TROUGH WILL MAINTAIN SOUTHWEST FLOW TO 20-35KT VCNTY SOUTH PASS TO KCPR INTO THE EARLY EVENING HOURS. && .FIRE WEATHER... WESTERLY FLOW WILL INCREASE ACROSS WESTERN AND CENTRAL WYOMING TUESDAY AND WEDNESDAY WITH PACIFIC MOISTURE IN THE FLOW PRODUCING INCREASED AREAS OF LIGHT SNOW IN THE WESTERN AND NORTHERN MOUNTAINS. INCREASED DOWNSLOPE WINDS ALONG AND EAST OF THE CONTINENTAL DIVIDE WILL PRODUCE WARMING ALONG AND NEAR THE EAST SLOPES OF THE MOUNTAINS. AWAY FROM THE MOUNTAINS IN THE BASINS TEMPERATURES WILL REMAIN COOL UNDER INVERSIONS OVER SNOW COVER. OVERALL TEMPERATURES WILL WARM. FAVORABLE TO HIGH RELATIVE HUMID TY WILL CONTINUE WITH GENERALLY LOW MIXING HEIGHTS. && .RIW WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...C.BAKER LONG TERM...ALLEN AVIATION...ALLEN FIRE WEATHER...C.BAKER