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000
FXUS65 KRIW 011734
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1034 AM MST SAT MAR 1 2014

.SHORT TERM...SATURDAY THROUGH MONDAY NIGHT

ROAR! THE MASCOT FOR THE FORECAST TODAY IS THE LION AT THE BEGINNING
OF THE MGM MOVIE PRODUCTIONS...IS USHERING MARCH LIKE A LION
TONIGHT AS A STORM IS ONGOING ACROSS THE COUNTY WARNING AREA WITH
MANY LOCATIONS REPORTING SNOW AT THIS POINT. HOWEVER...THERE ARE
SOME CONCERNS WITH THE FORECAST TONIGHT. SO FAR...THERE WERE SOME
HEAVY SNOWFALL REPORTS WEST OF THE DIVIDE WITH SOME OF THE TETONS
REPORTING CLOSE TO 2 FEET OF SNOW TODAY. HOWEVER...IN THE LOWER
ELEVATIONS EAST OF THE DIVIDE AMOUNTS HAVE NOT BEEN IMPRESSIVE.
MOST OF THE SNOW REPORTED SO FAR HAS BEEN FAIRLY LIGHT. THE
HEAVIEST SNOW IS STILL EXPECTED FROM LATE TONIGHT INTO SATURDAY
MORNING AS JET DYNAMICS GET INVOLVED. SATELLITE IMAGERY SHOWS THE
JET CORE MOVING INTO FAR SOUTHWESTERN WYOMING RIGHT NOW AND THIS
SHOULD GET HEAVIER SNOW GOING AS WE GET THE DYNAMICS FROM THE LEFT
FRONT QUADRANT. THE HEAVIEST SNOW SHOULD FOLLOW THIS PATH.
HOWEVER...WE ARE STARTING TO FAVOR THE LOWER END OF THE WARNING
AMOUNTS AT THIS TIME. WE HAD SOME THOUGHTS OF DOWNGRADING SOME OF
THE WARNINGS TO ADVISORIES. HOWEVER...DECIDED AGAINST SINCE THE
HEAVIEST SNOW IS STILL ON THE WAY. THE HEAVIEST SNOW SHOULD END
THIS EVENING AS THE DYNAMICS MOVE AWAY. MEANWHILE...OUT WEST
PERIODS OF SNOW WILL CONTINUE THROUGH THE DAY AS THE MOIST FLOW
CONTINUES WITH ACTIVITY TAPERING OFF TONIGHT AS THE BEST LIFT
MOVES AWAY. IT WILL ONCE AGAIN BE A DAY OF CONTRASTS IN
TEMPERATURES WITH MUCH WARMER TEMPERATURES WEST OF THE DIVIDE WITH
THE FLOW OF MILDER PACIFIC AIR AND VERY COLD TEMPERATURES TO THE
EAST. THE HIGH TEMPERATURE MAP HAS AROUND A 50 DEGREE SPREAD
AROUND THE COUNTY WARNING WITH BELOW ZERO TEMPERATURES IN NORTHERN
JOHNSON COUNTY AND SOME 40S IN THE FAR SOUTHWEST.

QUIETER WEATHER WILL RETURN EAST OF THE DIVIDE ON SUNDAY AS ZONAL
FLOW ALOFT WILL BRING DOWNSLOPING WINDS AND DRY WEATHER. WITH THE
SNOW COVER IN MOST PLACES...WE KEPT THE HIGH TEMPERATURES BELOW THE
MOS GUIDANCE. MEANWHILE...WEST OF THE DIVIDE...UPSLOPE FLOW WILL
CONTINUE AND KEEP THE CHANCE OF SNOW GOING ACROSS THE WESTERN
MOUNTAINS. THE GFS IS A BIT WETTER THAN THE NAM AT THIS POINT BUT
WITH THE UNCERTAINTY WE MADE FEW CHANGES. MONDAY LOOKS LIKE THE SAME
SITUATION WEST OF THE DIVIDE WITH MORE OROGRAPHIC SNOW SHOWERS
CONTINUING.  MEANWHILE...EAST OF THE DIVIDE WITH DOWNSLOPING
INCREASING AND THINGS BECOMING A BIT BREEZIER TEMPERATURES WILL
RECOVER TO NEAR AND IN SOME CASES ABOVE NORMAL LEVELS.

.LONG TERM...TUESDAY THROUGH SATURDAY

DISTURBED ZONAL FLOW OPEN TO THE PACIFIC WILL CONTINUE TUESDAY. THE
GLOBAL MODELS ARE NOW SHOWING A SHORT WAVE ON TUESDAY EVENING
DIGGING A BIT MORE...TILTING THE FLOW NORTHWEST AND BRINGING SOME
PRECIPITATION EAST OF THE DIVIDE. RIDGING BUILDS IN SHORTLY
THEREAFTER...SO IT WOULD BE A SHORT LIVED EVENT EAST OF THE DIVIDE
IF IT WERE TO HAPPEN AS ADVERTISED. THIS RIDGING COULD BE FLATTENED
A BIT ON WEDNESDAY BY ANOTHER PASSING DISTURBANCE OVER THE TOP OF
THE RIDGE...WHICH COULD BRING SOME POTENTIAL ACCUMULATING SNOW
TO THE NORTHERN MOUNTAINS FOR WEDNESDAY NIGHT. A MORE ORGANIZED
SYSTEM LURKS OFF OF THE NORTHWEST COAST AT THIS TIME...THIS COULD
KICK SOME MORE PACIFIC MOISTURE INTO THE REGION WITH SOME SHORT
WAVES MOVING ALONG AHEAD OF THE SYSTEM...POSSIBLY BRINGING MORE
PRECIPITATION TO THE WEST AND SOUTH FOR THURSDAY. THIS SYSTEM MOVES
ASHORE THURSDAY NIGHT INTO FRIDAY WITH MORE WIDESPREAD PRECIPITATION
SPREADING TO BOTH SIDES OF THE DIVIDE. THE TRACK OF THE JET STREAM
IS TRENDING FURTHER NORTH SO THERE COULD BE SOME UPPER LEVEL
DIVERGENCE SUPPLIED BY THE LEFT EXIT REGION...BUT IT IS STILL FAR
TOO EARLY TO TELL IF THIS WILL COME TO FRUITION. OVERALL...IT LOOKS
WET IN THE MOUNTAINS...MILD AND WINDY EAST OF THE DIVIDE FOR MUCH OF
THE WEEK WITH COOLING TEMPERATURES AND POSSIBLE PRECIPITATION FOR
THE ENTIRE FORECAST AREA BY THE END OF THE WEEK.

.AVIATION.../18Z ISSUANCE/

WIDESPREAD MVFR/LOW VFR CEILINGS...WITH PERIODS OF MVFR/IFR VSBY IN
SNOW ACROSS THE ENTIRE LOWER ELEVATIONS THROUGH THE PERIOD. THE
HEAVIEST AND MOST WIDESPREAD SNOWFALL IS EXPECTED THROUGH 06Z.
MOUNTAINS WILL REMAIN OBSCURED...WITH LIFR CONDITIONS IN SNOW AND
LOW CLOUDS OVER MOUNTAIN PASSES.

.FIRE WEATHER...

NO FIRE WEATHER CONCERNS EXPECTED WITH WIDESPREAD SNOWFALL AND
COLD AIR ON THE WAY. WINTER STORM WARNINGS ACROSS THE AREA EXCEPT
FOR SWEETWATER AND LOWER ELEVATIONS OF SUBLETTE COUNTIES.  LOW
MIXING HEIGHTS WITH POOR SMOKE DISPERSAL EXPECTED. SIGNIFICANT
SNOWFALL EXPECTED MOST AREAS. DRIER WEATHER WILL RETURN EAST OF
THE DIVIDE ON SUNDAY.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
WINTER STORM WARNING UNTIL 5 AM MST SUNDAY
WYZ001>020-022>025-027.

WINTER WEATHER ADVISORY UNTIL 5 AM MST SUNDAY WYZ026.

&&

$$

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