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000
FXUS65 KRIW 020941
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
241 AM MST SUN MAR 2 2014

.SHORT TERM...SUNDAY THROUGH TUESDAY NIGHT

THE LONG LIVED STORM IS FINALLY STARTING TO WIND DOWN ACROSS THE
AREA. THERE IS STILL SOME SNOW ACROSS THE WESTERN MOUNTAINS BUT
RADAR COVERAGE IS WEAKENING. WE MAY CANCEL THE WARNING EARLY BUT
THAT WILL BE A GAME TIME DECISION. MEANWHILE...EAST OF THE
DIVIDE...THE FLOW HAS TURNED MORE WEST TO NORTHWEST AND THAT HAS
LEAD TO THE FORMATION OF SOME OF THOSE DASTARDLY...PAIN IN THE
NECK...WISH THEY WOULD GO AWAY SNOW BANDS. ONE HAS FORMED NEAR
WORLAND AND ANOTHER RUNS FROM DUBOIS INTO THE NORTHERN WIND RIVER
BASIN. THEY SHOULD BE GONE BY MORNING...BUT WE COULD SEE A QUICK
INCH OR TWO OF SNOW FROM THEM IN SOME LOCATIONS. OTHERWISE...THE
STORY EAST OF THE DIVIDE IS THE BITTERLY COLD TEMPERATURES THIS
MORNING WITH TEENS BELOW ZERO ACROSS NORTHERN AND EASTERN AREAS AND
MOST AREAS BELOW ZERO. MEANWHILE...TEMPERATURES ARE MAINLY IN THE
20S WEST OF THE DIVIDE. ONE GOOD THING IS THAT THERE IS LITTLE WIND
RIGHT NOW...SO WIND CHILL TEMPERATURES SHOULD NOT BE A MAJOR FACTOR.

AS FOR TODAY...IT LOOKS MAINLY DRY EAST OF THEN DIVIDE. TEMPERATURES
WILL BE WARMER THAN YESTERDAY BUT STILL WELL BELOW NORMAL. WITH THE
FRESH SNOW COVER IN MANY LOCATIONS...WE KEPT HIGHS BELOW THE MOS
GUIDANCE. MEANWHILE...OUT WEST SOME SNOW SHOWERS WILL CONTINUE
THROUGH THE DAY. HOWEVER...THERE SHOULD BE A LULL IN ACTIVITY WITH
LIGHT ACCUMULATIONS SO WE MAY ACTUALLY HAVE A PERIOD WITH NO
HIGHLIGHTS. ITS BEEN A WHILE SINCE THAT OCCURRED.

AS FOR THE REST OF THE FORECAST...OUT WEST THERE WILL STILL BE THE MOIST
OROGRAPHIC FLOW CONTINUING. HOWEVER...WITH NO STRONG TRIGGERS FOR
THE SNOW HEAVY SNOW IS NOT ANTICIPATED. MODELS SEEM TO BE ZEROING IN
ON SUNDAY EVENING FOR A HEAVIER BURST OF SNOW IN THE NORTHWEST
MOUNTAINS. NOTHING LIKE THE PREVIOUS FEW DAYS THOUGH. THE CHANCE OF
SNOW WILL LINGER THROUGH MONDAY NIGHT ALTHOUGH NAILING DOWN A
HEAVIER PERIOD OF SNOW IS DIFFICULT AT THIS POINT. A SHORTWAVE
MOVING THROUGH TUESDAY COULD BRING A BETTER CHANCE OF SNOW BUT
AMOUNTS ARE UNCERTAIN AT THIS POINT. MEANWHILE...EAST OF THE DIVIDE
TEMPERATURES WILL SEE A WARMING TREND AS DOWNSLOPING FLOW INCREASES
MONDAY. THE GFS MOS NUMBERS APPEAR TO BE OUT TO LUNCH AND TOO WARM
BUT IT WILL BE SIGNIFICANTLY WARMER MONDAY THAN ON SUNDAY. FOR
TUESDAY THE GFS SHOWS SOME PRECIPITATION ABLE TO GET EAST OF THE
DIVIDE WHILE THE NAM IS MAINLY DRY. AT THIS POINT...WE WONT MAKE BIG
CHANGES IN CONTINUITY.

.LONG TERM...WEDNESDAY THROUGH SUNDAY

WEDNESDAY LOOKS DRY FOR MOST PLACES. SCATTERED LIGHT SNOW FOR THE
WESTERN MOUNTAINS...ESPECIALLY THE NW MOUNTAINS WHERE SOME MOISTURE
IS FORECAST TO RESIDE. BREEZY AREAS EAST OF THE DIVIDE IN THE
FAVORED PLACES. GFS MODEL HAS THE NEXT WEATHER SYSTEM MOVING THROUGH
THE REGION ON THURSDAY AND THURSDAY NIGHT. THE ECMWF MODEL IS SLOWER
WITH THIS SYSTEM AND WAITS UNTIL THURS NIGHT INTO FRIDAY. FOR NOW
WILL BRING IN A BETTER CHANCE OF PRECIP TO THE WEST LATE WED NIGHT
AND THURSDAY TO THE WESTERN MOUNTAINS AND FAR WEST VALLEYS. CAN
ADJUST THIS TIMING IF MODELS CHANGE. THEN KEEPING THE CHANCE OF
PRECIP IN THE WEST THURS NIGHT AND FRIDAY AS MOISTURE SEEMS TO
REMAIN OVER THE WEST THROUGH FRIDAY EVENING. HAVE A CHANCE OF PRECIP
ACROSS THE SOUTH THURS AND THURS NIGHT AS THIS SYSTEM MOVES THROUGH
THE REGION. OTHER PLACES EAST OF THE DIVIDE WILL SEE LOW CHANCE OF
RAIN OR SNOW SHOWERS THURS AFTERNOON AND THURS NIGHT. WILL KEEP LOW
CHANCE OF PRECIP EAST OF THE DIVIDE FOR FRIDAY AS GFS/ECMWF MODELS
HAVE SOME SORT OF TROUGH MOVING THROUGH THE AREA. CONDITIONS TO
DRY OUT FRI NIGHT OVER ALL AREAS. FOR NOW A DRY FORECAST NEXT
SATURDAY AND SUNDAY AS A RIDGE OF HIGH PRESSURE IS FORECAST...
PUSHING THE MOISTURE WELL TO THE NORTH. GETTING A RIDGE OVER THE
REGION HAS BEEN DIFFICULT THE PAST FEW WEEKS SO THIS WOULD BE A
WELCOME CHANGE ALBEIT BRIEF AS I LOOK FARTHER INTO NEXT WEEK. AS
FOR TEMPS...MILDER HIGHS WEDNESDAY AND THURSDAY THEN COLDER
FRIDAY. LOOKS TO WARM BACK UP NEXT SATURDAY AND SUNDAY. NOW THE
SNOW COVERED BASINS WILL SEE LESS WARMING ON CERTAIN DAYS DUE TO
THE LACK OF MIXING. HAVE MADE SOME ADJUSTMENTS IN HIGHS AND LOWS
TO ACCOUNT FOR THE SNOW COVER THAT IS QUITE DEEP IN PLACES IN THE
WESTERN AND NORTHERN BASINS.

&&

.AVIATION.../12Z ISSUANCE/

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

THE MAIN AVIATION CHALLENGE IS THE EXTENT IF ANY OF THE
STRATUS/PATCHY FOG THIS MORNING AS THE ARCTIC AIR MASS BEGINS TO
RETREAT. BY MIDDAY...19Z...MUCH OF THE CLOUDS WILL SCATTER OUT WITH
VFR CONDITIONS EXPECTED. THE MAIN EXCEPTION WILL BE LOW CLOUDS AND
SOME LIGHT SNOW OVER THE MOUNTAINS ALONG THE DIVIDE.

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

SNOW WILL CONTINUE ACROSS WESTERN MOUNTAINS AND FAR WESTERN VALLEYS
AT TIMES...WITH LITTLE ACTIVITY IN THE UPPER GREEN RIVER BASIN AND
SWEETWATER COUNTY THROUGH THE TAF FORECAST PERIOD. THE BEST SHOT FOR
SNOWFALL WILL OCCUR LATE THIS AFTERNOON INTO TONIGHT...BUT THE
INTENSITY WILL BE LIGHTER THAN WHAT OCCURRED YESTERDAY.
&&

.FIRE WEATHER...

LOW MIXING HEIGHTS WITH POOR SMOKE DISPERSAL EXPECTED WITH SOME
INVERSIONS TODAY. DRIER WEATHER WILL RETURN EAST OF THE DIVIDE ON
SUNDAY BUT TEMPERATURES WILL REMAIN VERY COLD. OCCASIONAL SNOW
WILL CONTINUE ACROSS THE WEST INTO EARLY NEXT WEEK. EXPECT A
WARMING TREND EARLY NEXT WEEK.
&&

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

&&

$$

SHORT TERM...HATTINGS
LONG TERM...AR
AVIATION...WM
FIRE WEATHER...HATTINGS