Area Forecast Discussion
Issued by NWS Riverton, WY

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000
FXUS65 KRIW 191021
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
321 AM MST MON JAN 19 2015

.SHORT TERM...MONDAY THROUGH WEDNESDAY NIGHT

AT THIS TIME...THE LAST TRAILING SHORTWAVE IS MOVING THROUGH THE
AREA WITH THE ECHOES ACROSS THE WEST GRADUALLY DECREASING SO STEADY
SNOW SHOULD BE OVER BY AROUND 5 AM. THE EXCEPTION IS ONE OF THOSE
PAIN IN THE BUTT SNOW BANDS THAT HAS POPPED UP FROM NEAR MORNA
JUNCTION ACROSS THE ABSAROKAS. IT IS LOCALIZED SO WE WILL NOT ISSUE
ANY HIGHLIGHTS. ALSO...THE WIND HAS DECREASED IN THE CODY FOOTHILLS
SO WE WILL LIKELY CANCEL THE HIGH WIND WARNING WITH THE MORNING
ISSUANCE.

OVERALL A MUCH QUIETER DAY WEATHERWISE TODAY. ONE MORE WEAK
SHORTWAVE WILL DROP SOUTHEASTWARD THROUGH THE AREA THIS AFTERNOON
AND EVENING WITH A ROUND OF SNOW SHOWERS. HOWEVER...THIS SHORTWAVE
HAS LITTLE MOISTURE TO WORK SO ANY SNOW SHOWERS ARE EXPECTED TO BE
LIGHT. MOST SNOW SHOWERS SHOULD REMAIN TO AREAS WEST OF THE DIVIDE
AND THE HIGHER ELEVATIONS. HOWEVER...WITH NORTHWEST FLOW THERE COULD
BE SOME SNOW SHOWERS POPPING UP EAST OF THE DIVIDE AND MAYBE EVEN
SOME OF THOSE PAIN IN THE NECK SNOW BANDS. THE MODELS ARE
NOTORIOUSLY BAD IN PINPOINTING THEM HOWEVER. THERE ARE SOME POPS EAST
OF THE DIVIDE AND SINCE THESE HAVE A GOOD A CHANCE OF VERIFYING AS
ANYTHING WE MADE FEW CHANGES. TEMPERATURES WILL COOL SOME BEHIND THE
FRONT BUT SHOULD NOT BE OVERLY CHILLY.

NORTHWEST FLOW CONTINUES FOR TUESDAY AS WELL. BOTH THE GFS AND NAM
MODELS STILL SHOW A FEW SNOW SHOWERS WITH THE NORTHWEST FLOW AND
WEAK FRONT PASSING THROUGH WITH THE GFS A BIT MORE BULLISH ON
COVERAGE THAN THE NAM...ESPECIALLY IN THE BIG HORN RANGE. AS A
RESULT WE DID INCREASE POPS A BIT. BUT AGAIN...WITH MOISTURE LACKING
ANY AMOUNTS ARE EXPECTED TO BE LIGHT. TEMPERATURES WILL BE COOLER
THAN RECENT DAYS...BUT NOTHING UNUSUAL FOR JANUARY. MAINLY DRY
WEATHER SHOULD RETURN FOR WEDNESDAY AS RIDGING BUILDS ACROSS THE

.LONG TERM...THURSDAY THROUGH MONDAY

THURSDAY LOOKS DRY WITH HIGH PRESSURE OVER THE REGION. A WEAK
WEATHER SYSTEM MAY IMPACT THE AREA FRIDAY BUT THE GFS AND ECMWF
MODELS HAVE ONLY MOUNTAIN PRECIP AND MAINLY OVER THE NORTH. WILL
KEEP LOW PRECIP CHANCE IN THE MOUNTAINS FRI AND FRI NIGHT. THE ECMWF
MODEL CONTINUES TO SHOW A MOIST NW FLOW DEVELOPING SATURDAY AND THEN
CONTINUING THROUGH SUNDAY NIGHT. THE GFS IS NOW TRENDING TOWARD THIS
PATTERN AS WELL TONIGHT. THUS CONFIDENCE IS HIGHER FOR SOME SNOW IN
THE NORTHWEST MOUNTAINS AND BIGHORN MOUNTAINS. LESS SNOW FOR THE
WIND RIVER AND SALT/WY RANGES IN THIS PATTERN. HAVE ADJUSTED PRECIP
CHANCE UPWARD A LITTLE MORE FOR SATURDAY AFTERNOON THROUGH SUNDAY
EVENING WITH DRYING TO OCCUR LATE SUNDAY NIGHT. THE LOWER ELEVATIONS
WILL BE MOSTLY DRY SATURDAY THROUGH SUNDAY. THE EXCEPTION MAY BE THE
NORTH AND EAST ZONES WHERE SOME LIGHT SNOW MIGHT OCCUR SATURDAY
NIGHT THROUGH SUNDAY MORNING. WILL HAVE TO WATCH THIS AS TIME GETS
CLOSER AND ADJUST AS NEEDED. MONDAY LOOKS DRY FOR THE REGION. AS FOR
TEMPS...HIGHS LOOK TO BE AT OR ABOVE SEASONAL NORMALS THURS THROUGH
SATURDAY. THEN EVEN MILDER HIGHS EXPECTED SUNDAY AND NEXT MONDAY.

&&

.AVIATION.../12Z ISSUANCE/

EAST OF THE DIVIDE...KCOD/KCPR/KLND/KRIW/KWRL ROUTES
ISOLD-SCT MVFR -SHSN WILL LINGER ACROSS THE SOUTH TODAY...MAINLY FROM
VCNTY INTERSTATE 80 AND SOUTH AFFECTING KRKS-KCPR ROUTES.  VFR
CONDITIONS WILL PREVAIL ELSEWHERE WITH DECREASING WIND SPEEDS
THROUGH THIS MORNING.

AN UPPER DISTURBANCE IN NW FLOW WILL BRING ISOLD-SCT MVFR -SHSN
SE PRIMARILY ALONG AND EAST OF A VCNTY KCOD-KWRL-KCPR LINE AFTER 00Z
TUESDAY ALONG WITH SURROUNDING MTNS MOSTLY OBSCURED ABOVE FL8-9KFT.

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

CLEARING ACROSS THE WESTERN VALLEYS THIS MORNING WILL LIKELY RESULT
IN SOME FOG FORMATION PARTIALLY OBSCURING TERRAIN...ESPECIALLY VCNTY
KJAC.  ISOLD-SCT MVFR SHSN ARE LIKELY TO LINGER VCNTY AND SOUTH OF
INTERSTATE 80 THROUGH TODAY.  AN UPPER DISTURBANCE WILL SPREAD
SCT-NMRS SHSN INTO THE NORTHERN MTNS LATE MONDAY AFTERNOON...INTO
VCNTY KJAC MONDAY EVENING.  SNOW SHOWERS ARE NOT EXPECTED TO MAKE IT
MUCH FURTHER SOUTH OF A VCNTY KJAC-KDUB LINE MONDAY NIGHT WITH A
DRIER AIRMASS/VFR CONDITIONS PREVAILING ACROSS THE SW MONDAY
NIGHT.

&&

.FIRE WEATHER...

TEMPERATURES WILL REMAIN ON THE COOL SIDE WITH FAVORABLE RELATIVE
HUMIDITY WITH WIDESPREAD SNOW COVER OVER MOST OF THE AREA.
GENERALLY LIGHT SNOW WILL FALL OVER THE WEST WITH MAINLY DRY WEATHER
EAST OF THE DIVIDE. GENERALLY MIXING HEIGHTS WILL BE LOW. WIND WILL
DECREASE TODAY.

&&

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

&&

$$

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







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