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000
FXUS65 KRIW 050610
AFDRIW

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RIVERTON WY
1110 PM MST TUE MAR 4 2014

.SHORT TERM...TONIGHT THROUGH WEDNESDAY

MOST OF THE HIGH ELEVATION SNOW AND LOW ELEVATION RAIN ASSOCIATED
WITH THE WEAK SHORTWAVE AND WEAK COOL FRONT HAS EXITED ALL BUT
SOUTHERN AND EASTERN SWEETWATER COUNTY AND SOUTHEAST NATRONA
COUNTIES. SOME OF THESE EXITING CONVECTIVE CELLS PRODUCED HEAVY
ENOUGH SNOW SHOWERS TO DROP THE VSBY TO 1/4 OF A MILE SUCH AS WHAT
OCCURRED AT RKS EARLIER TODAY. SOME OROGRAPHIC LIGHT SNOW
SHOWERS/FLURRIES  WILL CONTINUE IN THE FAR WEST THROUGH TONIGHT WITH
A SLIGHT INCREASE IN SNOW SHOWER ACTIVITY AFTER 06Z TONIGHT AS A
SLIGHT RIPPLE IN THE WEST NORTHWEST PROGRESSIVE FLOW MOVES ACROSS.
OTHERWISE A FLAT RIDGE WILL BUILD IN FROM THE WEST THROUGH WEDNESDAY
MAKING WEDNESDAY THE DRIEST MILD DAY IN QUITE A WHILE. WEST
SOUTHWEST WINDS WILL PICK UP SOMEWHAT BY WEDNESDAY FROM RKS TO CPR
AND ALONG THE EAST SIDE OF THE CONTINENTAL DIVIDE AS SOME OF THE 35
KNOT H7 WINDS SURFACE. THERE WILL BE SOME POCKETS OF LOW
TEMPERATURES IN THE TEENS IN THE LOWER BASINS TONIGHT WHERE SNOW
COVER IS WELL ESTABLISHED SUCH AS IN THE EASTERN BIG HORN BASIN.

.LONG TERM...WEDNESDAY NIGHT THROUGH TUESDAY

NEXT UPSTREAM SHORTWAVE AND ASSOCIATED MOISTURE WILL BEGIN IMPACTING
THE NORTHWEST MOUNTAINS WEDNESDAY NIGHT. BEST JET ENERGY WILL BE
JUST TO OUR NORTH UNTIL LATER THURSDAY AFTERNOON AND NIGHT. WESTERLY
700MB WIND SPEEDS INCREASE TO AROUND 40KTS ACROSS THE WESTERN
MOUNTAINS LATER THURSDAY. THUS...OROGRAPHICS FAVORABLE BUT
INSTABILITY NOT OVERLY IMPRESSIVE WITH MODERATE LAPSE RATES AT BEST.
STILL SHOULD HAVE A PERSISTENT PERIOD OF LIGHT SNOWFALL IN THIS
REGION FROM ABOUT 06Z/THU-06Z/FRI. BUMPED SNOW CHANCES UP SLIGHTLY
FOR THE TETONS AND THE SURROUNDING RANGES WITH BORDERLINE WARNING
AMOUNTS FOR THE TETONS AND SOUTHWEST YELLOWSTONE NATIONAL PARK.
VALLEY TEMPERATURES ON THURSDAY WILL LEAD TO LIGHT RAIN OR A MIX
BEFORE TURNING TO ALL SNOW AFTER 00Z/FRI. GENERALLY DRY AND WARM
CONDITIONS TO THE EAST IN DOWNSLOPING FLOW. PACIFIC COLD FRONT
PUSHING EAST THROUGH THE FORECAST AREA WILL PROBABLY HOLD OFF LONG
ENOUGH TO SEE MAXIMUM HEATING REALIZED EAST OF THE DIVIDE. ADJUSTED
MAX TEMPS UPWARD SLIGHTLY ACROSS JOHNSON AND NATRONA COUNTIES AS
PRE-FRONTAL WINDS SHOULD HELP BOOST TEMPS. CANNOT RULE OUT A 60
DEGREE READING IN THE EASTERN PORTION OF THE FORECAST AREA THURSDAY
AFTERNOON. COLDER AIR FILTERS INTO THE REGION ON FRIDAY WITH 700MB
TEMPS FALLING FROM +1C OR +2C ON THURSDAY TO -6C OR -7C ON FRIDAY.
TROUGH WILL SLIDE ACROSS THE STATE ON FRIDAY BUT APPEARS BEST ENERGY
MAY DIVE TO OUR SOUTH. HAVE CONTINUED OVERALL TREND OF PRECIP
CHANCES INCREASING EAST OF THE DIVIDE ON FRIDAY BEFORE TAPERING OFF
THROUGH SATURDAY MORNING. SNOW AMOUNTS LOOK UNIMPRESSIVE WITH
DYNAMICS LACKING. WITH THAT SAID...WOULD NOT BE SURPRISED TO SEE A
LITTLE RIPPLE IN NORTHWEST FLOW ALOFT HELP TO LINGER LIGHT SNOW
THROUGH SATURDAY MORNING AND FAVOR THE NORTHERN AND NORTHWEST
MOUNTAINS. RIDGE BUILDS IN BEHIND THIS TROUGH WITH RAPIDLY DRYING
AND WARMING CONDITIONS BY SATURDAY AFTERNOON. ENOUGH SUNSHINE AND
MODERATING 700MB TEMPS TO HELP READINGS CLIMB TO AT OR ABOVE NORMAL
IN MANY LOCALES. 700MB TEMPS FURTHER REBOUND ON SUNDAY WHEN READINGS
WILL AGAIN CLIMB INTO THE 50S FOR MOST AREAS EAST OF THE DIVIDE.
WESTERN VALLEYS TO BE AT OR ABOVE NORMAL ALTHOUGH INCREASING MID AND
HIGH CLOUDS AHEAD OF INCREASING WESTERLY FLOW COULD TEMPER THESE
HIGH TEMPS. RIDGE FOLDS OVER LATER SUNDAY ALLOWING FOR THE WESTERLY
FLOW TO BRING PACIFIC MOISTURE BACK TO THE FAR WEST BEGINNING LATE
SUNDAY AND SUNDAY NIGHT. ANOTHER ACTIVE SNOW PERIOD SET TO BEGIN THE
WEEK WEST OF THE DIVIDE. EASTERN AREAS CAN ANTICIPATE COOLER TEMPS
AND INCREASING CLOUDS FOR MONDAY BUT LITTLE IN THE WAY OF PRECIP.
THIS CHANGES TUESDAY AS THE NEXT TROUGH SWINGS ACROSS THE FORECAST
AREA FROM THE NORTHWEST. TUESDAY WILL BE COOLER WITH A BETTER CHANCE
OF SNOW ACROSS THE EAST WHILE SNOW CONTINUES IN THE WEST. SIMILAR TO
THE SYSTEM AT THE END OF THIS WEEK...THE BEST ENERGY IS LIKELY TO BE
TO OUR SOUTH SO ANYTHING SIGNIFICANT APPEARS UNLIKELY AT THIS TIME.

&&

.AVIATION.../06Z ISSUANCE/

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

AN AREA OF MID CLOUDS AND PERHAPS VERY ISOLATED SHOWER ACTIVITY OVER
NORTHERN AND CENTRAL WYOMING WILL QUICKLY PUSH SOUTHEAST OUT OF THE
AREA BY AROUND 09Z. OTHERWISE...DRY CONDITIONS WITH MAINLY LEE
ENHANCED HIGH CLOUDINESS AND SOME MID CLOUDS ARE EXPECTED
WEDNESDAY. THE BASINS AND VALLEYS WILL SEE FAIRLY LIGHT WINDS
THROUGH THE PERIOD WHILE THE MOUNTAINS...FOOTHILLS AND WIND CORRIDOR
FROM SOUTH PASS TO KCPR WILL BECOME BREEZY TO WINDY WEDNESDAY
MORNING. STRONG WINDS COULD DEVELOP OVER THE CODY FOOTHILLS
WEDNESDAY NIGHT...OR AT LEAST CREATE SOME LLWS AT KCOD TERMINAL.
COULD ALSO SEE SOME LLWS AT KLND WED NIGHT.

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

VALLEY FOG COULD BE THE MAIN ISSUE IN THE BASINS/VALLEYS FOR THE
REMAINDER OF TONIGHT INTO WEDNESDAY MORNING. ANY FOG WILL
LIFT/SCATTER OUT BY NOON. LOOKS LIKE MAINLY DRY CONDITIONS WILL
ACTUALLY OCCUR WEDNESDAY WITH THE LIGHT SNOW/FLURRIES CONFINED TO
MOUNTAIN TOPS AND PERHAPS YELLOWSTONE. THIS WILL CHANGE WEDNESDAY
NIGHT AS YET ANOTHER STORM SYSTEM APPROACHES THE REGION WITH SOME
SNOW BREAKING OUT ACROSS NORTHWEST WYOMING. A GOOD BET THAT KJAC
WILL SEE SNOW...WITH INCREASING CHANCES DURING WED NIGHT. SOUTH OF
KJAC...MAINLY DRY CONDITIONS ARE EXPECTED WED NIGHT. BREEZY WESTERLY
WINDS ARE EXPECTED OVER SWEETWATER COUNTY...WITH BREEZY SOUTHERLY
WINDS DEVELOPING IN JACKSON HOLE.

&&

.FIRE WEATHER...
NO FIRE WEATHER CONCERNS ARE EXPECTED THROUGH THE WEEK. WINDIER
AREAS WILL SEE FAIR SMOKE DISPERSAL WITH BETTER MIXING WITH SOME
INVERSIONS IN AREAS WITH MORE SNOW COVER. MAINLY DRY WEATHER IS
EXPECTED EAST OF THE CONTINENTAL DIVIDE WITH A GRADUAL WARMING
TREND. OCCASIONAL LIGHT SNOW WILL CONTINUE ACROSS THE WEST INTO
WEDNESDAY WITH ANOTHER MORE SUBSTANTIAL SNOW POSSIBLE WEDNESDAY
NIGHT AND THURSDAY.

&&

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

&&

$$

SHORT TERM...LIPSON
LONG TERM...CNJ
AVIATION...WM
FIRE WEATHER...LIPSON