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000
FXUS65 KRIW 041800
AFDRIW

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE RIVERTON WY
1100 AM MST TUE MAR 4 2014

.SHORT TERM...TUESDAY THROUGH THURSDAY NIGHT

YET MORE MOISTURE IS NOW MOVING INTO WESTERN WYOMING WITH YET
ANOTHER BATCH OF SNOW. THIS IS BEING AIDED BY THE RIGHT REAR QUAD OF
A JET STREAK MOVING ACROSS MONTANA-WYOMING BORDER. THERE WILL BE
LOCALLY HEAVY SNOW WITH THIS...BUT THE CURRENT SPS COVERS IT FAIRLY
WELL AND WE WILL CONTINUE IT. THERE WILL LIKELY BE SOME AMOUNTS OVER
6 INCHES...BUT THEY SHOULD BE RESTRICTED TO THE HIGHER PEAKS OVER
PASS LEVEL. THE HEAVIER PRECIPITATION SHOULD THEN SHIFT FURTHER TO
THE SOUTH AS A FRONT PRESSES OVER THE AREA. BOTH THE GFS AND NAM
SHOW A DECENT AMOUNT OF QPF OVER THE AREA FROM MIDDAY INTO THE
AFTERNOON. WITH THE MILD TEMPERATURES...MUCH OF THIS MAY FALL AS
RAIN HOWEVER. WITH THE MILD TEMPERATURES...RAIN AND MELTING
SNOWPACK...THERE COULD BE SOME POUNDING OF WATER. WE WILL CONTINUE
THE FLOOD ADVISORY FOR WESTERN LINCOLN COUNTY AS A RESULT.
MEANWHILE...EAST OF THE DIVIDE...EXPECT ANOTHER MILD DAY ALTHOUGH A
BIT COOLER WITH MORE CLOUD COVER EXPECTED. AS FOR PRECIPITATION EAST
OF THE DIVIDE...THE NAM HAS NONE AND THE GFS HAS BACKED OFF A BIT.
WE MAINTAINED SLIGHT POPS IN EASTERN AREAS BUT ANYTHING THAT FALLS
SHOULD NOT BE THAT HEAVY.

THERE SHOULD THEN BE A RELATIVE LULL IN THE PRECIPITATION OUT WEST
FROM TONIGHT INTO WEDNESDAY AS SOME TRANSITIONAL FLAT RIDGING MOVES
ACROSS THE STATE. THAT DOES NOT MEAN NO PRECIPITATION OUT
WEST...JUST LESS. IT WILL BE DRY EAST OF THE DIVIDE HOWEVER. IT WILL
ALSO BE ANOTHER MILD DAY WITH CONTINUED SNOW MELT. THE NEXT AND MORE
POTENT SYSTEM THEN MOVES INTO THE WEST ON WEDNESDAY NIGHT. THERE ARE
SOME SLIGHT TIMING DIFFERENCES BETWEEN THE MODELS SO WE DID NOT MAKE
BIG CHANGES TO CONTINUITY. THE BEST PRECIPITATION STILL LOOKS TO BE
ON THURSDAY AS SOME JET STREAK DYNAMICS GET INVOLVED AND INCREASE
UPPER LEVEL DIVERGENCE. THIS EVENT CERTAINLY LOOKS HIGHLIGHT WORTHY
AT THIS TIME. HOWEVER...THERE WILL BE WARMER AIR WITH THIS STORM
WHICH WOULD RAISE SNOW LEVELS. THE LATEST NAM SHOWS 700 MILLIBAR
TEMPERATURES RISING TO MINUS 2 CELSIUS WHICH WOULD RAISE SNOW LEVELS
TO 7500 FEET SO ACCUMULATIONS IN VALLEYS MAY BE HELD DOWN BEFORE
COLDER AIR MOVES IN BEHIND THE COLD FRONT. AS FOR EAST OF THE DIVIDE
FOR THURSDAY...THE CONCERN CHANGES TO WIND AS THE PRESSURE GRADIENT
TIGHTENS AND MID LEVEL WINDS INCREASE. THE NAM SHOWS 700 MILLIBAR
WINDS INCREASING TO 50 TO 60 KNOTS DURING THE DAY AND SOME OF THOSE
WOULD LIKELY MIX TO THE SURFACE. ALSO...THIS DOWNSLOPING FLOW WILL
LIKELY BRING ANOTHER DAY OF WARM TEMPERATURES. WE RAISED HIGH
TEMPERATURES A FEW DEGREES AS A RESULT. AS FOR PRECIPITATION EAST OF
THE DIVIDE...IT IS A BATTLE BETWEEN SOME DYNAMICS AND DOWNSLOPING
WITH AGAIN THE NAM THE DRIER MODEL. FOR NOW...WE MADE FEW CHANGES.

.LONG TERM...FRIDAY THROUGH TUESDAY

GFS/ECMWF MODELS CONTINUE TO SHOW UNSETTLED WEATHER OVER THE REGION
FRIDAY INTO FRIDAY NIGHT. WILL CONTINUE THE PRECIP CHANCE OVER THE
REGION WITH THE BEST CHANCE IN THE MOUNTAINS. BOTH MODELS BRING AN
UPPER RIDGE OVER THE AREA FOR SATURDAY AND MOST OF SUNDAY. DRY
CONDITIONS FOR THE REGION BOTH DAYS. HOWEVER...THERE IS A HINT OF
MOISTURE NOW COMING BACK TO THE NW MOUNTAINS BY 00Z MONDAY. DID
BRING IN LOW CHANCE OF RAIN OR SNOW TO NW MOUNTAINS SUNDAY PM. THE
NEXT WEATHER SYSTEM PASSES THROUGH THE AREA MONDAY. LOOKS LIKE
ANOTHER ROUND OF SNOW FOR THE WESTERN MOUNTAINS SUNDAY NIGHT AND
MONDAY WITH AMOUNTS STAYING UNDER HIGHLIGHT CRITERIA AT THIS
TIME. EAST OF THE DIVIDE MONDAY IT LOOKS LIKE ONLY ISOLATED PRECIP
ACTIVITY AS THE WEATHER SYSTEM PASSES BY. NEXT TUESDAY LOOKS
INTERESTING ON BOTH THE GFS AND ECMWF. THEY WISH TO DROP A TROUGH
INTO THE PACIFIC NW TUE MORNING AND TAKE IT SOUTHEAST TOWARD THE
GREAT BASIN BY TUE NIGHT. WILL HAVE A CHANCE OF PRECIP IN THE WEST
AND SOUTH NEXT TUE WHILE THE REST OF THE AREA WILL BE LEFT DRY FOR
NOW. PLENTY OF TIME TO WATCH HOW THIS EVOLVES. AS FOR TEMPS...IT
APPEARS THE LOWER ELEVATION SNOW COVER IN PARTS OF THE NORTH WILL
CONTINUE TO MELT THIS WEEK AND THERE MAY NOT BE MUCH LEFT BY THIS
WEEKEND...THUS ALLOWING THOSE PLACES TO WARM UP NICELY. FRIDAY
WILL BE COOLER DUE TO THE WEATHER SYSTEM PASSING BY. THEN WARMER
SATURDAY AND SUNDAY. A LITTLE COOLER NEXT MONDAY AND TUESDAY AS
MORE CLOUDS WILL BE AROUND AS WELL AS COLDER 800MB/700MB TEMPS.
WITH DAYLIGHT SAVINGS TIME STARTING THIS SUNDAY MORNING SPRING IS
GETTING EVER CLOSER AND SUNDAY`S HIGHS EAST OF THE DIVIDE MAY JUST
FEEL LIKE IT.

&&

.AVIATION.../18Z ISSUANCE/

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

A VERY WEAK COLD FRONT WILL PUSH ACROSS THE AREA...WITH ONLY A
SLIGHT CHANCE FOR SHOWER ACTIVITY AND A WIND SHIFT IN EASTERN
SWEETWATER AND SOUTHEAST NATRONA COUNTY. KCPR SHOULD EXPERIENCE
MAINLY JUST VIRGA. VFR CONDITIONS ARE EXPECTED AT TERMINALS WITH AN
OUTSIDE CHANCE OF BRIEF MVFR/IFR CONDITIONS IN A PASSING SHOWER.

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

SCATTERED TO NUMEROUS MOUNTAIN SNOW...AND VALLEY RAIN/SNOW SHOWERS
WILL OCCUR TODAY IN THE FAR WEST INCLUDING KJAC FROM A CONTINUATION
OF MOIST OROGRAPHIC FLOW KEEPING SNOW SHOWERS ONGOING. THUS EXPECT
MVFR/IFR CONDITIONS AT TIMES OVER THE FAR WEST...AND LEAST LIKELY IN
THE UPPER GREEN RIVER BASIN. IN THE MEANTIME...AN AREA OF RAIN AND
SNOW PRODUCING WIDESPREAD MVFR AND LOCAL IFR CONDITIONS WILL BE
EXITING SWEETWATER COUNTY TO THE SOUTH THROUGH THE AFTERNOON WITH
IMPROVING CONDITIONS EXPECTED AT KRKS WITH VFR CONDITIONS EXPECTED
TEHRE BY 21Z THIS AFTERNOON AS THE COLD FRONT CLEARS THE AREA. AFTER
03Z WEDNESDAY...CONDITIONS DRY OUT AND IMPROVE...WITH LIGHT
SNOW/FLURRIES CONFINED TO THE WESTERN MOUNTAINS. FOG WILL DISSIPATE
AROUND 12 NOON TODAY OVER SOUTH PASS.

&&

.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
WITH THE POSSIBLE EXCEPTION OF TUESDAY AFTERNOON OR EVENING AND
THURSDAY NIGHT. OCCASIONAL SNOW WILL CONTINUE ACROSS THE WEST INTO
TUESDAY WITH ANOTHER MORE SUBSTANTIAL SNOW POSSIBLE WEDNESDAY NIGHT
AND THURSDAY.

&&

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

&&

$$

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