Area Forecast Discussion
Issued by NWS Grand Junction, CO

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000
FXUS65 KGJT 260530
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
1030 PM MST TUE NOV 25 2014

.UPDATE...
ISSUED AT 908 PM MST TUE NOV 25 2014

EXTENSIVE CLOUD COVER ACROSS THE NERN HALF OF THE FORECAST AREA
WILL KEEP OVERNIGHT MINIMUMS RELATIVELY MILD. RAISED MINS AT A FEW
LOCALES BY A FEW DEGREES.

UPDATE ISSUED AT 619 PM MST TUE NOV 25 2014

MOISTURE FLUX RISES DURING THE NEXT 12 HOURS OVER NW COLORADO AS
A SHORT WAVE SLIDE SOUTHEAST IN THE LEE OF THE ROCKY MOUNTAINS.
WEST TO EAST GRADIENT ALONG THE DIVIDE IS PROMINENT DURING THE
NEXT 12 HOURS AS WELL AND THIS WILL HELP OROGRAPHIC SNOWFALL.
COLD FREEZING AIR TRAPPED IN THE YAMPA RIVER BASIN DEFINITELY
HELPS AND KEEPS THE AIR MASS SATURATED. NAM12/RAP13 SHOWING HEFTY
QPF AMOUNTS DURING THE OVERNIGHT PERIOD OVER THE PARK RANGE...AND
TO A LESSER EXTENT THE GORE RANGE. BOOSTED QPF/SNOW AMOUNTS AND
THAT PUSHED ZONE 4 INTO WARNING RANGE. WEB CAMS IN THE VICINITY
INDICATE SIGNIFICANT SNOW ACCUMULATIONS HAVE ALREADY OCCURRED.
REGARDING ZONE 12...WEB CAMS IN THIS ZONE SHOWED OBSCURED
MOUNTAINS. REMOTE SENSORS INDICATE ACCUMULATING SNOWFALL AS WELL
AND ELECTED TO HOIST THE ADVISORY THROUGH WED MORNING.

&&

.SHORT TERM...(TONIGHT THROUGH WEDNESDAY NIGHT)
ISSUED AT 249 PM MST TUE NOV 25 2014

IN BRISK NW FLOW THE LAST IN A SERIES OF OPEN WAVES IS BRINGING
SNOW TO NW COLORADO. A 120KT JET OVER NW CO WILL WEAKEN THIS
EVENING AND SHIFT EAST BY WEDNESDAY. STILL NW CO SNOWFALL
INTENSITY IS FORECAST TO INCREASE THIS EVENING. IDEALLY THESE
OVERRUNNING EVENTS WOULD HAVE COLDER AIR POOLED BELOW AND THE
ISOTHERMAL SATURATED LAYER SOMEWHERE NEAR MTN TOP LEVEL. THOUGH
THE PROFILE SHOWS DEEP SATURATION... NEITHER OTHER CONDITIONS
STRONGLY EXIST.

LIGHT SNOW HAS BEEN REPORTED AS FAR SOUTH AS GUNNISON BUT THE
BRUNT OF SNOWFALL WILL BE OVER THE PARK RANGE ESPECIALLY THE
ZIRKELS. THE LATEST SNOTEL REPORTS SHOW AROUND 6 INCHES OF NEW
ACCUMULATION NE OF STEAMBOAT SPRINGS. AROUND A FOOT OF SNOW IS
EXPECTED THERE BY WEDNESDAY NOON DIMINISHING TO AROUND 5 INCHES IN
THE ELK MTNS. DRIER AIR WORKS IN FROM THE TOP DOWN WEDNESDAY
MORNING BRINGING AN END TO SNOWFALL.

THEN DRY CONDITIONS WITH MODIFYING TEMPERATURES EXPECTED ON
WEDNESDAY AFTERNOON AS A DE-AMPLIFYING RIDGE BUILDS IN FROM THE
WEST. HIGH TERRAIN WINDS REMAIN BREEZY FROM THE WEST BUT VALLEY
WINDS WILL BE MAINLY TERRAIN DRIVEN.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 249 PM MST TUE NOV 25 2014

FLOW ALOFT BECOMES WESTERLY AFTER MIDWEEK AS THE AMPLIFIED WEST COAST
RIDGE BUILDS INLAND AND FLATTENS...WITH THE FORECAST AREA ENDING UP
ON THE SOUTHERN FRINGE OF THE UPPER JET/STORM TRACK. WARMING ALOFT
WILL CONTRIBUTE TO MORE STABLE CONDITIONS AND TEND TO FAVOR
INVERSIONS IN VALLEYS ESPECIALLY WHERE SNOW COVER PERSISTS.
SUBSEQUENTLY...HAVE CUT BACK ON HIGH TEMPS A FEW DEGREES FOR MANY
CENTRAL AND NRN VALLEYS THU AND FRI. LOOKS LIKE A SMALL EMBEDDED
WAVE CLIPS THE NORTH LATE ON THU WITH A BIT MORE SUBSTANTIAL
EMBEDDED WAVE MOVING ACROSS THE FORECAST AREA ON SUNDAY. BUT WITH
MODELS SHORT ON MOISTURE...WILL BRING SOME CLOUDS TO THE NORTH BUT
KEEP ANY MENTION OF PRECIP OUT OF THE FORECAST FOR NOW ON THU AND
SUN.

MODELS SHOW A NE PACIFIC TROUGH DEEPENING OFF THE WEST COAST EARLY
NEXT WEEK AND FORMING A CLOSED LOW ALONG THE NRN CALIF COAST MONDAY.
12Z GFS SHOWS THIS LOW/TROUGH KICKING INLAND AND ACROSS OUR AREA ON
TUE...WHILE THE 12Z ECMWF IS ABOUT 12-24 HRS SLOWER. BOTH SHOW
INCREASING MOISTURE MON NIGHT AND TUE IN SW FLOW AHEAD OF THE
TROUGH. WILL CARRY CHANCE POPS FOR THE MTNS ON TUE DUE TO THE
TIMING DIFFERENCES...BUT WITH THE POTENTIAL FOR A DECENT SHOT
MOISTURE HOVERING IN THE BACKGROUND FOR TUE-TUE NIGHT SHOULD
CONFIDENCE IMPROVE.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY NIGHT)
ISSUED AT 951 PM MST TUE NOV 25 2014

POCKETS OF LLWS ARE EXPECTED TO CONTINUE AT KVEL...KASE AND KEGE
THROUGH THE EARLY MORNING HOURS AS STRONG NW WINDS GRADUALLY LET
UP OVERNIGHT.

RESIDUAL SHOWERS OVER THE NORTH CENTRAL MOUNTAINS
OF WESTERN COLORADO WILL CONTINUE BUT ARE BECOMING MORE ISOLATED
AS THE NIGHT GOES ON. A FEW SHOWERS WILL CONTINUE MTN OBSCURATIONS
ACROSS NORTH CENTRAL COLORADO THROUGH ABOUT NOON TOMORROW BEFORE
CLEARING OUT. STRATUS ACROSS NORTHERN VALLEYS OF UTAH AND COLORADO
TONIGHT WILL CLEAR TOWARD DAYBREAK WEDNESDAY.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL NOON MST WEDNESDAY FOR COZ005-010-
     012-013.

     WINTER STORM WARNING UNTIL NOON MST WEDNESDAY FOR COZ004.

UT...NONE.
&&

$$

UPDATE...PF
SHORT TERM...JOE
LONG TERM...JAD
AVIATION...JAM


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