Area Forecast Discussion
Issued by NWS Grand Junction, CO

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000
FXUS65 KGJT 151112
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
412 AM MST MON DEC 15 2014

.SHORT TERM...(TODAY THROUGH TUESDAY)
ISSUED AT 411 AM MST MON DEC 15 2014

THE UPPER LOW POSITIONED OVER WESTERN KANSAS THIS MORNING...WILL
MOVE INTO IOWA BY LATE THIS AFTERNOON. AS A RESULT THE MOISTURE
WRAPPING AROUND THE LOW WILL CONTINUE TO SHIFT AWAY FROM OUR
FORECAST AREA. IN ADDITION TO THE DECREASE IN MOISTURE...A
SHORTWAVE THAT MOVED OVER THE NORTHERN EDGE OVERNIGHT WILL BE ON
ITS WAY EAST OF THE AREA BY DAYBREAK. HOWEVER SOME TRAILING COLD
AIR ALOFT...-26C AT 500MB...WILL SLIDE OVER NORTHWEST CO THIS
MORNING. THIS COLDER AIR ALOFT ALONG WITH THE LINGERING
MOISTURE AND WEAK OROGRAPHICS WILL KEEP SOME LIGHT SNOW ONGOING
OVER THE NORTHERN DIVIDE THROUGH THE MORNING. HOWEVER THE MOISTURE
AND LOW LEVEL INSTABILITY WILL CONTINUE TO BE ERODED AS A RIDGE
APPROACHES FROM THE WEST. THEREFORE SNOW WILL CONTINUE TO DIMINISH
THROUGH THE MORNING...AND ESPECIALLY IN THE AFTERNOON AS THE RIDGE
AXIS REACHES CENTRAL UT.

HAVE GONE AHEAD AND KEPT THE PATCHY FOG FOR THIS MORNING IN THE
VALLEYS. DUE TO THE RECENT WIDESPREAD PRECIPITATION...MOISTURE
WILL LINGER NEAR THE SURFACE IN MANY LOCATIONS. ALSO SINCE THE
CLOUD COVER HAS BEEN DIMINISHING EARLY THIS MORNING... ESPECIALLY
IN THE WEST AND SOUTH...TEMPERATURES WILL COOL AND MAY APPROACH
DEWPOINTS.

THE RIDGE AXIS WILL REACH WESTERN CO BY AROUND MIDNIGHT. MOISTURE
AHEAD OF THE NEXT DISTURBANCE WILL SPREAD INTO THE AREA ON THE
SOUTHWEST FLOW BEHIND THE RIDGE AXIS. A WEAK DISTURBANCE EJECTED
FROM THE NEXT WEST COAST TROUGH WILL PASS OVER THE AREA LATE
TONIGHT INTO TUESDAY AND MAY RESULT IN SOME SHOWERS OVER THE
NORTH. DO NOT EXPECT MUCH AS THIS WAVE WILL HAVE TO WORK INTO THE
MEAN RIDGE POSITION. HOWEVER THE MODELS ALL PAINT SOME
QPF...CENTERED MAINLY IN THE MORNING AND OVER THE NORTHERN HALF.
OTHER AREAS WILL SEE INCREASED CLOUDS...WHICH WILL BE MOST
EXTENSIVE IN THE MORNING.

TEMPERATURES WILL BE ON THE COOL SIDE TODAY BEHIND THE WEEKEND`S
STORM SYSTEM. HOWEVER THE HIGHS WILL BE NEAR TO SLIGHTLY BELOW
NORMAL FOR MID DECEMBER. TEMPS WILL CLIMB ABOVE NORMAL ON TUE IN
THE WARMER SOUTHWEST FLOW. LOWS TONIGHT WILL BE COLDER THAN THIS
MORNING`S...HOWEVER THEY WILL REMAIN ABOVE NORMAL AS THE CLOUDS
THICKEN OVER THE REGION OVERNIGHT.

.LONG TERM...(TUESDAY NIGHT THROUGH SUNDAY)
ISSUED AT 411 AM MST MON DEC 15 2014

EXTENDED PICTURE REMAINS MUDDLED AS MODELS STRUGGLE TO COME TO
CONSENSUS WITH THE PATTERN DURING THE REMAINDER OF THE WEEK. 00Z
ECMWF NOW MUCH QUICKER MOVING THE NEXT PACIFIC TROUGH TOWARD THE
AREA ON WEDNESDAY WITH GFS AND NAM SLOWER. CONSEQUENTLY...GREAT
SPREAD IN QPF OUTPUT WITH NAM SLOWEST HENCE DRIEST WITH ECMWF
WETTEST AND GFS SOMEWHERE IN BETWEEN. DESPITE DIFFERENCES...ALL
FAVORED THE SOUTHERN PORTION OF THE FORECAST AREA AS THE BULK OF
THE ENERGY IN THE SOUTHERN STREAM OF THE SPLITTING PACIFIC
TROUGH. POSSIBLY ENOUGH ENERGY AND MOISTURE FROM THIS SYSTEM TO
BRING ADVISORY LEVEL SNOW ACROSS THE SOUTHERN MOUNTAINS AND
ADJACENT FOOTHILL AREAS OF SOUTHEAST UTAH AND SOUTHWEST COLORADO
WEDNESDAY NIGHT INTO THURSDAY.

EC AND GFS INDICATED A LULL THURSDAY NIGHT THROUGH EARLY SATURDAY
IN A DRIER NORTHWEST FLOW. MODELS DIVERGE WITH THE NEXT SYSTEM
COMING OUT OF THE NORTHWEST LATE SATURDAY AFTERNOON OR EVENING. EC
TAKES ENERGY FARTHER SOUTH WHILE GFS FOCUSES TO THE NORTH.

PER PREVIOUS DISCUSSIONS...ACTIVE PATTERN WILL LIMIT TEMPERATURES
TO NEAR NORMAL VALUES DURING THE PERIOD.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 411 AM MST MON DEC 15 2014

THE NORTHERN AND CENTRAL COLORADO MOUNTAINS WILL REMAIN OBSCURED
THIS MORNING AS SNOW CONTINUES TO BE WRUNG FROM THE REMNANTS OF
THE PACIFIC STORM WHICH MOVED THROUGH THE AREA THIS WEEKEND.
ADDITIONAL LIGHT SNOW IS POSSIBLE AT KRIL...KEGE...AND KASE
THROUGH MIDDAY WHICH WILL RESULT IN IFR CIGS AND VSBY. PATCHY FOG
MAY IMPACT KGJT...KVEL...KTEX AND KMTJ THIS MORNING. OTHERWISE...
OUTSIDE OF THESE AREAS...AND DURING THE AFTERNOON AND OVERNIGHT
VFR CONDITIONS WILL PREVAIL.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...WINTER WEATHER ADVISORY UNTIL 6 AM MST EARLY THIS MORNING FOR
     COZ004-010-013.

UT...NONE.

&&

$$

SHORT TERM...EH
LONG TERM...NL
AVIATION...NL



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