Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 151726
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
1026 AM MST MON DEC 15 2014

.UPDATE...
ISSUED AT 1016 AM MST MON DEC 15 2014

SCATTERED SNOW SHOWERS HANGING ON ALONG THE CONTINENTAL DIVIDE
THIS MORNING...WITH LOW CLOUDS AND PATCHY FOG STILL BEING REPORTED
NEAR STEAMBOAT SPRINGS. NO SIGNIFICANT SNOWFALL AMOUNTS EXPECTED
THROUGH THE REMAINDER OF THIS MORNING. SHOWERS STILL EXPECTED TO
DIMINISH AND END BY EARLY THIS AFTERNOON WITH STRONG SUBSIDENCE
SETTLING IN AS HIGH PRESSURE ROLLS OVER THE AREA.

UPDATE ISSUED AT 603 AM MST MON DEC 15 2014

ALLOWED LAST WINTER WEATHER ADVISORIES FOR THE NORTHERN MOUNTAINS
TO EXPIRE. LIGHT SNOW WAS CONTINUING...HOWEVER...ADDITIONAL
ACCUMULATIONS WILL BE LIGHT AS SUBSIDENCE LEVEL SUBSIDENCE AND WAA
CAUSES SNOW TO DECREASE AND BECOME MORE SCATTERED IN COVERAGE.

&&

.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 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1016 AM MST MON DEC 15 2014

MVFR AND IFR CIGS AND VSBYS WILL CONTINUE ALONG THE NORTHERN
MOUNTAINS THROUGH 20Z...BEFORE IMPROVING WEATHER ARRIVES UNDER
STRENGTHENING SUBSIDENCE. TERMINAL SITES THAT WILL BE MOST
IMPACTED BY THIS CONTINUED LIGHT PRECIPITATION WILL BE KHDN...KSBS
AND KHDN. KEGE AND KASE WILL SEE A 30 PERCENT CHANCE FOR SHOWERS
THROUGH EARLY THIS AFTERNOON. AFTER 20Z...THE POTENTIAL FOR
PRECIPITATION WILL DROP EACH HOUR AS HIGH PRESSURE BUILDS IN. VFR
CONDITIONS EXPECTED ELSEWHERE AND WILL SPREAD INTO THE NORTHERN
MOUNTAINS THIS EVENING.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...NONE.
UT...NONE.
&&

$$

UPDATE...JDC
SHORT TERM...EH
LONG TERM...NL
AVIATION...JDC



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