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000
FXUS65 KGJT 110518
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
1018 PM MST TUE DEC 10 2013

.SHORT TERM...(TONIGHT THROUGH WEDNESDAY NIGHT)
ISSUED AT 327 PM MST TUE DEC 10 2013

VERY STABLE CONDITIONS WITH A DEEP SURFACE-BASED INVERSION WILL
PERSIST OVER MOST OF THE AREA THROUGH WED NGT. AN UPPER TROUGH
WILL PASS EAST OF THE AREA TONIGHT...WITH IT TRAILING END GLANCING
BY THE NORTHWEST CO MTNS. SCATTERED SNOW SHOWERS AND LIGHT
ACCUMULATIONS REMAIN OVER THE GORE AND PARK RANGES AND THE
FLATTOPS FOR TONIGHT. THE CLOUD COVER WILL PREVENT A BIGGER DROP
OFF IN TEMPERATURES AND SHOULD ALSO PREVENT THICK FOG AND STATUS
FROM FORMING. BELIEVE WITH NEARLY CLEAR SKIES EXPECTED
WEDNESDAY...MORE MOISTURE WILL BE FED INTO THE LOWER LAYERS OF THE
ATMOSPHERE AND LOW TEMP WILL BE QUITE COLD...SO HAVE INTRODUCED
LOW CLOUD AND FOG IN THE VALLEYS WED NIGHT.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 327 PM MST TUE DEC 10 2013

SPLIT FLOW INTO THE WESTERN CONUS WILL GENERALLY KEEP US IN A DRY
PATTERN THROUGH THE EXTENDED PERIOD. THIS PATTERN WILL BE
TEMPORARILY DISRUPTED BY THE LATE WEEK PERIOD AS THE SOUTHERN
STREAM LOW...CURRENTLY OFF THE NORTHERN BAJA...GETS A KICK
EASTWARD BY A HEALTHY NORTHERN STREAM SHORT WAVE TROF DIVING
THROUGH THE GREAT BASIN. OVER THE WEEKEND THESE TWO FEATURES PHASE
WITH A LOBE OF THE POLAR VORTEX OVER THE GREAT LAKES. THIS WILL
BRING ANOTHER ROUND OF INTERESTING WEATHER TO THE NEW
ENGLAND...WHILE OUT WEST HIGH PRESSURE REBUILDS WITH DRY NORTHWEST
FLOW INTO THE CENTRAL ROCKIES THAT PERSISTS INTO EARLY NEXT WEEK.

SO THE MAIN CHALLENGES TO THE FORECAST WILL CONTINUE TO BE VALLEY
TEMPERATURES WITH THE BATTLE BETWEEN THE PASSING SHORTWAVES AND
STRONG INVERSIONS. LOOKING AT THETA SURFACES...MOISTURE SEEMS TO BE
SPARSE OR TRANSPORTED AWAY FROM OUR CWA WITH BOTH OF THE SYSTEMS
LATE THIS WEEK. THE SOUTHERN SYSTEM REMAINS WELL TO OUR SOUTH BUT
SHOULD BRING BRUSH SOME HIGH CLOUDINESS ACROSS OUR SOUTHERN ZONES ON
THURSDAY. THIS SYSTEM WILL BE ON THE PLAINS BY SUNRISE FRIDAY...BUT
THE NORTHERN SYSTEM WILL BE RIGHT ON IT/S HEELS. LARGE SCALE ASCENT
IS MODERATE OVER WESTERN COLORADO FRIDAY AFTERNOON AHEAD OF THIS
WHICH WILL AID IN TOP DOWN SATURATION. AS THIS MOISTURE DROPS TO
MOUNTAIN TOP LEVEL OROGRAPHICS WILL BRING SOME LIGHT SNOW TO THE
NORTHERN MOUNTAINS. INSTABILITY INCREASES LATE IN THE DAY AS THE
TROF SWINGS PAST AND COLD AIR MOVES IN ALOFT. THESE SHOWERS MAY
PERSIST ON THE HIGH TERRAIN OF THE NORTH GOING INTO SATURDAY.

ON THE TEMPERATURE FRONT...INVERSIONS ARE HOLDING STRONG AND WILL
CONTINUE TO DO SO IT APPEARS. THERE IS NOT A STRONG REFLECTION AT
THE SURFACE WITH THE PASSING WAVE ON FRIDAY. THEREFORE WILL HAVE TO
LEAN MORE TOWARD PERSISTENCE FOR AFTERNOON HIGHS IN THE VALLEYS.
MOST GUIDANCE AND MODEL BLEND NOT MUCH HELP BUT THE EURO NUMBERS
SEEM TO HAVE A BETTER HOLD FOR WHATEVER REASON AND ARE RUNNING MORE
TOWARDS REALITY. SO WILL CONTINUE TO HOLD THE SNOW COVERED VALLEYS
BELOW FREEZING WHILE MID SLOPES SHOULD BE PUSHING INTO THE MID 30S.
COOLER AIR BEHIND THE WAVE MAY WEAKEN THE INVERSIONS A TAD BUT THIS
WILL MAINLY BE SEEN AS COOLER MOUNTAIN TEMPERATURES.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z WEDNESDAY EVENING)
ISSUED AT 1015 PM MST TUE DEC 10 2013

PATCHY FOG HAS BEEN OBSERVED IN THE KVEL AREA AND IS EXPECTED TO
INCREASE IN COVERAGE TONIGHT INTO WEDNESDAY. EXPECT PERIODS OF
1-3SM BR OVC003 THERE. OTHERWISE MOUNTAINS EAST OF A LINE FROM
KCAG TO KEGE MAY BE OBSCURED AT TIMES UNTIL 12Z IN FOG AND -SN.
ELSEWHERE VFR CONDITIONS WILL CONTINUE BUT WITH LOCALIZED FOG
RESTRICTING VSBY TO LESS THAN 1SM MAINLY ALONG RIVER BOTTOMS.


&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...NONE.

UT...NONE.

&&

$$

SHORT TERM...CC
LONG TERM...15
AVIATION...JOE