Area Forecast Discussion
Issued by NWS Grand Junction, CO

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000
FXUS65 KGJT 141845
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
1145 AM MST SUN DEC 14 2014

.UPDATE...
ISSUED AT 1140 AM MST SUN DEC 14 2014

LIGHT SNOW CONTINUES TO DIMINISH ACROSS EXTREME WESTERN AND
SOUTHWEST COLORADO AND HAVE DROPPED A FEW MORE LOCATIONS FROM THE
WINTER HIGHLIGHT LIST. DEEP UPPER LOW CONTINUES TO SPIN SLOWLY
EAST ACROSS THE PANHANDLES OF TEXAS AND OKLAHOMA WITH MOISTURE
WRAPPING BACK AROUND THE SYSTEM. LOW LEVEL NORTHERLY FLOW ACROSS
WESTERN COLORADO WILL ALLOW SNOW TO CONTINUE THROUGH THIS
AFTERNOON ACROSS THE NORTHWEST SAN JUANS AND HAVE EXTENDED THE
WARNING IN THIS AREA UNTIL 6 PM THIS EVENING. NORTHERN AND CENTRAL
MOUNTAINS ARE STILL RECEIVING STEADY SNOWFALL PER WEB CAMS AND
SPOTTER REPORTS SO NO ADJUSTMENTS TO HIGHLIGHTS NEEDED IN THOSE
AREAS. WILL BE ADJUSTING POP GRIDS SHORTLY TO FIT CURRENT TRENDS
AND EXPECTED CONDITIONS THROUGH THE REMAINDER OF THIS AFTERNOON.

UPDATE ISSUED AT 743 AM MST SUN DEC 14 2014

DENSE FOG HAS DISSIPATED ACROSS SOUTHEAST UTAH AND SOUTHWEST
COLORADO ACCORDING TO SPOTTER REPORTS...WEB CAMS AND SURFACE
OBSERVATIONS. STILL EXPECT PATCHY FOG FOR A FEW MORE HOURS...BUT
THE WIDESPREAD DENSE FOG IS NO LONGER EXPECTED. AS A RESULT...HAVE
CANCELLED THE DENSE FOG ADVISORY. WILL BE TAKING A CLOSER LOOK AT
SNOW HIGHLIGHTS OVER THE NEXT HOUR OR SO...ALTHOUGH EARLY
INDICATIONS ARE MOST LOCATIONS HAVE RECEIVED SOME SNOW WITH THE
EXCEPTION OF THE GRAND VALLEY WHICH STAYED JUST ABOVE FREEZING ALL
NIGHT. ALSO RECEIVED A FEW REPORTS OF 12 PLUS INCHES ACROSS THE
SAN JUANS WITH SNOW STILL FALLING AT KTEX.

UPDATE ISSUED AT 609 AM MST SUN DEC 14 2014

DROPPED WINTER WEATHER ADVISORIES FOR THE MOUNTAINS OF EASTERN
UTAH AND THE GRAND VALLEY IN WEST-CENTRAL COLORADO. SKIES HAD
LARGELY CLEARED OVER THE LA SAL AND ABAJO MOUNTAINS WHILE THE HRRR
AND RAP13 INDICATED ONLY LIGHT LOCALIZED SNOWFALL OVER THE
TAVAPUTS PLATEAU AND THE EASTERN UINTA MOUNTAINS. MEANWHILE...WARM
SURFACE TEMPERATURES LIMITED ANY SNOW ACCUMULATION IN THE GRAND
VALLEY AND SNOW HAD STOPPED FOR THE TIME BEING. SCATTERED SNOW
SHOWERS REMAIN A POSSIBILITY FOR THE VALLEY...HOWEVER
ACCUMULATIONS ARE UNLIKELY.

&&

.SHORT TERM...(TODAY THROUGH MONDAY)
ISSUED AT 435 AM MST SUN DEC 14 2014

THE PACIFIC STORM CONTINUES TO EVOLVE AS IT TRACKS ACROSS THE
REGION AND BRINGS WIDESPREAD PRECIPITATION TO OUR FORECAST AREA.
THE FIRST LOW CIRCULATION THAT SPUN UP AT THE BASE OF THE MAIN TROUGH
PASSED OVER THE FOUR CORNERS AROUND MIDNIGHT...AND IS TRACKING
ACROSS NORTHERN NEW MEXICO EARLY THIS MORNING. AT 3 AM MST...OUR
FORECAST AREA IS MOSTLY ON THE BACKSIDE OF THIS DISTURBANCE.
HOWEVER IT STILL LOOKS LIKE SOME LINGERING ENERGY IS AFFECTING OUR
SOUTHEAST CORNER IN THE VICINITY OF PAGOSA SPRINGS. THE RADAR LOOP
SHOWS THAT A CIRCULATION HAS DEVELOPED OVER ROUGHLY WEST-CENTRAL
CO EARLY THIS MORNING AS A NORTHWEST FLOW DEVELOPED BEHIND THE
SOUTHERN LOW...WITH A SOUTHEAST FLOW OVER THE EASTERN PORTION OF
THE FORECAST AREA...NORTHEAST OF THE SOUTHERN LOW. THE VAD WIND
PROFILE AND SATELLITE LOOPS INDICATE THAT THIS SOUTHEAST FLOW IS
MOST PROMINENT AT THE UPPER LEVELS. SO EXPECT THAT WITHIN A FEW
HOURS THE NORTHWEST FLOW WILL DOMINATE THE ENTIRE AREA AS THE MAIN
TROUGH AXIS SHIFTS EAST. WHEN THIS HAPPENS...NORTHWEST CO AND THE
NORTHERN DIVIDE MOUNTAINS WILL BECOME THE FOCUS OF THE BEST
SNOWFALL. OTHERWISE MOISTURE WILL BEGIN TO DIMINISH FROM THE WEST
AND SOUTHWEST TODAY FOR A DOWNTURN IN ACTIVITY ELSEWHERE.
TEMPERATURES WILL GENERALLY BE NEAR NORMAL...WHICH IS COOLER THAN
WE HAVE SEEN FOR AWHILE.

OF NOTE...DUE TO THE DEEP MOISTURE AND WIDESPREAD
PRECIPITATION...AREAS OF FOG HAVE DEVELOPED ACROSS WESTERN CO AND
EASTERN UT. EXPECT THIS WILL DIMINISH BY LATE MORNING.

ANOTHER SHORTWAVE WILL DROP OUT OF THE NORTHWEST LATE TODAY AND
THIS EVENING...BRINGING SOME REINFORCING COLD AIR ACROSS THE
NORTH. THIS AND THE FAVORABLE NORTHWEST OROGRAPHICS WILL KEEP SNOW
ONGOING OVER THE NORTHERN CO MOUNTAINS THROUGH TONIGHT. THEREFORE
HAVE EXTENDED THE ADVISORIES FOR THE MOUNTAINS NEAR ASPEN AND
NORTHWARD. THANKS TO BOU FOR THE COORDINATION. THE REMAINDER OF
THE AREA SHOULD SEE SOME CLEARING SKIES...AND THUS MUCH COOLER
NIGHTTIME LOWS.

LINGERING SHOWERS OVER THE NORTHERN MOUNTAINS WILL DIMINISH
THROUGH THE DAY ON MONDAY. THE DAY WILL REMAIN ON THE COOL
SIDE...WITH HIGHS POSSIBLY COUPLE DEGREES COOLER THAN TODAY`S.

.LONG TERM...(MONDAY NIGHT THROUGH SATURDAY)
ISSUED AT 435 AM MST SUN DEC 14 2014

SHORTWAVE RIDGE IN PLACE OVER THE REGION MONDAY NIGHT BUT MOISTURE
WILL BEGIN TO MOVE THROUGH THE RIDGE AS ANOTHER SHORTWAVE IS
EJECTED FROM THE MEAN TROUGH OVER THE EASTERN PACIFIC. ISENTROPIC
UPGLIDE AND JET DIVERGENCE WORKING ON PACIFIC MOISTURE WILL BRING
LIGHT SHOWERS TO THE REGION BY TUESDAY MORNING. THE INTENSITY OF
THIS ACTIVITY UNIMPRESSIVE AND RELATIVELY SHORT-LIVED AS
TEMPERATURE ADVECTION BECOMES NEUTRAL LATER IN THE DAY TUESDAY
BRINGING AN END TO PRECIPITATION.

THE PROGRESSIVE PATTERN CONTINUES DURING THE REMAINDER OF THE WEEK
...THOUGH MODELS STRUGGLE WITH TIMING OF THE NEXT SHORT WAVE
TROUGH COMING OFF THE PACIFIC. AS IS USUALLY THE CASE...THE GFS IS
FASTER THAN THE ECMWF THOUGH BOTH MODELS WERE SIMILAR IN
SPLITTING THE INCOMING SHORTWAVE TROUGH. IN EITHER CASE...QPF
OUTPUT NOT ALL THAT IMPRESSIVE FROM TUESDAY NIGHT THROUGH THURSDAY
NIGHT SO NOT EXPECTING SIGNIFICANT SNOWFALL ACCUMULATIONS FROM
THIS SYSTEM. NEXT SHORT WAVE COULD REACH THE AREA SATURDAY
ACCORDING TO GFS...THOUGH SLOWER ECMWF HOLDS MOISTURE OFF UNTIL
SATURDAY NIGHT.

UNSETTLED CONDITIONS THROUGH THE COMING WEEK WILL KEEP
TEMPERATURES NEAR SEASONAL NORMS.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON)
ISSUED AT 1041 AM MST SUN DEC 14 2014

BACK SIDE OF THIS STORM IS BRINGING THE TYPICAL UNSTABLE FLOW
FAVORING NORTH FACING SLOPES AND VALLEYS. THIS IS BRINGING
IFR/LIFR CONDITIONS TO KASE AND KEGE IN SNOW AND LOW CLOUDS. IN
THIS FLOW THE LOWER FLIGHT CRITERIA IS EXPECTED TO DOMINATE OVER
MUCH OF THE NEXT 12 HOURS. ALSO IN THE UINTA BASIN STRATUS IS
SLOWLY ERODING AND VFR EXPECTED OVER THE NEXT FEW HOURS. OVER THE
REMAINDER OF THE NEXT FEW HOURS...KTEX SHOULD BE IMPROVING WITH A
MIX OF VFR AND MVFR CONDITIONS. THE RECENT PRECIPITATION AND DRIER
AIR ALOFT MAY BRING AREAS OF FOG AGAIN TO THE VALLEYS BUT
CONFIDENCE NOT OVER THE TOP ATTM.


&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL 6 PM MST THIS EVENING FOR COZ002-
     003-008-009-012.

     WINTER STORM WARNING UNTIL 6 PM MST THIS EVENING FOR COZ018.

     WINTER WEATHER ADVISORY UNTIL 6 AM MST MONDAY FOR COZ004-010-013.

     WINTER WEATHER ADVISORY UNTIL MIDNIGHT MST TONIGHT FOR COZ005.

UT...NONE.
&&

$$

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



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