062  
FXUS65 KGJT 141728  
AFDGJT  
 
AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE GRAND JUNCTION CO  
1028 AM MST THU DEC 14 2017  
   
SHORT TERM
 
(TODAY THROUGH FRIDAY)  
ISSUED AT 226 AM MST THU DEC 14 2017  
 
THE SHORTWAVE TROUGH CONTINUED TO SWEEP SOUTHEASTWARD ACROSS  
EASTERN UTAH AND WESTERN COLORADO EARLY THIS MORNING AND THE COLD  
FRONT ASSOCIATED WITH THIS SYSTEM HAD EXITED TO THE SOUTH.  
SNOWFALL ASSOCIATED WITH THIS SYSTEM EXTENDED FROM THE LOWER  
ELEVATIONS OF NORTHWEST COLORADO ACROSS COLORADO'S MOUNTAINS  
ACCORDING TO AUTOMATED SENSORS, RADAR, AND WEB CAMS AS OF 3 AM  
MST. HOWEVER, NORTHERN AND CENTRAL MOUNTAIN SKI AREA SNOW STAKES  
SHOWED VERY LIGHT SNOW ACCUMULATIONS SO FAR OF JUST AN INCH OR  
LESS. MEANWHILE, SUBSIDENCE ON THE BACKSIDE OF THE TROUGH HAS  
BROUGHT CLEARING TO THE EASTERN UINTA BASIN AND SNOW HAS ENDED AT  
KDWX, KCAG AND KEEO AND WAS DECREASING AT KHDN AND KSBS.  
 
EXPECT IMPROVING CONDITIONS TO WORK SOUTHEASTWARD ACROSS THE  
REGION DURING THE MORNING AS THE TROUGH AXIS SHIFTS SOUTH OF THE  
AREA LATER THIS MORNING. SNOW RATES SHOULD REMAIN UNIMPRESSIVE AND  
THEREFORE DO NOT ANTICIPATE SIGNIFICANT IMPACTS FROM SNOW OVER THE  
HIGHER PASSES EARLY TODAY. SNOW WILL END BEFORE NOON FOR MOST  
LOCATIONS BUT MAY LINGER IN THE SOUTHEAST SAN JUANS A BIT LONGER.  
TEMPERATURES WILL BE COOLER IN THE MOUNTAINS WITH LESS PRONOUNCED  
CHANGES ACROSS THE VALLEYS THIS AFTERNOON. IN FACT, COLD FRONTAL  
PASSAGE WILL CAUSE SOME PREVIOUSLY INVERTED VALLEYS TO BECOME A  
BIT WARMER TODAY WHICH IS A BIT COUNTERINTUITIVE, THOUGH INCREASED  
SUNSHINE WILL ALSO HELP.  
 
DRY NORTHERLY FLOW ALOFT WILL RESULT IN CLEAR SKIES AND COLD  
OVERNIGHT LOWS TONIGHT. SINGLE DIGITS AND TEENS WILL BE THE NORM  
FOR MUCH OF THE AREA. MIDSLOPES AND PORTIONS OF SOUTHEAST UTAH  
WILL BE A BIT MILDER WITH LOWS IN THE LOWER TO MID 20S. FLOW ALOFT  
BACKS TO THE NORTHWEST FRIDAY AHEAD OF THE NEXT PACIFIC TROUGH.  
ATMOSPHERIC MOISTURE REMAINS LOW SO DRY WEATHER WILL CONTINUE,  
THOUGH CLOUDS WILL BE INCREASING FROM THE NORTHWEST LATER IN THE  
DAY AHEAD OF THE PREVIOUSLY MENTIONED TROUGH. TEMPERATURES WILL  
MODERATE IN THE MOUNTAINS WITH LITTLE CHANGE EXPECTED IN THE  
UNSEASONABLY MILD VALLEYS.  
   
LONG TERM
 
(FRIDAY NIGHT THROUGH WEDNESDAY)  
ISSUED AT 226 AM MST THU DEC 14 2017  
 
THE AXIS OF THE UPPER LEVEL RIDGE WILL BEGIN TO BE FLATTENED  
FRIDAY NIGHT AND INTO EARLY SATURDAY AS THE NEXT SHORTWAVE TROUGH  
DROPS INTO THE NORTHERN GREAT BASIN. MID AND HIGH LEVEL CLOUDS  
WILL INCREASE AHEAD OF THIS SYSTEM WITH ISOLATED TO SCATTERED HIGH  
BASED SHOWERS DEVELOPING AS EARLY AS SATURDAY AFTERNOON, THOUGH  
DIFFERENCES IN THE ARRIVAL AND TRACK OF THIS SYSTEM VARY BETWEEN  
MODELS. EITHER WAY, THIS WILL BE A QUICK MOVING STORM AND IS ONLY  
EXPECTED TO PRODUCE ANOTHER ROUND OF LIGHT SNOW FOR THE MOUNTAINS  
AS IT MOVES ACROSS OUR AREA INTO SUNDAY.  
 
WEAK TRANSITORY RIDGING LOOKS TO RETURN TO THE REGION EARLY NEXT  
WEEK, ALLOWING SKIES TO MOSTLY CLEAR AND TEMPERATURES TO  
MODERATE THROUGH ABOUT THE MID WEEK POINT. MODEL SOLUTIONS REALLY  
BEGIN TO DIVERGE FROM THIS POINT ONWARDS IN REGARDS TO THE  
PROGRESSION OF THE NEXT PACIFIC STORM. THE GFS HANDLES THIS STORM  
AS A LONGWAVE TROUGH, DIGGING INTO THE WESTERN CONUS THROUGHOUT  
THE LATTER HALF OF NEXT WEEK. THE EURO ON THE OTHER HAND IS  
CONSIDERABLY SLOWER AND DOESN'T INTRODUCE THE SYSTEM ONSHORE UNTIL  
LATE THURSDAY/FRIDAY, SO CONFIDENCE IN THE LONG TERM REMAINS LOW  
AT THIS POINT. ON THE BRIGHT SIDE, WE HAVE TRANSITIONED TO A MORE  
PROGRESSIVE WEATHER PATTERN GOING INTO THE SECOND HALF OF DECEMBER  
WHICH TENDS TO PROMISE SOME PERIODS OF ACTIVE WEATHER!  
 

 
   
AVIATION
 
(FOR THE 18Z TAFS THROUGH 18Z FRIDAY AFTERNOON)  
ISSUED AT 1021 AM MST THU DEC 14 2017  
 
AS EXPECTED, KEGE AND KASE HAVE BEEN DOWN IN THE IFR CATEGORY MOST  
OF THE MORNING THANKS TO LOW CEILINGS AND VISBILITIES FROM FOG AND  
SNOW SHOWERS. STILL THINKING THAT WARMING OF THE ATMOSPHERE WILL  
CAUSE SOME OF THE CLOUDS TO BURN OFF IN THE NEXT HOUR OR TWO FOR  
THOSE AREAS AND TAF FOLLOWS SUIT. WILL AMEND AS NECESSARY IF LOW  
LEVEL MOISTURE OVERCOMES WARMING AND KEEPS CLOUDS IN THE PICTURE.  
KMTJ ALSO REPORTING LOW CLOUDS AT THIS HOUR BUT JUST TO THE NORTH  
OF THE AIRPORT, CLEARING CONDITIONS CAN BE FOUND. ALSO ANTICIPATE  
THEY'LL GO VFR IN THE NEXT HOUR OR SO. ONCE THE CLOUDS LIFT, SOME  
FOG WILL BE POSSIBLE FOR KEGE OVERNIGHT BUT CONFIDENCE NOT HIGH  
ENOUGH YET TO INCLUDE IN TAF.  
 

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

 
 

 
 
SHORT TERM...NL  
LONG TERM...MMS  
AVIATION...TGR  
 
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