Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 290951
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
251 AM MST SAT NOV 29 2014

.SHORT TERM...(TODAY THROUGH SUNDAY)
ISSUED AT 250 AM MST SAT NOV 29 2014

THE AXIS OF A LOW-AMPLITUDE RIDGE WAS SLIDING EAST THIS MORNING AS
AN OPEN WAVE WAS PUSHING THROUGH THE PACIFIC NW. SOUTHWEST
GRADIENT WINDS HAD MIXED DOWN INTO CRAIG OVERNIGHT BRINGING MILD
TEMPERATURES THERE. FRIDAYS VERY MILD TEMPERATURES WILL BE
LOWERED A FEW DEGREES TODAY AS 700MB TEMPERATURES COOL. THE
INCREASING SW GRADIENT WINDS WILL HELP TO MIX OUT SOME SHELTERED
VALLEY LOCATIONS FOR A BIT OF A WARMUP THERE. THE MOUNTAIN
SNOWPACK WILL UNDERGO ANOTHER FREEZE- THAW CYCLE.

THE TROUGH WILL WORK THROUGH THE NORTHERN ROCKIES THIS EVENING AND
THE NORTHERN PLAINS ON SUNDAY. THIS WILL SAG A WEAK FRONTAL BAND
INTO THE NORTH TONIGHT THAT WILL BE A FOCUS FOR LIGHT MAINLY
MOUNTAIN SHOWERS ON SUNDAY. DIURNAL TEMPERATURE SPREAD...BOTH THE
MORNING LOWS AND AFTERNOON HIGHS...WILL BE TRIMMED UNDER GUSTY
MTN-TOP WINDS AND INCREASING CLOUDS.

.LONG TERM...(SUNDAY NIGHT THROUGH FRIDAY)
ISSUED AT 250 AM MST SAT NOV 29 2014

SUNDAY NIGHT THE WEAK COLD FRONT THAT MOVED INTO THE AREA FROM THE
NORTH WILL MAKE A LITTLE PROGRESS TO THE SOUTH...PROBABLY NOT
REACHING THE ROAN AND TAVAPUTS PLATEAUS...AND BRING ISOLATED TO
SCATTERED PRECIP TO THE NORTHERN MOUNTAINS OF CO AND UT. MOST OF
THE COLDER AIR ASSOCIATED WITH THIS FEATURE WILL PLUNGE DOWN THE
FRONT RANGE. THE FRONT WILL WAVE BACK TO THE NORTH AS A WARM FRONT
LATE SUNDAY NIGHT AND MONDAY MORNING...AS A RIDGE BUILDS NORTH AND
INTO THE GREAT BASIN. WARMER TEMPERATURES AND DRY CONDITIONS WILL
ADVECT INTO THE AREA MON AND TUE AND THE MIDRANGE MODELS REMAIN IN
GOOD AGREEMENT THROUGH TUESDAY.

TUE NIGHT WILL SEE THE NEXT PACIFIC STORM BEGINNING TO INFLUENCE
WEATHER ACROSS THE WESTERN STATES. THE GFS SHOWS THE SOUTHERN
STREAM STREAKING EAST AND GRABBING SOME OF THE MOISTURE...AND
CREATING A DRY SLOT OVER SE UT AND MOST OF SOUTHERN CO WED. THE
ECMWF KEEPS THE TWO JETSTREAMS MORE IN PHASE AND DOES NOT SHOW THE
DRY SLOT DEVELOPING. THE OVERALL IMPRESSION FROM THESE SOLUTIONS
IS OF A STORM THAT WILL BE WEAKENING AS IT MOVES THROUGH THE GREAT
BASIN AND INTO EASTERN UT AND WESTERN CO WEDNESDAY THROUGH
THURSDAY.

THURSDAY AND FRIDAY SHOW IMPORTANT DIFFERENCES IN THE MODEL
SOLUTIONS AS THE GFS BRINGS ANOTHER TROUGH OVER THE SOUTHWEST U.S.
AND MAINTAINS A PREDOMINATELY SOUTHWESTERLY FLOW OVER THE AREA.
THIS FLOW PUSHES MOISTURE NORTH AND OUT OF THE FORECAST AREA. THE
ECMWF BUILDS ANOTHER RIDGE OVER THE GREAT BASIN...RESULTING IN
NORTHWEST FLOW OVER THE AREA AND MOISTURE FOR OROGRAPHIC MOUNTAIN
SHOWERS THROUGH THURSDAY OVER THE NORTHERN HALF OF THE FORECAST
AREA. THESE TWO VERY DIFFERENT SOLUTIONS BRING UNCERTAINTY TO THE
FORECAST FOR THE END OF THE WORKWEEK.

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 250 AM MST SAT NOV 29 2014

VFR CONDITIONS WILL DOMINATE THROUGH SUNDAY MORNING. HIGH CLOUD
CEILINGS WILL START TO LOWER AFT 06Z TONIGHT MAINLY NORTH OF A
LINE FROM KVEL TO KSBS. MECHANICAL AND LEE-SIDE TURBULENCE WILL
BE POSSIBLE WITH STRONGER WINDS AT MOUNTAIN TOP LEVEL.

&&

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

$$

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



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