Area Forecast Discussion
Issued by NWS Grand Junction, CO

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50

000
FXUS65 KGJT 260437
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
1037 PM MDT SAT OCT 25 2014

.UPDATE...
ISSUED AT 1029 PM MDT SAT OCT 25 2014

MIDDLE AND HIGH LEVEL CLOUDS HAVE BEGUN TO SPREAD ACROSS THE AREA
FROM WEST TO EAST...AS A WEAK SHORTWAVE TROUGH ALOFT EJECTS AHEAD
OF AN APPROACHING STRONGER PACIFIC SYSTEM. THESE CLOUDS WILL
THICKEN SOMEWHAT OVERNIGHT BUT PRECIPITATION IS ONLY EXPECTED TO
BE ISOLATED OVER THE HIGHEST ELEVATIONS.

&&

.SHORT TERM...(TONIGHT THROUGH SUNDAY NIGHT)
ISSUED AT 249 PM MDT SAT OCT 25 2014

WARM SOUTHWEST FLOW WITH PLENTY OF SUNSHINE HAS ALLOWED FOR
POSSIBLE RECORD HIGH TEMPERATURES THIS AFTERNOON. BUT THE CLEAR
SKIES WILL NOT LAST AS MID LEVEL ENERGY FROM ARIZONA STREAMS
TOWARD THE NORTH NORTHEAST INTO THE WESTERN SLOPE LATER TONIGHT.
LATEST VISUAL SATELLITE IMAGES SHOW SHALLOW CONVECTION OVER PARTS
OF CENTRAL ARIZONA. AS THIS MOISTURE GETS LIFTED OVER THE HIGH
COUNTRY...A FEW SHOWERS WILL DEVELOP OVER THE MOUNTAIN TOPS. NOT
SURE HOW MUCH AREAL COVERAGE OF SHOWERS WILL ACTUALLY OCCUR...BUT
THE HIGHER RESOLUTION MODELS GIVE DECENT MOUNTAIN COVERAGE WITH
AMOUNTS AROUND A TENTH OF AN INCH /0.10/. WOULD LIKE TO SEE SOME
DBZ RETURNS ON THE ARIZONA RADARS...BUT AS OF 2030Z THERE HAVE
BEEN NO ECHOES. IN THE GRIDS WILL SHOW AT LEAST ISOLATED SHOWER
COVERAGE WITH THE SNOW LEVELS FAIRLY HIGH. CLOUD COVER WILL KEEP
TEMPERATURES RELATIVELY MILD OVERNIGHT.

THE BREAKDOWN OF THE STRONG RIDGE WILL BE WELL UNDERWAY BY SUNRISE
ON SUNDAY AS THE POLAR JET REFORMS OVER THE NORTHERN ROCKIES AND
PULLS THE WESTERN TROUGH INLAND. THE SUBTROP MOISTURE SOURCE SEEN IN
SATELLITE IMAGERY AS CLOUDINESS OVER WESTERN ARIZONA WILL BE MOVING
THROUGH OUR CWA DURING THE EARLY MORNING HOURS. THE BUBBLY NATURE OF
THE CLOUD COVER TO THE SOUTHWEST SUGGESTS THE PRESENCE OF AT LEAST
WEAK INSTABILITY. LARGE SCALE FORCING WILL BE ABSENT SUNDAY MORNING
BUT CROSS SECTIONS SHOW THE MOISTURE SATURATING MOUNTAIN TOP LEVEL.
OROGRAPHICS AND INSTABILITY APPEAR TO BE SUFFICIENT ENOUGH TO
PRODUCE SHOWERS AT THE HIGH ELEVATIONS OVER THE COLORADO MOUNTAINS
AND HAVE HIGHER POPS MAINLY ABOVE 10000 FEET. SOME OF THE MODELS
GUIDANCE SUGGESTS MOUNTAIN VALLEYS GETTING SOME LIGHT PRECIPITATION.
CAN NOT RULE THIS OUT BUT CONFIDENCE VERY LOW...SO POPS ARE TRENDED
THIS WAY IN THE LOWER ELEVATIONS. QPF AMOUNTS SHOULD BE LIGHT WITH
THIS LEADING PUSH OF MOISTURE. THE PUSH OF STRONGER DYNAMICS IN THE
FORM OF QG FORCING FROM THE WESTERN TROUGH AND POLAR JET COMES
SUNDAY EVENING INTO EARLY MONDAY MORNING. THE FOCUS FOR THIS LARGE
SCALE LIFT WILL BE OVER NORTHERN COLORADO WHERE PRECIPITATION
REMAINS FAVORED OVER THE NORTHERN COLORADO MOUNTAINS. A MID TO LOW
LEVEL BOOST TO THE LIFT AND OROGRAPHICS WILL COME FROM A PASSING
FRONT. THE FLAT TOPS...PARK...NORTHERN GORE AND HIGH ELKS APPEAR TO
BE THE FOCUS POINT OF THE ABOVE INGREDIENTS. THE MISSING PIECE WILL
BE FAVORABLE DENDRITICS FOR GOOD SNOW PRODUCTION SO SUB ADVISORY
AMOUNTS IN THE 1 TO 3 INCH RANGE STILL LOOK ON TRACK TO AFFECT THE
HIGHER PEAKS...AND POSSIBLY RABBIT EARS AND VAIL PASS. THE QUICK
MOVEMENT OF THE SYSTEM ALSO SHOULD LIMIT HIGHER AMOUNTS.

.LONG TERM...(MONDAY THROUGH SATURDAY)
ISSUED AT 249 PM MDT SAT OCT 25 2014

BY MONDAY THE TROUGH AXIS WILL HAVE MOVED TO THE PLAINS WITH
SUBSIDENCE AND DRIER NORTHWEST FLOW SETTING UP ACROSS EASTERN UTAH
AND WESTERN COLORADO. COOLER AIR ALOFT AND RESIDUAL MOISTURE MAY
KEEP SOME SHOWERS OVER THE EASTERN HIGH MOUNTAINS BUT ISOLATED AT
BEST. THE BIGGER STORY WILL BE THE COOLER AIR FILTERING IN BEHIND
THE COLD FRONT. THERE IS SOME FAIRLY CHILLY AIR BACK IN THE
NORTHERN/CANADIAN ROCKIES THAT WILL PULLED DOWN AND HIGHS WILL BE
SOME 20 OR MORE DEGREES COLDER THAN THE RECORD HIGHS SEEN TODAY
UNDER THE RIDGE. CLEAR SKIES IN THE AIRMASS MONDAY NIGHT INTO
TUESDAY LOOKS MORE LIKELY TO BRING A SEASON ENDING FREEZE TO ALL BUT
FAR SOUTHEAST UTAH BY SUNRISE. THE NORTHWEST FLOW WILL KEEP HIGHS
MORE NEAR NORMAL THROUGH MID WEEK AS A PASSING SYSTEM TO THE NORTH
RE-ENFORCES THE COOL AIRMASS. A RIDGE REBOUNDS GOING IN THE LATE
WEEK PERIOD AND THIS SHOULD AGAIN PUSH TEMPERATURES UP ABOVE NORMAL
GOING INTO NEXT WEEKEND...WITH DRY CONDITIONS PERSISTING.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SUNDAY NIGHT)
ISSUED AT 1029 PM MDT SAT OCT 25 2014

SCATTERED TO BROKEN CLOUDS MID AND HIGH LEVEL CLOUDS WILL CONTINUE
OVERNIGHT BRINGING ISOLATED SNOW SHOWERS ABOVE 10K FEET. VFR
CONDITIONS ARE EXPECTED TO PREVAIL FOR THE MOUNTAIN AIRPORTS
THROUGH SUNDAY AFTERNOON. SUNDAY EVENING THE NEXT PACIFIC SYSTEM
WILL MOVE INTO THE GREAT BASIN. SOUTHWEST WINDS WILL INCREASE AT
THE SURFACE AND OVER THE MOUNTAINS...CREATING MOUNTAINWAVE
TURBULENCE. AS THE SURFACE COLD FRONT PUSHES INTO THE AREA LATE IN
THE EVENING...CLOUDS AND PRECIPITATION WILL INCREASE...ESPECIALLY
OVER AREAS NORTH OF ABOUT KCNY TO KGUC. MOUNTAINS WILL BECOME
OBSCURED AND MVFR CIGS AND VSBYS WILL BE POSSIBLE AT KVEL...KCAG...
KHDN...AND KSBS.

&&

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

$$

UPDATE...CC
SHORT TERM...PF/PF/15
LONG TERM...15
AVIATION...CC



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.