000
FXUS65 KGJT 071940
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
1240 PM MST FRI MAR 7 2014

.UPDATE...
ISSUED AT 1233 PM MST FRI MAR 7 2014

UPGRADED GRAND MESA (ZONE 9) TO A WINTER STORM WARNING FOLLOWING
SPOTTER REPORTS OF 12 INCHES AT POWDERHORN SKI RESORT AND 9 INCHES
AT GRAND MESA LODGE. BONHAM RESERVOIR REPORTED 5 INCHES AS OF EARLIER
THIS MORNING. NORTHERLY OROGRAPHIC FLOW AND CONVECTIVE INSTABILITY
SHOULD CONTINUE TO FAVOR SNOW/SNOW SHOWERS ESPECIALLY ON THE
NORTH FACING SLOPES THIS AFTERNOON.

FOR SIMILAR REASONING...NORTHWEST TO NORTH FLOW AND CONVECTIVE
INSTABILITY..DECIDED TO ALSO ISSUED A WINTER WEATHER ADVISORY FOR
THE NORTHWEST SAN JUAN MOUNTAINS (ZONE 18) FOR ELEVATIONS ABOVE
9000 FT. NAM12 FORECAST SOUNDING INDICATED LOW TO MID-LEVEL FLOW
BECOMING FAVORABLE FOR POSSIBLE HEAVY SNOW ACCUMULATIONS ALONG HWY
550 IN THE UNCOMPAHGRE GORGE BETWEEN OURAY AND RED MTN PASS. THIS
ADVISORY GOES UNTIL MIDNIGHT TONIGHT.

UPDATE ISSUED AT 1011 AM MST FRI MAR 7 2014

MID-LEVEL TROUGH AXIS ABOUT AT THE UT/CO BORDER TROUGH WILL CONTINUE
MOVING EAST BUT ALSO GET STRETCHED TO THE SOUTHWEST AS A BACKSIDE
JET MAX OVER WRN NV HEADS FOR AZ. BEST SNOWFALL WAS ALONG THE COLD
FRONT AHEAD OF THE UPPER TROUGH WITH SOME AREAS OVER THE CO MTNS
LIKELY PICKING UP 2-3 INCHES RATHER QUICKLY THIS MORNING. 15Z RAP
MODEL KEEPS CONVECTIVE INSTABILITY AROUND THIS AFTERNOON AS
PRECIPITATION TRANSITION TO SHOWERS AS THE LARGER-SCALE LIFT SHIFTS
TO THE EAST. NORTH TO NORTHWEST FLOW BEHIND THE TROUGH WILL FAVOR
NORTHERN SLOPES THIS AFTERNOON...AND WILL CONTINUE TO KEEP AN EYE ON
THE NW SAN JUANS...SPECIFICALLY THE UNCOMPAHGRE GORGE FOR LOCALIZED
HEAVIER ACCUMULATIONS...FOR A POTENTIAL WINTER HIGHLIGHT. FOR
NOW...WILL LEAVE THE CURRENT SET OF ADVISORIES AS IS.

&&

.SHORT TERM...(TODAY THROUGH SATURDAY)
ISSUED AT 358 AM MST FRI MAR 7 2014

COLD FRONT IS SHOWING UP NICELY IN RADAR MOSAIC THIS
MORNING...ADVANCING ACROSS EC UTAH AND NORTHWEST COLORADO...WITH
METAR AT CANYONLANDS VERIFYING THE ECHOS. FAIRLY ROBUST FRONT WITH
THE GUSTY WINDS BUT IT ALSO HELPED DROP CLOSE TO A QUARTER OF AN
INCH OF RAIN AT VERNAL EARLIER. COLD AIR IS NOTICEABLY ABSENT AND
MOISTURE KEEPING SURFACE DEW POINTS HIGH. SNOTELS IN THE EASTERN
UINTAS SHOW 2-4 INCHES AND LITTLE HOPE OF GETTING MUCH MORE
TODAY. NORTHWEST FLOW WILL BE CAA BUT THINK PRECIPITATION WILL
BECOME MORE SCATTERED AND CONVECTIVE AS THE LARGE SCALE FORCING
MOVES TO THE EAST THROUGH THE DAY. HOLDING HOPE THAT THE
CONVECTIVE POTENTIAL ALONG WITH FRONTAL CIRCULATIONS AND REMAINING
JET DYNAMICS CAN BRING SOME BEEFIER SNOW AMOUNTS TO THE NORTHERN
AND CENTRAL MOUNTAINS THROUGH THE MORNING. ON THE FENCE AS FAR AS
THE NORTHERN SAN JUANS ARE CONCERNED. FRONT WILL BE IN THE REGION
THIS MORNING AS STRONGER UPPER LEVEL FORCING MOVES THROUGH...THEN
CAA NORTHERLY FLOW SETS UP FOR THE AFTERNOON. CONVECTIVE POTENTIAL
STRONG ENOUGH TO MENTION ISOLATED STORMS IN THE SOUTH LOOKING AT
LPI AND DAY 1 OUTLOOK. MOST OF THE LTG SHOULD COINCIDE WITH THE
MAIN VORT LOBE AND LOWERED TROP DIVING ACROSS THE 4 CORNERS FROM
MID MORNING ONWARD. THERE MAY BE LOCALIZED AMOUNTS OVER 6 INCHES
BUT FEEL THE COVERAGE DOES NOT JUSTIFY THE IMPACT OF AN ADVISORY
ATTM. CONVECTION DOES HAVE A WAY OF INVALIDATING THAT LAST
STATEMENT AND MET TRENDS FOR TEX HAVE TAKEN AN INTERESTING
TURN...BUT FOR NOW WILL HOLD THE COURSE. TEMPERATURES WILL TAKE A
DIP DOWNWARD WITH THE FROPA BUT STILL LOOK TO END UP NEAR
SEASONAL.

THIS STORM SYSTEM WILL BE RE-FOCUSING EAST OF THE DIVIDE THIS
EVENING AS THE JET REFORMS ON THE UPSTREAM SIDE OF THE PARENT TROF.
OROGRAPHIC SNOW MAY CONTINUE INTO THE EARLY MORNING HOURS BUT THE
UPPER FLOW WILL BACKING FROM THE NORTH TO THE NORTHEAST AND LEAVING
AREAS EAST OF THE DIVIDE UNDER THE GUN. SKIES WILL BE CLEARING IN THE
NORTH AND WEST WHICH SHOULD BRING IN A CHILLIER NIGHT. RIDGING BUILD
BACK IN FOR SATURDAY AND EXCEPT FOR SOME ISOLATED SHOWERS OVER THE
SOUTHERN MOUNTAINS PLENTY OF SUNSHINE LOOKS ON TAP. TEMPERATURES MAY
WARM A FEW DEGREES WITH THE SUNSHINE BUT MID LEVEL ADVECTION LOOK
COOL TO NEUTRAL AT BEST.

.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 358 AM MST FRI MAR 7 2014

MID LEVEL TROUGH WILL HAVE MOVED SOUTH OF COLORADO BY SATURDAY
EVENING...REPLACED BY A BUILDING RIDGE ACROSS THE INTERMOUNTAIN
RIDGE. SATURDAY NIGHT TURNS CLEAR AND STAYS SUNNY ON SUNDAY. RIDGE
FLATTENS ON SUNDAY NIGHT WITH INCREASING WESTERLY FLOW IN ADVANCE
OF A PROMINENT PACIFIC SHORT WAVE. WITH RELATIVELY WARM TEMPS
ALOFT AND AFTERNOON MIXING...TEMPS MAY BE A FEW DEGREES WARMER THAN
WHAT THE BIAS CORRECTED GUIDANCE REFLECTS AND PUSHED A LITTLE
HIGHER.

GFS/ECMWF INDICATE A POTENTIALLY IMPACTFUL SYSTEM MOVING ACROSS
UTAH AND COLORADO NEXT TUESDAY. STRONG PREFRONTAL WINDS WOULD BE
FOLLOWED BY A DYNAMIC FRONT AND RAPIDLY LOWERING SNOW LEVELS. THE
STRUCTURE OF THIS SYSTEM BETWEEN THE GFS AND ECMWF DIFFER
SIGNIFICANTLY THAT IS DEPENDENT ON UPSTREAM RIDGE AMPLIFICATION.
THE ECMWF SHOWS A PROGRESSIVE SHORT WAVE WHILE THE GFS SHOWS SOME
ENERGY BREAKING OFF AND FORMING A CLOSED LOW CIRCULATION OVER
UTAH. AGREEMENT ON THE TIMING OF THIS FEATURE WARRANTS LIKELY POPS
FOR THE NRN MOUNTAINS...BUT MUCH UNCERTAINTY ON THE EVOLUTION OF
THIS WEATHER MAKER.

WILL NOT FIGHT AGAINST THE CONSENSUS SOLUTION THAT INDICATE THAT
ANY RAIN OR SNOW SHOWERS WILL BE WANING ON WEDNESDAY...FOLLOWED
BY DRY WEATHER FOR THURSDAY.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1011 AM MST FRI MAR 7 2014

PRECIPITATION WILL TURN FROM WIDESPREAD VALLEY RAIN AND MOUNTAIN NOW
THIS MORNING TO MORE SHOWERS FAVORING THE MOUNTAINS AND NORTH SLOPES
THIS AFTERNOON. THIS WILL RESULT IN SOME IMPROVEMENT AT THE TAF AND
SKI COUNTRY AIRPORTS BUT ALSO MORE VARIABLE FLIGHT RESTRICTIONS AT
TIMES. ISOLD THUNDERSTORMS WITH SMALL HAIL/GRAUPEL AND GUSTY WINDS
ARE POSSIBLE SOUTH OF A KCNY-KGUC LINE UNTIL 00Z THIS EVENING.
GENERALLY VFR CONDITIONS ARE EXPECTED ACROSS ERN UT AND FAR NW CO
THIS AFTERNOON. FOG POSSIBLE AT KEGE/KMTJ/KRIL TONIGHT AS SKIES
GRADUALLY CLEAR.


&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...WINTER WEATHER ADVISORY UNTIL MIDNIGHT MST TONIGHT ABOVE 9000
     FEET FOR COZ018.

     WINTER STORM WARNING UNTIL 8 PM MST THIS EVENING ABOVE 9000 FEET
     FOR COZ009.
     WINTER WEATHER ADVISORY UNTIL 6 PM MST THIS EVENING COZ004-013.
     WINTER WEATHER ADVISORY UNTIL 8 PM MST THIS EVENING ABOVE 9000
     FEET FOR COZ010-012.

UT...NONE.

&&

$$

UPDATE...JAD
SHORT TERM...15
LONG TERM...PF
AVIATION...JAD