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000
FXUS65 KGJT 022240
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
340 PM MST MON MAR 2 2015

.SHORT TERM...(TONIGHT THROUGH TUESDAY NIGHT)
ISSUED AT 339 PM MST MON MAR 2 2015

THIS EVENING WILL SEE THIS LONG DURATION STORM TRANSITION FROM THE
WARM PHASE OUT AHEAD OF A SURFACE COLD FRONT AND UPPER LEVEL LOW
PRESSURE TROUGH...INTO A COLDER PHASED STORM. THE COLD FRONT AND THE
FIRST UPPER THROUGH WILL PASS OVER THE AREA THIS EVENING...THEN A
SECOND UPPER DISTURBANCE WILL SWEEP OVER THE AREA LATE TUE-TUE
NIGHT.

FOR SOME DETAILS...THE UPPER SW-NE ORIENTED JET HAS STRENGTHENED
OVERHEAD EARLY THIS AFTERNOON. THE JET CORE WILL REACH THE 4-CORNERS
BY 5PM...THEN TO 165-175KT OVER THE SAN JUANS TO WEST ELK RANGES
BY MID-LATE EVENING. THIS COINCIDES WITH THE SURFACE FRONT THAT IS
FAST APPROACHING FROM THE WEST. THE FRONT IS SCHEDULED TO REACH
EASTERN UT LATE THIS AFTERNOON...AND FAR WESTERN CO EARLY THIS
EVENING. IT WILL THEN SWEEP FROM WEST TO EAST EXITING THE EASTERN
EDGE OF THE FORECAST AREA BY AROUND MIDNIGHT. DUE TO THE
INTERACTION OF THE FRONT AND THE UPPER JET WILL GO AHEAD AND HOIST
A BLIZZARD WARNING ABOVE 10KFT FOR THE WESTERN SAN JUANS TO THE
WEST ELKS AND SAWATCH RANGES WHERE VERY STRONG WINDS WILL COMBINE
WITH HEAVY SNOW FOR WHITEOUT CONDITIONS AT TIMES TONIGHT. THIS
WILL RUN FROM 6PM THIS EVENING UNTIL 6AM TUESDAY MORNING FOR THE
MOST EXTREME HOURS.

VERY WARM TEMPERATURES HAVE SPREAD IN AHEAD OF THE FRONT WITH SNOW
LEVELS QUITE HIGH THIS AFTERNOON. ALSO THE AIR MASS HAS BECOME MORE
UNSTABLE WITH LIGHTNING EVIDENT UPSTREAM...MAINLY OVER SOUTHERN NV.
HOWEVER A COUPLE STRIKES HAVE NOW BEEN SEEN OVER SOUTHEAST UT.
THEREFORE I HAVE ADDED A SLIGHT CHANCE OF THUNDERSTORMS THROUGH
EARLY THIS EVENING ACROSS SOUTHEAST UT/SOUTHWEST CO. WIDESPREAD
PRECIPITATION WILL CONTINUE...AND EVEN INCREASE IN THE VICINITY OF
THE FRONT...WITH SNOW LEVELS FALLING. BY MID-LATE EVENING THE
PRECIPITATION TYPE SHOULD BE ALL SNOW IN ALL THE VALLEYS. HAVE GONE
AHEAD AND KEPT THE HIGHLIGHTS OUT FOR THE NORTHERN VALLEYS AS THEY
SHOULD CHANGE OVER TO SNOW THIS EVENING...WITH GOOD ACCUMULATIONS
ESPECIALLY THROUGH TONIGHT. ALSO HOISTED A SNOW ADVISORY FOR THE
UINTA BASIN AS THEY WILL ALSO ACCUMULATE ADDITIONAL SNOW
OVERNIGHT...WHICH SHOULD BEGIN TO AFFECT TRAVEL.

ONCE THE FRONT PASSES TONIGHT...SNOW SHOULD DIMINISH IN THE VALLEYS
TOWARDS DAYLIGHT. THEN ACTIVITY WILL AGAIN PICK UP TUE AFTERNOON
AS THE NEXT UPPER DISTURBANCE APPROACHES FROM THE WEST. NOT SURE
THE MOUNTAINS WILL SEE MUCH OF A DOWNTURN. HOWEVER THE JET SHIFTS
EAST THROUGH THE DAY ON TUE...SO WINDS WILL LET UP AND BECOME LESS
OF A HAZARD. THIS SECOND DISTURBANCE IS COLDER WITH -28C/ TO
-32C/NORTH AT 500 MB BY 12Z WED MORNING. FROM AROUND TUE AFTERNOON
ONWARDS THE NORTH WILL BE FAVORED AS THE FLOW CHANGES TO A MORE
WEST THEN NORTHWEST DIRECTION...AND THE COLDEST AIR ALOFT WILL
MOVE OVER THOSE ZONES. BY LATE TUE NIGHT LOOK FOR CLEARING
CONDITIONS FROM THE WEST BEHIND THE TROUGH AXIS. THIS WILL ALSO
BRING MUCH COLDER TEMPERATURES TO THE AREA.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 339 PM MST MON MAR 2 2015

THE LAST TROUGH WILL HAVE JUST BE EXITING THE AREA WEDNESDAY WITH
SOME RESIDUAL SHOWERS POSSIBLE OVER THE SPINE OF THE ROCKIES. BY
AND LARGE THOUGH...MOSTLY SUNNY SKIES WITH TEMPS 10 TO 15 DEGREES
BELOW NORMAL AS MUCH COLDER CANADIAN AIR DROPS DOWN FROM THE
NORTH. ASIDE FROM THAT...NOT TOO MUCH TO TALK ABOUT AS A LARGE
RIDGE COVERS THE WESTERN THIRD OF THE COUNTRY THURSDAY ONWARDS.

A WEAK KINK IN THE FLOW THURSDAY MAY CAUSE A FEW SHOWERS OVER THE
NRN MTNS THOUGH GFS HAS REMOVED ANY SIGN OF PRECIP. LEFT SCHC IN
FORECAST WITH MINIMAL QPF EXPECTED.

THE REMAINDER OF THE LONGTERM WILL BRING PLENTY OF SUNNY SKIES AND
WARMING TEMPERATURES FOR ALMOST THE ENTIRE CWA.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z TUESDAY AFTERNOON)
ISSUED AT 1029 AM MST MON MAR 2 2015

SCATTERED SHOWERS THIS MORNING FROM I-70 SOUTH WILL BECOME
NUMEROUS THIS AFTERNOON AS A COLD FRONT SWEEPS THE REGION. NORTH
OF I-70 SHOWERS WILL BE WIDESPREAD THROUGH THE DAY. RAIN/SNOW
LINE VARIES FROM 8000FT SOUTH TO 6500 NORTH. CIGS WILL TREND
LOWER WITH VFR BECOMING MVFR.

LOW LEVEL WIND SHEAR POSSIBLE ACROSS THE FORECAST AREA THIS
MORNING THAT WILL MIX DOWN THIS AFTERNOON. WIDESPREAD G25KT WITH
MORE LOCALIZED G40KT POSSIBLE EVEN INTO THE VALLEYS AS THE COLD
FRONT PASSES. MODERATE TO STRONG MECHANICAL TURBULENCE WILL OCCUR
WITH THE FRONT TIMED AT 18Z-21Z IN EASTERN UTAH TO 21-02Z ACROSS
WESTERN COLORADO. DURING THE FRONTAL PASSAGE...ALL TAF SITES WILL
HAVE VIS BLO 3SM BR IN RAIN OR SNOW (SNOW LEVEL LOWERING TO NEAR
THE VALLEY FLOORS) WITH CIGS BELOW ILS BREAKPOINTS.


&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER STORM WARNING UNTIL 5 PM MST TUESDAY FOR COZ001-002-009-
     010-012-017>019.

     BLIZZARD WARNING UNTIL 6 AM MST TUESDAY FOR COZ012-018-019.

     WINTER STORM WARNING UNTIL 9 AM MST WEDNESDAY FOR COZ003>005-013.

UT...WINTER STORM WARNING UNTIL 5 PM MST TUESDAY FOR UTZ023-025-028.

     WINTER WEATHER ADVISORY UNTIL 6 AM MST TUESDAY FOR UTZ024.

&&

$$

SHORT TERM...EH
LONG TERM...TGR
AVIATION...TGJT