Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 030433
AFDGJT

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

.UPDATE...
ISSUED AT 930 PM MST MON MAR 2 2015

COLD FRONT WAS EXITING STAGE RIGHT MONDAY EVENING AND COLD AIR WAS
POURING INTO THE REGION. INITIALLY THE COLD ADVECTION IS FROM THE
SW BUT VEERING IS ALREADY SEEN IN THE PROFILER TO BE MORE OUT OF
THE WEST ON TUESDAY.

THE AFTERNOON BALLOON RELEASE HERE AT THE GRAND JUNCTION AIRPORT
CAPTURED A WIND SPEED OF 186KTS/214MPH AT JUST ABOVE 30KFT! THIS
JET IS CURRENTLY STRETCHED FROM NW NM TO DENVER AND WILL CONTINUE
TO PUSH OFF TO THE EAST TONIGHT AND TUESDAY. BUT THE HIGH COUNTRY
WILL CONTINUE TO BLOW HARD OVERNIGHT WITH G50MPH REPORTED AT
TELLURIDE AIRPORT AT 9PM AS AN EXAMPLE.

SNOW ACCUMULATIONS ARE SHIFTING TO THE EAST TONIGHT. HAVE UPDATED
THE FORECAST TO LOWER POPS FOR SE UTAH AND SW COLORADO TONIGHT
INTO TUESDAY MORNING. THE WARNINGS FOR THE LA SAL AND ABAJO MTNS
WILL NEED TO BE EVALUATED THIS EVENING. LITTLE ADDITIONAL SNOWFALL
IS EXPECTED UNTIL TUESDAY AFTERNOON BUT THE WIND AND BLOWING SNOW
WILL CONTINUE TO PRODUCE BITTER TRAVEL WEATHER.

SOME THUNDERSTORM ACTIVITY EXPECTED ON TUESDAY AFTERNOON AS THE
FINAL AND STRONGEST COLD FRONT APPROACHES FROM THE NORTH. LAPSE
RATES CLIMB TO NEAR 8 C/KM IN THE AFTERNOON OVER WESTERN COLORADO.
THESE STORMS WILL HAVE LESS MOISTURE TO WORK WITH. THE FRONT
SWEEPS N-S THROUGH THE REGION TUESDAY NIGHT FINALLY SHIFTING THE
WINDS ALOFT FROM WEST TO NORTH. THIS KEEPS WEDNESDAY MORNING
TEMPERATURES ONLY SOMEWHAT BELOW NORMAL. SHOWERS ARE NOW PROGGED
TO CONTINUE OVER THE EASTERN MTNS THROUGH WEDNESDAY...FAVORING NW-
FACING SLOPES. THEN TEMPERATURES PLUMMET WEDNESDAY NIGHT. IN CASE
YOU HAVE FORGOTTEN DURING THIS MILD MILD COLD SEASON...THIS WILL
BE A REMINDER THAT WINTER IS NOT OVER. SINGLE DIGIT VALLEY
TEMPERATURES WILL BE WIDESPREAD WITH THE MOST MOUNTAIN SITES BELOW
ZERO.

UPDATE ISSUED AT 738 PM MST MON MAR 2 2015

PULLED DOWN THE WINTER WEATHER ADVISORY FOR THE EASTERN UINTA
BASIN. LOSS OF LIFT ASSOCIATED WITH FROPA AND SHIFT TO A MORE
WESTERLY FLOW ALOFT WORKS AGAINST ADDITIONAL SNOWFALL
ACCUMULATION. WILL...HOWEVER...MENTION FOG IN THIS AREA AS KVEL
SENSOR REPORTING VSBY OF LESS THAN 1 MILE DUE TO SATURATED AIR
MASS AND LIGHT WINDS. REMAINING HILITES APPEARED ON TRACK AND DO
NOT ANTICIPATE FURTHER CHANGES.

&&

.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 LONG TERM WILL BRING PLENTY OF SUNNY SKIES
AND WARMING TEMPERATURES FOR ALMOST THE ENTIRE CWA.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z TUESDAY EVENING)
ISSUED AT 930 PM MST MON MAR 2 2015

THE COLD FRONT WAS NEAR THE CONTINENTAL DIVIDE AND SHIFTING EAST
AT 04Z. THE JET STREAM WAS OVER THE SOUTH AND EAST AND ALSO
SHIFTING EAST. MTN TOP WINDS CONTINUE AT AROUND 50KTS THIS EVENING
SO EXPECT LLWS ISSUES TO CONTINUE THROUGH TUESDAY MORNING FOR
MOST AIRFIELDS. IN ADDITION...MODERATE TO SEVERE TURBULENCE IS
POSSIBLE IN THE LEA OF MOUNTAIN PEAKS AND RIDGES. THE EASTERN TAF
SITES...KASE AND KEGE ALONG WITH KTEX...CAN EXPECT PERIODS OF
MVFR CIGS AND VSBY IN RAIN AND IFR CONDITIONS IN SNOW THROUGH THE
NIGHT AND INTO TUESDAY MORNING. BEHIND THE FRONT AND IN THE
MOUNTAINS EXPECT ALL SNOW AND OBSCURATION. A SECONDARY SYSTEM WILL
PUSH OVER THE AREA TUESDAY AFTERNOON RESULTING IN SCATTERED TO
NUMEROUS SNOW SHOWERS AND ISOLATED THUNDERSTORMS.


&&

.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.

&&

$$

UPDATE...JOE
SHORT TERM...EH
LONG TERM...TGR
AVIATION...NL



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