Area Forecast Discussion
Issued by NWS Grand Junction, CO

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000
FXUS65 KGJT 132344
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
444 PM MST SAT FEB 13 2016

.SHORT TERM...(TONIGHT THROUGH SUNDAY NIGHT)
ISSUED AT 444 PM MST SAT FEB 13 2016

THE FIRST WEAK WAVE WAS WORKING THROUGH THE NORTHERN ROCKIES THIS
AFTERNOON WITH THE SECOND STRONGER WAVE MAKING LANDFALL IN
WASHINGTON. NW FLOW STRENGTHENS TONIGHT WITH COLD ADVECTION.
MOISTURE IS LIMITED THOUGH WITH ONLY LIGHT SNOW SHOWERS EXPECTED
TOWARDS SUNRISE IN THE ELKHEAD-ZIRKEL MTN RANGES. TEMPERATURES
WILL COOL IN MOST MTN LOCATIONS WHILE VALLEYS WILL BE A BIT MILDER
THAN THE LAST FEW MORNINGS. COOLER AIR OVER THE AREA AND MOIST
NORTHWEST FLOW WITH EMBEDDED DISTURBANCES TO BRING THE NEXT ROUND
OF SNOW MAINLY TO HIGHER ELEVATIONS IN NORTHWEST COLORADO STARTING
IN THE PARK RANGE SUNDAY MORNING. DYNAMIC LIFT EXPECTED TO BE
QUITE LIMITED AS THE NEXT WEATHER SYSTEM WILL BE FIGHTING THE
LONGWAVE RIDGE TO HAVE AN IMPACT ON OUR CWA. THUS EXPECT
OROGRAPHICS TO BE THE MAIN LIFT COMPONENT FOR SIGNIFICANT SNOW
ACCUMULATIONS. PRESENTLY HAVE A WINTER WX ADVISORIES IN EFFECT FOR
THE NORTHWEST CO MTNS AND THE UPPER YAMPA RIVER BASIN STARTING AT
VARIOUS TIMES ON SUNDAY AND WINDING DOWN MONDAY EVENING.
POSSIBILITY THAT THE ADVISORY MAY NEED TO BE EXTENDED A LITTLE
LONGER THAN PRESENTLY FORECAST IF THE NAM IS CORRECT IN HOLDING ON
LONGER TO THE H7-H5 MOISTURE IN NW CO.

GREATEST SNOWFALL RATES EXPECTED SUNDAY AFTERNOON AND SUNDAY
NIGHT...COINCIDING WITH THE NOSE OF AN H3 JET OVER NW CO WITH
TROPOSPERIC WINDS OF 80-90 KTS. AND THAT IS ABOUT THE EXTENT OF
ANY SIGNIFICANT DYNAMIC LIFT. TEMPERATURES TO SUPPORT DENDRITIC
GROWTH WILL BE ELEVATED AND NOT AT THE LEVEL WHERE OROGRAPHIC LIFT
IS SUPPORTED. AND H7 TEMPERATURES ONLY EXPECTED TO COOL TO MINUS 6
TO MINUS 7 C. NONETHELESS...THE PERSISTENCE OF SNOWFALL IN THE
OROGRAPHICALLY FAVORED HIGHER ELEVATIONS OF NW CO SHOULD SUPPORT
SIGNIFICANT STORM TOTAL ACCUMULATIONS...MOSTLY IN THE 4-8 INCH
RANGE...BUT LIKELY PRODUCING LOCALLY HIGHER AMOUNTS IN EXCESS OF
12 INCHES ALONG THE CONTINENTAL DEVIDE NORTH OF RABBIT EARS PASS.

BLOWING AND DRIFTING SNOW WILL BE THE OTHER IMPACT FROM THIS
SNOWFALL EVENT...WITH THE MOST SIGNIFICANT WINDS EXPECTED LATE
SUNDAY THROUGH MONDAY.

SOME SNOW ACCUMULATIONS ALSO EXPECTED IN AREAS ADJOINING THE
ADVISED ZONES...THOUGH WITH LESSER AMOOUNTS THAT ARE PRESENTLY
NOT EXPECTED TO REACH ADVISORY CRITERIA.

EXPECT A COOL DOWN OF MAX TEMPERATURES ON SUNDAY...WITH SIMILAR
OR SLIGHTLY HIGHER TEMPERATURES ON MONDAY AS H7 TEMPERATURES RISE
ABOUT 2 DEGREES C OVER SUNDAY.

.LONG TERM...(TUESDAY THROUGH SATURDAY) ISSUED AT 400 PM MST SAT
FEB 13 2016

AN UPPER RIDGE IS EXPECTED TO MOVE BACK OVER OUR AREA TUESDAY AND
WEDNESDAY FOR A RETURN OF BENIGN WEATHER AND RE-STRENGTHENING OF
SURFACE-BASED INVERSION IN THE VALLEYS PRONE TO INVERSIONS.

THEN THE NEXT PACIFIC WEATHER SYSTEMS POISED TO CROSS OUR AREA
BEGINNING LATE WEDNESDAY WILL BE WEAKENED AS THEY ENCOUNTER THE
LONG-WAVE UPPER RIDGE POSITION WHICH SHOULD REMAIN FIRMLY IN PLACE
OVER THE WESTERN STATES THROUGH AT LEAST THE END OF NEXT WEEK.

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z SUNDAY EVENING) ISSUED
AT 436 PM MST SAT FEB 13 2016

VFR CONDITIONS EXPECTED AT ALL TAF SITES EXCEPT VERNAL FOR THE
NEXT ~20 HOURS. KASE WILL BEGIN TO DETERIORATE AFTER 21Z SUNDAY
AFTERNOON DUE TO A WEATHER DISTURBANCE BRINGING SNOW AND BLOWING
SNOW TO THE NORTH CENTRAL MOUNTAIN AREAS OF COLORADO. STRONG NW
GRADIENT WINDS AT AND ABOVE MTN TOP LEVEL WILL KEEP TURBULENCE
ELEVATED AND THE POSSIBILITY OF LOW LEVEL WIND SHEAR. MOUNTAINS
ACROSS NW COLORADO WILL BECOME PARTIALLY OBSCURED BEGINNING AROUND
18Z SUNDAY.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY FROM 8 AM SUNDAY TO MIDNIGHT MST MONDAY
     NIGHT FOR COZ004.

     WINTER WEATHER ADVISORY FROM 11 AM SUNDAY TO MIDNIGHT MST MONDAY
     NIGHT FOR COZ005-013.

     WINTER WEATHER ADVISORY FROM 2 PM SUNDAY TO 5 PM MST MONDAY FOR
     COZ010.

UT...NONE.
&&

$$

SHORT TERM...JOE/JRP
LONG TERM...JRP
AVIATION...TGJT


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