Area Forecast Discussion
Issued by NWS Grand Junction, CO

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FXUS65 KGJT 171716
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
1016 AM MST WED DEC 17 2014

.UPDATE...
ISSUED AT 1002 AM MST WED DEC 17 2014

BAND OF SNOW SHOWERS IS MOVING THROUGH THE I-70 CORRIDOR AROUND 10
AM SETTING OFF WIDESPREAD SNOW SHOWERS. RADAR SHOWS IT MOVING
NORTH OF THE INTERSTATE BY 11 AM OR SO. THE 12Z NAM IS STILL
KEYING ON SIGNIFICANT SNOWFALL IN SE UTAH ARCING UP MESA COUNTY
INTO THE FLAT TOPS. BLANDING NUCLA CORTEZ DURANGO PAGOSA HAVE HAD
LITTLE TO NO PRECIP THIS MORNING. THE NAM GENERALLY STILL
OVERDOING SNOW AMOUNTS.

&&

.SHORT TERM...(TODAY THROUGH THURSDAY)
ISSUED AT 407 AM MST WED DEC 17 2014

A MOIST BUT WEAKLY ORGANIZED SYSTEM IS BEGINNING TO MAKE ITS WAY
INTO THE FORECAST AREA WITH THE MAIN ENERGY CURRENTLY SOUTH OF
THE FOUR CORNERS. THIS WEAK H7 LOW PRESSURE SYSTEM HAS SHOWN SOME
STRENGTHENING ON IR AND WATER VAPOR SATELLITE THIS MORNING WHICH
ALIGNS WELL WITH THE MODELED NAM QC FORCING. WX MODELS INDICATE
H7 TEMPERATURES DROPPING THROUGHOUT THE DAY TODAY...WHICH MADE
TODAY/S FORECAST RATHER TRICKY DUE TO SNOW LEVEL CONFIDENCE
ISSUES. EXPECTING FAIRLY WIDESPREAD SHOWERS ACROSS SW COLORADO
TODAY AND REACHING AS FAR NORTH AS THE I-70 CORRIDOR...BUT THE
BULLSEYE LOOKS TO BE OVER SW COLORADO. DECIDED TO ISSUE WINTER WX
ADVISORIES FOR THE SOUTHWEST COLORADO VALLEY ZONES AS WELL AS THE
PARADOX VALLEY THINKING WITH TEMPS CURRENTLY IN THE LOWER 30S AND
EXPECTATIONS OF THEM DROPPING THROUGHOUT THE DAY THAT SNOW SHOULD
NOT MIX IN WITH RAIN FOR VERY LONG IF AT ALL. DECIDED TO KEEP
OTHER AREAS OUT OF HAZARD PRODUCTS FOR NOW AS CONFIDENCE IS JUST
NOT ALL THAT HIGH ON HOW THIS SYSTEM WILL MATERIALIZE TODAY.

WIDESPREAD SHOWERS WILL BEGIN TO TAPER OFF TONIGHT...BUT THE SNOW
WILL NOT COMPLETELY STOP ACROSS THE FORECAST AREA. ISO TO SCT
SHOWERS WILL OCCUR ACROSS THE REGION ON THURSDAY WITH THE TAIL END
OF THIS SYSTEM WRAPPING SOME MOISTURE BACK INTO THE AREA.

.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 407 AM MST WED DEC 17 2014

RESIDUAL MOISTURE IN NORTHWEST FLOW WILL CONTINUE TO BRING SOME
LIGHT SNOW TO THE DIVIDE MOUNTAINS THURSDAY NIGHT. DRY WEATHER
RETURNS TO THE AREA FRIDAY AS A SHORTWAVE RIDGE FORMS AHEAD OF THE
NEXT LOW AMPLITUDE SHORTWAVE TROUGH MOVING INLAND FROM THE
PACIFIC. MUCH OF THE ENERGY ASSOCIATED WITH THIS SYSTEM WILL PASS
SOUTH OF THE FORECAST AREA ON SATURDAY LIMITING SNOWFALL ACROSS
THE REGION.

NORTHWEST FLOW DEVELOPS OVER THE AREA IN THE WAKE OF THIS SYSTEM
AS HIGH PRESSURE BUILDS OVER THE EASTERN PACIFIC. MODELS WERE
CONSISTENT IN DEPICTING A LENGTHY FETCH OF MOISTURE STRETCHING
FROM THE GULF OF ALASKA PASSING OVER THE NORTHERN DIVIDE
MOUNTAINS BEGINNING SATURDAY NIGHT. STRENGTHENING WINDS BENEATH A
140 KT JET WILL PROVIDE GOOD OROGRAPHIC LIFT ACROSS THE NORTHERN
AND CENTRAL COLORADO MOUNTAINS. APPEARS MODELS SETTING THE STAGE
FOR PERSISTENT SNOW OVER COLORADO/S NORTHERN AND CENTRAL MOUNTAINS
WHICH COULD LAST INTO MIDWEEK. IF LATEST MODELS VERIFY...THERE IS
A STRONG CHANCE THAT SIGNIFICANT ACCUMULATIONS WILL OCCUR ACROSS
NORTHERN AND CENTRAL COLORADO DURING THIS PERIOD.

NOT EXPECTING ANY APPRECIABLE CHANGES IN TEMPERATURES DURING THIS
PERIOD SO LOOK FOR NEAR NORMAL READINGS TO CONTINUE.

&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY NOON)
ISSUED AT 1015 AM MST WED DEC 17 2014

SNOW WILL CONTINUE THROUGH THURSDAY MORNING AS THE UPPER TROUGH
SLIDES EASTWARD JUST SOUTH OF THE UTAH/COLORADO BORDER. FAVORED
AREAS EXPECTED TO BE PRIMARILY ALONG AND SOUTH OF THE I-70
CORRIDOR DURING THIS TIME FRAME. CONSEQUENTLY...EXPECT WIDESPREAD
MOUNTAIN OBSCURATIONS FROM THE CENTRAL MOUNTAINS SOUTHWARD.
PROLONGED PERIODS OF IFR CIGS AND VSBY IN SNOW ARE LIKELY FOR
KMTJ...KTEX...AND KDRO WITH STRONG CHANCES FOR PERIODS MVFR AND
IFR CONDITIONS FOR KCNY...KGJT...KRIL...KEGE...AND KASE. AFT 12Z
THURSDAY IMPROVING CONDITIONS TO WIDESPREAD VFR WITH OCNL MTN
OBSCURATION THROUGH 18Z.


&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL 3 AM MST THURSDAY FOR COZ009-018-
     019.

     WINTER WEATHER ADVISORY UNTIL 11 PM MST THIS EVENING FOR
     COZ020>023.

UT...NONE.
&&

$$

UPDATE...JOE
SHORT TERM...JAM
LONG TERM...NL
AVIATION...NL



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