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000
FXUS65 KGJT 212215
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
315 PM MST WED JAN 21 2015

.SHORT TERM...(TONIGHT THROUGH THURSDAY NIGHT)
ISSUED AT 315 PM MST WED JAN 21 2015

MOIST SHORT WAVE CENTERED OVER ERN ARIZONA TRACKS EASTWARD WITH
THE DEEPEST MOISTURE OVER NW NEW MEXICO. DIGGING SHORT WAVE FROM
WYOMING WILL INTERACT WITH THE LEAD SHORT WAVE AND CARVES OUT A
SHARP CYCLONIC FLOW OVER THE FOUR CORNERS. AS THE SECONDARY WAVES
DIVES TOWARD SERN UTAH...MOISTURE SPREADS WESTWARD ACROSS LA PLATA
AND ARCHULETA COUNTIES. A BLEND OF HIGHER RESOLUTION MODELS
PLACES THE BEST SNOW ACCUMULATIONS EAST OF PAGOSA SPRINGS AND
SOUTHERN HINSDALE COUNTY...WITH LESSER AMOUNTS THAT EXTEND TO THE
LA PLATA MOUNTAINS RIDGE LINE (OR WEST OF HIGHWAY 550). WINTER
WEATHER ADVISORY ALREADY HOISTED FOR THE ERN HALF OF THE SOUTHWEST
SAN JUANS.

UPPER LOW CONTINUES TO ARC SOUTHWARD INTO ERN ARIZONA AND SRN NEW
MEXICO. SNOW WILL TAPER OFF QUICKLY EARLY THURSDAY MORNING WITH
RAPID CLEARING FROM THE NORTH. DRIER AND COLDER AIR SPREADS
SOUTHWARD...BUT THIS FRESH AIR MASS DOES NOT CONTAIN ARCTIC AIR.
DEFINITELY MUCH COOLER...BUT NOT BITTER JANUARY COLD. A FEW SUB
ZERO READINGS CAN BE EXPECTED ACROSS NW COLORADO AND SOME OF THE
HIGH MOUNTAIN VALLEYS.

BRISK NORTHEAST WIND WITH GUSTS TO 25 MPH HAVE DEVELOP OVER PARTS
OF ERN UTAH. THESE HAVE BEEN ERRATIC THUS FAR...BUT EXPECT THESE
BREEZES TO PREVAIL INTO TONIGHT. BUT THE GRADIENT TAPERS OFF ON
THURSDAY...BUT LIGHT NE BREEZES WILL PERSIST INTO THE AFTERNOON.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 315 PM MST WED JAN 21 2015

IN A HIGHLY AMPLIFIED PATTERN...THIS FORECAST AREA COMES UNDER
THE INFLUENCE OF A LARGE WEST COAST RIDGE. WEAK DISTURBANCES
DIVING SE OVER THE EAST SIDE OF THE RIDGE MAY PRODUCE SOME LIGHT
SNOWFALL MAINLY IN THE ZIRKEL AND ELKHEAD MOUNTAINS FRIDAY THROUGH
SUNDAY...THOUGH BOTH THE GFS AND EC KEEP THE ENTIRE F0RECAST AREA
DRY THROUGH THESE PERIODS. TEMPERATURES WILL BE AT OR JUST BELOW
NORMAL ON FRIDAY THEN RECOVER SATURDAY AND RISE ABOVE NORMAL
SUNDAY INTO MONDAY AS THE RIDGE PROGRESSES OVERHEAD. STAYED BELOW
GUIDANCE IN THE VALLEY BOTTOMS WHERE INVERSIONS WILL STRENGTHEN
WITH TIME. BASIN FOG IS A CONCERN BUT IS NOT A GIVEN WITH THE
AIR MASS EXCHANGE GOING ON NOW.

MONDAY A LOW OFF THE CENTRAL BAJA COAST BEGINS TO LIFT. THE GFS
BRINGS THE LOW INTO THE GREAT BASIN WHILE THE EC KEEPS THE ENERGY
ALONG THE WEST COAST. THE GFS WOULD PRODUCE SOME SHOWERS FAVORING
THE SOUTH WHILE THE EC SOLUTION WOULD BE DRY. THIS SYSTEM WILL BE
QUITE MILD WITH 700MB TEMPS IN THE -2C TO -4C RANGE BY TUESDAY
NIGHT-WEDNESDAY. SO THE WETTER GFS WOULD PRODUCE HIGH SNOW LEVELS.
ON THE PLUS SIDE THIS SYSTEM MAY HAVE RELATIVELY DEEP MOISTURE
AVAILABLE WITH 700MB SPECIFIC HUMIDITIES AT 4 G/KG. TYPICALLY
THOUGH...WEAKLY ORGANIZED LOWS LIKE THIS ONE MOVING INTO A MEAN
RIDGE HAVE LESS WEATHER IMPACT.

THE RIDGE REBUILDS FOR NEXT WEDNESDAY INTO THURSDAY WITH A TROUGH
FORMING OVER CALIFORNIA FOR THE LAST FEW DAYS OF JANUARY.



&&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z THURSDAY AFTERNOON)
ISSUED AT 1118 AM MST WED JAN 21 2015

MOUNTAINS WILL BE PARTIALLY OBSCURED ALONG THE COLORADO SPINE
TOWARD THE SAN JUAN MOUNTAINS. AIRPORTS AFFECTED WILL BE KASE AND
KDRO WITH PERIODS OF LIGHT SNOW LOWER CIGS AND VIS TO AROUND 3SM.
LIGHT SNOW WILL BE IN THE VICINITY OF KEGE AND KTEX...BUT A 20 TO
30 PERCENT CHANCE THAT LIGHT SNOW DRIFTS OVERHEAD AT THESE SITES.

KVEL...FOG IS NOT EXPECTED TO RETURN DURING THIS FORECAST PERIOD.

ALL OTHER TAF SITES ARE EXPECTED TO STAY VFR.


&&

.GJT WATCHES/WARNINGS/ADVISORIES...
CO...WINTER WEATHER ADVISORY UNTIL 6 AM MST THURSDAY FOR COZ019.

UT...NONE.
&&

$$

SHORT TERM...PF
LONG TERM...JOE
AVIATION...PF