000
FXUS65 KGJT 040014
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
514 PM MST TUE MAR 3 2015

.UPDATE...
ISSUED AT 514 PM MST TUE MAR 3 2015

APPROACHING SHORTWAVE WITH SURFACE FRONT SLOWLY MAKING THEIR WAY
THROUGH EASTERN UTAH. INSTABILITY HAS RESULTED IN MORE SHOWERY
ACTIVITY ACROSS THE AREA WHICH MODELS SUGGEST WILL LINGER INTO THE
EVENING. GIVEN TIMING AND POSITIONING OF THESE FEATURES WILL
EXTEND ALL HILITES WITH THE EXCEPTION OF THE EASTERN UINTA
MOUNTAINS BEHIND THE FRONT/TROUGH AXIS. DO NOT EXPECT A LOT IN
TERMS OF ACCUMULATIONS...BUT THERE WILL LIKELY BE IMPACTS ON
ROADWAYS DURING THIS PERIOD. PLAN TO DROP HILITES FOR CENTRAL
YAMPA RIVER BASIN...THE UNCOMPAHGRE PLATEAU AND THE SOUTHWEST SAN
JUAN MOUNTAINS AT 9PM MST.

&&

.SHORT TERM...(TONIGHT THROUGH WEDNESDAY NIGHT)
ISSUED AT 401 PM MST TUE MAR 3 2015

THE LATEST UPPER WAVE AND ITS LOWER LEVEL FRONT ARE IMPACTING THE
FORECAST AREA LATE THIS AFTERNOON AS THEY APPROACH FROM THE
NORTHWEST. INSTABILITY SHOWERS DEVELOPED LATE THIS MORNING AND ARE
EXPECTED TO CONTINUE INTO THE EVENING AT LEAST...AND LONGER OVER
THE NORTHEAST HALF. THIS SURFACE FRONT IS NOT AS DISTINCTIVE AS
THE ONE YESTERDAY...BUT MUCH COOLER AIR WILL FILTER INTO THE AREA
OVERNIGHT. BY 12Z WED MORNING 700 MB TEMPERATURES WILL RANGE FROM
-10C/SOUTH TO -17C/NORTH...WITH -27C/SOUTH TO -32C/NORTH AT
500MB. THE UPPER TROUGH AXIS WILL ALSO MOVE ACROSS THE AREA
EXITING BY DAYBREAK. IT APPEARS THAT THE NORTHWEST FLOW BEHIND
THIS TROUGH WILL BE SIGNIFICANTLY DRIER THAN WHAT WE HAVE SEEN
RECENTLY...SO A MARKED DOWNTURN IN SNOW IS EXPECTED LATE TONIGHT
INTO EARLY WEDNESDAY. FOR TONIGHT...HAVE GONE AHEAD AND EXTENDED
THE WARNINGS FOR THE CENTRAL MOUNTAINS AS SNOW WILL CONTINUE AHEAD
OF THE TROUGH AXIS...WITH SOME HEAVY SHOWERS THIS EVENING. THIS
WAVE STAYS STRONGEST AND MORE PROLONGED OVER THE NORTH...WITH THE
BETTER ACTIVITY SHORTER FOR SOUTHERN EDGE OF THE FORECAST AREA.
THEREFORE WILL NOT EXTEND THE WARNINGS FOR THE SOUTHERN MOUNTAINS.

ON WEDNESDAY WE WILL FINALLY SEE THE END OF THIS LONG DURATION
WINTER STORM. HOWEVER TEMPERATURES WILL REMAIN BELOW NORMAL AND
SOME SHOWERS WILL PERSIST OVER THE MOUNTAINS THROUGH THE
AFTERNOON...LINGERING LONGEST ALONG THE CONTINENTAL DIVIDE. THEN
DUE TO THE MUCH DRIER AND STILL COLD AIR MASS...NIGHTTIME LOWS
WED NIGHT WILL PLUMMET...WITH SOME BELOW ZERO READINGS.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 401 PM MST TUE MAR 3 2015

THE NERN PACIFIC RIDGE EXPANDS INLAND AS THE UPPER TROUGH SHIFTS
EASTWARD...WITH THE RIDGE AXIS ENDING UP ALONG THE WEST COAST. THE
EXITING TROUGH IS EXPECTED TO LEAVE AN AREA OF LOWER PRESSURE OVER
AZ/NM/NRN BAJA HOWEVER...WHICH THEN PERSISTS THROUGH THE WEEKEND.
THE 12Z CANADIAN AND ECMWF MODELS EVEN TRY TO FORM A WEAK REX BLOCK
ALONG THE COAST BUT KEEP THE UPPER LOW LITTLE TOO FAR EAST.
NEVERTHELESS...LOOKS LIKE SPLIT FLOW DEVELOPS OFF THE WEST COAST
WITH GENERALLY NW FLOW ACROSS OUR AREA DOWNSTREAM OF THE UPPER
RIDGE. AN EMBEDDED SHORTWAVE TROUGH DIVES SOUTHEAST ACROSS CO ON
THU BUT CARRIES LITTLE MOISTURE. SHORTWAVE TROUGHS ARE ALSO SHOWN
PASSING SATURDAY AND ABOUT MONDAY BUT AGAIN WITH QUITE LIMITED
MOISTURE. OVERALL ALL...LOOKING GENERALLY DRY THU-MON. MODELS SHOW
RIDGE THEN BREAKING DOWN MON NIGHT AND TUESDAY AS A MORE
SUBSTANTIAL PACIFIC TROUGH WORKS ACROSS THE GREAT BASIN.

AS STATED IN AN EARLIER DISCUSSION...COLD TEMPS APPEAR IN STORE THU
MORNING AND AGAIN THURSDAY NIGHT/FRIDAY MORNING. MOSTLY CLEAR SKIES
AND DRIER AIR WILL PROMOTE NIGHTTIME RADIATIONAL COOLING. SURFACE
INVERSIONS WILL LIMIT MIXING IN THE VALLEYS AND WENT ON THE COLDER
END OF TEMP GUIDANCE FOR HIGHS THURSDAY AND FRIDAY. TEMPS WILL
CONTINUE TO MODERATE THIS WEEKEND RETURNING TO NEAR NORMAL BY
SUNDAY...AND EVENING WARMING A BIT ABOVE NORMAL MONDAY AND
TUESDAY.

&&

.AVIATION...(FOR THE 00Z TAFS THROUGH 00Z WEDNESDAY EVENING)
ISSUED AT 401 PM MST TUE MAR 3 2015

AN UPPER LEVEL DISTURBANCE WILL CONTINUE TO SWEEP SLOWLY EASTWARD
OVER THE REGION THROUGH LATE WEDNESDAY MORNING. SNOW SHOWERS
ASSOCIATED WITH THIS DISTURBANCE WILL CONTINUE TO IMPACT AREAS
EAST AND NORTH OF A KDWX-KCNY-K4BL-KDRO-KPSO LINE THIS EVENING. AS
A RESULT...EXPECT WIDESPREAD MOUNTAIN OBSCURATION THROUGH 07Z/WED
WITH 50 TO 70 PERCENT PROBABILITY FOR IFR CONDITIONS IN SNOW
SHOWERS AT AIRFIELDS DELINEATED PREVIOUSLY.

FROM 07Z TO 12Z...SNOW SHOWERS WILL FAVOR THE CENTRAL AND
NORTHWEST SAN JUAN MOUNTAINS OF COLORADO WITH MOUNTAIN
OBSCURATIONS PREVALENT. TAF SITES KEGE...KASE...KTEX...AND
POSSIBLY KMTJ CONTINUE TO FACE GOOD CHANCES FOR PERIODS OF IFR
CIGS AND/OR VSBY IN SNOW THROUGH SUNRISE. ELSEWHERE VFR CONDITIONS
WILL BE THE RULE. EXPECT SNOW SHOWERS TO DECREASE OVER THE
COLORADO MOUNTAINS THROUGH THE DAY ON WEDNESDAY WITH LITTLE CHANCE
THAT SHOWER ACTIVITY TO SPILL OVER ADJACENT AIRPORTS.


&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...WINTER STORM WARNING UNTIL 5 AM MST WEDNESDAY FOR COZ009-010-012.

     WINTER STORM WARNING UNTIL MIDNIGHT MST TONIGHT FOR COZ018.

     WINTER STORM WARNING UNTIL 9 PM MST THIS EVENING FOR COZ002-017-
     019.

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

UT...NONE.

&&

$$

UPDATE...NL
SHORT TERM...EH
LONG TERM...JAD
AVIATION...NL