000
FXUS65 KGJT 061107
AFDGJT
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
407 AM MST TUE JAN 6 2009
...PERSISTENT SNOW AND BLOWING SNOW EXPECTED OVER MOST MOUNTAINS
TODAY THROUGH WEDNESDAY...
.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT...
COMPLEX STORM CONTINUES...BUFFETING THE NORTHERN MOUNTAINS
IN A MOIST NW FLOW THROUGH THESE PERIODS.
CURRENTLY: -27C COLD CORE AND ASSOCIATED DEFORMATION ZONE PRODUCED
WIDESPREAD SNOWFALL OVER THE CENTRAL CWA OVERNIGHT. THIS
FEATURE IS WORKING OVER THE CONTINENTAL DIVIDE THIS MORNING
INCREASING SNOWFALL IN THE PARK/FLATTOPS/GORE/ELK RANGES. MORNING
TEMPERATURES ARE 30 DEGREES WARMER THAN 24HRS AGO...UP TO A BALMY 14
ABOVE IN CRAIG. IN THE CENTRAL MOUNTAINS...SNOTELS AND RADAR
INDICATE THAT SIGNIFICANT SNOWFALL MAY HAVE ACCUMULATED ON A LINE
FROM MEEKER TO OURAY THROUGH THE ROAN PLATEAU...GRAND MESA...AND NW
SAN JUAN MTNS. BUT WITH LITTLE ADDITIONAL SNOWFALL EXPECTED TODAY
WILL HOLD OFF ON ADVISORIES THERE. SKIERS AT POWDERHORN AND
TELLURIDE MAY HAVE SOME POWDER SHOTS TO ENJOY TODAY.
TODAY: FORECAST SOUNDING OVER THE PARK RANGE INDICATES THE MTN
TOP LAYER IS SATURATED AT -14C AND MARGINALLY UNSTABLE. SO WE MAY
SEE SOME LOCALLY DEEP FLUFFY SNOW ACCUMULATE IN THE PARK TODAY.
FURTHER WEST...INCREASING STABILITY IS DIMINISHING SHOWERS AHEAD OF
WARM ADVECTION CLOUDS IN NORTHERN UTAH. SO HAVE DECREASED POPS IN NE
UTAH/NW CO FOR TODAY AND ONLY LIGHT ACCUMULATIONS EXPECTED IN THE
WESTERN MTNS.
TONIGHT-WEDNESDAY: ALONG WITH THE STRONG MOIST WARM ADVECTION...MTN
TOP/700-600MB WINDS INCREASE FROM 15-25KTS SUSTAINED TODAY TO 40-
50KTS. THE PARK RANGE WILL LIKELY SEE ITS BEST ACCUMULATIONS TONIGHT.
BUT SUCH STRONG WINDS AND RESULTING BLOWING SNOW JUSTIFY A WARNING
ACROSS THE PARK RANGE AND NEARBY MTN ADVISORIES. CLOUDS AND SHOWERS
APPEAR TO HAVE ERODED THE COLD POOL OVER THE YAMPA RIVER VALLEY...SO
CONFIDENCE FOR ADVISORY SNOW AMOUNTS IN STEAMBOAT LOWERED. THIS NEEDS
TO BE WATCHED BY THE DAY SHIFT.
WEDNESDAY NIGHT: GRADIENT WINDS SLACKEN AND MOISTURE DIMINISHES
QUICKLY AS A SHORTWAVE RIDGE APPROACHES FROM THE WEST.
.LONG TERM...THURSDAY THROUGH MONDAY...
A SHORTWAVE RIDGE WILL RESIDE OVER THE FORECAST AREA THURSDAY
PROVIDING DRY CONDITIONS. THE RIDGE WILL MOVE EAST THURSDAY NIGHT
WITH AN UPPER TROUGH MOVING IN BEHIND IT. MODELS HAVE SLOWED THIS
SYSTEM DOWN A LITTLE THE PAST COUPLE OF RUNS AND ARE STILL NOT
TOTALLY IN LINE WITH THEIR SOLUTIONS. THE MODELS HAVE TRENDED
TOWARD A SPLITTING OF THE TROUGH AS WELL WITH A CIRCULATION MOVING
SOUTH OF THE DESERT SOUTHWEST. LOW CONFIDENCE WITH THIS SYSTEM RIGHT
NOW SO KEPT THE TIMING GENERALLY THE SAME AS PREVIOUS FORECAST...
WITH THE BULK OF THE MOISTURE AND FORCING OCCURRING ON FRIDAY AND
LINGERING ACROSS THE SOUTH INTO SATURDAY. DRIER NORTHWEST WILL
PREVAIL LATE OVER THE WEEKEND INTO MONDAY WITH SOME LIGHT OROGRAPHIC
SNOWFALL OVER THE NORTHERN MOUNTAINS NEAR THE CONTINENTAL DIVIDE
POSSIBLE. NO MAJOR CHANGES TO THE TEMPERATURE FORECAST WITH VALLEY
INVERSIONS LIKELY TO KEEP LOW ELEVATION TEMPERATURES BELOW GUIDANCE
THROUGH MUCH OF THE PERIOD.
&&
.AVIATION...
WIDESPREAD MVFR AND IFR CIGS AND VSBYS WILL CONTINUE OVER THE
NORTHERN AND CENTRAL MOUNTAINS OF WESTERN COLORADO. SNOW IS EXPECTED
TO LOWER VSBYS IN KHDN...KASE AND KEGE WHILE KCAG AND KEEO WILL SEE
IMPROVING CONDITIONS THIS AFTERNOON. BUT CIGS LOWER ONCE AGAIN LATE
THIS AFTN AS ANOTHER SURGE OF MOISTURE WORKS IN FROM THE NORTHWEST.
MTN TOP WINDS WILL INCREASE TO AROUND 50KTS FOR MODERATE TO SEVERE
TURBULENCE ALONG AND EAST OF MTN RANGES. STRONG MTN WAVES WILL
OCCUR EAST OF THE CONTINENTAL DIVIDE TONIGHT AND WEDNESDAY.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
.CO...WINTER STORM WARNING FOR THE NORTHERN MOUNTAINS THROUGH
6 PM WEDNESDAY...ZONE 4.
WINTER WEATHER ADVISORY THROUGH 6 PM WEDNESDAY FOR THE
UPPER YAMPA RIVER VALLEY AND THE CENTRAL MOUNTAINS...
ZONE 5/10/13.
.UT...NONE.
$$
SHORT TERM.....JOE
LONG TERM......TAL
AVIATION.......JOE
