FXUS65 KGJT 011006
AFDGJT

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GRAND JUNCTION CO
306 AM MST TUE DEC 1 2009

.SHORT TERM...TODAY THROUGH WEDNESDAY NIGHT...

UPPER TROUGH WILL DIG SOUTHEAST ALONG THE ROCKIES AND WESTERN PLAINS
OVER THE NEXT 48 HRS. TROUGH IS CURRENTLY MOVING OUT OF SW CANADA
WITH THE ASSOCIATED COLD FRONT IN SRN MT. FRONT LOOKING PRETTY DRY
FROM A LACK OF PRECIP IN SFC OBS ACROSS MT AND SW CANADA. THE COLD
FRONT IS EXPECTED TO REACH NE UT/NW CO EARLY THIS EVENING AND
THEN SLOWLY CONTINUE SOUTH ACROSS THE FORECAST AREA TONIGHT AND WED.
700 MB N-NW OROGRAPHICS NOT IMPRESSIVE...AND MOISTURE LACKING WITH
700 MB SPECIFIC HUMIDITY BELOW 3 G/KG TONIGHT...AND LESS THAN 2 G/KG
BY WED EVE. MODEL QPF FOLLOWS SUIT WITH ONLY LIGHT PERCIP AMTS
FORECAST. BEST DYNAMIC AND FRONTOGENETIC FORCING SHOWN OVER NW CO
TONIGHT AND WEST-CENTRAL CO WED MORNING AND SHOULD BE ENOUGH TO
SQUEEZE OUT SOME SNOW FOR THE NRN AND CENTRAL MTNS. ACCUMULATIONS
WILL BE LIGHT HOWEVER...ON THE ORDER OF 1-3 INCHES MAINLY NEAR THE
DIVIDE. A FEW SNOW SHOWERS MAY ALSO OCCUR IN THE SAN JUAN MTNS LATE
TONIGHT AND WED...BUT BY AND LARGE...SE UT/SW CO WILL STAY DRY.
TROUGH WILL CONTINUE SINKING S ACROSS THE REGION WED NIGHT.

MOST NOTICEABLE WILL THE COLDER AIR ON WED. 700 MB TEMPS DROP TO
AROUND -15C TO -17C ACROSS THE NORTH AND CENTRAL AREAS BY WED EVE AS
THE COLDER AIR SPREADS OVER THE REGION. HIGH TEMPS WED WILL BE AS
MUCH AS 10 DEGS COLDER THAN TODAY...AND WED NIGHT LOOKS QUITE COLD
WITH LOW TEMPS IN THE SINGLE DIGITS OR TEENS FOR ALL BUT FAR SE UT.

.LONG TERM...THURSDAY THROUGH SUNDAY...

TROF AND ASSOD COLD FRONT WILL BE MOVING THRU CO AT START OF PERIOD
KICKING OFF SOME MTN SNOW SHOWERS...ESPECIALLY OVR CONTINENTAL
DIVIDE...THUR AFTN AND NIGHT.  QPF AMTS CONTINUE TO REMAIN LOW
HOWEVER AS RIDGE TO THE W CUTS OFF ANY PACIFIC MOISTURE THAT COULD
BE ENTRAINED IN SYSTEM.  COLDEST AIR OF THE SEASON WILL DROP DOWN
FROM THE N THUR NIGHT CAUSING TEMPS TO PLUMMET TO SUBZERO READINGS
ACROSS MUCH OF THE FORECAST AREA BY FRI MORNING.  HIGHS WILL REBOUND
TO 30S FOR VALLEYS AND 20S FOR MOST MTN REGIONS THROUGHOUT MOST OF
LONG TERM.

TRANSITORY RIDGE WILL SLIDE OVER AREA FRI AND SAT UNTIL ANOTHER COLD
FRONT DROPS DOWN FROM CANADA REINFORCING THE COLD AIRMASS ALREADY IN
PLACE SAT AFTN.  MODELS CONTINUE TO HIGHLIGHT PRECIP OVER NRN/CEN
MTNS WHERE FAVORABLE OROGRAPHIC LIFT AND NWLY FLOW WILL...ONCE
AGAIN...CAUSE SOME SNOWFALL THRU END OF LONG-TERM.  TRACK OF THIS
SYSTEM QUITE SIMILAR TO PREVIOUS FRONT SO LACK OF MOISTURE WILL
PRECLUDE MUCH SNOWFALL ACCUMULATION AS INDICATED BY LOW QPF AMTS.
LOOKING BEYOND SUNDAY SHOWS INTERESTING SCENARIO SHAPING UP FOR
EARLY NEXT WEEK BUT WAY TOO EARLY TO RELY ON MODEL DATA ESPECIALLY
AS SOLNS HAVE CHANGED SIGNIFICANTLY BTWN RUNS.

&&

.AVIATION...
VFR CONDITIONS WILL PREVAIL TODAY AHEAD OF A COLD FRONT APPROACHING
FROM THE N THIS AFTERNOON. THE COLD FRONT SHOULD REACH A KVEL-KHDN
LINE ABOUT 00Z-03Z WED...THEN SLOWLY MOVE SOUTH ACROSS THE AREA
TONIGHT THROUGH WED MORNING. CLOUDS WILL LOWER ACROSS THE N BETWEEN
00Z-06Z NEAR AND BEHIND THE FRONT AS MVFR/LOCALLY IFR CIGS DEVELOP IN
-SN ACROSS THE MTNS AROUND KSBS AND OVER THE FLATTOPS. THE LOWER CIGS
AND AREAS OF -SN WILL MOVE SOUTH ACROSS THE CENTRAL CO MTNS AFTER
06Z WED.

&&

.GJT WATCHES/WARNINGS/ADVISORIES...

CO...NONE.
UT...NONE.

&&

$$

SHORT TERM...JAD
LONG TERM....TGR
AVIATION.....JAD