FXUS65 KBOU 012200
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER CO
300 PM MST TUE DEC 01 2009

.SHORT TERM...MODELS IN PRETTY GOOD AGREEMENT ON THE PATTERN THROUGH 
WEDNESDAY. THE MAIN DIFFERENCE IS THE MOISTURE AS THE NAM IS DRIER. 
IT GIVES LOWER POPS AND SNOWFALL AMOUNTS WITH ONLY 1-2 INCHES AROUND 
DENVER. OTHER MODEL GUIDANCE HAS A BIT MORE MOISTURE...AND THE NAM 
APPEARS TO BE UNDERDOING WHAT IS HAPPENING NOW UPSTREAM. NICE 
PRECIPITATION SHIELD WILL SAG OVER THE AREA LATE TONIGHT AND EARLY 
WEDNESDAY. FAIRLY GOOD AGREEMENT ON THE MAXIMUM LIFT COMING OVER THE 
NORTHERN MOUNTAINS TOWARD DENVER AROUND SUNRISE. NOTHING GOING ON 
ABOVE ABOUT 600 MB...BUT BELOW THIS IT IS MOIST AND STABILITY IS 
LOW. ALSO DECENT TEMPERATURES FOR DENDRITE GROWTH...SO WE SHOULD 
MAKE THE MOST OF THE SHALLOW MOISTURE. UPPED SNOW AMOUNTS A LITTLE 
TO FOCUS ON THAT AREA AND TIMEFRAME. LOWERED TEMPS JUST A COUPLE OF 
DEGREES BUT SOMEWHAT SKEPTICAL OF ANY TEMPERATURE RECOVERY IN DENVER 
AT ALL TOMORROW. IN THE NORTHEAST THERE WILL LIKELY BE SOME THINNING 
OF THE CLOUDS AND POSSIBLY EVEN CLEARING THAT COULD KEEP SOME HEAT 
IN UNTIL SUNSET.

.LONG TERM...FOR WEDNESDAY NIGHT AND THURSDAY...A LONG WAVE TROUGH 
WILL BE CENTERED FM THE UPPER MIDWEST/GREAT LAKES REGIONS INTO 
CANADA.  OVER CO...A MDT TO STR NWLY FLOW ALOFT WILL BE IN PLACE.  
ANOTHER CANADIEN COLD FRONT IS PROGGED TO PUSH THROUGH THE CWFA LATE 
WEDNESDAY NIGHT INTO FRIDAY MORNING...AS A SHORT WAVE CYCLES 
SOUTHWARD INTO THE STATE.  SPATIAL CROSS-SECTIONS SHOW MOST FVBL 
COMBINATION OF UPSLOPE/QG ASCENT (ALBEIT WEAK) WILL OCCUR LATE 
THURSDAY MORNING INTO THE AFTN.  WL GO AHD AN UP POPS TO A CHC 
CATEGORY FOR LOCATIONS IN NEAR THE FOOTHILLS AND PALMER DIVIDE ON 
THURSDAY.  PROJECTED SNOWFALL WL AGAIN BE LIGHT...MAYBE AN INCH OR 
LESS. GUIDANCE FOR THURSDAY/S HIGHS ALSO COLDER THAN PRVSLY FCST SO 
I LOWERED THOSE AS WELL.  A COLD NORTHERLY FLOW IS PROGGED TO 
CONTINUE OVER EASTERN COLORADO FOR THURSDAY NIGHT AND FRIDAY.  
TEMPERATURE ARE EXPECTED TO MODIFY SOMEWHAT FOR FRIDAY/SATURDAY.    
PATTERN WL BE DRY SO NO SNOW EXPECTED. MDLS STILL NOT HANDLING THE 
PATTERN VERY WELL FOR THE WEEKEND.  LATEST RUNS SHOW MORE OF A DRY 
ZONAL FLOW FOR SATURDAY WITH AN ELONGATED SPLITTING TROF EXTENDING 
FM NEAR HUDSON BAY TO OVER THE SNAKE RIVER VALLEY OF SRN IDAHO BY 
00Z SUNDAY.  MSTR IS PROGGED TO GRADUALLY INCREASE WITH LIGHT SNOW 
DEVELOPING IN THE MTNS BY SUNDAY/MONDAY.  TOO MUCH UNCERTAINTY TO 
TINKER WITH THE GRIDS TOO MUCH BEYOND FRIDAY SO WL LEAVE THINGS AS 
THEY WERE UNTIL THE MDLS CAN MAKE NICE AND ACHIEVE SOME SORT OF 
GENERAL CONSENSUS.      

&&

.AVIATION...SNOW IS EXPECTED TO ARRIVE IN DENVER BETWEEN 02Z AND 
04Z. IT WILL BE PRETTY LIGHT AT FIRST...THEN MORE SIGNIFICANT AFTER 
MIDNIGHT THROUGH WEDNESDAY MORNING. MVFR CONDITIONS SHOULD DEVELOP 
EARLY THIS EVENING...WITH IFR/LIFR CONDITIONS AFTER MIDNIGHT THROUGH 
MUCH OF THE DAY WEDNESDAY. THE MAIN ISSUE WILL BE LOW CEILINGS THAT 
MAY PERSIST EVEN AS THE SNOW DIMINISHES. WINDS SHOULD DECREASE 
BEFORE THE SNOW DEVELOPS...THOUGH THERE STILL MAY BE SOME DRIFTING 
DUE TO THE LOW DENSITY OF THE SNOW. BEST GUESS TOTAL SNOWFALL IS 2-3 
INCHES AT DIA AND 3-5 INCHES AT APA AND BJC.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...NONE. 

$$

GIMMESTAD/COOPER