FXUS65 KBOU 281105
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER CO
400 AM MST SAT NOV 28 2009

.SHORT TERM...COLD FRONT WAS MOVING ACROSS EASTERN WYOMING EARLY 
THIS MORNING AND WILL MOVE ACROSS NORTHEAST COLORADO BY MID 
MORNING.  THIS WILL USHER IN COOLER AIR AND AN INCREASE IN LOW LEVEL 
MOISTURE.  MEANWHILE...CLOUDS WILL GRADUALLY THICKEN THIS MORNING AS 
BAND OF HIGH CLOUDS SPREAD NORTHEAST ACROSS COLORADO.  TEMPERATURES 
WILL BE NOTICEABLY COOLER TODAY BEHIND THE FRONT...BUT STILL NEAR OR 
SLIGHTLY ABOVE NORMAL FOR THIS TIME OF YEAR.  BY LATE THIS 
AFTERNOON...MOISTURE DEEPENS JUST ENOUGH TO BRING A SLIGHT CHANCE OF 
SNOW TO THE MOUNTAINS.

BY TONIGHT...THE ODDS OF ANY MEASURABLE SNOWFALL APPEAR TO BE 
DECREASING AS MOISTURE...LIFT...AND UPSLOPE COMPONENT ARE ALL QUITE 
LIMITED.  THE Q-G VERTICAL MOTION FIELDS SHOW ONLY MINIMAL LIFT AT 
BEST...AND UPSLOPE BY THIS EVENING IS ADVERTISED TO ONLY BE ABOUT 
5-10 KNOTS AND BELOW 10 THOUSAND FEET.  HAVE THEREFORE CUT THE 
CHANCE OF MEASURABLE SNOWFALL TONIGHT...WITH MAINLY FLURRIES 
EXPECTED OVER THE PLAINS AND ONLY UP TO AN INCH POSSIBLE IN THE 
MOUNTAINS AND FOOTHILLS.

.LONG TERM...AS THE PRESENT WEATHER SYSTEM DIVES TOO FAR SOUTH TO 
BRING MUCH WEATHER TO NORTHEAST COLORADO...WE ARE LEFT UNDER THE 
DEFORMATION ZONE ON THE NORTH SIDE OF THE UPPER LOW.  FLOW WILL BE 
WEAK AND DYNAMIC LIFT WILL ALSO BE WANING.  AFTER SOME LINGERING 
SNOW SHOWERS SUNDAY MORNING THE NEXT FEW DAYS SHOULD BE DRY WITH 
TEMPERATURES CLOSE TO CLIMATOLOGY.  THE COLD AIR THAT MOVES INTO THE 
REGION LATER TODAY WILL HANG AROUND FOR AWHILE AS THE WEAK FLOW 
PATTERN ALOFT WILL DO LITTLE TO MOVE ANY WARMER OR COOLER AIR INTO 
THE AREA.  FOR THE LATTER HALF OF THE WEEK IT APPEARS THAT WE WILL 
GET INTO A LITTLE STRONGER NORTHWESTERLY FLOW ALOFT...BUT THE MODELS 
ARE NOW SHYING AWAY FROM ANY STRONG INTRUSION OF COLDER AIR.  FOR 
WED-FRI I WARMED UP THE TEMPERATURES A CATEGORY OR SO... BUT AM 
STILL SOME 5-10 DEGREES COOLER THAN THE LATEST MOS GUIDANCE.  DID 
NOT MAKE ANY CHANGES TO THE PRECIPITATION FORECASTS SINCE IT IS HARD 
TO TELL RIGHT NOW HOW MUCH MOISTURE WILL BE COMING DOWN THE BACK 
SIDE OF THE PACIFIC NORTHWEST UPPER RIDGE.   

&&

.AVIATION...A COLD FRONT AND SUSTAINED NORTH-NORTHEAST WINDS AROUND 
15 KNOTS ARE STILL ON TRACK TO MOVE ACROSS THE FRONT RANGE AIRPORTS 
IN THE 16Z-17Z TIME PERIOD.  MOISTURE IS NOT ALL THAT IMPRESSIVE 
BEHIND THE FRONT...SO TIMING DEVELOPMENT OF LOWER STRATUS DECK AND 
ILS APPROACHES IS DIFFICULT.  AT THIS POINT...MOST LIKELY SCENARIO 
IS FOR STRATUS TO DEVELOP IN THE 23Z-02Z TIME FRAME AS BOUNDARY 
LAYER COOLS AND MOISTENS.  HEIGHT OF STRATUS DECK WOULD BE AROUND 
THE 2000-3000 FOOT LEVEL...WITH POTENTIAL FOR 1000-1500 FOOT RANGE 
AFTER 04Z TONIGHT.  THREAT OF SNOW APPEARS TO BE DECREASING AS 
AIRMASS IS NOT VERY MOIST AND UPSLOPE WEAKENS THROUGH THE NIGHT...SO 
VCSH IS BEST CATEGORY AFTER 04Z.

&&

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

$$

BARJENBRUCH/KDRBY