FXUS65 KBOU 102128
AFDBOU
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER CO
227 PM MST THU DEC 10 2009
.SHORT TERM...DRY AND MODERATE WESTERLY FLOW ALOFT WILL REMAIN IN
PLACE THROUGH FRIDAY...WITH THE GRADUAL WARMUP CONTINUING. THE
CROSS MOUNTAIN FLOW WILL WEAKEN TO ABOUT 30 KNOTS...BUT A FAIR
MOUNTAIN TOP STABLE LAYER SHOULD KEEP A MOUNTAIN WAVE AND GUSTY
WINDS GOING ACROSS THE FRONT RANGE MOUNTAINS AND FOOTHILLS...WITH
WIND GUSTS INTO THE 40-50 MPH RANGE IN THE WIND PRONE AREAS. THERE
IS ABOUT 6C IN WARMING OVER THE LAST 24 HOURS SO THAT WILL BRING
HIGH TEMPS UP SEVERAL MORE DEGREES FRIDAY DESPITE THE INCREASE IN
HIGH CLOUDS. LOW TEMPERATURES WILL AGAIN BE VERY COLD WITH MAINLY
CLEAR SKIES AND GENERALLY LIGHT WINDS TONIGHT. THE EXCEPTION OF
COURSE WILL BE IN THE FRONT RANGE MOUNTAINS AND FOOTHILLS WHERE
BREEZY CONDITIONS AND WARM ADVECTION WILL SUPPORT A...SOMEWHAT...
RELATIVELY WARMER NIGHT BUT STILL VERY COLD WIND CHILLS OF ZERO TO
15 BELOW.
.LONG TERM...MAINLY WESTERLY QUASI-ZONAL FLOW WILL REMAIN OVER THE
STATE THROUGH AT LEAST THE WEEKEND WITH A FEW WEAK DISTURBANCES.
THIS PATTERN WILL RESULT IN WARMER CONDITIONS FOR THE AREA AS
HEIGHTS INCREASE AND PUSH THE ARCTIC AIRMASS BACK NORTH. THIS
PATTERN WILL ALSO BRING A CHANCE OF SNOW TO THE MOUNTAINS AND KEEP
THE PLAINS DRY WITH A LEE SURFACE TROUGH REMAINING IN PLACE. THE
WESTERLY FLOW ALOFT COMBINED WITH LOW LEVEL PRESSURE GRADIENTS WILL
KEEP STRONG GUSTY WINDS OVER THE MOUNTAINS AND DOWN THE FOOTHILLS.
TEMPERATURES ARE EXPECTED TO REACH INTO THE UPPER 40S BY SATURDAY
AND SUNDAY ON THE PLAINS. A WEAK TROUGH WILL ARRIVE FRIDAY NIGHT
INTO SATURDAY WITH A SLIGHTLY STRONGER DISTURBANCE AHEAD OF THE NEXT
TROUGH ARRIVING SUNDAY. HOWEVER SLIGHTLY SOUTHWEST FLOW ALOFT FOR
BOTH DISTURBANCES WILL KEEP SNOW AMOUNTS VERY LIGHT...KEEPING ANY
ACCUMULATIONS MAINLY ALONG AND WEST OF THE CONTINENTAL DIVIDE. THE
MOUNTAINS OF WESTERN JACKSON COUNTY WILL HAVE THE BEST CHANCE FOR
ACCUMULATIONS. AREAS EAST OF THE DIVIDE ARE EXPECTED TO STAY DRY
THROUGH THE MIDDLE PART OF NEXT WEEK DUE TO THE DOWNSLOPE FLOW. THE
NEXT TROUGH WILL DRAG ARCTIC AIR SOUTH AGAIN...WITH THE TROUGH
MOVING OVER COLORADO ON MONDAY. TEMPERATURES ARE EXPECTED TO DROP
INTO THE MID 30S...BY NO MEANS AS COLD AS WHAT WE HAVE EXPERIENCED
FOR THE LAST COUPLE DAYS. THE POSSIBILITY OF LIGHT SNOW REMAINS
MONDAY IF WINDS TURN NORTHERLY...WILL KEEP THE 10 POPS FOR THIS
SYSTEM BUT EXPECT THINGS TO BE DRY. WESTERLY FLOW ALOFT WEAKENS MID
NEXT WEEK AS AN UPPER LEVEL RIDGE DEVELOPS. THE LATEST GFS IS
HINTING AT A CLIPPER SLIDING SOUTH ON WEDNESDAY AND
THURSDAY...HOWEVER THIS SEEMS TO BE THE OUTLIER WITH THE ECMWF
SHOWING THE RIDGE CONTINUING TO BUILD THEREFORE WILL CONTINUE WITH A
WARMING AND DRYING TREND. THIS WILL LIKELY DECREASE OR END ANY
THREAT OF SNOW FOR THE MOUNTAINS.
&&
.AVIATION...VISUAL LANDING CONDITIONS WILL PERSIST THROUGH FRIDAY...
WITH ONLY AN INCREASE IN HIGH CLOUDS ABOVE 20 THOUSAND FEET ON
FRIDAY. WEAK SURFACE BOUNDARY WITH A SHIFT TO NORTHWEST WINDS WAS
CURRENTLY LOCATED ON THE NORTHWEST SIDE OF KDEN...TRYING TO MAKE
SLOW SOUTHEAST PROGRESS SO WILL HAVE TO WATCH THIS. OTHERWISE
SOUTH/SOUTHWEST WINDS WILL PREVAIL FROM TONIGHT THROUGH MOST OF
FRIDAY. AT KBJC...OCCASIONAL GUSTY WEST WINDS EXPECTED WITH GUSTS
TO 25-30 KNOTS POSSIBLE FROM LATE EVENING THROUGH FRIDAY MORNING
&&
.BOU WATCHES/WARNINGS/ADVISORIES...NONE.
$$
BARJENBRUCH/KRIEDERMAN