FXUS65 KBOU 291327
AFDBOU

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE DENVER CO
627 AM MST SUN NOV 29 2009

UPDATED AVIATION SECTION

.SHORT TERM...VERY LIGHT SNOW/FLURRY BAND THAT DEVELOPED LAST 
EVENING IN THE ESTES PARK-GREELEY CORRIDOR HAS PRETTY MUCH 
DISSIPATED EARLY THIS MORNING AS IT MOVED TOWARD DENVER.  DONT SEE 
MUCH MORE THAN A FEW FLURRIES POSSIBLE EARLY THIS MORNING SOUTH OF 
THE I-70 CORRIDOR AS DRIER AIR CONTINUES TO PUSH SOUTHWARD.  SOME 
WEAK SUBSIDENCE NOTED AS WELL...SO SKIES SHOULD BE CLEARING LATER 
THIS MORNING AS STRATUS BURNS OFF.  HIGHS TODAY WILL BE CAPABLE OF 
REACHING THE MID 40S ACROSS THE PLAINS PER FORECAST SOUNDINGS AND 
MOSTLY SUNNY SKIES THIS AFTERNOON.

MAINLY CLEAR SKIES AND LIGHT WINDS WILL ALLOW FOR GOOD RADIATIONAL 
COOLING TONIGHT.

.LONG TERM...NOT MANY CHANGES TO MAKE TO THE FORECAST PACKAGE THIS 
TIME AROUND.  INITIALLY WE WILL BE UNDER THE DRY AND SUBSIDENT 
REGION IN THE DEFORMATION AREA NORTH OF A CUTOFF LOW OVER NORTHERN 
MEXICO.  WINDS ALOFT WILL BE WEAK AND MOSTLY SUNNY WEATHER WILL BE 
THE RESULT.  EVENTUALLY THE UPPER LOW WILL EJECT ACROSS THE 
SOUTHEAST U.S. AND THE FLOW PATTERN OVER THE WESTERN U.S. WILL 
TRANSITION TO HIGHER AMPLITUDE...ACCORDING TO THE GFS AND ECMWF.  
THE TWO MODELS HAVE DIFFERENT TIMING AND DETAIL DIFFERENCES BEYOND 
72 HOURS...MAKING IT DIFFICULT TO CHOOSE ONE MODEL OVER THE OTHER.  
THE PROGRESSION OF CUTOFF LOWS ALWAYS PRESENTS PROBLEMS FOR THE 
MODELS...SO THIS ONE IS PROBABLY NO DIFFERENT.  IN THIS CASE...THE 
GFS AND ECMWF MOVE THE UPPER LOW OVER THE GULF COAST BY WEDNESDAY 
NIGHT AND THURSDAY...ALLOWING A STRONG RIDGE TO BUILD OVER THE WEST 
COAST.  AS THIS OCCURS...COLORADO WILL COME UNDER NORTHWESTERLY FLOW 
ALOFT AND BE OPEN TO COOLER AIR AT THE SURFACE MOVING OUT OF 
CANADA.  UNDER THE NORTHWESTERLY FLOW SOME BANDED PRECIPITATION MAY 
BE POSSIBLE AT TIMES...BUT UNDER THESE CIRCUMSTANCES...WHERE THE 
HEMISPHERIC FLOW PATTERN IS GETTING READY TO GO THROUGH QUITE A 
TRANSFORMATION...IT IS HARD TO PLACE MUCH DETAIL IN ANY GIVEN 
FORECAST PERIOD.  WE WILL NEED TO WAIT AND SEE HOW THE CUTOFF LOW 
EVOLVES AND EVENTUALLY EJECTS EASTWARD...AND WILL ALSO NEED TO KEEP 
AN EYE ON HOW MUCH COLD AIR DEVELOPS OVER NORTHERN CANADA OVER THE 
NEXT WEEK.  COOLER TEMPERATURES AND A SLIGHT CHANCE OF SNOW DURING 
THE SECOND HALF OF THE WEEK WILL BE SUFFICIENT FOR NOW.

&&

.AVIATION...STRATUS DECK IS ALREADY ERODING QUICKLY FROM THE NORTH 
EARLY THIS MORNING AS DRIER AND MORE SUBSIDENT AIR SPREADS 
SOUTHWARD.  THIS HAS ALLOWED PATCHY DENSE GROUND FOG TO DEVELOP IN 
LOW LYING AREAS NORTH OF DIA...BUT ENOUGH DRAINAGE AT DIA SHOULD 
PREVAIL TO KEEP FOG THREAT JUST NORTH OF THE AIRPORT.  OTHERWISE 
VISUAL LANDING CONDITIONS WILL PREVAIL THROUGH TONIGHT.  LIGHT 
SOUTHERLY WINDS THIS MORNING EXPECTED TO TREND MORE EAST/SOUTHEAST 
BY AFTERNOON WITH WEAK ANTICYCLONE DEVELOPING.  THEN TYPICAL 
SOUTH/SOUTHWEST DRAINAGE WINDS TONIGHT.

&&

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

$$

BARJENBRUCH/KDRBY