FXUS65 KBOU 241056
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER CO
355 AM MST THU DEC 24 2009

.SHORT TERM...THE BACK EDGE OF LIGHT SNOW HAD SHIFTED TO A LINE FROM 
NEAR FORT MORGAN TO DEER TRAIL AS OF 330 AM...AND THIS WILL CONTINUE 
TO PUSH EASTWARD.  THE 400 MB POT VORT LOBE LINED UP NICELY WITH 
THIS FEATURE...WHICH SHOULD MAKE IT TO THE EASTERN BORDER BY 
15-16Z.  JUST A COUPLE OF FLURRIES LEFT BEHIND THIS WITH PARTIAL 
CLEARING NOTED ON OBS TO THE NORTHWEST.  IN THE MOUNTAINS...THE 
OROGRAPHICS HAD IMPROVED..BUT MOISTURE WAS VERY SHALLOW SO SNOW 
SHOWERS THERE WILL ALSO BE DECREASING THIS MORNING.  OTHERWISE WE 
SHOULD SEE PLENTY OF SUNSHINE TODAY WITH DRIER NORTHWEST FLOW ALOFT 
ACROSS THE FORECAST AREA.  THE WINDS WILL STILL BE AN ISSUE OVER THE 
NORTHEAST PLAINS...BUT THE GRADIENT IS NOT AS STRONG TODAY SINCE 
STORM IN THE CENTRAL U.S. DOES NOT REALLY GET WOUND UP UNTIL 
TONIGHT.  AS A RESULT...WE SHOULD SEE A LULL IN THE WINDS LATER 
TODAY INTO THIS EVENING BEFORE WINDS PICK UP AGAIN LATER IN THE 
NIGHT.  HAVE OPTED TO KEEP THE WINTER WEATHER ADVISORY FOR THE 
NORTHEASTERN CORNER SINCE SOME RURAL ROADS WERE CLOSED OUT THERE AND 
SOME BLOWING AND DRIFTING WAS STILL A PROBLEM.  HOWEVER...AS WINDS 
RELAX LATER TODAY WE MAY BE ABLE TO ALLOW THIS TO EXPIRE EARLY.

THE MOISTURE...ALBEIT LIMITED...ASSOCIATED WITH THE UPPER LOW 
DROPPING INTO WESTERN NEBRASKA TONIGHT SHOULD BE JUST ENOUGH TO 
BRING A FEW SNOW SHOWERS BACK INTO THE MOUNTAINS AND ACROSS THE 
NORTHEASTERN PLAINS LATER TONIGHT.  

TEMPERATURES WILL REMAIN QUITE COLD TODAY AND SHOULD STRUGGLE TO 
REACH 20F ACROSS THE PLAINS DESPITE THE SUNSHINE.

.LONG TERM...THE LATEST NAM...GFS AND ECMWF RUNS ALL HAD SIMILAR 
SOLUTIONS AT 500 MB THROUGH ALMOST 48 HOURS...LENDING SOME CREDENCE 
TO THE IDEA THAT MOISTURE IS GOING TO BE WRAPPING AROUND THE 
NORTHWEST SIDE OF THE UPPER CIRCULATION...WELL INTO NORTHEAST 
COLORADO.  Q-G DIAGNOSTICS PACKAGE SHOWS SOME RISING MOTIONS NEAR 
THE SURFACE...RELATED TO THE NORTHERLY SURFACE FLOW AROUND THE 
MATURING CENTRAL PLAINS CYCLONE.  AT HIGHER ELEVATIONS...Q-G MOTIONS 
ARE ALL SUBSIDENT OVER COLORADO.  HAVE INCREASED THE POPS OVER THE 
PLAINS ON CHRISTMAS DAY AND CHRISTMAS NIGHT TO 20-40 PERCENT WITH 
THE HIGHEST POPS IN THE NORTHEAST CORNER.  OVER THE FOOTHILLS AND 
EAST OF THE CONTINENTAL DIVIDE...FLOW IS GOING TO BE NORTHWESTERLY 
AND DOWNSLOPING.  WEST OF THE DIVIDE...THE NORTHWESTERLY FLOW AND 
MOIST LOW LEVELS WILL GENERATE LIGHT OROGRAPHIC SNOW SHOWERS THROUGH 
CHRISTMAS DAY.  ACCUMULATIONS SHOULD BE LESS THAN A COUPLE INCHES.  

GETTING BACK TO THE PLAINS...IN ADDITION TO SOME LIGHT SNOW WHICH 
MAY MAKE IT AS FAR SOUTHWEST AS THE AIRPORT...SURFACE WINDS ARE 
EXPECTED TO REALLY INCREASE.  FOR THE TIME BEING WILL STICK WITH THE 
SUSTAINED SPEEDS IN THE MID AND UPPER 20S FROM THE PREVIOUS FORECAST 
PACKAGE.  DEPENDING ON WHAT LATER MODEL RUNS SHOW...A WINTER WEATHER 
ADVISORY FOR SNOW AND BLOWING SNOW MAY BE NECESSARY FOR CHRISTMAS 
DAY AND CHRISTMAS NIGHT.  THE NEWLY FALLEN SNOW IS GOING TO BE VERY 
PRONE TO BLOWING AND DRIFTING AS THE WINDS PICK UP.  SINCE IT IS 
PRESENTLY IN THE THIRD AND FOURTH PERIOD...WILL NOT ISSUE ANY 
HIGHLIGHTS.  THE REST OF THE FORECAST PACKAGE REMAINS UNCHANGED AS 
SPLIT FLOW OVER THE GREAT BASIN AND A BLOCKING RIDGE ALOFT OVER THE 
NORTHERN ROCKIES WILL LEAVE COLORADO WITH VERY LITTLE FLOW AND 
DYNAMIC FORCING FOR A FEW DAYS.  TEMPERATURES WILL GRADUALLY 
MODERATE...BUT SHOULD REMAIN BELOW NORMAL VALUES THROUGH THE 
MAJORITY OF NEXT WEEK.  

&&

.AVIATION...CLOUDS WERE BREAKING UP WITH VISUAL LANDING CONDITIONS 
DEVELOPING EARLY THIS MORNING.  THE VISUAL LANDING CONDITIONS WILL 
PREVAIL THROUGH TONIGHT WITH LIGHT SURFACE WINDS.  STRONGER WINDS 
EXPECTED FRIDAY.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...WINTER WEATHER ADVISORY FOR THE
    NORTHEASTERN CORNER OF COLORADO UNTIL 5 PM MST TODAY...ZONES 
    48>51.

$$

BARJENBRUCH/KDRBY