FXUS65 KBOU 082135
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER CO
235 PM MST TUE DEC 8 2009

.SHORT TERM...THE UPPER LEVEL LOW ASSOCIATED WITH TODAYS SNOW IS 
CURRENTLY OVER EASTERN COLORADO AND CONTINUES TO LIFT NORTHEAST. 
BACK EDGE OF SNOW IS SLOWLY MOVING EAST AS WELL...ALREADY EAST OF 
THE DENVER INTERNATIONAL AIRPORT. SKIES ARE CLEARING ALONG THE 
FOOTHILLS AND METRO AREAS AS NORTHWESTERLY FLOW BEHIND THE STORM 
MOVES OVER THE MOUNTAINS AND DOWNSLOPES. NOT MUCH WARMING IS 
EXPECTED HOWEVER AS COLD AIR CONTINUES TO SLIDE SOUTH ON THE 
BACKSIDE OF THE LOW. THE SNOW IS EXPECTED TO CONTINUE ALONG AND EAST 
OF A LINE FROM KIMBALL NEBRASKA TO LIMON TONIGHT WITH DECREASING 
SNOWFALL AMOUNTS. COLD TEMPERATURES AND GUSTY NORTHERLY WINDS WILL 
CAUSE WIND CHILL TEMPERATURES TO DIP BETWEEN 18 AND 25 DEGREES BELOW 
ZERO OVER THE FAR EASTERN PLAINS...HENCE THE WIND CHILL ADVISORY FOR 
LINCOLN...ELBERT AND EASTERN DOUGLAS COUNTIES AND THE MENTION IN THE 
WINTER WEATHER ADVISORY OVER WASHINGTON...LOGAN...SEDGWICK AND 
PHILLIPS COUNTIES. THE WINDS ARE EXPECTED TO DIMINISH AROUND 
MIDNIGHT TONIGHT AS THE LOW MOVES FARTHER AWAY...ALLOWING THE WIND 
CHILL TEMPERATURES TO WARM UP A BIT. THESE WINDS WILL ALSO CAUSE 
VISIBILITY PROBLEMS AS THEY PICK UP THE FALLING AND RECENTLY FALLEN 
SNOW OVER THE PLAINS. THIS TOO WILL DIMINISH AROUND MIDNIGHT. THE 
FAVORED NORTHWEST FLOW ALOFT WILL KEEP SNOW FALLING OVER THE 
MOUNTAINS TONIGHT THROUGH WEDNESDAY. HAVE KEPT THE ADVISORY GOING 
FOR THE HIGH COUNTRY THROUGH WEDNESDAY MORNING AS MOISTURE IS QUITE 
SHALLOW AFTER THIS.  WILL HAVE TO REVISIT THIS TO SEE IF IT NEEDS TO 
BE EXTENDED. ANOTHER PROBLEM WILL BE WINDS OVER THE 
MOUNTAINS...GUSTS UP TO 60 MPH THROUGH THE HIGH PASSES. THIS WILL 
CREATE DANGEROUS DRIVING IN BLOWING SNOW IN THE RECENT DRY SNOWFALL. 
LOW TEMPERATURES TONIGHT WILL BE BELOW ZERO OVER ALL THE FORECAST 
AREA AS SKIES CLEAR AND COLD AIR CONTINUES TO SPREAD SOUTH ACROSS 
THE STATE. THE WARMEST READINGS WILL MOST LIKELY BE ALONG THE 
FOOTHILLS FROM THE SLIGHT DOWNSLOPING WEST TO NORTHWESTERLY 
WINDS...EXPECTED RIGHT AROUND ZERO. 

WEDNESDAY WILL BE MOSTLY CLEAR AND COLD OVER THE PLAINS WITH SNOW 
AND VERY GUSTY WINDS CONTINUING OVER THE MOUNTAINS. 

.LONG TERM...COLORADO WILL REMAIN UNDER A STRONG NORTHWEST FLOW 
PATTERN WED NIGHT AND THURSDAY BEFORE THE FLOW STARTS TO WEAKEN A 
BIT ON FRIDAY. THE MAIN CONCERN WILL BE THE STRONG WINDS IN THE 
MOUNTAINS AND HIGHER EAST SLOPES THROUGH THIS PERIOD. CROSS SECTIONS 
INDICATE STRONG CROSS BARRIER FLOW OF 50-60KT...HOWEVER SHEAR 
PROFILE NOT CONDUCIVE TO AN AMPLIFIED MTN WAVE AS THE STRONG JET 
ALOFT LINGERS ACROSS THE AREA. WITH THIS IN MIND THE STRONGEST WINDS 
WILL REMAIN OVER THE HIGHER EAST SLOPES AND WILL PROBABLY SEE A 
WEAKER REFLECTION OF THE WAVE AT THE SURFACE. ALSO WITH THE 
LINGERING COLD AIR ON THE PLAINS...THE WINDS WON'T BE ABLE TO 
PENETRATE VERY FAR EASTWARD. THERE WILL CONTINUE TO BE SOME SHALLOW 
MOISTURE IN THE MOUNTAINS BUT FLOW TURNS A BIT MORE SOUTHWESTERLY 
AND LOWERING LAPSE RATES WILL KEEP POPS IN THE SCATTERED CATEGORY 
FOR THURSDAY. WINDS ALOFT DECREASE A BIT ON FRIDAY BUT THIS RESULTS 
IN A BETTER CHANCE FOR AN AMPLIFIED WAVE. OVERALL...A WINDY PERIOD 
FOR THE MOUNTAINS AND EAST SLOPES. ADDED SOME BLOWING SNOW TO THE 
MTN GRIDS AND LATER SHIFTS CAN DECIDE IF THERE IS ENOUGH WIND TO 
WARRANT BLOWING SNOW ADVISORIES. 

MOISTURE INCREASING AGAIN FOR THE MOUNTAINS ON FRIDAY NIGHT AND 
SATURDAY AHEAD OF NEXT WEAKENING IMPULSE COMING ONSHORE IN 
CALIFORNIA. AGAIN...WILL KEEP POPS IN THE SCATTERED CATEGORY AS MTN 
TOP WINDS ARE MORE SOUTHWEST AND NOT AS CONDUCIVE TO WIDESPREAD 
SNOWFALL. FOR LOWER ELEVATIONS...A DRY PERIOD AND A GRADUAL WARMUP 
THROUGH THE WEEKEND...WITH COLDER TEMPERATURES IN LOW LYING AREAS 
AND RIVER VALLEYS. THE GFS DOES BRING A WEAK FRONT DOWN ON SUN NIGHT 
AND MONDAY WITH A BRIEF PERIOD OF UPSLOPE FLOW. NO POPS FOR NOW AS 
WE ARE STILL OUT IN DAY 7 AND SYSTEM LOOKS FAIRLY WEAK AT THIS 
TIME. 

&&

.AVIATION...MVFR CEILINGS AND VISIBILITIES WILL CONTINUE TO IMPROVE 
THIS AFTERNOON...VFR CONDITIONS EXPECTED AROUND 00Z OR SHORTLY 
AFTER. ISOLATED SNOW SHOWERS WILL CONTINUE THROUGH 00Z WITH LESS 
THAN 0.5 INCH ACCUMULATION EXPECTED. NORTHERLY WINDS WILL BE 
DIMINISHING AROUND 00Z AND ARE EXPECT TO BECOME DRAINAGE AFTER 04Z.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...WINTER WEATHER ADVISORY FOR SNOW  
      AND BLOWING SNOW TODAY THROUGH WEDNESDAY MORNING AT            
      12Z FOR ZONES...31/33/34.
     WINTER WEATHER ADVISORY FOR THE NORTHEAST PLAINS THROUGH 5 PM
      TODAY FOR ZONES...48>51. 
     WIND CHILL ADVISORY FOR THE PALMER DIVIDE AND ADJACENT
      EASTERN PLAINS THROUGH 10 PM TONIGHT FOR ZONES...41/46/47.  

$$
KRIEDERMAN/ENTREKIN