FXUS65 KBOU 152114
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER CO
214 PM MST TUE DEC 15 2009

.SHORT TERM...WESTERLY FLOW WAS STRENGTHENING THIS AFTERNOON WITH  
GUSTY WEST WINDS DEVELOPING OVER THE MOUNTAINS AND FOOTHILLS AGAIN.  
THESE WINDS ARE EXPECTED TO GRADUALLY INCREASE INTO THE EVENING 
HOURS AS MOUNTAIN TOP STABLE LAYER AND SURFACE GRADIENT BOTH 
STRENGTHEN.  GIVEN CROSS MOUNTAIN FLOW OF 30-35 KTS AND GOOD STABLE 
LAYER...GUSTS AROUND 50 MPH CAN BE EXPECTED IN THE WIND PRONE AREAS 
WITH A FEW SPOTS APPROACHING 60 MPH ABOVE TIMBERLINE.  BY LATE 
WEDNESDAY MORNING...CROSS MOUNTAIN FLOW AND STABLE LAYER ARE BOTH 
WEAKENING SO WINDS SHOULD RELAX BY AFTERNOON.

ON THE PLAINS...COLDER LOW LEVEL AIR WAS SCOURING OUT QUITE QUICKLY 
ACROSS THE EASTERN PLAINS.  HOWEVER...SHALLOW COLD POOL WAS STILL 
SITTING TIGHT IN THE GREELEY-FORT COLLINS-LONGMONT AREA.  WHILE THE 
ATMOSPHERE WILL CONTINUE TO GRADUALLY WARM THROUGH WEDNESDAY...WE DO 
EXPECT A RATHER THICK BATCH OF MID/HIGH LEVEL CLOUDINESS TO HOLD 
TEMPERATURES BACK A FEW DEGREES...SO THERE SHOULD NOT BE MUCH MORE 
WARMING FROM TODAYS HIGHS IN THE SUNSHINE.

.LONG TERM...A ZONAL WESTERLY FLOW ACROSS THE REGION ON WEDNESDAY 
EVENING WILL QUICKLY BECOME MERIDIONAL AS A TROUGH OVER THE PACIFIC 
NORTHWEST MOVES OVER THE NORTHERN ROCKIES BY THURSDAY MORNING. 
WEDNESDAY NIGHT TEMPERATURES WILL REMAIN QUITE SEASONABLY WARM WITH 
WARMEST READINGS NEAR THE FOOTHILLS AGAIN. FLOW ALOFT WILL BECOME 
NORTHWEST THURSDAY AS A JET DIGS DOWN THE BACKSIDE OF THE TROUGH. 
MOISTURE CARRIED BY THIS TROUGH WILL MOST LIKELY START AFFECTING THE 
MOUNTAINS OF THE GORE RANGE WEDNESDAY NIGHT...THEN SPREAD OVER THE 
REST OF THE NORTHERN COLORADO MOUNTAINS THURSDAY. A COLD FRONT WILL 
DESCEND OVER THE NORTHEASTERN COLORADO THURSDAY EVENING BRINGING A 
SLIGHT CHANCE OF SNOW TO THE PLAINS WITH ONLY LIGHT ACCUMULATIONS 
EXPECTED. THE MOUNTAINS WILL LIKELY SEE SNOW THROUGH FRIDAY EVENING 
IN THE CONTINUED NORTHWEST FLOW. DYNAMICS ARE NOT THE MAIN PLAYER 
WITH THIS SYSTEM SO WILL HAVE TO RELY ON OROGRAPHICS MORE WITH A JET 
NEARBY. RIGHT NOW...TOTALS OF 2 TO 5 INCHES WITH THE GREATEST 
AMOUNTS ON WESTERN SLOPES NORTH OF I-70 SEEM REASONABLE. WILL TRY TO 
REFINE AMOUNTS IN THE NEXT SHIFT OR TWO. TEMPERATURES FRIDAY WILL BE 
ABOUT 5 TO 10 DEGREES COLDER IN THE POST FRONTAL AIRMASS...HOWEVER 
DEPENDING ON HOW QUICKLY THE SYSTEM MOVES OUT AND SKIES CLEAR...IT 
COULD MORE LIKE 2 TO 5 DEGREES COLDER.

FROM SATURDAY ON...MODELS ARE KEEPING THE STATE UNDER A GENERAL 
NORTHWEST FLOW PATTERN THROUGH MONDAY. HOWEVER THE GFS HAS SHOWN IN 
THE PAST TWO RUNS A SHORTWAVE TROUGH MOVING THROUGH SUNDAY WHILE THE 
ECMWF REMAINS SHOWING CONTINUED STRAIGHT NORTHWEST FLOW. HAVE ADDED 
A SLIGHT CHANCE OF SNOW FOR THE MOUNTAINS THROUGH SUNDAY TO ACCOUNT 
FOR THE UNCERTAINTY. HAVE NOT MADE ANY CHANGES FROM THIS POINT 
THROUGH EARLY NEXT WEEK AS UNCERTAINTY REMAINS.

&&

.AVIATION...VISUAL LANDING CONDITIONS WILL PERSIST THROUGH WEDNESDAY.
MAINLY SOUTH/SOUTHWEST WINDS WILL PREVAIL AT KDEN AND KAPA WITH 
SPEEDS GENERALLY UNDER 15 KNOTS.  AT KBJC...VARIABLE WINDS THIS 
AFTERNOON SHOULD TRANSITION TO GUSTY WESTERLY SURFACE WINDS UP TO
30 KNOTS AS MOUNTAIN WAVE AND LEE TROUGH STRENGTHEN THIS EVENING AND 
CONTINUE INTO WEDNESDAY MORNING.

&&

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

$$

BARJENBRUCH/KRIEDERMAN