FXUS65 KPUB 151145
AFDPUB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PUEBLO CO
445 AM MST TUE DEC 15 2009

.SHORT TERM...
(TODAY AND TONIGHT)

MAIN CONCERN IN SHORT TERM IS EXTENT OF LOW CLOUDS/BR THIS MORN.
AREA OF LOW CLOUDS/FG HAS FORMED NR KLHX THIS MORN...AND CALM 
CONDITIONS WITH OCCASIONAL LIGHT ERLY FLOW...ALONG WITH SHORT WAVE 
RIDGE ALOFT...MAY HELP EXPAND THIS AREA OF CLOUDS OVR THE NEXT FEW 
HOURS. HAVE ADDED PATCHY FOG TO THE ERN ZONES THRU ABOUT 
15-16Z...AND ALSO FOR THE SAN LUIS VALLEY WHERE THERE ARE ALSO LIGHT 
WINDS AND A BIT MORE SFC MOISTURE. KPUB IS CURRENTLY HOLDING AT 6SM 
AND MAY SEE A BRIEF PERIOD OF PATCHY FG EARLY THIS MORN.

OTHERWISE...EXPECT ANOTHER PLEASANT DAY WITH TEMPS CLIMBING TO 
AROUND 50 DEG OR HIGHER ALONG THE I-25 CORRIDOR THIS AFTERNOON.
WILL MAINTAIN THE LOWEST TEMPS OUT BY THE CO-KS BORDER...WHICH WILL 
BE FLIRTING WITH THE EDGE OF THE SHALLOW COLD AIR MASS TO THE E MUCH 
OF TODAY. WHILE LOW CLOUDS SHOULD MIX OUT LATER THIS MORN...SHOULD 
SEE TEMPS A BIT LOWER OUT EAST TODAY. CONSIDERABLE WAA WILL OCCUR 
E OF THE MTS...AND THIS WILL LEAD TO A FAIRLY MILD NIGHT OVR THE E 
SLOPES AND SRN FRONT RANGE TONIGHT. A BIT COOLER ONCE AGAIN OVR THE 
LOWER ARKANSAS. POPS WILL REMAIN NIL THRU TONIGHT...WITH JUST SOME 
HIGH CLOUDS MOVING IN LATER TONIGHT FROM AN APPROACHING SHORTWAVE TO 
THE NW. ROSE

.LONG TERM...
(WEDNESDAY THROUGH MONDAY)

...MILD WEDNESDAY...THEN PICTURE LESS CLEAR...

STILL LOOKS LIKE WEDNESDAY SHOULD TURN OUT MILD AND DRY UNDER HIGH 
PRESSURE AND LIGHT DOWNSLOPE FLOW.  AFTERNOON HIGH TEMPERATURES SHOULD 
END UP ABOUT 5 TO 10 DEGREES ABOVE AVERAGE IN MOST AREAS.

MODELS ARE IN GENERAL CONSENSUS ON BRINGING A SHORTWAVE THROUGH THE 
AREA ON THURSDAY THAT WILL DROP TEMPERATURES BACK TO NORMAL OR BELOW 
FOR THURSDAY AND FRIDAY.  IN THE GFS...THE SYSTEM DOES NOT LOOK LIKE 
MUCH OF A PRECIPITATION MAKER.  IT LACKS BOTH MOISTURE AND 
STRENGTH.  HOWEVER...THE ECMWF MODEL IS A LITTLE STRONGER WITH THE 
FEATURE...GENERATING MORE WIDESPREAD LIGHT SNOWFALL.  FOR RIGHT 
NOW...BEST FORECAST IS TO INDICATE THAT SYSTEM WILL TRIGGER A FEW 
AREAS OF LIGHT SNOW AS IT MOVES THROUGH...ESPECIALLY OVER THE 
CENTRAL MOUNTAINS...WHERE 3 TO 5 INCHES COULD FALL FROM THURSDAY 
THROUGH FRIDAY. ANY ACCUMULATIONS ELSEWHERE ARE GENERALLY LOOKING 
LIKE AN INCH OR LESS.

ON SATURDAY...WHICHEVER MODEL YOU BELIEVE...THE THURSDAY/FRIDAY 
SYSTEM SHOULD MOVE OFF TO THE EAST...LEAVING GENERALLY DRY AND 
MILDER CONDITIONS.

FORECAST BECOMES VERY UNCERTAIN AFTER SATURDAY. THE 06Z GFS40 BRINGS 
ANOTHER SHORTWAVE THROUGH COLORADO SATURDAY NIGHT AND 
SUNDAY...RESULTING IN COOLING TEMPERATURES AND ANOTHER CHANCE FOR 
SNOW SHOWERS...WHILE THE 00Z ECMWF REALLY DOESN'T HAVE THIS FEATURE. 

THEN FOR SUNDAY NIGHT AND MONDAY...THE ECMWF BUILDS A SHARPER RIDGE 
OVER THE ROCKIES AND A DEEPER TROUGH OVER THE GREAT LAKES REGION 
THAN THE 06Z GFS DOES.  THIS HAS BIG IMPLICATIONS ON SOUTHERN 
COLORADO WEATHER.  IF THE ECMWF IS CORRECT...IT COULD MEAN A MUCH 
STRONGER INTRUSION OF COLD AIR INTO EASTERN COLORADO THAN THE GFS 
WOULD SUGGEST.  THE ECMWF SOLUTION WOULD ALSO BETTER HELP THE 
PROSPECTS FOR LIGHT SNOW ON THE PLAINS GIVEN THE DEEPER COLD AIR AND 
STRONGER JET OVER THE AREA.  

SO...CAN'T GET TOO FANCY WITH THE FORECAST AT THIS TIME.  WILL 
GENERALLY PLAY IT CONSERVATIVE FOR SUNDAY AND MONDAY UNTIL WE CAN 
GAIN CONFIDENCE ON HOW THIS WILL ALL PLAY OUT. LW

&&

.AVIATION...
PATCHY FG AND BR WILL BE THE MAIN CONCERN THIS MORN...THROUGH ABOUT
16Z. COULD SEE SOME AREAS OF LOW CLOUDS HANG ON A BIT LONGER CLOSE 
TO THE KS BORDER. KCOS SHOULD STAY CLEAR THIS MORN...BUT CONDITIONS 
AT KPUB AND KALS A BIT LESS CERTAIN...AS LIGHT ERLY WINDS TO CALM 
CONDITIONS...ALONG WITH CLEAR SKIES...COULD LEAD TO A BRIEF PERIOD 
THIS MORN OF BR AND/OR FG. ANY VIS RESTRICTIONS SHOULD CLEAR BY MID 
MORN. WINDS WILL CONTINUE TO BE FAIRLY LIGHT FOR THE NEXT 24 H. ROSE

&&

.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

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