FXUS65 KPUB 012358 AAA
AFDPUB

AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PUEBLO CO
458 PM MST TUE DEC 1 2009

.UPDATE...

AM SENDING OUT A QUICK UPDATE TO THE GRIDS/ZONES TO ACCOUNT
FOR SLOWING OF PRECIP ASSOCIATED WITH THE COLD FRONT MOVING
THROUGH ERN CO. BASED ON CURRENT OBS...WITH SN STILL FAR TO THE N
IN WY...AND CLOUD COVERAGE JUST STARTING TO DEVELOP OVR THE SRN
FRONT RANGE...ONSET OF PRECIP WILL LIKELY HOLD OFF MOST SPOTS
UNTIL AFTER MIDNIGHT. HAVE REMOVED POPS FOR THIS EVE AND TRIMMED
BACK SRN ZONES THROUGH 12Z. BEST POPS LOOK TO BE TOMORROW MORNING.
ROSE

&&

.PREV DISCUSSION... /ISSUED 324 PM MST TUE DEC 1 2009/ 

SHORT TERM...
(TONIGHT AND WEDNESDAY)

..WINTER RETURNS...

CURRENTLY...THE SOUTHERN UPPER CLOSED LOW WAS TRACKING EASTWARD 
ACROSS THE TRANSPECOS REGION OF TEXAS TUE AFTN...SPREADING SOME 
CLOUD COVER UP ACROSS THE SE CORNER OF COLORADO. MEANWHILE...THE 
NEXT WEATHER MAKER FOR THE STATE WAS IN THE FORM OF A LONGWAVE 
TROUGH DROPPING DOWN OUT OF CANADA AND ACROSS THE NORTHERN ROCKIES. 
THIS WAS PRODUCING SOME CLOUD COVER OVER THE NORTHERN PART OF THE 
STATE...BUT WAS ALSO PUSHING A COLD FRONT DOWN ACROSS THE PALMER DVD 
AS OF 130 PM. THE COLD AIR WAS NOT FILTERING DOWN SOUTH JUST 
YET...BUT GUSTY N-NE WINDS AND DEWPOINTS IN THE SINGLE DIGITS WERE 
MARKING THIS FRONTAL PASSAGE.

TONIGHT AND TOMORROW...THE UPPER TROUGH CONTINUES DROPPING SOUTH 
INTO THE CENTRAL PORTIONS OF THE COUNTRY...WITH STRENGTHENING 
UPSLOPE FLOW AND AVAILABLE MOISTURE ALLOWING SNOW TO BREAK OUT OVER 
THE PALMER DVD...RAMPART RANGE AND SOUTHERN FRONT RANGE LATER 
TONIGHT. BOTH NAM AND GFS MODELS TEND TO START PCPN RIGHT AROUND 
06Z...SO BROKE UP THE POP GRID ON THE FRONT END TO SOMEWHAT DELAY 
PCPN ONSET AND INCOMING CLOUD SHIELD. BY 06Z HOWEVER...SNOW IS 
EXPECTED TO SPREAD ACROSS MUCH OF THE AREA AND LAST THROUGH THE DAY 
TOMORROW. FOCUS AREAS WILL BE THE CENTRAL AND EASTERN MTS...PALMER 
DVD...RAMPART RANGE AND IMMEDIATELY ADJACENT PLAINS. INITIALLY THE 
FAR E PLAINS AND EVEN THE SLV SHOULD NOT SEE MUCH BY WAY OF SNOW. 
HOWEVER...THE EASTERLY PUSH SHOULD GET DEEP ENOUGH THAT BY WED AFTN 
THE COLDER AIR AND MOISTURE WILL SPILL OVER LA VETA AND START SNOW 
IN THE VALLEY. SNOW AMOUNTS ARE EXPECTED TO BE IN THE 1-2 INCH RANGE 
FOR EL PASO COUNTY AND THE RAMPART RANGE OVERNIGHT TONIGHT...THEN A 
POSSIBLE 2-4 INCHES ALONG THE E MTS AND PALMER DVD THRU THE DAY 
TOMORROW. AS FOR TEMPS...THIS SYSTEM WILL PACK SOME VERY COLD 
AIR...NEGATIVE 12 TO 16C AT 700 MB...ZERO TO NEG 7C AT 850 MB BY WED 
AFTN. THEREFORE...COLD MIN TEMPS TONIGHT AT AROUND 20F FOR THE E 
PLAINS WILL SEE LITTLE CHANGE THROUGHOUT THE DAY TOMORROW. 27

LONG TERM...
(WEDNESDAY NIGHT THROUGH NEXT TUESDAY)

UPPER JET DIGS INTO THE GREAT BASIN LATE WEDNESDAY NIGHT INTO
THURSDAY...PRODUCING GENERALLY WEAK BUT LONG-LIVED UPWARD MOTION
ACROSS COLORADO THROUGH THURSDAY AFTERNOON. COLD AIR REMAINS
LOCKED IN PLACE OVER THE STATE...WITH WEAK 700 MB COLD ADVECTION
PERSISTING THROUGH FRIDAY MORNING. SURFACE AND MID LEVEL UPSLOPE
FLOW FADES AWAY FROM LATE WED NIGHT INTO EARLY THU...WITH PERHAPS
A WEAK COLD SURGE THU AFTERNOON PRODUCING A RETURN TO WEAK
NORTHEAST WINDS FOR A TIME THROUGH THU EVENING. WILL THUS KEEP
CHANCE FOR LIGHT SNOW GOING THROUGH THU EVENING...WITH HIGHEST
POPS ALONG AND JUST WEST OF I-25. NOT LOOKING LIKE A BIG
EVENT...BUT WITH VERY COLD AIR MASS...FAVORED EAST MOUNTAIN SLOPES
COULD SEE SEVERAL INCHES OF FLUFFY DRY SNOW. CONTINUED TO NUDGE
MAX TEMPS DOWNWARD THU...WITH MOST AREAS STRUGGLING TO REACH 25F
BY AFTERNOON. TROUGH MOVES EAST FRIDAY...WITH BRIEF UPPER RIDGE
ENDING PRECIP MOST AREAS FRI/SAT...THOUGH TEMPERATURES WILL
STRUGGLE TO REACH 40F AS AIR MASS WILL BE SLOW TO WARM. MODIFIED
ARCTIC AIR MASS WEDGES BACK INTO THE PLAINS SAT NIGHT...WITH COLD
AIR LOCKED OVER THE PLAINS THROUGH THE MIDDLE OF NEXT WEEK. UPPER
LEVEL DETAILS STILL RATHER UNSETTLED...BUT MOST MODELS SUGGEST
STRONG UPPER LEVEL JET WILL BE LOCATED OVERHEAD...PROVIDING PLENTY
OF LIFT FOR SNOW OVER AT LEAST THE MOUNTAINS FROM SUNDAY INTO
TUESDAY.

AVIATION...KALS AND MUCH OF THE SLV SHOULD EXPECT VFR CONDITIONS
FOR THE NEXT 12 HRS...WITH POSSIBLE MVFR CONDITIONS DEVELOPING
AFTER 12Z TOMORROW MORNING AS SHOW SHOWERS ENCROACH UPON THE AREA.

NE-E SFC FLOW WILL CONTINUE AND STRENGTHEN THROUGH THE NIGHT AND 
INTO WED...AS LIGHT SNOW BREAKS OUT ACROSS THE PALMER DVD AND 
RAMPART RANGE AFTER MIDNIGHT TONIGHT. MVFR CONDITIONS ARE EXPECTED 
OVERNIGHT AND THROUGH THE DAY TOMORROW FOR KPUB AND KCOS...AND ALL 
ALONG THE E MTS AND I25 CORRIDOR FOR LIGHT SNOW...LOWERING CEILINGS 
AND OCNL VSBY DOWN TO 3SM.

&&

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

$$

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