FXUS65 KPUB 011053
AFDPUB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PUEBLO CO
353 AM MST TUE DEC 1 2009

.SHORT TERM...
(TODAY AND TONIGHT)

...ONE LAST PLEASANT DAY...

UPPER LOW CONTINUES TO SPIN OVER NORTHERN MEXICO AND WILL DRIFT 
EASTWARD INTO WEST TEXAS THIS AFTERNOON.  UPPER LEVEL RIDGE 
STRETCHES FROM THE GREAT BASIN INTO COLORADO WHILE FAST MOVING 
TROUGH DIGS ACROSS THE NORTHERN ROCKIES.  DIGGING TROUGH WILL SHIFT 
THE RIDGE SOUTH AND EAST THROUGH THIS AFTERNOON AND WILL SEND A COLD 
FRONT SOUTH ACROSS THE REGION.  MODELS IN DECENT AGREEMENT ON THE 
FRONT ARRIVING INTO THE KCOS AREA AROUND 15Z AND SPREADING SOUTH 
OVER THE EASTERN PLAINS BY 21Z.  AHEAD OF THE FRONT...NORTHWESTERLY 
FLOW ALOFT WILL MIX DOWN ALLOWING TEMPERATURES TO ONCE AGAIN RISE 
INTO THE MID 50S OVER SOUTHEASTERN COLORADO.  

UPPER TROUGH CONTINUES TO DROP SOUTH INTO NORTHERN COLORADO 
OVERNIGHT.  MAIN SURGE OF COLD AIR IS FORECAST TO ARRIVE AROUND 03Z 
WITH TEMPERATURES AT 700 MB DROPPING RAPIDLY TO LESS THAN -10C BY 
TOMORROW MORNING.  SURFACE TO 850 MB FLOW TURNS NORTHEASTERLY 
PROVIDING UPSLOPE FLOW.  UPSLOPE WILL PROVIDE UPWARD VERTICAL MOTION 
THROUGH THE DENDRITIC SNOW GROWTH REGION WITH MODELS BREAKING OUT 
SNOW ACROSS THE PALMER DIVIDE AND PIKES PEAK AREA BY 06Z.  SNOW WILL 
SPREAD SOUTH ALONG THE LEE SLOPES AND SANGRE DE CRISTO RANGE THROUGH 
MORNING.  EXPECT 2 TO 4 INCHES OF SNOW NEAR PIKES PEAK...UP TO 2 
INCHES ALONG THE PALMER DIVIDE AND SANGRE DE CRISTO RANGE AND LESS 
THAN AN INCH OVER THE LEE SLOPES AND ADJACENT PLAINS.  WINDS WILL BE 
GUSTY ACROSS THE PLAINS THIS EVENING AND OVERNIGHT BEHIND THE FRONT 
AND WILL PRODUCE WIND CHILLS IN THE SINGLE DIGITS TO LOW TEENS 
THROUGH TOMORROW MORNING.  MOZLEY

.LONG TERM...
(WEDNESDAY THROUGH MONDAY)

SHORTWAVE TROF DIGS SOUTH INTO CO WED WITH RELATIVELY DEEP UPSLOPE
FLOW DEVELOPING ALONG THE I25 CORRIDOR. A RELATIVELY DEEP LAYER OF
MSTR OVR THE SE MTS AND ALONG THE I25 CORRIDOR...SHOULD LEAD TO A
GOOD CHANCE FOR SNOW....WHICH CONTINUES INTO WED NIGHT. ALTHOUGH LATE
WED NIGHT IT LOOKS LIKE THE UPSLOPE SHOULD WEAKEN. THUS IT LOOKS
LIKE THE BEST TIME-FRAME FOR SNOW ACCUMULATIONS IN THESE AREAS
WILL OCCUR WED AFTERNOON THROUGH THE FIRST HALF OF WED
NIGHT...ALTHOUGH ACCUMULATIONS AT THIS TIME DO NOT LOOK LIKE THEY
WILL BE ALL THAT SIGNIFICANT. H7 TEMPS COOL FOR WED...RANGING FROM
AROUND -5C OVR THE SAN LUIS VALLEY TO AROUND -16C OVER THE PALMER DVD.
HIGHS WED LOOK LIKE THEY WL BE IN THE 20S TO LOWER 30S OVER THE SE
PLAINS AND HIGH VALLEYS...AND COOLER OVR THE MTS. THU THE
SHORTWAVE TROF MOVES SOUTH OF THE AREA...WITH ANOTHER ONE MOVING
OVR THE STATE THU NIGHT...WITH COLD NW FLOW CONTINUING OVR THE
AREA...WITH H7 TEMPS ON THU RANGING FROM AROUND -13C OVR THE SAN
LUIS VALLEY TO ABOUT -18 TO -20C OVR THE SE PLAINS...WL COOL MAX
TEMPS SOME MORE FOR THU. THE MSTR DECREASES OVR THE AREA THU...BUT
SOME LIGHT SNOW SHOWERS WL STILL BE POSSIBLE. 

THE GFS AND ECMWF SHOW DRY WEATHER THEN FOR FRI AND SAT. NORTHERLY
FLOW ALOFT WL BE FOUND OVR THE AREA FRI...BUT THE GFS DOES SHOW
TEMPS WARMING SLIGHTLY...BUT TEMPS WL STILL BE WELL BELOW NORMAL.
THE FLOW ALOFT THEN BECOME WESTERLY FOR SAT AS A NEW UPR TROF IS
EXPECTED TO DIG INTO ID...WITH TEMPS MODERATING EVEN MORE BUT
THEY STILL SHOULD BE SEVERAL DEGREES BELOW NORMAL. SAT/SAT NIGHT A
FRONT MOVES INTO THE AREA AS THE UPR TROF DROP A LITTLE SOUTH WE
COULD SEE SOME PCPN DEVELOP SAT NIGHT...ALTHOUGH THE 06Z RUN OF
THE GFS KEEPS THE PCPN TO OUR NORTH AND EAST...AND THE ECMWF IS
ALSO DRY OVR THE CWA. THE GFS HAS AN INCREASE IN MSTR OVR THE AREA
FOR SUN AND MON...ALONG WITH UPLSOPE FLOW ALONG AND NR THE SE MTS
SO IT DEVELOP SOME PCPN. TEMPS COOL AGAIN THEN FOR SUN AND MON.

&&

.AVIATION...
VFR CONDITIONS ARE EXPECTED THROUGH THIS AFTERNOON BEFORE SNOW 
SHOWERS BEGIN TO IMPACT THE KCOS AND KPUB TERMINALS TONIGHT.  COLD 
FRONT IS FORECAST TO DROP SOUTH ACROSS THE EASTERN COLORADO PLAINS 
REACHING KCOS BY 15Z AND KPUB BY 18Z.  WINDS WILL TURN NORTHERLY 
BEHIND THE FRONT WITH GUSTS UP TO 25KTS.  CLOUD COVER WILL INCREASE 
THIS EVENING WITH SNOW DEVELOPING BETWEEN WED/03Z AND 06Z WITH MVFR 
CONDITIONS LIKELY AT KCOS AND KPUB AFTER 03Z.  SNOW WILL BE LIGHT 
WITH UP TO AN INCH AT KCOS AND LESS THAN AN INCH AT KPUB.  

KALS WILL SEE VFR CONDITIONS THROUGH TONIGHT.  MOZLEY

&&

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

$$

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