FXUS65 KPUB 301132
AFDPUB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PUEBLO CO
432 AM MST MON NOV 30 2009

.SHORT TERM...
(TODAY AND TONIGHT)

QUIET DAY ON STORE FOR SOUTHERN COLORADO AS HIGH PRESSURE BUILDS 
ACROSS THE REGION.  UPPER LOW CONTINUES TO DRIFT ACROSS NORTHERN 
MEXICO WHILE AN UPPER LEVEL RIDGE WRAPS INTO COLORADO FROM THE GREAT 
BASIN.  DRY AIR AND NORTHERLY FLOW IN THE MID AND UPPER LEVELS WILL 
KEEP ALL PRECIPITATION WELL TO THE SOUTH.  LIGHT DOWNSLOPE FLOW WILL 
HELP TEMPERATURES WARM TODAY INTO THE MID TO UPPER 50S OVER THE 
EASTERN PLAINS AND UPPER 30S TO LOW 40S ACROSS THE HIGHER 
ELEVATIONS.  

UPPER TROUGH WILL BEGIN TO DROP OUT OF WESTERN CANADA FLATTENING THE 
RIDGE OVERHEAD AND TURNING FLOW ALOFT NORTHWESTERLY.  DRY AIR OVER 
THE REGION AND CLEAR SKIES WILL ALLOW FOR RADIATIONAL 
COOLING...HOWEVER MODELS INDICATING SOME MIXING AND DOWNSLOPE WHICH 
WILL LIMIT JUST HOW COLD THE AREA GETS.  CURRENTLY HAVE LOWS IN THE 
UPPER TEENS TO LOW 20S OVER THE EASTERN PLAINS AND SINGLE DIGITS 
OVER THE SAN LUIS VALLEY.  IF WINDS CAN DECOUPLE OVER THE EASTERN 
PLAINS...TEMPERATURES MAY BE A FEW DEGREES ON THE WARM SIDE.  MOZLEY

.LONG TERM...
(TUESDAY THROUGH MONDAY)

...A TREND TOWARDS MUCH COLDER TEMPERATURES BY MID WEEK WITH A 
POTENTIAL PATTERN CHANGE BY NEXT WEEKEND...

00Z AND 06Z RUNS HAVE TRENDED WESTWARD WITH THE TRACK OF THE NEXT 
UPPER TROF DROPPING OUT OF CANADA INTO THE NRN U.S ROCKIES AND PLAINS 
BY TUESDAY.  AS A CONSEQUENCE...H7 TEMPS ARE NOW PROGGED TO DROP TO 
AROUND -12 TO -15C BY WEDNESDAY. IN THE MEANTIME...TUESDAY WILL BE 
ANOTHER MILD DAY WITH COLD AIR BEHIND THE FRONT DROPPING THROUGH THE 
SOUTHEAST PLAINS BY LATE TUESDAY AFTERNOON.  LOW LEVELS SATURATE 
OVERNIGHT TUESDAY NIGHT WITH STRATUS AND POTENTIAL FOR LIGHT 
SNOW/FLURRIES DEVELOPING ALONG THE EASTERN SLOPES OF THE SOUTHEAST 
MOUNTAINS FORCED MAINLY BY SHALLOW LOW LVL NE UPSLOPE FLOW. COULD
EVEN BE SOME PATCHY FREEZING DRIZZLE TUES NIGHT DEPENDING ON HOW
COLD AND HOW SATURATED THE COLUMN GETS. 00Z GFS WAS MORE HEAVY
HANDED WITH QPF THAN ITS PREVIOUS RUNS WHILE NAM WAS NEARLY DRY.
FOR NOW WILL KEEP HIGH ISOLATED POPS ACROSS THE PALMER
DIVIDE/TELLER COUNTY AND NE FACING SLOPES OF THE WETS. WEDNESDAY
WILL BE SIGNIFICANTLY COLDER WITH MORNING CLOUDS/FOG PINNED UP
ALONG THE LOWER EASTERN SLOPES OF THE SE MTS. LATEST GUIDANCE HAS
COME IN WITH MAX TEMPS WED AND THURS IN THE 20S AND 30S...WHICH
LOOKS MORE REASONABLE GIVEN THE MORE WESTWARD EXTENT OF COLD CORE
IN LATEST SET OF MODELS. HAVE DROPPED BACK MAX TEMPERATURES
CONSIDERABLY BOTH DAYS AS DEEP NORTHERLY FLOW ALOFT WILL KEEP COLD
1025-1030 SFC HIGH ENTRENCHED ACROSS THE EASTERN PLAINS.

MODEL DISCREPANCIES START TO GROW BY LATE WEEK THROUGH NEXT
WEEKEND. GFS DROPS MORE ENERGY DOWN FROM CANADA INTO THE NRN U.S.
ROCKIES WHICH CLOSES OFF AS IT DROPS TO THE SOUTH ACROSS NV BY 00Z
MON. ECMWF KEEPS THIS ENERGY OFF THE WEST COAST WITH SHORTWAVE
RIDGING OVER THE WRN US...MOVING OVER CO FOR SATURDAY THEN
TRANSITIONING TO ZONAL FLOW BY MONDAY. SO WHILE GFS SHOWS
MODERATING TEMPERATURES FOR FRI WITH FLOW BECOMING MORE ZONAL
ALOFT AHEAD OF CLOSED LOW DROPPING SOUTHWARD FROM CANADA...ECMWF
KEEPS COLD AIR ENTRENCHED ACROSS THE EASTERN PLAINS ON WESTERN
FRINGES OF WRN US UPPER RIDGE. LOTS OF UNCERTAINTY HERE...BUT FOR
NOW LEANED FORECAST MORE TOWARDS THE ECMWF AND COOLED MAX TEMPS
FOR FRIDAY. GFS DROPS NEXT FRONT AND CHANCE FOR PRECIPITATION
ACROSS THE AREA FOR SATURDAY...WHILE ECMWF SUGGEST A DRY AND
WARMING TREND FOR THE WEEKEND WITH NEXT POTENTIAL FOR
PRECIPITATION HOLDING OFF UNTIL MONDAY. GIVEN THE
UNCERTAINTIES...WILL HOLD THE COURSE WITH CURRENT SET OF GRIDS FOR
NEXT WEEKEND AND BEYOND. -KT

&&

.AVIATION...
VFR CONDITIONS WILL PREVAIL AT ALL TAF SITES THROUGH TOMORROW.  MOZLEY

&&

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

$$

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