FXUS65 KPUB 302234
AFDPUB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PUEBLO CO
334 PM MST MON NOV 30 2009
.SHORT TERM...
(TONIGHT AND TUESDAY)
CURRENTLY...UPPER CLOSED LOW WAS OVER MEXICO THIS
AFTERNOON...SPREADING SOME CLOUD COVER UP INTO CENTRAL NM BUT
NOTHING UP ACROSS COLORADO. ABUNDANT SUN WAS EVIDENT ACROSS THE
STATE WITH LIGHT WINDS AND AS OF 3 PM TEMPS HAVE WARMED INTO THE 30S
AND 40S FOR THE HIGHER ELEVATIONS...50S ACROSS THE PLAINS.
TONIGHT AND TOMORROW...
THE SOUTHERN LOW STAYS OVER MEXICO AND WESTERN TEXAS FOR THE NEXT 24
HRS SO IT REMAINS A NONISSUE FOR THE CWA. A LONGWAVE TROUGH IS
FORECAST TO DROP DOWN OUT OF CANADA TONIGHT...PRODUCING A LARGE AREA
OF PCPN OVER MT AND WY TOMORROW AS THE TROUGH AXIS DROPS SOUTH.
HOWEVER...COLORADO REMAINS BETWEEN THE TWO MAIN WEATHER FEATURES
THROUGH MIDDAY TUES...THEN A SFC COLD FRONT IS EXPECTED TO DROP
SOUTH ACROSS THE EASTERN HALF OF CO. THIS DRY COLD FRONT IS
SCHEDULED TO REACH THE PALMER DVD RIGHT AROUND 18Z...THEN QUICKLY
SURGE SOUTH AND REACH THE CO/NM BORDER BETWEEN 21Z-00Z. A WIND SHIFT
TO THE N-NE IS PLANNED THROUGH THE AFTN FOR THE E PLAINS WITH
FRONTAL PASSAGE...BUT IT SEEMS THAT THE TRULY COLDER AIR WILL NOT
FILTER DOWN UNTIL THE EVENING.
THEREFORE...DRY CONDITIONS ARE EXPECTED TO CONTINUE OVER THE NEXT 24
HRS. CLEAR SKIES WITH A BIT OF WIND TONIGHT WILL PRODUCE COLD MIN
TEMPS VERY SIMILAR TO MON AM...AND MAX TEMPS TOMORROW SHOULD HAVE
ENOUGH TIME TO WARM INTO THE 40S FOR THE HIGH VALLEYS...AND 50S FOR
THE E PLAINS. MOORE
.LONG TERM...
(TUESDAY NIGHT THROUGH NEXT MONDAY)
...WELCOME TO WINTER....
COLD AIR AND NORTHEAST UPSLOPE FLOW DEEPEN TUESDAY EVENING
FOLLOWING THE FROPA...WITH AIR MASS SATURATING AND LIGHT SNOW
BEGINNING OVER THE EASTERN MOUNTAINS AND PALMER DIVIDE BY
MIDNIGHT. PRECIP SPREADS SOUTH OVER THE I-25 CORRIDOR AND
REMAINDER OF THE EASTERN MOUNTAINS BY EARLY WEDNESDAY
MORNING...WITH WEAK UPWARD MOTION AIDED BY NOSE OF UPPER JET
DIGGING SOUTH INTO WRN CO. COLD AIR LOOKS DEEP/COLD ENOUGH THAT
PRECIP SHOULD BE SNOW (VERSUS FREEZING DRIZZLE)...WITH POTENTIAL
FOR AT LEAST A FEW INCHES OF FLUFFY LOW WATER CONTENT SNOW OVER
TELLER COUNTY/PALMER DIVIDE OVERNIGHT. INCREASED POPS TO REFLECT
INCREASING CONFIDENCE IN AT LEAST SOME LIGHT SNOW ALONG AND WEST
OF I-25.
ON WEDNESDAY...COLD AIR MASS COVERS THE EASTERN HALF OF THE
AREA...WITH SOME LIGHT SNOW/FLURRIES CONTINUING ALONG THE EASTERN
MOUNTAINS AND OVER THE I-25 CORRIDOR...ESPECIALLY IN THE MORNING.
COULD SEE A COUPLE INCHES OF ACCUMULATION OVER FAVORED EAST SLOPES
OF THE SANGRES/WETS AND NORTH SLOPE OF THE RATON MESA BY LATE
AFTERNOON AS BEST LIFT SHIFTS SOUTHWARD. GIVEN DEEP COLD AIR AND
CLOUD COVER OVER THE REGION...CHOPPED SEVERAL DEGREES OFF MAX
TEMPS...WITH READINGS PROBABLY NOT REACHING THE FREEZING MARK OVER
MUCH OF THE EASTERN HALF OF THE AREA.
COLD AIR REMAINS ENTRENCHED OVER THE AREA WEDNESDAY NIGHT AND
THURSDAY...THOUGH WITH UPSLOPE FLOW WEAKENING...EXPECT LIGHT SNOW
TO TAPER OFF TO A FEW FLURRIES BY EARLY THU MORNING. GFS THEN
SUGGESTS FLURRIES/LIGHT SNOW COULD CONTINUE OVER THE ERN MOUNTAINS
MUCH OF THE DAY THU...WHILE NAM IS MAINLY DRY. KEPT JUST SOME
ISOLATED POPS IN PLACE FOR NOW...MAY NEED TO NUDGE THESE UPWARD IF
GFS VERIFIES. JET REMAINS OVERHEAD THU AFTERNOON...WITH MODELS
SUGGESTING A BROKEN MID LEVEL CLOUD DECK COVERING THE PLAINS THROUGH
THU EVENING. THESE CLOUDS SHOULD COMBINE WITH CONTINUED WEAK COLD
ADVECTION TO KEEP MAX TEMPS VERY CHILLY...WITH READINGS AGAIN
MAINLY IN THE 20S TO NEAR 30.
SOME SLOW MODERATION IN TEMPS FORECAST THU NIGHT INTO FRIDAY AS
UPPER TROUGH PULLS AWAY AND WEAK LEE TROUGHING REDEVELOPS FRI
AFTERNOON. STILL...WITH 700 TEMPS REMAINING MINUS 10C OR
COLDER...30S TO NEAR 40 MAY BE THE BEST WE CAN DO. WITH JET
OVERHEAD...MAY STILL SQUEEZE OUT SOME FLURRIES OVER THE HIGHER MTN
PEAKS...THOUGH TREND WILL BE TOWARD DRIER CONDITIONS.
STILL GOOD DEAL OF UNCERTAINTY REGARDING THE FORECAST FOR THE
WEEKEND INTO EARLY NEXT WEEK...THOUGH BOTH GFS/ECMWF ARE TRENDING
TOWARD SOME SORT OF CUT-OFF/CLOSED LOW SOMEWHERE OVER THE
NORTHWEST U.S. BY SUNDAY. SHOULD SEE A CONTINUED MODERATING TREND
SAT AS WESTERLY FLOW PUSHES AWAY FROM THE MOUNTAINS...THOUGH COLD
ARCTIC AIR MAY SLOSH BACK WESTWARD ACROSS THE PLAINS SAT
NIGHT...RETURNING MUCH OF THE EAST BACK INTO THE DEEP FREEZE
SUNDAY. FORECAST IS RATHER BROADBRUSH AND NOT TOO COLD AT THIS
POINT...AS WESTERN EDGE OF SHALLOW COLD AIR MASS IS VERY DIFFICULT
TO FORECAST THIS FAR OUT. WOULD APPEAR WESTERN MOUNTAINS GET IN ON
SOME SNOW EARLY NEXT WEEK AS MOISTURE PUSHES EASTWARD FROM THE
PACIFIC...THOUGH TIMING AMONG THE VARIOUS MODELS VARIES BY A
COUPLE DAYS. --PETERSEN
&&
.AVIATION...VFR CONDITIONS ARE EXPECTED FOR THE NEXT 24 HOURS AT
THE THREE MAIN TAF SITES...KCOS...KPUB AND KALS. SFC COLD FRONT
IS FORECAST TO DROP SOUTH ACROSS THE PALMER DVD AND KCOS BETWEEN
18Z AND 21 Z...SHIFTING WINDS TO A MORE N-NE DIRECTION AND
INCREASING CLOUD COVER...THEN REACHING KPUB AFTER 21Z.
HOWEVER...VFR CONDITIONS ARE EXPECTED TO PERSIST.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
27/10
