FXUS65 KPUB 092225
AFDPUB
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PUEBLO CO
325 PM MST WED DEC 9 2009
.SHORT TERM...
(TONIGHT AND TOMORROW)
CURRENTLY...A COLD AIR MASS REMAINS OVER SOUTHERN COLORADO THIS
AFTERNOON. BITTERLY COLD TEMPERATURES WILL BE TRAPPED IN THE
MOUNTAINS AND HIGH VALLEYS THIS EVENING. WINDS ARE STILL HOWLING
OVER THE HIGHER MOUNTAINS AND ALONG THE CONTINENTAL DIVIDE...WITH
OCCASIONAL GUSTS TO 50 KNOTS CONTINUING AT MONARCH...WOLF CREEK AND
COTTONWOOD PASSES. DOESN'T APPEAR TO BE MUCH SNOW FALLING...BUT
WITH THE STRONG WINDS...THERE WILL BE WIDESPREAD BLOWING AND
DRIFTING SNOW THAT SHOULD CONTINUE UNTIL MIDNIGHT OVER BOTH THE
CENTRAL AND SOUTHWEST MOUNTAINS...MAINLY ABOVE 10K FEET.
TONIGHT...THE GUSTY WINDS IN THE CENTRAL AND SOUTHWEST MOUNTAINS
WILL DECREASE AROUND MIDNIGHT. THERE STILL MAY STILL BE AREAS OF
PATCHY BLOWING SNOW INTO THE EARLY MORNING HOURS. COLD AIR WILL BE
TRAPPED IN THE HIGH VALLEYS AND THE ELEVATED TERRAIN. EXPECT WIND
CHILL ADVISORY CONDITIONS WITH RANGES OF -15 TO -25 DEGREES IN THE
SAN LUIS VALLEY AND -25 TO -40 DEGREES IN THE HIGHER TERRAIN.
AREAS ALONG THE I-25 CORRIDOR AND THE EASTERN PLAINS WILL BE
SLIGHTLY WARMER THAN LAST NIGHT...DUE TO A WEAK LEE TROUGH MOVING
THROUGH THE PLAINS AND THE RESULTING DOWNSLOPE FLOW.
TOMORROW...THE REMAINS OF THE UPPER LEVEL TROUGH WILL MOVE THROUGH
THE INTERMOUNTAIN WEST TONIGHT INTO TOMORROW. A NEAR STATIONARY
UPPER LEVEL RIDGE REMAINS OVER THE PACIFIC COAST. ZONAL FLOW WILL
CONTINUE THROUGH TOMORROW. GUSTY UPPER LEVEL FLOW WILL CONTINUE THAT
MAY ALLOW FOR SOME PATCHY BLOWING SNOW IN AREAS ABOVE 10K FEET.
.LONG TERM...
(THURSDAY NIGHT THROUGH WEDNESDAY)
NOT MUCH IN THE WAY OF CHANGES FOR THE LONG TERM WITH MODELS STILL
IN GOOD AGREEMENT ON THE UPCOMING PATTERN. EXPECT DRY CONDITIONS
THURSDAY NIGHT THROUGH FRIDAY AS THE CANADIAN POLAR LOW CONTINUES
TO SHIFT NORTHEAST. WEAK SHORTWAVE TROUGH WILL MOVE ACROSS THE
DESERT SOUTHWEST BY FRIDAY WITH SNOW DEVELOPING OVER THE WESTERN
AND CENTRAL MOUNTAINS BY FRIDAY EVENING. NOT MUCH IN THE WAY OF
FORCING OR MOISTURE TO WORK WITH SO ACCUMULATIONS WILL BE LIGHT.
FLOW ALOFT TURNS WESTERLY WITH MIXING ALONG THE LEE SLOPES WITH
HIGHS IN THE UPPER 30S. INVERSIONS LOOK TO HOLD ON ALONG THE
ARKANSAS RIVER VALLEY ON THE EASTERN PLAINS SO TEMPERATURES LOOK
TO REMAIN COOLER THERE FRIDAY AFTERNOON. IF THE INVERSION CAN MIX
OUT THEN TEMPERATURES MAY BE A GOOD 5 DEGREES WARMER THAN THOSE
FORECAST.
THE NEXT SHORTWAVE TROUGH TO MOVE THROUGH THE SOUTHERN STREAM WILL
BEGIN TO IMPACT THE WESTERN MOUNTAINS ON SATURDAY NIGHT. THERE ARE A
FEW TIMING DIFFERENCES IN THE MODELS WITH THE ECMWF A BIT FASTER.
KEPT A SLIGHT CHANCE OF SNOW OVER THE MOUNTAINS FRIDAY NIGHT
THROUGH SATURDAY...HOWEVER THERE WILL PROBABLY BE A DECENT BREAK
DURING THE DAY ON SATURDAY BETWEEN THE DEPARTING SHORTWAVE AND
THE NEXT ONE THAT WILL ARRIVE.
THE SHORTWAVE SATURDAY NIGHT WILL DIG ACROSS THE FOUR CORNERS
REGION AND INTO NORTHERN NEW MEXICO ON SUNDAY. MODELS CONSISTENT
ON DEVELOPING DECENT AMOUNTS OF QPF OVER THE CENTRAL AND WESTERN
MOUNTAINS WITH SYSTEM DYNAMICS WRAPPING UP OVER SOUTHERN COLORADO
AND SUBTROPICAL MOISTURE PULLED UP FOR THE EASTERN PACIFIC. AREAS
IN THE EASTERN SAN JUANS HAVE THE POTENTIAL OF SEEING SEVERAL MORE
INCHES OF SNOWFALL LATE SATURDAY NIGHT TROUGH SUNDAY NIGHT AS
TROUGH MOVES ACROSS THE REGION. THE CENTRAL MOUNTAINS WILL ALSO
SEE ACCUMULATING SNOWS HOWEVER FLOW ALOFT WILL NOT BE AS FAVORABLE
FOR OROGRAPHICS SO TOTALS WILL LIKELY BE LESS THAN THOSE FURTHER
SOUTH. TEMPERATURES OVER THE PLAINS WILL WARM WITH WESTERLY FLOW
ALOFT PROMOTING MIXING WITH HIGHS IN THE 40S TO NEAR 50 SATURDAY
AND SUNDAY. COLD FRONT DROPS SOUTH OVER THE PLAINS SUNDAY NIGHT AS
THE UPPER TROUGH BEGINS TO MOVE INTO THE SOUTHERN PLAINS. THERE
MAY ALSO BE A QUICK SHOT OF LIGHT SNOW OVER THE EASTERN PLAINS AND
LEE SLOPE MONDAY BEHIND THE COLD FRONT BUT MODELS HAVE NOT
BE CONSISTENT ON THIS IDEA. HIGHS WILL ONLY TOP OUT IN THE UPPER
30S TO LOW 40S MONDAY.
PATTERN SHIFTS HEADING INTO TUESDAY AND WEDNESDAY WITH UPPER RIDGE
BUILDING OVER THE WESTERN CONUS. THIS WILL SHIFT EASTWARD AS WE
HEAD INTO THE MIDDLE OF THE WEEK WITH WARMING TEMPERATURES AND DRY
CONDITIONS OVER THE REGION. MOZLEY
&&
.AVIATION...
VFR CONDITIONS WILL CONTINUE THROUGH THE PERIOD. BLOWING
AND DRIFTING SNOW WILL BE WIDESPREAD IN AREAS NEAR THE MOUNTAINS
UNTIL AROUND MIDNIGHT. PATCHY AREAS OF BLOWING SNOW MAY OCCUR ALONG
THE CONTINENTAL DIVIDE UNTIL MORNING. THE DOWNSLOPE FLOW AND THE
SNOW ON THE GROUND MAY ALLOW FOR PATCHY FOG BRIEFLY TOMORROW
MORNING.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 5 PM MST THIS AFTERNOON FOR COZ058-
060-066-068.
WIND CHILL ADVISORY UNTIL 5 PM MST THIS AFTERNOON FOR COZ058>060-
063-066-068.
&&
$$
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