FXUS65 KPUB 291722 AAA
AFDPUB
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PUEBLO CO
1022 AM MST SUN NOV 29 2009
.UPDATE...
HAVE UPDATED THE FORECAST TO ACCOUNT FOR CLEARING WORKING QUICKLY
SOUTH ACROSS THE AREA...AS UPPER LOW AND FORCING FOR PRECIP
CONTINUE TO MOVE AWAY. DROPPED THE ADVISORY FOR THE EASTERN SAN
JUANS AS ONLY LIGHT SNOW WITH LITTLE ACCUMULATION IS NOW
EXPECTED. ALSO DROPPED MENTION OF SNOW FOR AREAS ALONG AND NORTH
OF THE ARKANSAS RIVER...AND MAY NEED TO END POPS OVER THE
REMAINDER OF THE AREA BY EARLY AFTERNOON UNLESS -SHSN REDEVELOP
NEAR THE NM BORDER.
&&
.PREV DISCUSSION... /ISSUED 415 AM MST SUN NOV 29 2009/
SHORT TERM...
(TODAY AND TONIGHT)
CURRENTLY...UPPER LOW CONTINUES TO DROP SOUTH INTO NORTHERN MEXICO
WHILE AN UPPER TROUGH SWINGS INTO THE CENTRAL PLAINS. SNOW HAS
DEVELOPED AS ADVERTISED OVER THE EASTERN SAN JUANS...SPREADING INTO
THE SAN LUIS VALLEY AND THE SOUTHERN SANGRE DE CRISTO RANGE. THE
HEAVIEST PRECIPITATION REMAINS WELL TO THE SOUTH OVER CENTRAL NEW
MEXICO...CLOSER TO THE UPPER LOW. LIGHT SNOWFALL HAS BEEN REPORTED
AT WOLF CREEK PASS AND ALAMOSA EARLY THIS MORNING.
MODELS ARE IN GOOD AGREEMENT THROUGH THE SHORT TERM IN REGARDS TO
STORM TRACK...BUT STILL VARYING IN HOW MUCH SNOWFALL OUR SOUTHERN
ZONES WILL SEE. FOLLOWED ALONG WITH THE SREF/NAM WITH REGARDS TO
SNOW AMOUNTS. SNOW WILL CONTINUE TO SPREAD NORTHWARD EARLY THIS
MORNING IMPACTING THE WESTERN MOUNTAINS...SAN LUIS VALLEY...SOUTHERN
SANGRE DE CRISTO RANGE...AND THE RATON MESA THROUGH THIS AFTERNOON.
THE GOING WINTER WEATHER ADVISORY FOR THE EASTERN SAN JUANS LOOKS
GOOD WITH MOST LOCATIONS SEEING 4 TO 6 INCHES WITH LOCALIZED AREAS
SEEING UP TO 9 INCHES. ELSEWHERE...2 TO 4 INCHES OF SNOW ARE
EXPECTED OVER THE SOUTHERN SANGRE DE CRISTO RANGE AND RATON MESA
ALONG THE CO/NM BORDER. THE LEE SLOPES AND ADJACENT PLAINS
INCLUDING THE I-25 CORRIDOR WILL ONLY SEE A DUSTING TO AN INCH OF
SNOWFALL. NOT AS CONFIDENT IN HOW FAR NORTH SNOWFALL WILL MAKE
IT...SO LOCATIONS NORTH OF U.S. HIGHWAY 50...INCLUDING KCOS MAY NOT
SEE MUCH MORE THAN FLURRIES.
UPPER LOW CONTINUES EAST ACROSS NORTHERN MEXICO WITH AN UPPER LEVEL
RIDGE WRAPPING AROUND THE LOW INTO COLORADO OVERNIGHT. MODELS ALL
IN AGREEMENT WITH SNOWFALL ENDING BY 03Z-06Z AS THE BEST UPPER LEVEL
SUPPORT MOVES OFF TO THE SOUTHEAST AND DRY AIR WORKS ITS WAY IN FROM
THE NORTH. TEMPERATURES WILL BE COLD OVERNIGHT WITH LIGHT
WINDS...CLEARING SKIES AND SOME SNOW COVER. LOWS WILL BOTTOM OUT IN
THE TEENS TO LOW 20S OVER THE EASTERN PLAINS...WITH NEAR ZERO
READINGS IN THE SAN LUIS VALLEY. 88
LONG TERM...
(MONDAY THROUGH SATURDAY)
..2 POTENTIAL SYSTEMS OF CONCERN DURING THE LONG RANGE...
UPPER LOW TO THE SOUTH WILL MOVE EASTWARD ACROSS OLD MEXICO INTO CEN
TX BY 00Z WED. ASIDE FROM SOME HIGH CLOUDS AT TIMES ACROSS SRN
PORTIONS OF THE FCST AREA...SC/SE CO WILL REMAIN DRY WITH REBOUNDING
TEMPERATURES AS LEE TROF REDEVELOPS AND WARMER MID LVL TEMPS MOVE IN
FROM THE NORTHWEST OVER THE FLAT UPPER RIDGE.
ATTENTION THEN TURNS TO THE 1ST OF 2 SYSTEMS WHICH WILL DROP INTO
THE NRN US ROCKIES FROM CANADA MONDAY NIGHT. THIS SYSTEM IS STILL
PROGGED BY THE MAJORITY OF THE MODELS TO SWEEP INTO THE NRN PLAINS
ON TUESDAY SENDING A COLD FRONT THROUGH EASTERN COLORADO DURING THE
AFTN. HOW AMPLIFIED AND HOW FAR WEST THIS ENERGY WILL TRACK AS IT
SKIRTS THROUGH THE NRN ROCKIES IS STILL IN QUESTION. 00Z NAM WAS
THE MOST AMPLIFIED AND FARTHEST WEST WITH THE TRACK THAN OTHER
MODELS AND AS A CONSEQUENCE DROPPED COLDER AIR INTO SOUTHEAST
COLORADO TUES NIGHT/WED. HOWEVER...06Z NAM HAS TRENDED TOWARDS
THE LESS AMPLIFIED/FARTHER EAST GFS AND ECMWF SOLNS SO HAVE
DISCOUNTED THE 00Z NAM RUN FOR NOW. LOW LVLS SHOULD SATURATE TUES
NIGHT ACROSS THE EASTERN MTS/ADJACENT PLAINS WITH MODELS
SUGGESTING SOME STRATUS AND PERHAPS SOME LIGHT SNOW/FLURRIES IN
WEAK NE UPSLOPE FLOW. BEST CHANCE WILL BE ACROSS THE PIKES PEAK
REGION...THOUGH AT THIS POINT...ISOLATED POPS SEEM TO BEST HANDLE
IT AS MOST OF THE FORCING WITH THIS SYSTEM WILL PASS WELL OFF TO
THE NORTHEAST. DOUBT THERE WILL BE MUCH IN THE WAY OF ACCUMULATIONS.
WRN MTS WILL NOT SEE AS MUCH AFFECT FROM THIS SYSTEM AND HAVE
BACKED OFF ON POPS IN THOSE AREAS.
COLDER TEMPERATURES ARE EXPECTED FOR WED/THURS WITH DEEP NORTHERLY
FLOW ALOFT AND 1020 SFC HIGH SETTLING SOUTHWARD THROUGH THE PLAINS.
KEPT MAX TEMPS BELOW GUIDANCE THESE DAYS AS MEXS MID 40S TO LOWER
50S LOOK A LITTLE TOO OPTIMISTIC FOR THE PLAINS. CURRENT FORECAST
HAS ISOLATED POPS ACROSS THE MOUNTAINS/ADJACENT PLAINS BOTH DAYS
WHICH LOOKS OKAY FOR NOW. GFS DROPS UPPER JET SOUTHWARD ACROSS ROCKIES
WED NIGHT/THURS WITH THE POSSIBILITY OF SOME INCREASED DYNAMIC
FORCING FOR LIGHT PCPN ACROSS NRN/EASTERN SECTIONS OF THE
DISTRICT.
LONG RANGE MODEL SOLNS DIVERGE FOR FRIDAY AND SATURDAY WITH
OPERATIONAL GFS DROPPING ANOTHER LOW INTO THE NRN US ROCKIES WITH
ADDITIONAL JET ENERGY DROPPING OUT OF CANADA AND CLOSING OFF AN
UPPER LOW OVER THE GREAT BASIN BY SAT NIGHT. QUITE A SPREAD IN GFS
ENSEMBLE MEMBERS THOUGH AND 00Z ECMWF IS COMPLETELY OUT OF
PHASE...DEPICTING A RIDGE MOVING INTO THE GREAT BASIN ON SAT
INSTEAD. GIVEN THE UNCERTAINTIES MADE FEW CHANGES TO DAYS 6 AND 7.
-KT
AVIATION...
SNOW IS MOVING NORTHWARD INTO SOUTH CENTRAL COLORADO THIS MORNING
WITH LIGHT SNOWFALL BEING REPORTED AT KALS. OBS AT KALS HAVE
INDICATED VISIBILITIES AND CIGS DROPPING TO 1 SM AND VV004 AT
TIMES. CONDITIONS AT KALS WILL CONTINUE TO FLUCTUATE BETWEEN MVFR
AND IFR THROUGH THIS AFTERNOON AS SNOW IMPACTS THE TERMINAL.
SNOWFALL AND LOWERED CIGS WILL CAUSE MOUNTAIN OBSCURATIONS AROUND
KALS. SNOWFALL WILL BEGIN TO DECREASE IN COVERAGE THIS AFTERNOON
WITH IMPROVING CONDITIONS TO VFR AFTER MON/06Z. UP TO AN INCH OF
SNOW IS EXPECTED THROUGH THIS AFTERNOON AT KALS.
LOWERED CIGS ARE PRODUCING MVFR CONDITIONS AT BOTH KCOS AND KPUB
THIS MORNING. EXPECT SNOW TO DEVELOP BY MID MORNING AND IMPACT BOTH
TAF SITES THROUGH THIS AFTERNOON. SNOW WILL BE LIGHT AND MAY MIX
WITH RAIN THIS AFTERNOON AT KPUB. THE MAIN IMPACT WILL BE MVFR
CONDITIONS DUE TO CIGS AND MOUNTAIN OBSCURATIONS TO THE WEST. VFR
CONDITIONS WILL PREVAIL AT BOTH KCOS AND KPUB AFTER MON/03Z. 88
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
10/27
