FXUS65 KPUB 231754 AAA
AFDPUB
AREA FORECAST DISCUSSION...UPDATED
NATIONAL WEATHER SERVICE PUEBLO CO
1054 AM MST WED DEC 23 2009
.UPDATE...
HAVE UPDATED THE FORECAST TO DROP THE WARNING FOR THE SAN
JUANS...DOWNGRADE THE WARNING FOR ERN KIOWA COUNTY...AND DROP
ADVISORIES ALONG THE I-25 CORRIDOR. STORM IS MID WAY THRU NM...AND
COOLER CLOUD TOPS MAINLY E OF OUR AREA. STILL SOME LIGHT SNOW OVR
THE ERN AND NRN MTS...SO WILL KEEP ADVISORIES GOING THERE WITH
TRAVEL OVR THE PASSES REMAINING HAZARDOUS...AND ALSO WILL KEEP SN
AND BLSN ADVISORIES GOING FOR THE ERN PLAINS...WHERE NRLY WINDS WILL
INCREASE OVERNIGHT AND THRU THU. ROSE
&&
.PREV DISCUSSION... /ISSUED 515 AM MST WED DEC 23 2009/
SHORT TERM...
(TODAY AND TONIGHT)
FORECAST CONCERNS INCLUDE SNOWFALL AMOUNTS AND WHEN TO LET HEADLINES
EXPIRE...
COMPLICATED PATTERN WHICH CONTINUES TO EVOLVE AS UPPER LOW BEGINS TO
EMERGE INTO THE SOUTHERN PLAINS LATER TODAY AND NORTHERN STREAM
SYSTEM DROPS INTO THE NRN U.S. ROCKIES. LATEST MODEL RUNS ARE NOW
TAKING THE SOUTHERN STREAM ENERGY MORE TO THE SOUTH THAN RUNS FROM
LAST NIGHT...WITH THE SECONDARY NORTHERN STREAM SYSTEM POSSIBLY A
BIGGER PLAYER AS IT DROPS IN FROM THE NORTH LATER TONIGHT.
CURRENTLY AXIS OF BEST ISENTROPIC UPGLIDE CONTINUES TO STREAM ACROSS
EASTERN SECTIONS OF THE FORECAST AREA...UP THRU WRN KS AND INTO
NORTHEAST CO. CLOUD TOP COOLING NOT ALL THAT IMPRESSIVE OVER OUR
AREA ON IR SATELLITE IMAGERY...WHICH MAKES SENSE SINCE MODELS ARE
NOT TERRIBLY STRONG WITH THE UPGLIDE. IN FACT...IN PAST COUPLE
HOURS...AREA OF SNOW HAS PULLED AWAY FROM THE I-25 CORRIDOR WITH MID
LVL H7 CIRCULATION APPEARING TO PULL AWAY TO THE EAST TOWARDS KLHX
RESULTING IN MORE DRYING NORTHWESTERLY FLOW OFF THE PALMER. WAS
TEMPTED TO PULL DOWN WINTER WEATHER ADVISORIES FOR PORTIONS OF THE
EASTERN MTNS AND I-25 CORRIDOR INCLUDING PUEBLO...SRN EL PASO AND
WESTERN FREMONT COUNTIES...BUT LATEST NAM APPEARS TO TIGHTEN UP THE
MID LVL CIRCULATION TO THE EAST AS THE LOW MOVES OUT ONTO THE
PLAINS...AND HENCE TRIES TO SPREAD PCPN BACK INTO THE I-25 CORRIDOR
BY LATE MORNING TO AROUND 2 PM. AFTER THAT TIME...FLOW ALOFT
BECOMES MORE NORTHERLY...AND BEST UPGLIDE PULLS OFF TO THE
NORTHEAST. FOR THE SOUTHERN CIRCULATION...APPEARS BEST AXIS OF
UPGLIDE STAYS TOO FAR SOUTH TO AFFECT SOUTHEAST CO. THUS FOR THE
BIGGER PICTURE...OVERALL HEAVIEST SNOW (WHICH WILL BE GENERALLY
LIGHT TO MODERATE AT BEST) WILL BE THIS MORNING...WITH SNOWFALL
DECREASING BY AFTERNOON. HAVE BACKED OFF ON SNOW AMOUNTS IN CURRENT
GRID PACKAGE. LATEST MODELS ARE KEEPING SNOW GOING OVER MUCH OF THE
WESTERN SECTIONS OF THE FORECAST AREA THROUGH TODAY...SO HAVE
EXTENDED SOUTHWEST MOUNTAIN HEADLINES THROUGH THIS AFTERNOON. THIS
LINES UP WELL WITH SURROUNDING OFFICES.
ALTHOUGH SNOW GENERALLY DECREASES BY LATE AFTERNOON OVER MUCH OF THE
DISTRICT...WINDS WILL BE ON THE INCREASE. SO THREAT ON THE PLAINS
WILL TRANSITION FROM A MODERATE SNOWFALL EVENT...TO A MAINLY LIGHT
SNOW AND BLOWING SNOW EVENT...ESPECIALLY INTO THIS EVENING AND
OVERNIGHT AS SECONDARY FRONT DROPS IN. MODELS KEEP SOUNDINGS
SATURATED OVERNIGHT SO IT WON/T BE DIFFICULT TO GENERATE A FEW
INCHES OF FLUFFY SNOW. CURRENT HIGHLIGHTS FOR THE CENTRAL AND
EASTERN MOUNTAINS AND PLAINS EXTEND THROUGH TONIGHT...AND WILL LEAVE
THESE AS IS FOR NOW. NORTH WINDS WILL INCREASE BEHIND THE FRONT
ACROSS THE EASTERN PLAINS...SO DEPENDING ON HOW MUCH SNOW FALLS THIS
MORNING THROUGH EARLY AFTERNOON...BLOWING SNOW COULD STILL BE A
PROBLEM. OVERALL THINK WINTER WEATHER ADVISORIES FOR THE EASTERN
MOUNTAINS AND PLAINS HANDLE THE OVERALL SITUATION. SOME AREAS WILL
PROBABLY COME UP A LITTLE SHORT ON THE SNOWFALL AMOUNTS.
LONG TERM...
(THURSDAY THROUGH TUESDAY)
METEOROLOGICAL ISSUES FOR THE LONG TERM INCLUDE COLD
TEMPERATURES...SNOW/BLOWING SNOW POTENTIAL...GUSTY WINDS AND
WIND CHILLS NEARING ADVISORY LEVELS AT TIMES.
RECENT COMPUTER SIMULATIONS...FORECAST MODEL SOUNDINGS AND
REAL-TIME DATA SUGGEST THAT INITIAL CLOSED LOW WILL BE CENTERED
OVER NORTH TEXAS BY 12Z THURSDAY WITH SECONDARY CLOSED UPPER LOW
LOCATED OVER EASTERN MONTANA AT 12Z THURSDAY. BY 00Z
FRIDAY...INITIAL CLOSED UPPER LOW IS ROTATING INTO
ARKANSAS...WHILE SECONDARY CLOSED UPPER LOW SHIFTS INTO
NORTHEASTERN COLORADO. THEN FROM APPROXIMATELY 18Z
FRIDAY UNTIL 18Z SATURDAY...INTENSIFYING CLOSED LOW WOBBLES OVER
WESTERN ILLINOIS...BEFORE PUSHING OFF INTO THE NORTHEASTERN UNITED
STATES BY SUNDAY.
FOR SENSIBLE WEATHER...WILL CONTINUE WITH GENERALLY SCATTERED
LIGHT SNOW ACTIVITY ON THURSDAY WITH INCREASED CHANCES OF BLOWING SNOW
DEVELOPING AS ENHANCED WINDS DEVELOP(ESPECIALLY EASTERN SECTIONS)
IN WAKE OF PREVIOUSLY MENTIONED INTENSIFYING CLOSED UPPER LOWS.
TEMPERATURES ON THURSDAY WILL BE WELL BELOW LATE DECEMBER
CLIMATOLOGICAL AVERAGES WITH THE COOLEST MAXIMUM TEMPERATURES OF
THE LONG TERM PROJECTED TO OCCUR ON THURSDAY.
WIND CHILL READINGS WILL NEAR WIND CHILL ADVISORY LEVELS FROM
THURSDAY NIGHT INTO CHRISTMAS MORNING AND THEN AGAIN FROM FRIDAY
EVENING INTO SATURDAY MORNING. WFO PUEBLO WILL CONTINUE TO
MONITOR CLOSELY AND ISSUE WIND CHILL HIGHLIGHTS IF LATER DATA
SUGGEST THAT COLDER TEMPERATURES AND/OR STRONGER WINDS WILL BE
POSSIBLE.
ALSO...HAVE PAINTED ADDITIONAL SNOW AMOUNTS IN THE 1 TO
7 INCH RANGE FOR PORTIONS OF THE CENTRAL MOUNTAINS FROM THURSDAY
NIGHT INTO CHRISTMAS FRIDAY. ALSO...GUSTY WINDS AT TIMES...ESPECIALLY
EASTERN SECTIONS...WILL BE A CONCERN FROM THURSDAY INTO THE
WEEKEND.
ANOTHER ITEM TO NOTE IS THAT ANOTHER RELATIVELY PROLONGED
PERIOD OF UNSEASONABLY COLD TEMPERATURES SHOULD OCCUR FROM
WEDNESDAY INTO THE WEEKEND(ALTHOUGH TEMPERATURES WILL NOT BE AS
EXTREME AS OCCURRED THIS PAST DECEMBER 6TH TO DECEMBER 10TH 2009).
NEVERTHELESS...TEMPERATURES MAY NOT EXCEED THE FREEZING MARK FOR
AREAS SUCH AS COLORADO SPRINGS AND PUEBLO UNTIL LATE THIS
WEEKEND.
FINALLY...GRADUALLY IMPROVING TEMPERATURES AS WELL AS GENERALLY DRY
CONDITIONS SHOULD THEN BE NOTED OVER THE CWFA FROM LATER IN THE
WEEKEND INTO EARLY NEXT WEEK.
AVIATION...
VARIABLE CIGS EXPECTED AT TAF SITES THROUGH THIS MORNING AS
NORTHERLY FLOW INCREASES OFF THE PALMER DVD...PUSHING BRUNT OF
HEAVIER SNOW OFF TO THE EAST. COULD SEE ANOTHER ROUND OF LIGHT SNOW
SPREAD IN TOWARDS LATE MORNING BRINGING MVFR TO OCCASIONAL IFR CIGS
UNDER -SHSN BACK TO THE AREA. THE SAN LUIS VALLEY WILL SEE GENERALLY
MVFR CIGS THROUGH THE MORNING WITH OCCASIONAL IFR CIGS UNDER THE
LIGHT TO MODERATE SNOW SHOWERS. EXPECT AN IMPROVING TREND IN CIGS
TOWARDS EARLY AFTERNOON...WITH WINDS INCREASING FROM THE NORTH.
COULD BE SOME BLSN AT KCOS LATER THIS AFTN. OVERNIGHT...ANOTHER
COLD FRONT DROPS IN AND LIGHT SNOW IS EXPECTED TO SPREAD ACROSS THE
REGION ONCE AGAIN. COULD SEE A COUPLE INCHES OF FLUFFY SNOW AT THE
TAF SITES WITH THIS SECOND WAVE ALONG WITH MVFR TO OCCASIONAL IFR
CIGS. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 5 PM MST THURSDAY FOR COZ095>099.
WINTER WEATHER ADVISORY UNTIL 5 AM MST THURSDAY FOR COZ058>061-
064>066-072>075-078>080.
&&
$$
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