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000
FXUS65 KPUB 071112
AFDPUB

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PUEBLO CO
412 AM MST SAT DEC 7 2013

.SHORT TERM...(TODAY AND TONIGHT)
ISSUED AT 347 AM MST SAT DEC 7 2013

...HEAVY SNOW FOR THE CONTINENTAL DIVIDE THROUGH TONIGHT...CONTINUED
COLD WITH PERIODIC LIGHT SNOW FOR THE SOUTHEAST PLAINS...

UPPER TROF CARVING OUT ACROSS THE WESTERN U.S WILL DROP TOWARDS THE
GREAT BASIN AND WESTERN CO LATER TODAY...THEN ACROSS COLORADO
TONIGHT.  THIS WILL BRING ANOTHER UPSWING IN SNOW ACROSS THE
CONTINENTAL DIVIDE LATER THIS MORNING THROUGH THE AFTERNOON...THEN
ACROSS THE SOUTHEAST PLAINS THIS AFTERNOON THROUGH TONIGHT. THERE
ARE A COUPLE OF CONCERNS WITH THIS SYSTEM WHICH COULD LEAD TO A MORE
WIDESPREAD HIGH IMPACT EVENT.  FIRST IS THE INSTABILITY THAT WILL
COME IN WITH THIS SYSTEM.  MODEL SOUNDINGS SHOW VERY STEEP LAPSE
RATES...PARTICULARLY ACROSS WESTERN SECTIONS OF THE AREA
TODAY...SPREADING ACROSS EASTERN SECTIONS DURING THE OVERNIGHT
HOURS.  SOUNDINGS ARE DEEPLY MOIST ACROSS THE CONTDVD...AND ALONG
WITH SOUTHWEST UPSLOPE FLOW...VERY INTENSE SNOWFALL RATES WILL BE
POSSIBLE ACROSS THE EASTERN SAN JUAN MOUNTAINS.  FOR THE CENTRAL
MTS...SOUTHWEST FLOW ISN`T AS OROGRAPHICALLY FAVORABLE...BUT
CONVECTIVELY HEAVY SNOW COULD RESULT IN LOCALLY HEAVY ACCUMS
ANYWAY.  CURRENT ADVISORIES AND WARNINGS LOOK ON TRACK SO NO CHANGES
NEEDED.  HOWEVER WITH THE INSTABILITY WILD CARD...ITS POSSIBLE THAT
LOCATIONS NOT IN THESE HIGHLIGHT AREAS COULD PICK UP SOME LOCALLY
HEAVY SNOWFALL.  HAVE INCREASED POPS AND SNOW AMOUNTS ACROSS THE
ARKANSAS RIVER VALLEY OF CHAFFEE COUNTY.  HAVE AROUND 2 TO 5 INCHES
OF SNOW FOR THE BUENA VISTA AND SALIDA AREAS INTO SUNDAY MORNING FOR
NOW. THESE COULD NEED TO BE INCREASED IF A BAND OF HEAVY SNOW SETS
UP IN THIS AREA.  THERE WILL BE A DRY SLOT LURKING ALONG OUR
SOUTHERN BORDER WHICH COULD CUT BACK ON SNOW ACCUMS FOR THE
SOUTHWEST MTS LATE TONIGHT...BUT WITH THE COMBINATION OF OROGRAPHICS
AND INSTABILITY EARLY ON...THINK THAT WARNING CRITERIA SHOULD BE
MET.

ACROSS THE SOUTHEAST PLAINS...STILL DEALING WITH FLURRIES EARLY THIS
MORNING WHERE SOUTHEAST UPSLOPE FLOW WITHIN THE ARCTIC AIRMASS
CONTINUES.  ALTHOUGH SOUNDINGS ARE NOT ALL THAT DEEPLY SATURATED (IN
FACT THERE IS AN AREA OF CLEARING EXTENDING FROM KTAD TO KLHX)
AIRMASS IS SO COLD THAT ANY WEAK LIFT FROM THE UPSLOPE IS ABLE TO
SQUEEZE OUT SOME SNOW FLAKES.  WITH TIME...LOW LEVEL EAST TO
SOUTHEAST FLOW WILL INCREASE AND STRATUS SHOULD FILL BACK IN TOWARDS
THE MTS THIS AFTERNOON AND EVENING WITH ISOLATED SNOW SHOWERS POSSIBLE
AS WEAK UPGLIDE DEVELOPS AHEAD OF THE APPROACHING STORM SYSTEM.
HAVE BUMPED UP POPS INTO THE SCATTERED CATEGORY OVERNIGHT FOR THE
PIKES PEAK REGION.  SANGRES AND EASTERN PORTIONS OF THE SAN LUIS
VALLEY COULD ALSO PICK UP A QUICK BURST OF SNOW THIS EVENING AS
UPPER TROF APPROACHES.  THEN DRY SLOT SHOULD PUT A QUICK END TO IT
TOWARDS EARLY SUNDAY MORNING.  HAVE KEPT TEMPS SIMILAR TO
YESTERDAY`S VALUES FOR THE PLAINS WHERE PERSISTENT ARCTIC AIRMASS
WILL REMAIN IN PLACE.  FOR THE SAN LUIS VALLEY...BREEZY SOUTH TO
SOUTHWEST WINDS WILL HELP TEMPS WARM INTO THE MID 20S BY AFTERNOON
BEFORE SNOW SHOWERS MOVE IN.

WINDS WILL ALSO INCREASE ACROSS THE HIGHER ELEVATIONS WITH GUSTS
OVER 50 MPH POSSIBLE ACROSS THE HIGHER AREAS.  THIS WILL LEAD TO
AREAS OF BLOWING SNOW OVER THE MTN PASSES...PARTICULARLY ALONG THE
CONTDVD THIS AFTERNOON AND TONIGHT.  THIS WILL ALSO PUSH WIND CHILLS
DOWN INTO THE -20 TO -35 DEGREE RANGE INTO TONIGHT WITH HYPOTHERMIA
A BIG THREAT FOR ANYONE EXPOSED TO THE ELEMENTS TONIGHT. ALL IN
ALL...A HIGH IMPACT EVENT FOR THE MTS ALONG THE CONTDVD AND TRAVEL
THROUGH THESE AREAS THIS AFTERNOON AND TONIGHT SHOULD NOT BE TAKEN
LIGHTLY.  IF YOU MUST TRAVEL...BE SURE TO CARRY A WINTER SURVIVAL
KIT.   -KT

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 347 AM MST SAT DEC 7 2013

NOT MUCH CHANGE TO THE FORECAST THINKING THROUGH THE EXTENDED
PERIOD WITH COLD CONDITIONS THROUGH MONDAY...BEFORE DRY AND WARMER
WEATHER MOVES ACROSS THE REGION BY MID WEEK.

AN UPPER LEVEL TROUGH WILL BE MOVING ACROSS THE ROCKIES SUNDAY
MORNING WITH ONGOING SNOW ACROSS THE CONTINENTAL DIVIDE. THE
HEAVIEST SNOWFALL IS EXPECTED OVER THE SAN JUAN RANGE WHERE THE
MOST FAVORABLE OROGRAPHIC FLOW WILL EXIST. SNOW WILL BE HEAVIEST
SUNDAY MORNING WITH THE TROUGH AXIS RIGHT OVERHEAD. AT LEAST
MODERATE TO HEAVY SNOW IS ALSO EXPECTED OVER THE CENTRAL MOUNTAINS
THROUGHOUT THE DAY ON SUNDAY. MORE ISOLATED ACTIVITY IS EXPECTED
OVER THE EASTERN MOUNTAINS...INTO THE PALMER DIVIDE ON SUNDAY.
ACROSS THE PLAINS...A COLD FRONT WILL ARRIVE BY MIDDAY WITH A
NORTHERLY WIND SHIFT ACROSS THE AREA. GIVEN A MORE NORTHERN STORM
TRACK...AND LACK OF AN EASTERLY COMPONENT TO THE LOW TO MID LEVEL
WINDS...HAVE A FEELING MOST OF THE PLAINS WILL REMAIN DRY ON
SUNDAY. THERE COULD BE A FEW FLURRIES...BUT NO ACCUMULATIONS ARE
ANTICIPATED ACROSS THE PLAINS AT THIS TIME.

MODELS IN GOOD AGREEMENT WITH THE UPPER SYSTEM TRANSITIONING EAST
INTO THE CENTRAL PLAINS BY SUNDAY AFTERNOON WITH SNOW INTENSITIES
DROPPING OFF ACROSS THE MOUNTAINS. THE PERIOD OF HEAVIEST SNOWFALL
FOR THE SAN JUAN RANGE WILL COME TO AN END BY SUNDAY AFTERNOON
WITH LIGHT SNOW INTO SUNDAY EVENING. AS FLOW TRANSITIONS TO
NORTHWESTERLY ALOFT...THE CENTRAL MOUNTAINS WILL LIKELY SEE A
PERIOD OF MODEST SNOWFALL SUNDAY AFTERNOON AND EVENING...BEFORE
DECREASING TO LIGHT SNOW SUNDAY NIGHT THROUGH MONDAY MORNING. ALL
SNOWFALL WILL COME TO AN END BY MONDAY AFTERNOON AS THE SYSTEM
PULLS AWAY FROM THE AREA.

TEMPERATURES WILL REMAIN COLD ACROSS THE REGION SUNDAY AND MONDAY
WITH HIGHS IN THE TEENS TO LOW 20S FOR THE LOWER ELEVATIONS.
OVERNIGHT LOWS WILL REMAIN FRIGID WITH SUBZERO TEMPERATURES FOR
MUCH OF THE REGION.

BEYOND MONDAY...BROAD NORTHWESTERLY FLOW WILL PERSIST ACROSS THE
AREA THROUGH WEDNESDAY BEFORE UPPER LEVEL RIDGING MOVES INTO THE
ROCKIES FOR THURSDAY AND FRIDAY. EXPECT WARMING CONDITIONS FOR
TUESDAY AND WEDNESDAY WITH HIGHS IN THE 30S. THE PERSISTENT
NORTHWEST FLOW COULD PRODUCE A COUPLE OF LIGHT SNOW SHOWERS FOR
THE CENTRAL MOUNTAINS...BUT OVERALL COVERAGE WILL BE PRETTY
LIMITED SO HAVE LEFT THEM OUT OF THE FORECAST FOR NOW. BY
THURSDAY...TEMPERATURES ALOFT WARM AND WARMER AIR WILL MOVE INTO
THE REGION. AFTERNOON HIGHS WILL LIKELY WARM WELL INTO THE 40S
WITH A FEW 50S POSSIBLE ACROSS THE PLAINS.  MOZLEY

&&

.AVIATION...(FOR THE 12Z TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 347 AM MST SAT DEC 7 2013

FOR KALS...VFR CONDITIONS ARE EXPECTED TODAY WITH GUSTY SOUTHWEST
WINDS 15-25 KTS IN THE AFTERNOON.  SCATTERED -SHSN WILL SPREAD IN
DURING EVENING WITH SOME BRIEF MVFR CIGS/VIS POSSIBLE.  MEANWHILE...MTS
ALONG THE CONTDVD WILL SEE MTN OBSCURATIONS AND IFR TO LIFR CIGS/VIS
IN +SN BLSN SPREAD IN DURING THE AFTERNOON. THESE CONDITIONS WILL
CONTINUE TONIGHT WITH SOME IMPROVEMENT IN THE SOUTHERN AREAS TOWARDS
EARLY SUNDAY MORNING.  MTN OBSCURATIONS WILL SPREAD INTO THE
SOUTHEAST MOUNTAINS DURING THE LATE AFTERNOON AND EVENING HOURS. -KT

&&

.PUB WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 5 PM MST
SUNDAY FOR COZ066.

WINTER STORM WARNING FROM 11 AM THIS MORNING TO 5 PM MST SUNDAY
FOR COZ068.

WINTER WEATHER ADVISORY FROM 11 AM THIS MORNING TO 5 AM MST
MONDAY FOR COZ058>061.

&&

$$

SHORT TERM...KT
LONG TERM...MOZLEY
AVIATION...KT