Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 291022
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
322 AM MST THU JAN 29 2015

.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 322 AM MST THU JAN 29 2015

A SMALL AREA OF LIGHT RAIN MIXED WITH SNOW CONTINUES NR A FORT
COLLINS TO GREELEY TO FORT MORGAN LINE EARLY THIS MORNING.  THIS
AREA APPEARS TO BE ASSOCIATED WITH AN UPPER LEVEL JET ALONG WITH
SOME POTENTIAL VORTICITY.  APPEARS MOST OF THIS ACTIVITY WILL END
AROUND SUNRISE.  OTHERWISE THERE IS QUITE A BIT OF MOISTURE UP TO
AROUND 600 MB OVER THE AREA WHICH HAS PRODUCED WIDESPREAD CLOUDS AND
SOME VERY LIGHT SNOW OVER THE HIGHER MTNS.

FOR THIS AFTN THRU TONIGHT AN UPPER LEVEL RIDGE WILL BUILD INTO THE
AREA WITH THE FLOW ALOFT BECOMING MORE SWLY.  SOME DEEPER MOISTURE
MAY AFFECT THE MTNS LATE TONIGHT WHICH WILL PRODUCE A CHC OF
LIGHT SNOW MAINLY SOUTH OF I-70. OVER NERN CO IT WILL BE DRY THIS
AFTN AND TONIGHT. CLOUD COVER MAY LINGER INTO THE AFTN HOURS ALONG
THE FRONT RANGE BUT SHOULD BEGIN TO DECREASE BY LATE IN THE DAY.
AS FOR HIGHS READINGS WILL COOL BACK TO SEASONAL LEVELS OVER THE
PLAINS AS HIGH PRES RESIDES OVER NERN CO.

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 322 AM MST THU JAN 29 2015

MAIN FORECAST CONCERNS STILL SURROUND SNOW CHANCES AHEAD OF SLOW
MOVING SOUTHWEST TROUGH.

ON FRIDAY...WE STILL EXPECT A RELATIVELY MILD DAY DESPITE THE
INCREASE AND THICKENING OF MID LEVEL CLOUDS. UPPER LEVEL RIDGE IS
IN PLACE...BUT MODELS ARE STILL CONSISTENT BRINGING INCREASING
CLOUD COVER THROUGHOUT THE DAY AS DEEP MOISTURE PLUME SHIFTS
NORTHEAST THROUGH THE RIDGE. ENOUGH MOISTURE BY AFTERNOON FOR A
FEW SNOW SHOWERS IN THE HIGH COUNTRY...BUT ACCUMULATIONS SPOTTY
AND MAINLY AN INCH OR LESS. ON THE PLAINS...THERE IS A WEAK COLD
FRONT ADVERTISED TO MOVE THROUGH LATE IN THE DAY. AS A RESULT...A
WEAK UPSLOPE COMPONENT DEVELOPS WHICH COULD ALLOW A FEW SHOWERS TO
SPREAD ONTO THE PLAINS BY EVENING AND DURING THE OVERNIGHT HOURS
FRIDAY NIGHT.

PERSISTENT BUT WEAK Q-G VERTICAL MOTION EXISTS OVER THE AREA
THROUGH MOST OF THIS PERIOD AND INTO SATURDAY AS WELL. PLENTY OF
MOISTURE IS AVAILABLE SATURDAY BUT AT THE SAME TIME THERE IS VERY
LITTLE OROGRAPHIC FORCING. THE WEAK SYNOPTIC SCALE SUPPORT ALONG
WITH WEAK Q-G LIFT WOULD RESULT IN A DECENT CHANCE OF LIGHT SNOW.
WILL HAVE CHANCE POPS MOST AREAS FOR SATURDAY...WITH SOMEWHAT
HIGHER POPS IN THE MOUNTAINS. THERE IS ALSO AN UPPER LEVEL
DEFORMATION ZONE AND FRONTOGENESIS OVER THE REGION THAT COULD
PRESENT ITSELF IN BANDED PRECIP...BUT OVERALL DONT ANTICIPATE
ANYTHING MORE THAN LIGHT SNOW GIVEN THE LACK OF SIGNIFICANT
FORCING MECHANISMS. IT SHOULD CERTAINLY BE NOTED THE ECMWF AND
EVEN A FEW OF THE GFS ENSEMBLES ARE FARTHER SOUTH WITH THIS WHOLE
SETUP...WHICH COULD KEEP MOST PRECIPITATION TO OUR SOUTH.

BY SATURDAY NIGHT...PRECIPITATION THREAT WILL BE SHIFTING AWAY TO
OUR SOUTH AND EAST AS SYSTEM IS EXPECTED TO BE SHEARED SOUTHEAST BY
FAST APPROACHING NORTHERN BRANCH ENERGY. THIS WILL LIKELY BRING A
REINFORCING SHOT OF COLDER AIR FOR SUNDAY. HAVE OPTED TO KEEP A
DRY FORECAST IN PLACE SUNDAY BUT THIS COULD CHANGE IF NORTHERN
BRANCH ENERGY IS STRONGER...AND WE ARE IN NORTHWEST FLOW WHICH IS
ALWAYS SOMETHING TO WATCH.

FOR MONDAY AND TUESDAY...STRONGER NORTHWEST FLOW PATTERN WILL
LIKELY DOMINATE RESULTING IN A GOOD CHANCE OF SNOW FOR THE
NORTHERN COLORADO MOUNTAINS...AND ALSO PERIODS OF GUSTY WINDS TO
THE FRONT RANGE FOOTHILLS AND NEARBY PLAINS. MONDAY SHOULD BE A
FAIRLY WINDY BUT WARMER DAY ON THE PLAINS WITH STRONGEST
DOWNSLOPE NOTED BY MODEL ENSEMBLES. TUESDAY AND WEDNESDAY COULD
FEATURE A COUPLE OF COLD FRONTS ARRIVING ACROSS THE PLAINS
BRINGING A CHANCE OF LIGHT SNOW BACK INTO THE FORECAST. THIS ALL
SEEMS PLAUSIBLE GIVEN EXPECTATION FOR NORTHWEST FLOW PATTERN
THROUGH THE MID PART OF NEXT WEEK.

&&

.AVIATION...(FOR THE TAFS THROUGH 12Z FRIDAY MORNING)
ISSUED AT 322 AM MST THU JAN 29 2015

CLOUD DECK BETWEEN 5500-7000 FT MAY LINGER THRU 18Z BEFORE
DECREASING BY MID AFTN...OTHERWISE APPEARS ANY LIGHT PCPN EARLY THIS
MORNING WILL STAY NORTH OF DIA.  WINDS EARLY THIS MORNING HAVE HAD A
LIGHT WNW COMPONENT.  BY 15Z WINDS SHOULD BECOME LIGHT ELY AND THEN
MORE SELY BY 20Z.  FOR THIS EVENING WINDS WILL BECOME SLY AND REMAIN
SO OVERNIGHT.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
NONE.
&&

$$

SHORT TERM...RPK
LONG TERM...BARJENBRUCH
AVIATION...RPK


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