Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 271125
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
425 AM MST FRI FEB 27 2015

.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 425 AM MST FRI FEB 27 2015

SNOWFALL ACROSS THE NORTH CENTRAL AND NORTHEAST COLORADO WILL TAKE
A BREAK TODAY AS WEAK SUBSIDENCE MOVES ACROSS THE
STATE...DOWNSTREAM FROM THE NEXT DEVELOPING TROUGH WHICH IS MOVING
DOWN FROM THE PACIFIC NORTHWEST. THE ARCTIC AIRMASS IS WELL
ENTRENCHED OVER THE EASTERN HALF OF THE STATE WITH MORNING LOWS
DROPPING BELOW ZERO IN THE DENVER METRO AREA AND TO THE SINGLE
DIGITS ELSEWHERE. SKIES WILL BE PARTLY TO MOSTLY CLOUDY THROUGH
THE DAY AS THE COLD AIRMASS STRUGGLES WITH HIGH RELATIVE HUMIDITY
VALUES AND COLD AIR BEING UNABLE TO HANG ON TO THE MOISTURE. IN
THE MOUNTAINS...WESTERLY FLOW ALOFT WILL CONTINUE WITH ENOUGH
MOISTURE TO PRODUCE SCATTERED SNOW SHOWER ACTIVITY THROUGH MOST OF
THE DAY AND OVERNIGHT. SOME OF THIS CLOUD COVER WILL MOVE OUT OVER
THE PLAINS BY EVENING WITH A SLIGHT CHANCE THAT SOME SNOW FLURRIES
WILL DEVELOP THROUGH THIS EVENING AND OVERNIGHT.

TEMPERATURES WILL REMAIN COLD THROUGH TODAY AND TONIGHT WITH HIGHS
ONLY MAKING IT TO THE MID AND UPPER TEENS AT MOST LOCATIONS. SNOW
COVER ON THE GROUND WILL BE HELPING HOLD TEMPERATURES DOWN IN
SPITE OF THE CHANCE THAT PARTLY SUNNY SKIES WILL DEVELOP FROM TIME
TO TIME.

OVER THE EASTERN PALMER DIVIDE...SOUTHERLY WINDS ARE EXPECTED TO
INCREASE THIS AFTERNOON WHICH MAY PRODUCE SOME BLOWING SNOW OUT IN
LINCOLN COUNTY. WILL NEED TO GET AN IDEA OF HOW MUCH SNOW IS ON
THE GROUND OUT THERE BEFORE TAKING ANY ADDITIONAL ACTION. FORECAST
WILL MENTION AREAS OF BLOWING SNOW FOR NOW.

.LONG TERM...(SATURDAY THROUGH THURSDAY)
ISSUED AT 425 AM MST FRI FEB 27 2015

AN UPPER LEVEL TROUGH WILL MOVE SE INTO NEVADA AND CAILFORNIA ON SAT
AND REMAIN THERE THRU SUN.  THIS WILL ALLOW FOR SWLY FLOW ALOFT
ACROSS THE AREA BOTH DAYS WITH MINOR DISTURBANCES EMBEDDED IN THE
FLOW.  CROSS-SECTIONS SHOW DECENT MOISTURE DEPTH IN THE MTNS FM SAT
AFTN INTO SUN MORNING WITH FAVORABLE MID LVL LAPSE RATES AND SOME
MID LVL ASCENT.  WITH SWLY WINDS AT 700 MB TYPICALLY THIS WOULD
FAVOR ZNS 31 AND 33 FOR HEAVIER SNOWFALL.  THUS MAY NEED AN ADVISORY
FOR THESE AREAS SAT AFTN INTO SUN MORNING.

AT LOWER ELEVATIONS A FNTL BNDRY WILL MOVE SOUTH INTO NERN CO SAT
AFTN INTO SAT EVENING WITH A SLIGHT INCREASE IN LOW LVL UPSLOPE
FLOW.  WITH SOME MID LVL ASCENT AND FAVORABLE LAPSE RATES SHOULD SEE
A BETTER CHC OF SNOW BY LATE SAT AFTN INTO SAT EVENING ESPECIALLY IN
THE NRN FOOTHILLS AND ADJACENT PLAINS.  IN ADDITION STRONGER WINDS
ALOFT WILL BE MOVING OVER THE AREA AS WELL SO COULD SEE SOME HEAVIER
BANDED SNOWFALL.  AS FOR HIGHS ON SAT WILL KEEP READINGS IN THE 20
TO 25 DEGREE RANGE OVER THE PLAINS.

ON SUN CROSS-SECTIONS SHOW MOISTURE DEPTH DECREASING IN THE MTNS
HOWEVER WILL STILL SEE PERIODS OF LIGHT SNOW ESPECIALLY IN THOSE
AREAS FAVORED BY SWLY FLOW. AT LOWER ELEVATIONS LIGHT ELY LOW LVL
FLOW WILL BE IN PLACE WITH A SHALLOW LYR OF MOISTURE UP TO AROUND
700 MB. WITH STILL SOME WK MID LVL ASCENT SHOWN OVER NRN CO ALONG
WITH LOCATION OF UPPER LEVEL JET MAY STILL SEE AT LEAST A CHC OF
LIGHT SNOW MAINLY IN AND NR THE FOOTHILLS DURING THE DAY. AS FOR
HIGHS WILL KEEP READINGS IN THE LOWER TO MID 20S ALTHOUGH AREAS
OVER THE FAR NERN PLAINS MAY RISE TO AROUND 30.

FOR MON THE UPPER LEVEL TROUGH OVER CALIFORNIA AND NEVADA WILL BEGIN
TO MOVE ENE AS ANOTHER UPPER LEVEL TROUGH MOVES INTO THE NWRN US.
THIS WILL ALLOW FOR SWLY FLOW ALOFT TO CONTINUE OVER THE AREA.
MOISTURE DEPTH WILL INCREASE IN THE MTNS WITH FAVORABLE MID LVL
LAPSE RATES SO ONCE AGAIN SHOULD SEE A BETTER CHC OF SNOW IN
THOSE AREAS FAVORED BY SWLY FLOW ALOFT. EAST OF TTHE MTNS SFC LOW
PRES WILL DVLP OVER ERN CO WITH SLY LOW LVL FLOW DEVELOPING. THIS
SHOULD ALLOW FOR SOME MODERATION OF TEMPS WITH READINGS RISING
BACK INTO THE 30S. AS FOR PCPN CHANCES WILL KEEP LOW POPS OVER THE
PLAINS.

BY MON NIGHT INTO TUE A RATHER COMPLEX PTRN APPEARS TO BE SETTING
UP.  THE GFS AND CMC MODEL EJECT THE UPPER LEVEL TROUGH OVER THE
SWRN US ACROSS THE AREA MON NIGHT INTO EARLY TUE AS A SECONDARY
TROUGH MOVES INTO THE NWRN US.  MEANWHILE THE ECMWF DOES NOT EJECT
THE SWRN US TROUGH AND TRIES TO PHASE IT WITH THE NRN STREAM INTO
ONE MAIN TROUGH.  AS A RESULT THIS LEADS TO SIGNIFICANT DIFFERENCES
IN RELATION TO PCPN DEVELOPMENT MON NIGHT INTO TUE.

AT THE SFC THE GFS AND CMC MODELS SHOW LOW PRES OVER SERN CO MON
NIGHT AS ANOTHER CDFNT MOVES INTO NERN CO WHICH ENHANCES UPSLOPE
FLOW WITH THE POTENTIAL FOR SIGNIFICANT SNOWFALL MON NIGHT INTO TUE
MORNING ACROSS THE AREA AS THE FIRST PIECE OF ENERGY MOVES ACROSS.
MEANWHILE THE ECMWF HARDLY HAS ANY PCPN SINCE IT HAS ONE
CONSOLIDATED TROUGH MUCH FURTHER WEST WHICH KEEPS MOST OF THE PCPN
OVER WRN CO.

FOR TUE AFTN INTO TUE NIGHT THE GFS AND CMC MODEL MOVE THE SECONDARY
UPPER LEVEL TROUGH ACROSS THE AREA WITH UPSLOPE FLOW REMAINING OVER
NERN CO WITH SOME ADDITIONAL SNOWFALL POSSIBLE.  MEANWHILE THE ECMWF
BRINGS THE MAIN UPPER LEVEL TROUGH ACROSS WITH ITS BEST CHC OF
PCPN MAINLY TUE NIGHT INTO EARLY WED. AT THIS POINT REALLY HARD TO
SAY WHICH SCENARIO WILL PAN OUT SO FOR NOW WILL JUST HAVE CHC POPS
FM MON NIGHT THRU TUE NIGHT UNTIL IT BECOMES MORE CLEAR AS TO WHAT
WILL TRANSPIRE. HIGHS BOTH TUE AND WED WILL BE SEVERAL DEGREES BLO
NORMAL.

&&

.AVIATION...(FOR THE TAFS THROUGH 12Z SATURDAY MORNING)
ISSUED AT 425 AM MST FRI FEB 27 2015

THE PRESENCE OF THE ARCTIC AIRMASS WILL MAKE FORECASTING CLOUD
HEIGHTS VERY TRICKY TODAY. ON THE ONE HAND THE AIRMASS IS GETTING
DRY BECAUSE OF THE COLD TEMPERATURES...BUT ON THE OTHER HAND LOW
LEVEL CLOUDS DEVELOP AS THE LAST OF THE MOISTURE FALLS OUT. SNOW
FLURRIES HAVE ENDED AT KDEN AND KAPA WITH NO CEILINGS BEING
REPORTED. BUT AT KBJC...A FEW SNOW FLURRIES AND IFR CEILINGS
LINGER. WILL WRITE THE TAFS WITH GENERALLY VFR CONDITIONS THROUGH
THE NEXT 24 HOURS. THERE MAY BE AN INCREASE IN MID-LEVEL CLOUDS
THIS EVENING AS CLOUDINESS FROM THE MOUNTAINS DRIFTS DOWNWIND.
WINDS WILL BE CONTINUING OUT OF THE SOUTH DUE TO THE STRONG
SURFACE HIGH PRESSURE AREA OVER THE CENTRAL AND SOUTHERN PLAINS.

&&

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

$$

SHORT TERM...DANKERS
LONG TERM...RPK
AVIATION...DANKERS


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