Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 231046
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
446 AM MDT MON MAR 23 2015

.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 446 AM MDT MON MAR 23 2015

A PERIOD OF INCREASING WESTERLY FLOW ALOFT IS GOING TO BRING
CHANGES TO THE WEATHER FOR THE NEXT FEW FORECAST PERIODS. THROUGH
TODAY...SOUTHERLY WINDS ON THE PLAINS ARE GOING TO BE ENHANCED BY
A DEEPENING LEE-SIDE TROUGH JUST TO THE EAST OF THE FOOTHILLS.
WIND GUSTS OF 20 TO 30 MPH CAN BE EXPECTED. TEMPERATURES ARE
EXPECTED TO REMAIN IN THE MID AND UPPER 60S WITH MINIMUM RELATIVE
HUMIDITIES IN THE UPPER TEENS TO LOWER 20S. A FEW AREAS ON THE
PALMER DIVIDE WILL BE CLOSE TO RED FLAG CRITERIA FOR A COUPLE
HOURS...BUT NOT QUITE ENOUGH TO ISSUE ANY HIGHLIGHTS. THESE AREAS
RECEIVED A PRETTY GOOD SHOT OF RAINFALL LAST WEDNESDAY WHICH HAS
PROBABLY HELPED VEGETATION TO BEGIN GREENING UP.

IN THE MOUNTAINS...INCREASING MOISTURE AHEAD OF A SHORT WAVE THAT
WILL MOVE OVER COLORADO TONIGHT MAY PRODUCE SOME SNOW SHOWERS
DURING THE AFTERNOON HOURS. MORE SHOWERS ARE EXPECTED OVERNIGHT AS
THE BULK OF MOISTURE AND DYNAMICS ASSOCIATED WITH THE UPPER LEVEL
IMPULSE MOVE ACROSS THE STATE. RAIN SHOWERS AND POSSIBLY SOME
THUNDERSTORMS WILL MOVE OUT ONTO THE PLAINS OVERNIGHT...MAINLY TO
THE NORTH OF DENVER. A MIX OF RAIN AND SNOW WILL BE POSSIBLE ON
THE PLAINS AFTER MIDNIGHT.

ALSO TONIGHT...WINDS WILL BEGIN INCREASING IN THE MOUNTAINS AND
FOOTHILLS AS THE WESTERLY FLOW AT MID LEVELS AND ALOFT INCREASE.
MOUNTAIN AREAS MAY SEE A LITTLE BIT OF BLOWING SNOW AS THE WINDS
INCREASE. BREEZY CONDITIONS WILL SPREAD ONTO THE PLAINS LATE
TONIGHT...BUT THE STRONGEST WINDS ARE NOT EXPECTED UNTIL TUESDAY
MORNING.

.LONG TERM...(TUESDAY THROUGH SUNDAY)
ISSUED AT 446 AM MDT MON MAR 23 2015

AN UPPER LEVEL TROUGH WILL EXIT NRN CO EARLY ON TUE WITH RATHER STG
WNW FLOW ALOFT THRU THE DAY.  CROSS-SECTIONS SHOW DRIER AIR WILL
MOVE INTO THE AREA WITH MID LVL SUBSIDENCE.  THUS SNOW SHOULD
GRADUALLY DECREASE IN THE MTNS DURING THE MORNING HOURS WITH ONLY A
SLIGHT CHC OF SHOWERS OVER THE FAR ERN PLAINS.  BY AFTN EXPECT DRY
CONDITIONS AT LOWER ELEVATIONS WITH ONLY A CHC OF -SHSN IN THE MTNS.
WINDS WILL BE GUSTY THRU THE DAY WITH SPEEDS STAYING JUST BLO HIGH
WIND CRITERIA FM THE FOOTHILLS ACROSS THE PLAINS MOST OF THE DAY.
THERE MAY BE A SMALL WINDOW FOR HIGH WINDS BETWEEN 12Z AND 15Z AS
INITIAL STG SUBSIDENCE BEHIND THE UPPER LEVEL TROUGH MOVES ACROSS
NRN CO HOWEVER DUE TO SHORT DURATION AND LIMITED COVERAGE WILL NOT
ISSUE A HIGH WIND WATCH.  AS FOR HIGHS READINGS WILL DROP BACK INTO
THE LOWER TO MID 60S OVER NERN CO.

FOR TUE NIGHT THRU WED THE FLOW ALOFT WILL BECOME MORE NWLY.  A
POTENTIAL DISTURBANCE EMEDDED IN THIS FLOW MAY TRACK ACROSS NRN CO
ON WED WITH SOME MID LVL ASCENT THRU THE AFTN HOURS ALONG WITH
FAVORABLE LAPSE RATES.  IN ADDITION A CDFNT WILL MOVE ACROSS NERN CO
IN THE MORNING HOURS WITH NNE LOW LVL FLOW.  SNOW SHOULD INCREASE IN
THE MTNS LATE TUE NIGHT AND CONTINUE THRU WED AFTN.  AT LOWER
ELEVATIONS THERE MAY BE A CHC OF SOME PCPN ON WED ESPECIALLY IN AND
NR THE FOOTHILLS AND ACROSS THE PALMER DIVIDE.  BUFFER SOUNDINGS
SHOW AIRMASS WILL BE COLD ENOUGH FOR SNOW LEVELS TO DROP DOWN TO
AROUND 5000 FT.  AS FOR HIGHS WILL HAVE LOWERED READINGS INTO THE
MID 40S TO LOWER 50S ACROSS NERN CO DUE TO FASTER FNTL PASSAGE.

BY WED NIGHT THE UPPER LEVEL DISTURBANCE WILL EXIT THE AREA WITH
DRIER AIR SPREADING ACROSS IN NWLY FLOW ALOFT.  THUS PCPN CHANCES
SHOULD END IN MOST AREAS EARLY IN THE EVENING ALTHOUGH THERE MAY
BE SOME LINGERING -SHSN IN THE MTNS OVERNIGHT. FOR THU INTO THU
NIGHT STG NNW FLOW ALOFT WILL BE OVER THE AREA WITH AN UPPER LEVEL
JET ACROSS NERN CO. AS HAS BEEN THE CASE THE LAST SEVERAL NIGHTS
THE GFS SHOWS ANOTHER FNT MOVING ACROSS NERN CO BY LATE AFTN WITH
INCREASING UPSLOPE FLOW AND MOISTURE BY THU EVENING. MEANWHILE THE
LAST TWO RUNS OF THE ECMWF HAVE BEGRUDGINGLY TRENDED A LITTLE MORE
TO THE GFS SOLUTION. AT THIS POINT CONFIDENCE IS STILL NOT HIGH AS
WHAT WILL HAPPEN BUT IT APPEARS IF THERE IS ANOTHER CHC OF PCPN IT
WILL OCCUR MAINLY THU NIGHT. AS FOR HIGHS IF THE CURRENT TIMING OF
THE FNT IS ACCURATE READINGS MAY REBOUND BACK INTO THE LOWER TO
MID 50S BEFORE IT COMES ACROSS.

ON FRI THE FLOW ALOFT WILL BECOME MORE NLY WITH THE UPPER LEVEL JET
STILL OVER NERN CO.  BOTH THE ECMWF AND GFS SHOW SOME MOISTURE
LINGERING OVER THE AREA THRU THE MORNING HOURS SO THERE STILL COULD
BE A SLIGHT CHC OF PCPN.  BY AFTN DRIER AIR SHOULD BEGIN TO SPREAD
OVER NRN CO SO THE THREAT OF PCPN SHOULD END.  AS FOR HIGHS WILL
KEEP READINGS NEAR SEASONAL NORMALS OVER NERN CO.

FOR THE WEEKEND AN UPPER LEVEL RIDGE WILL BUILD INTO THE AREA ON SAT
WITH DRY CONDITIONS AND WARMER TEMPERATURES.  ON SUN THE ECMWF SHOWS
A WK FNT AFFECTING NERN CO WITH SLIGHTLY COOLER TEMPS WHILE THE GFS
HOLDS THE FNT OFF UNTIL SUN NIGHT.  FOR NOW WILL KEEP READINGS IN
THE UPPER 60S TO LOWER 70S OVER THE PLAINS.

&&

.AVIATION...(FOR THE TAFS THROUGH 12Z TUESDAY MORNING)
ISSUED AT 446 AM MDT MON MAR 23 2015

GUSTY SOUTH WINDS ARE EXPECTED THROUGH MUCH OF THE DAY WITH SPEEDS
UP TO 25 KNOTS. CEILINGS SHOULD REMAIN WELL ABOVE 6000 FEET AGL
WITH UNLIMITED VISIBILITIES. LATE IN THE AFTERNOON COULD SEE WINDS
SHIFTING TO A WESTERLY DIRECTION AND CONTINUING TO GUST 20 TO 25
KNOTS. WINDS AT KDEN SHOULD TAPER OF DURING THE EVENING BUT
WESTERLY WINDS WILL LIKELY CONTINUE AT KBJC ALL NIGHT LONG.
CEILINGS WILL BEGIN COMING DOWN BETWEEN 8 PM AND MIDNIGHT AND
A CHANCE OF RAIN WILL EXIST AFTER MIDNIGHT. TEMPERATURES SHOULD
REMAIN IN THE LOWER 40S...SO NO SNOW IS EXPECTED AT THIS TIME.

&&

.FIRE WEATHER...
ISSUED AT 446 AM MDT MON MAR 23 2015

FIRE DANGER WILLL INCREASE ON TUE WITH THE MOST LIKELY PERIOD FOR
RED FLAG CONDITIONS BETWEEN 18Z AND 00Z AS HUMIDITY LEVELS DROP
BELOW 20 PERCENT AS GUSTY NORTHWEST WINDS OCCUR FM THE NRN
FOOTHILLS ACROSS THE PLAINS. NOT SURE ABOUT ZN 241 BEING IN THE
WATCH SINCE THIS AREA HAD UP TO AN INCH OF RAIN BACK ON THE 19TH
HOWEVER WILL KEEP IT IN THE WATCH.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...
FIRE WEATHER WATCH FROM TUESDAY MORNING THROUGH TUESDAY EVENING
FOR COZ238-241>251.

FIRE WEATHER WATCH FROM TUESDAY MORNING THROUGH TUESDAY
AFTERNOON FOR COZ215.

&&

$$

SHORT TERM...DANKERS
LONG TERM...RPK
AVIATION...DANKERS
FIRE WEATHER...RPK


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