000
FXUS65 KBOU 282209
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
309 PM MST FRI NOV 28 2014

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 308 PM MST FRI NOV 28 2014

WESTERLY FLOW ALOFT WILL PERSIST THROUGH TONIGHT AND THEN TURN
SLIGHTLY SOUTH OF DUE WEST ON SATURDAY. THIS WILL KEEP MILD AND DRY
CONDITIONS OVER THE AREA THROUGH SATURDAY AFTERNOON. PACIFIC
MOISTURE WILL CONTINUE TO PRODUCE WAVE CLOUDS INTO SATURDAY
AFTERNOON. MAY FINALLY SEE SOME CLEARING OF THE WAVE CLOUDS LATE
SATURDAY AFTERNOON AS DRIER AIR ALOFT MOVES IN. TEMPERATURES TONIGHT
WILL BE MILD DUE TO THE WARM AIRMASS...CLOUD COVER AND BREEZY
CONDITIONS IN AREAS. THE AIRMASS WILL BE SLIGHTLY COOLER
SATURDAY...BUT STILL WARM ENOUGH FOR 60S ACROSS NORTHEAST COLORADO.
BECAUSE OF DOWNSLOPE WINDS SPREADING ACROSS THE PLAINS...A FEW LOWER
70S WILL BE POSSIBLE.

WINDY CONDITIONS WILL CONTINUE OVER THE MOUNTAINS AND FOOTHILLS
TONIGHT AND SATURDAY. WIND PRONE LOCATIONS COULD SEE GUSTS TO 70
MPH...HOWEVER MOST LOCATIONS WILL SEE GUSTS UNDER 50 MPH. A BETTER
MOUNTAIN WAVE IS EXPECTED TO FORM SATURDAY NIGHT WHICH COULD PRODUCE
WIDESPREAD STRONG WINDS.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 308 PM MST FRI NOV 28 2014

BIGGEST CONCERN DURING THIS PERIOD IS THE THREAT OF STRONG...
POTENTIALLY DOWNSLOPE WINDS IN THE FRONT RANGE FOOTHILLS SATURDAY
NIGHT. MODELS PAST COUPLE OF DAYS HAVE BEEN TRENDING TOWARDS THIS
EVENT...BUT LATEST RUNS HAVE CONVINCED TO HOIST A HIGH WIND WATCH
FOR COLORADO FORECAST ZONES 35 AND 36. PRONOUNCED MID-LEVEL
CONVERGENCE AND SUBSIDENCE ON THE SOUTH SIDE OF A 120+KT JET CORE
UP OVER WYOMING...AND A DEEPLY AMPLIFIED MOUNTAIN WAVE MAY ALL
COME TOGETHER TO PRODUCE POWERFUL DOWNSLOPE/CHINOOK WINDS IN THE
FOOTHILLS. MODEL CROSS SECTIONS INDICATE 40-60KT SUSTAINED WINDS
OVERNIGHT WITH THE POTENTIAL FOR GUSTS TO AROUND 80KTS ON EAST
FACING SLOPES ROUGHLY ABOVE 9000 FEET. LACK OF PRECIP IN THE HIGH
COUNTRY GIVES ME SOMEWHERE MORE CONFIDENCE THAT THIS EVENT WILL
OCCUR. OF COURSE ALL DEPENDS ON WHERE THE JET FINALLY SETS UP AND
THE DEPTH OF THE MTN TOP INVERSION. THE HIGH WIND WATCH HAS BEEN
ISSUED FOR THE PERIOD FROM 5 PM MST SATURDAY UNTIL 6 AM MST
SUNDAY.

NEXT IS THE CANADIAN COLD FRONT WHICH MODELS STILL SHOW BACKING INTO
NORTHEAST COLORADO EARLY SUNDAY MORNING. MODELS SHOW THE FRONT WITH
ITS LIGHT NORTHEAST SFC WINDS AND SHALLOW MOISTURE SPREADING OVER
THE NORTHEAST CORNER OF THE STATE BY 15Z/SUNDAY...AND EVENTUALLY UP
AGAINST THE FOOTHILLS BEFORE THE NOON HOUR. THE POST FRONTAL AIRMASS
NOW APPEARS TO CONTAIN A BIT MORE LOW-LEVEL MOISTURE AND THROUGH THE
DAY AS THE COLDER AIR PILES UP AGAINST THE FRONT RANGE...IT NOW
APPEARS AREAS EAST OF THE MTNS WILL REMAIN SOCKED IN WITH LOW CLOUDS
FOR MOST OF THE DAY. MODELS SOUNDINGS ALSO SUPPORT THE DEVELOPMENT OF
SMALL ICE CRYSTAL GROWTH POSSIBLY RESULTING IN AREAS OF SNOW
FLURRIES OR BRIEF LIGHT SNOWFALL. TEMPERATURE PROFILE MAY ALSO
SUPPORT POCKETS OF FREEZING DRIZZLE. AT THIS TIME...DO NOT SEE ANY
ACCUMULATION...EXCEPT PERHAPS IN THE LOWER FOOTHILLS AND AREAS RIGHT
UP AGAINST THE FOOTHILLS LATE AFTERNOON AND EARLY EVENING WHERE SNOW
AMTS SHOULD BE UNDER AN INCH. SUNDAY NIGHT...LOW CLOUDS ON THE
PLAINS WILL BE SLOW TO MOVE OUT WHILE HIGHER ELEVATIONS COULD SEE
AREAS OF LIGHT SNOWFALL WITH THE JET STREAM SLAGGING SOUTH OVER THE
AREA. EVEN IN THE HIGH COUNTRY SNOW AMOUNTS SHOULD BE ON THE LIGHT
SIDE...GENERALLY LESS THAN 2 INCHES OVER HIGHER ELEVATION IN THE
NORTHERN MTN RANGES.

BY MONDAY...THE JET STREAM AND ITS PLUME OF PACIFIC MOISTURE LIFTS
AWAY FROM COLORADO AS UPPER LEVEL RIDGING GETS UNDERWAY OVER THE
GREAT BASIN. THE LOW CLOUDS AND COLDER AIR IN THE PLAINS WILL ALSO
BEGIN MIGRATING EASTWARD...BUT DAYTIME TEMPERATURES ARE STILL
EXPECTED TO BE BELOW AVERAGE.

TUESDAY LOOKS WARMER AND DRY ALTHOUGH MODELS SHOW MID AND HIGH LEVEL
MOISTURE SPREADING IN FROM THE SOUTHWEST AHEAD OF A DEEP UPPER LEVEL
TROUGH AND CYCLONE SPINNING OFF THE CALIFORNIA COAST. BY WEDNESDAY
MODELS SHOW MORE OF THIS MOISTURE REACHING COLORADO THEREBY
INCREASING THE CHANCE OF SNOW IN THE HIGH COUNTRY. WHEREAS LOWER
ELEVATIONS EAST OF  THE MTNS APPEAR TO REMAIN DRY WITH GRADUALLY
WARMING TEMPERATURES.

&&

.AVIATION...(FOR THE TAFS THROUGH 00Z SATURDAY LATE AFTERNOON)
ISSUED AT 308 PM MST FRI NOV 28 2014

EASTERLY WINDS ARE EXPECTED TO BECOME LIGHT AND TURN SOUTHERLY AFTER
00Z IN THE DENVER AREA. SOME GUSTY WEST WINDS WILL BE POSSIBLE LATE
TONIGHT AND SATURDAY MORNING AT KBJC WHERE GUSTS TO 30 KNOTS WILL BE
POSSIBLE. HIGHS CLOUDS WILL CONTINUE THROUGH SATURDAY MORNING AND
DECREASE DURING THE AFTERNOON.

&&

.BOU WATCHES/WARNINGS/ADVISORIES...HIGH WIND WATCH FOR THE FRONT
RANGE FOOTHILLS ZONES 35 AND 36. WATCH RUNS FROM 5 PM MST SATURDAY
UNTIL 6 AM MST SUNDAY.

&&

$$

SHORT TERM...MEIER
LONG TERM...BAKER
AVIATION...MEIER

NWS BOU Office Area Forecast Discussion