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000
FXUS65 KBOU 090811
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
111 AM MST MON DEC 9 2013

.AVIATION...AREAS OF MVFR CEILINGS HAVE DEVELOPED MOST LIKELY IN
RESPONSE TO SHALLOW EASTERLY FLOW WRAPPING AROUND DENVER CYCLONIC
CONVERGENCE ZONE. THIS SHOULD REMAIN IN PLACE BUT EVENTUALLY
STRONGER WESTERLY COMPONENT DEVELOPING ALOFT SHOULD BE ABLE TO
SCOUR THE LOWER CLOUD DECK EAST OF THE FRONT RANGE AIRPORTS BY
OR SHORTLY BEFORE DAYBREAK.

&&

.PREV DISCUSSION... /ISSUED 926 PM MST SUN DEC 8 2013/

UPDATE...

SHORT TERM...WIDE BAND OF MAINLY MID AND HIGH-LEVEL CLOUDS IN
THE VICINITY OF THE 600-400 MB POSITIVELY TILTED TROUGH AXIS
NOW CROSSING CENTRAL UTAH AND CENTRAL WYOMING WILL SWING EAST-
SOUTHEASTWARD OVER COLORADO LATE TONIGHT/EARLY MONDAY MORNING.
NOT SEEING MUCH IN THE WAY OF PRECIP COMING FORM THESE CLOUDS...
BUT AS BAND OF MOISTURE PASSES OVER THE HIGHER TERRAIN IN
COLORADO...SPECIFICALLY NORTH CENTRAL COLORADO...SHOULD SEE SNOW
DEVELOPING IN THE NEXT FEW HOURS. FORCING APPEARS WEAK AND
INSTABILITY ONLY MARGINAL...SO ANY ACCUMULATION SHOULD BE
LIGHT...GENERALLY 2 INCHES OR LESS. STILL NOT EXPECTING ANY
SNOWFALL ON THE PLAINS WITH PASSAGE OF THIS SHORTWAVE TROUGH LATE
TONIGHT EXCEPT PERHAPS IN THE NORTHEAST CORNER OF THE STATE WHERE
THEY COULD SEE A DUSTING OF SNOW TOWARDS DAWN. APPROACHING CLOUD
COVER SHOULD SLOW DOWN TO DROP IN TEMPERATURES IF NOT CAP THEM OFF
NEAR THEIR PRESENT READINGS IN SOME AREAS...SUCH AS ALONG THE BASE
OF THE FOOTHILLS AND HIGH MOUNTAIN VALLEYS. MADE ADJUSTMENTS TO
THE TEMPERATURE GRIDS TO REFLECT THIS. ALSO ADJUSTED THE SKY COVER
AND WEATHER GRIDS TO MATCH UP BETTER WITH THE FORWARD PROGRESS OF
THE TROUGH.

AVIATION...OVER THE NEXT 2-4 HOURS...DENVER AREA AIR TERMINALS
SHOULD SEE MID-CLOUDS FILLING THE SKY AND CLOUD BASES LOWERING TO
7000-8000 FEET AGL. THERE IS A SLIGHT CHANCE SOME AREAS COULD SEE
A FEW SNOW FLURRIES AS THE CORE OF THIS CLOUD BAND PASSES OVER THE
AREA BETWEEN 06Z AND 09Z TONIGHT. OTHERWISE CONTINUED DRY. SOUTH-
SOUTHEAST WINDS OF 7-14KT WINDS AT DIA AND APA FORECAST TO BECOME
SOUTH-SOUTHWEST AT 4-8KTS BY AROUND 08Z. LIGHTER WIND SPEEDS
LIKELY AT BJC.

PREV DISCUSSION... /ISSUED 316 PM MST SUN DEC 8 2013/

SHORT TERM...THE SNOW IS PRETTY MUCH OVER ACROSS THE CWA...EVEN IN
THE MOUNTAINS. NORTH-NORTHWESTERLY BOUNDARY LAYER WINDS ARE
COMING UP OVER THE PLAINS AT THIS TIME. SATELLITE PICTURES ARE
SHOWING A BATCH OF CLOUDS UPSTREAM OVER WYOMING...IDAHO AND
MONTANA MOVING THIS WAY. MODELS SHOW WEST-SOUTHWESTERLY FLOW ALOFT
FOR THE CWA OVERNIGHT. THE BACK SIDE OF THE UPPER TROUGH AXIS
MOVES INTO THE CWA MONDAY AFTERNOON...WITH NORTHERLY FLOW ALOFT
OVER THE WESTERN CWA BY 00Z LATE AFTERNOON. BY MONDAY...PRETTY
STRONG SYNOPTIC SCALE DOWNWARD MOTION IS OVER THE FORECAST AREA
ACCORDING TO THE QG VERTICAL VELOCITY FIELDS. THE BOUNDARY LAYER
FLOW WILL ATTEMPT TO GO TO NORMAL DIURNAL PATTERNS OVERNIGHT
.THEN DOWNSLOPING WESTERLIES ARE PROGGED ON MONDAY. FOR MOISTURE
.IT DRIES OUT SIGNIFICANTLY OVER THE EASTERN HALF OF THE CWA
TONIGHT...STAYING PRETTY DRY MONDAY. MOISTURE SLOWLY DECREASES
OVER THE MOUNTAINS TONIGHT INTO MONDAY MORNING. THE QPF FIELDS
HAVE A TAD OF MEASURABLE SNOW IN THE HIGH COUNTY OVERNIGHT. FOR
POPS...WILL LEAVE "CHANCE"S IN THE MOUNTAINS OVERNIGHT...THEN
"SLIGHT CHANCE"S MONDAY MORNING. THIS WITH THE SATELLITE PICTURES
IN MIND. FOR TEMPERATURES...IT SHOULD BE PRETTY COLD TONIGHT WITH
THE CLEARING EXPECTED. MONDAY`S HIGHS LOOK A BIT WARMER THAN
TODAY`S...BUT NOT MUCH.

LONG TERM...THE LONGWAVE TROUGH MOVES EAST EARLY IN THE
WEEK...LEAVING US IN A GENERALLY DRY AIRMASS WITH FAIRLY LIGHT
WESTERLY FLOW ALOFT. THERE ARE SEVERAL WEAK SHORTWAVES RUNNING
AROUND. FIRST TWO RIPPLES IN THE NORTHERN STREAM ABOUT MONDAY
NIGHT AND AGAIN TUESDAY NIGHT. THESE SHOULD KEEP SOME CLOUD COVER
AND MAY BRING A LITTLE SNOW TO THE HIGH COUNTRY. BY WEDNESDAY WE
ARE UNDER A FLAT RIDGE WITH FAIRLY WARM AIR ALOFT. HOWEVER THERE
WILL BE A WEAK FRONT BEHIND THE TUESDAY NIGHT SHORTWAVE THAT WILL
LIKELY KEEP TEMPERATURES ON WEDNESDAY ABOUT THE SAME AS TUESDAY.
A LITTLE BETTER AGREEMENT ON THE WEAK SYSTEM IN THE SOUTHERN
STREAM FOR THU/FRI...MOST OF THE IMPACT SOUTH OF US AND ALSO
PRETTY DRY ANYWAY. WILL LIMIT THE MENTION OF ANY SNOW CHANCE TO
THE MOUNTAINS. STILL MORE UNCERTAINTY ABOUT THE NEXT UPSTREAM
TROUGH...BUT THE CONSENSUS IS WEAKER AND STILL A PRETTY DRY
ENVIRONMENT.

AVIATION...WINDS WILL BE WEAK MUCH OF THE NIGHT...AND WILL TRY TO
GO DRAINAGE AT SOME POINT. DOWNSLOPING WESTERLIES LOOK TO BE A
GOOD BET ON MONDAY...BUT SPEEDS DO NOT LOOK SIGNIFICANT. THERE
SHOULD BE NO MORE CEILING ISSUES AT DIA TONIGHT OR MONDAY.

&&

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

$$

SHORT TERM...BAKER
LONG TERM....GIMMESTAD
AVIATION...BARJENBRUCH