Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 281014
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
314 AM MST WED JAN 28 2015

.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 300 AM MST WED JAN 28 2015

MAIN FEATURE TODAY WILL BE WEAK UPPER LEVEL DISTURBANCE WHICH WILL
MOVE ACROSS COLORADO DURING THE DAY. MOISTURE IS RATHER LIMITED
WITH THIS SYSTEM BUT THE OROGRAPHIC FLOW WILL BECOME MORE
FAVORABLE FROM THE WEST AND NORTHWEST IN THE MOUNTAINS AS THE DAY
WEARS ON. WILL CONTINUE MAINLY CHANCE POPS IN THE MOUNTAINS AND A
BIT HIGHER IN ZONE 31 WITH AMOUNTS UP TO A COUPLE OF INCHES BY
LATER THIS EVENING. AS THE TROF MOVES ACROSS THE STATE...INCREASING
SUBSIDENT FLOW BY AFTERNOON. THIS WILL HELP INCREASE THE WINDS ON
THE PLAINS AS LOW LEVELS MIX OUT. GUSTS UP TO 45 MPH CAN BE
EXPECTED ON THE PLAINS BEFORE DECREASING TONIGHT AS AIRMASS
DECOUPLES AND STRONGEST SUBSIDENCE MOVES EAST OF COLORADO.

INITIALLY EARLY THIS MORNING...GUSTY WINDS CONTINUE IN THE HIGHER
MOUNTAINS AND FOOTHILLS. HAVE NOTED SOME GUSTS UP TO 50 MPH IN
WIND PRONE AREAS AS 88D STILL SHOWING NICE WIND SIGNATURE ACROSS
WESTERN BOULDER COUNTY.  CROSS SECTIONS SHOW WAVE ACTIVITY WILL
DECREASE BY MID MORNING AS MOUNTAIN TOP INVERSIONS DISSIPATE AND
LOW LEVELS MIX OUT. AS SURFACE HIGH PRESSURE BUILDS SOUTHWARD FROM
WYOMING TONIGHT...LOW LEVEL FLOW TURNS MORE NORTHEAST WHICH MAY
RESULT IN SOME STRATUS DEVELOPING. MOISTURE LOOKS SHALLOW SO DON`T
EXPECT ANY PRECIP WITH THIS ON THE PLAINS BUT COULD BE A FEW
SHOWERS OVER HIGHER FOOTHILLS.

.LONG TERM...(THURSDAY THROUGH TUESDAY)
ISSUED AT 300 AM MST WED JAN 28 2015

AN UPPER LEVEL RIDGE WILL BUILD INTO THE AREA ON THU AS SFC HIGH
PRES OVER ERN CO SHIFTS EASTWARD INTO THE CNTRL PLAINS BY THU NIGHT.
CROSS-SECTIONS SHOW LIMITED MOISTURE IN THE MTNS THRU THE AFTN SO
WILL ONLY MENTION A SLIGHT CHC OF -SHSN OVER THE HIGHER PEAKS.  EAST
OF THE MTNS OUTSIDE OF SOME MORNING CLOUDS WILL KEEP FCST DRY.
HIGHS ON THU WILL FINALLY DROP BACK TO SEASONAL LEVELS OVER THE
PLAINS.

ON FRI AN UPPER LEVEL TROUGH WILL BECOME BETTER ORGANIZED OVER THE
SWRN US WITH SSW FLOW ALOFT.  SATELLITE SHOWS ABUNDANT MOISTURE
CURRENTLY SW OF THE BAJA AREA WHICH WILL MOVE INTO THE AREA.
DESPITE ABUNDANT MOISTURE LAPSE RATES ARE RATHER MARGINAL WITH ONLY
WK MID LVL ASCENT.  THUS ANY SNOW WILL BE LIGHT IN THE MTNS WITH THE
BEST CHC MAINLY SOUTH OF I-70.  OVER NERN CO THERE WILL BE A LOT OF
CLOUDS HOWEVER AT THIS POINT IT APPEARS IT WILL BE DRY THRU THE AFTN
HOURS.  AS FAR AS TEMPS WITH ABUNDANT CLOUD COVER HIGHS MAY STAY
SIMILAR TO THU DESPITE A FEW DEGREES OF WARMING IN THE 850-700 MB
LYR.

FOR FRI NIGHT INTO SAT THE UPPER LEVEL TROUGH OVER THE SWRN US WILL
STAY WELL SOUTH OF THE AREA AS A WK UPPER LEVEL TROUGH APPROACHES FM
THE NW. BOTH THE  ECMWF AND GFS SHOW A WK SURGE OF COOLER AIR
MOVING INTO NERN FRI NIGHT INTO EARLY SAT WITH WK UPSLOPE FLOW.
MEANWHILE AT THE SAME TIME WK MID LVL ASCENT IS FCST ACROSS THE
AREA. HOWEVER LAPSE RATES ARE RATHER STABLE. OVERALL WILL KEEP IN
A GOOD CHC OF LIGHT SNOW IN THE MTNS WITH A CHC OF LIGHT PCPN OVER
NERN CO. WET BULB ZEROS BECOME COLD ENOUGH FOR PCPN TO FALL MAINLY
AS SNOW AT LOWER ELEVATIONS. AS FOR HIGHS WILL KEEP READINGS
MOSTLY IN THE MID TO UPPER 30S OVER NERN CO.

BY SAT EVENING ANOTHER SURGE OF COLDER AIR WILL MOVE INTO NERN CO
WITH UPSLOPE FLOW AS THE WK UPPER LEVEL TROUGH MOVES ACROSS.  THUS
COULD SEE ANOTHER CHC OF LIGHT SNOW DURING THE EVENING HOURS.  IN
THE MTNS OROGRAPHICS WILL BECOME MORE FAVORABLE SAT EVENING AS THE
FLOW BECOMES MORE NWLY.  IN ADDITION LAPSE RATES WILL BECOME MORE
UNSTABLE AS WELL SO SHOULD SEE A GOOD CHC OF SNOW.

ON SUN DRIER AIR WILL SPREAD ACROSS THE AREA IN INCREASING NWLY FLOW
ALOFT.  APPEARS ENOUGH MOISTURE WILL LINGER IN THE MTNS FOR A SLIGHT
CHC OF -SHSN.  OVER NERN CO WILL KEEP FCST DRY WITH HIGHS IN THE
30S.

FOR MON AND TUE RATHER STG WNW FLOW ALOFT WILL BE OVER THE AREA.
CROSS-SECTIONS SHOW PERIODS OF MOISTURE AFFECTING THE MTNS BOTH DAYS
WITH DECENT LAPSE RATES ESPECIALLY MON NIGHT THRU TUE.  THUS THIS
SHOULD LEAD TO A FAVORABLE SETUP FOR PERIODS OF SNOW.  AT LOWER
ELEVATIONS A SFC LEE TROUGH WILL DEVELOP NR THE FOOTHILLS ON MON
WITH SFC HIGH PRES OVER THE CNTRL PLAINS.  AT THIS POINT IT LOOKS
DRY OVER NERN CO ON MON WITH HIGHS RANGING FM THE LOWER TO MID 40S
ALONG THE FRONT RANGE WITH MID TO UPPER 30S OVER THE FAR NERN
CORNER.

&&

.AVIATION...(FOR THE TAFS THROUGH 12Z THURSDAY MORNING)
ISSUED AT 300 AM MST WED JAN 28 2015

GUSTY WEST WINDS WILL CONTINUE AT BJC THROUGH EARLY THIS WITH
GUSTS UP TO 35KT. WINDS AT KDEN/KAPA WILL BE SOUTHWEST THIS AM
THEN TURN NORTHWEST AS LOW LEVELS MIX OUT THIS AFTERNOON. ALREADY
ADJUSTED DEN TAF FOR SOME GUSTY WINDS THIS AFTERNOON AND MAY
INCREASE A BIT MORE IN 12Z TAF ISSUANCE. MAINLY MID-HI LEVEL CLOUD
COVER TODAY. WINDS TURN MORE NORTHEAST FOR A TIME TONIGHT WHICH
MAY DEVELOP A HIGH STRATUS DECK LATER TONIGHT. DECK SEEMS SHALLOW
SO NO MENTION OF ANY PRECIP.

&&

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

$$

SHORT TERM...ENTREKIN
LONG TERM...RPK
AVIATION...ENTREKIN


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