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AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
335 AM MDT SAT AUG 1 2015

.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 252 AM MDT SAT AUG 1 2015

ELONGATED UPPER HIGH EXTENDING FROM THE PACIFIC NORTHWEST AND
STRETCHING SOUTHEAST THROUGH TEXAS WITH RESULTANT NORTHWEST FLOW
ALOFT OVER NORTHERN COLORADO. AIRMASS IN THIS FLOW IS RATHER DRY
AND STABLE OVER FAR NORTHERN COLORADO AND QG FIELDS STILL SHOWING
SUBSTANTIAL SUBSIDENT AIRMASS IN THE 500-700MB LAYER OVER THE
NORTHEAST PLAINS. BEST MOISTURE WILL AGAIN REMAIN OVER SOUTHERN
COLORADO AND EXTENDING TO JUST SOUTH OF THE INTERSTATE 70
CORRIDOR. SOUNDINGS INDICATE CONTINUED CAPPING INVERSION IN THE
MID LEVELS ON THE PLAINS WHILE LOW LEVEL WARMING CONTINUES WITH
READINGS A FEW DEGREES HIGHER TODAY. WILL CONTINUE THE TREND OF
LOWER POPS OVER SOUTHERN PORTIONS OF THE CWA.

.LONG TERM...(SUNDAY THROUGH FRIDAY)
ISSUED AT 252 AM MDT SAT AUG 1 2015

SHORTWAVE TROUGH PIVOTING AROUND A DEEP UPPER LOW OFF THE NRN 
CALIFORNIA COAST IS FCST TO SWING OVER THE 4-CORNERS REGION SUNDAY 
MORNING...THEN OVER CENTRAL COLORADO BY LATE AFTERNOON...AND 
EVENTUALLY OVER THE COLORADO FRONT RANGE BY MONDAY MORNING. MODELS 
BEST RESOLVE THIS FEATURE IN THE 700-500 MB LAYER WITH THE WAVE 
SHOWING UP STRONGEST ON THE NAM AND WEAKEST ON THE CANADIAN GEM. 
ECMWF APPEARS TO BE A SUITABLE COMPROMISE AMONG THE  OPERATIONAL 
MODELS. THAT SAID...ECMWF INDICATES SOME AMPLIFICATION IN THIS S/W 
TROUGH AS IT SLOWLY PASSES OVER COLORADO DURING THE DAY SUNDAY. ITS 
PASSAGE WEAKENS AND DISPLACES EASTWARD THE RESIDENT UPPER RIDGE AND 
THE SHIFT TO SWLY FLOW ALOFT TAPS INTO A REGION OF SUBTROPICAL 
MOISTURE POOLED OVER NRN NEW MEXICO/NERN ARIZONA. ECMWF QG OMEGA 
FIELDS INDICATE ONLY WEAK LIFT WITH THIS FEATURE AND YET THE EC
AND OTHER MODELS SHOW LIGHT/MODERATE QPF OVER MUCH OF SWRN/CNTRL
COLORADO BY SUNDAY EVENING. NAM AND TO A LESSER DEGREE THE
GFS...SHOW A FEW BANDS OF LIGHT QPF EXTENDING EASTWARD OVER THE
PLAINS OF NERN COLORADO BY LATE AFTERNOON WITH A MOIST AND
MARGINALLY UNSTABLE E-SELY LOW-LEVEL FLOW. NOT SHOWING UP IN THIS
LATEST MODEL RUN IS THE BAND OF 1200-2200 J/KG OF CAPE OVER THE
PALMER DIVIDE LATE SUNDAY AFTERNOON. HOWEVER THE NAM INDICATES A
NW-SE BAND OF 1000-1400 CAPE STRADDLING THE NERN CORNER OF THE
STATE AT THAT TIME. CAPES ON THE OTHER MODELS UNDER 250 J/KG.
THEREFORE HAVE LESS CONFIDENCE THAT T-STORMS CAPABLE OF
HAIL...HVY RAINFALL AND STG GUSTY WINDS WILL FORM OVER THE PALMER
DIVIDE. FOR NOW WILL STICK WITH 30-50 PCT POPS IN THE HIGH COUNTRY
AND 10-30 PCT POPS AT LOWER ELEVATIONS ON SUNDAY. AND WITH GREATER
CLOUD COVER GOING WITH MAX TEMPS A DEG OR TWO LOWER THAN THOSE ON
SATURDAY.
 
SUNDAY NIGHT/MONDAY...EXPECT TO SEE CONSIDERABLE MID/HIGH-LEVEL
CLOUDINESS WITH PASSAGE OF THE SHORTWAVE. MODELS INDICATE THE BEST
FORCING AND MID-LEVEL INSTABILITY OVER MTN AREAS OVERNIGHT AND
OVER THE NERN PLAINS DURING THE DAY. DURING THE DAY...MODELS SHOW
A 700-500 MB SHEAR/DEFORMATION AXIS AND A SFC TROUGH/DRYLINE
MOVING OUT ACRS THE NERN PLAINS. MODELS NOT INDICATING MUCH 0-3 KM
CAPE AND LAPSE RATES ONLY MARGINALLY UNSTABLE PRESUMABLY BECAUSE
OF ALL OF THE CLOUD COVER. STILL MODELS INDICATE SEVERAL POCKETS
OF LIGHT QPF ON THE PLAINS. PREVIOUS FORECAST HAD 10-20 PCT POPS
AT LOWER ELEVATIONS. NOW CHANCE OF MEASURABLE PRECIP LOOKS
SLIGHTLY BETTER. SO WILL RAISE POPS BY 10-20 PCT. MONDAY SHOULD BE
COOLER WITH HIGHS 2-3 DEG F LOWER THAN THE DAY BEFORE.

ON TUESDAY...ERN PORTIONS OF THE CWA MAY STILL FEEL MODEST AFFECTS 
OF THE SHORTWAVE IN THE FORM OF COOLER TEMPS AND UPSLOPE CLOUDINESS
ALONG THE FRONT RANGE DURING THE MORNING HRS. SHORTWAVE MOVES EAST
OF THE STATE BY AFTERNOON ALLOWING THE UPPER RIDGE TO REGAIN ITS
HOLD ON THE REGION. WITH COOLING AT LOW LEVELS AND WARMING
ALOFT...SEE ONLY A SLIGHT CHANCE OF PRECIP/T-STORMS OVER THE
HIGHER SLOPES OF THE FRONT RANGE IN THE AFTERNOON...AND ACRS THE
FAR NERN CORNER OF THE STATE AS THE BACK SIDE OF THE S/W TROUGH
BRUSHES THE AREA.

ON WEDNESDAY...MODELS SHOW THE UPPER RIDGE OVER THE CNTRL/SRN ROCKY 
MTN REGION CONTINUING TO GAIN STRENGTH. LOCAL AIRMASS ALSO CONTINUES 
TO WARM AND DRY WITH HIGHS ON WEDNESDAY LIKELY TO BE THE WARMEST OF 
THE WEEK WITH MID-90S MAX TEMPS COMMON ON THE PLAINS.  

ROUNDING OUT THE WEEK...MEDIUM RANGE MODELS SHOW THE UPPER RIDGE
HOLDING STRONG OVER THE ROCKY MTN REGION...ALTHOUGH ITS NORTHERN
FRINGE FLATTENS AS A SHORTWAVE TROUGH RACES EAST ACRS MONTANA AND
WYOMING ON THURSDAY. NOT LOOKING FOR ANY PRECIP ON THURSDAY EXCEPT
PERHAPS A FEW LATE DAY SHWRS OVER THE HIGH MTNS. FRIDAY APPEARS
TO START OUT DRY. THEN MODELS SHOW A WEAK DISTURBANCE ROUNDING THE
TOP OF THE RIDGE AND GENERATING A SMATTERING OF SHWRS/T-STORMS AS
IT PASSES OVER THE FCST AREA DURING THE AFTERNOON. FOR NOW WILL
STICK WITH LOW POPS. TEMPS THURSDAY AND FRIDAY NEAR TO SLIGHTLY
BELOW AVERAGE WITH FRIDAY BEING THE COOLER DAY.

&&

.AVIATION...(FOR THE TAFS THROUGH 12Z SUNDAY MORNING)
ISSUED AT 252 AM MDT SAT AUG 1 2015

VFR TODAY WITH MINIMAL IMPACTS TODAY AS ANY CONVECTION WILL
REMAIN WELL SOUTH OF TERMINALS. COULD BE SOME RETURN OUTFLOW FROM
SHOWERS TO OUR SOUTH. OTHERWISE SOUTH TO SOUTHEAST SURFACE WINDS
WILL BECOME SOME SORT OF EASTERLY COMPONENT THIS AFTERNOON.  

&&

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

$$

SHORT TERM...ENTREKIN
LONG TERM...BAKER
AVIATION...ENTREKIN

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