Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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000
FXUS65 KBOU 170200
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
800 PM MDT SAT AUG 16 2014

.UPDATE...
ISSUED AT 800 PM MDT SAT AUG 16 2014

THE FEW SHOWERS AND STORMS THAT FORMED OVER THE FAR NORTHEAST
CORNER OF COLORADO AND OVER PARK COUNTY ARE COMING TO AN END.
COULD SEE CONVECTION LINGER UNTIL 9 PM OVER PARK
COUNTY...OTHERWISE EXPECT DRY CONDITIONS UNDER MOSTLY CLEAR SKIES
FOR THE REST OF TONIGHT. MADE MINOR ADJUSTMENTS TO THE FORECAST TO
REFLECT THE CURRENT TRENDS.

&&

.SHORT TERM...(THIS EVENING THROUGH SUNDAY)
ISSUED AT 200 PM MDT SAT AUG 16 2014

THE CONVECTIVE CLOUDINESS IS OVER THE WESTERN HALF OF THE CWA AND
THE SOUTHERN BORDER AND IT IS ALL PRETTY FLAT. THE RADAR HAS A
COUPLE OF VERY WEAK ECHOES OVER PARK COUNTY. THE DEW POINTS HAVE
DROPPED SIGNIFICANTLY OVER ALL THE PLAINS SAVE THE NORTHEAST
CORNER. READINGS ARE NOW IN THE 30S TO MID 40S F FOR MOST OF THE
PLAINS. THE AIRCRAFT SOUNDINGS ARE STILL SHOWING A PRETTY STRONG
CAP AROUND 500 MB. MODELS HAVE THE UPPER RIDGE CENTER OVER THE
FOUR CORNERS TONIGHT AND SUNDAY. THE FLOW ALOFT IS WESTERLY AT 25
TO 40 KNOTS. THE SYNOPTIC SCALE ENERGY IS BENIGN TONIGHT AND
SUNDAY. FOR THE MOST PART...NORMAL DIURNAL WIND PATTERNS WILL
PREVAIL. MOISTURE IS SPARSE BUT NOT TOTALLY ABSENT ON SUNDAY. THE
BOUNDARY LAYER DEW POINTS ARE PROGGED TO BE IN THE 30S TO MID 40S
F ON SUNDAY. THERE IS SOME CAPE OVER THE MOUNTAINS AND FAR EAST
THIS EVENING...AND JUST OVER THE MOUNTAINS FOR SUNDAY AFTERNOON.
THE PRECIPITABLE WATER PROGS SHOW 0.30 INCH OVER THE MOUNTAINS TO
0.90 INCH OVER THE FAR NORTHEAST CORNER TONIGHT. VALUES DROP ABOUT
0.10 INCH FOR SUNDAY AFTERNOON. JUST THE GFS HAS A TAD OF
MEASURABLE RAINFALL FOR THE CWA THIS EVENING. THERE IS SOME ON ALL
THE MODELS SUNDAY AFTERNOON OVER THE MOUNTAINS ONLY AND AMOUNTS
ARE MINIMAL. FRO POPS...10-20%S FOR THE MOUNTAINS AND FOOTHILLS
THIS EVENING AND AGAIN SUNDAY AFTERNOON. FOR TEMPERATURES...
SUNDAY`S HIGHS COULD BE 0- 1 C WARMER THAN THIS AFTERNOON`S HIGHS.

.LONG TERM...(SUNDAY NIGHT THROUGH SATURDAY)
ISSUED AT 200 PM MDT SAT AUG 16 2014

DEEPENING UPPER TROUGH OFF THE WEST COAST AND MID-LEVEL
RIDGING OVER THE ROCKY MTN REGION WILL DICTATE THE DIRECTION OF
WEATHER TRENDS ACROSS THE FORECAST AREA NEXT WEEK. DURING THE
MONDAY/MONDAY NIGHT TIME FRAME...MODELS SHOW RETROGRESSION OF THE
UPPER RIDGE TO A POSITION OVER THE EASTERN GREAT BASIN. THIS CAUSES
A SHIFT TO NWLY FLOW ALOFT WHICH ALLOWS A WEAK SFC COLD FRONT TO
SLIP INTO NORTHEAST COLORADO DURING THE DAY. NAM AND GFS SHOW A
STEADY INCREASE IN LAYER PW VALUES WITH EAST-NORTHEAST POST-
FRONTAL BNDRY LAYER FLOW. BY 00Z/TUE PW VALUES ALONG THE FRONT
RANGE INCREASE FROM AROUND 0.60 INCH IN THE MORNING TO AROUND 0.90
INCH BY EVENING. THE INFLUX OF SLIGHTLY COOLER BNDRY LAYER AIR
APPEARS TO COUNTER THE RISE IN MOISTURE WHICH WOULD NORMALLY
DESTABILIZE THE PLAINS AIRMASS. SFC BASED CAPES LOOK FLAT...BARELY
500 J/KG OVER THE FRONT RANGE AND LESS THAN 200 J/KG ON THE
PLAINS. ALTHOUGH THE NAM INDICATES A SWATH OF 1000-1250 J/KG CAPE
ACRS THE NERN CORNER OF THE CWA AROUND 00Z/TUE POSSIBLY ALONG A
STALLED OUT FRONTAL BNDRY OR PERHAPS IN RESPONSE TO COOLING ALOFT
WITH THE TAIL-END OF A SHORTWAVE PASSING BY. MODEL CROSS SECTIONS
INDICATE HIGH BASED CONVECTION POPPING OVER AND ALONG THE FRONT
RANGE AROUND MID-AFTERNOON AND OVER HIGHER REACHES OF THE PALMER
DIVIDE BY LATE-AFTERNOON. PRESENT FORECAST HAS A SLIGHT CHANCE OF
T-STORMS FOR THESE AREAS AND A BETTER CHANCE OF STORMS OVER THE
HIGH RIDGES. THAT SAID...EXCEPT FOR INTRODUCING LOW POPS FOR THE
FAR CORNER OF THE CWA...WILL NOT STRAY FAR FROM THE CURRENT
MONDAY/MONDAY NIGHT FCST.

AS THE WEEK PROGRESSES...THE UPPER RIDGE AXIS SHIFTS EAST BACK OVER
COLORADO BY TUESDAY MORNING AND EAST OF THE STATE BY TUESDAY NIGHT
AS THE WESTERN TROUGH MOVES ONSHORE. MODELS SHOW THE RESUMPTION OF A
DEEP SOUTH-SOUTHWESTERLY FLOW WHICH TRANSPORTS WAVES OF SUBTROPICAL
MOISTURE NORTHWARD ALONG THE SPINE OF THE ROCKIES UP OVER COLORADO
TUESDAY AND WEDNESDAY. MODELS SHOW SOME DRY SLOTTING ON THURSDAY
AND/OR FRIDAY AS TRANSPORT WINDS BRIEFLY TURN WEST-SOUTHWESTERLY AS
THE UPPER TROUGH MOVES ACRS THE NRN ROCKIES. BY SATURDAY...THE GFS
MODEL SHOWS THE UPPER RIDGE CENTERED OVER THE OK-KS-MO-AR REGION
AND THE WESTERN TROUGH CURVING OUT A CLOSED LOW OVER CNTRL
CALIFORNIA. THE RESULTANT LARGE CIRCULATION RESUMES THE MONSOON
FLOW OVER COLORADO. THE EUROPEAN MODEL SHOW THE CORE OF THE UPPER
RIDGE A BIT FARTHER EAST AND THE WESTERN TROUGH CLOSING OFF OVER
THE PACIFIC NORTHWEST. FROM THIS MODEL SATURDAY DOE NOT LOOK AS
MOIST FOR COLORADO. SEEINGS THAT THIS IS STILL SEVERAL DAYS
AWAY...WILL TREND TOWARDS CLIMATOLOGY AND KEEP A SLIGHT CHANCE OF
T-STORMS EACH DAY IN THE FCST FOR THE MTNS AND NEARBY PLAINS AND
DRY ON THE PLAINS. SEE ONLY A SLIGHT DAY-TO-DAY CHANGE IN
TEMPERATURES BEYOND TUESDAY.

&&

.AVIATION...(FOR THE TAFS THROUGH 06Z SUNDAY EVENING)
ISSUED AT 800 PM MDT SAT AUG 16 2014

AN OUTFLOW BOUNDARY MAY CAUSE WINDS TO INCREASE OUT OF THE EAST
AROUND 03Z. WINDS ARE THEN EXPECTED TO TURN CLOCKWISE AND END UP
SOUTHERLY AROUND 06Z. MOSTLY CLEAR SKIES WILL PREVAIL THROUGH
SUNDAY MORNING. JUST A SLIGHT CHANCE FOR THUNDERSTORMS SUNDAY
AFTERNOON WITH THE BEST CHANCE BEING SOUTH AND WEST OF THE DENVER
AREA.

&&

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

$$

UPDATE...MEIER
SHORT TERM...RJK
LONG TERM...BAKER
AVIATION...MEIER



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