Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 200150
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
750 PM MDT SUN OCT 19 2014

.UPDATE...
ISSUED AT 748 PM MDT SUN OCT 19 2014

A FEW VERY LIGHT SHOWERS ARE IN THE MTNS SOUTH OF I-70 WHICH WILL
END IN THE NEXT HOUR OR SO.

&&

.SHORT TERM...(THIS EVENING THROUGH MONDAY)
ISSUED AT 326 PM MDT SUN OCT 19 2014

A BROAD SPLIT FLOW PATTERN DOMINATES THE WESTERN CONUS AT THIS
TIME. LARGE NORTHERN STREAM UPPER RIDGE BOWS WELL UP INTO SOUTH
CENTRAL CANADA AS A SOUTHERN STREAM CLOSED LOW TRACKS ALONG THE
ARIZONA/MEXICO BORDER. A SECONDARY WEAK MID-LEVEL VORT MAXIMA OVER
SOUTH CENTRAL COLORADO WAS RESPONSIBLE FOR THE BROKEN CLOUD COVER
AND ISOLATED SHOWERS POPPING OVER THE HIGH TERRAIN IN PARK AND
SUMMIT COUNTIES. OTHERWISE A DRY N-NWLY FLOW HAS DRIED OUT THE
HIGH PLAINS AIRMASS WITH HARDLY A CLOUD TO BE SEEN. WEAK
ANTICYCLONIC UPSLOPE FLOW ON THE PLAINS WAS BEGINNING TO TURN
SELY AS A WEAK SHORTWAVE TROUGH IN THE NWLY FLOW ALOFT BRUSHES
THE AREA. AFTERNOON TEMPERATURES STILL MANAGED TO REACH THE 70S
WITH UPPER 70S ACRS THE NERN CORNER OF THE STATE. TEMPS IN THE
HIGH VALLEYS EVEN MANAGED TO CLIMB INTO THE MID AND UPPER 60S...
QUITE WARM FOR THIS TIME OF YEAR.

TONIGHT...SHOULD SEE THE LAST OF THE HIGH COUNTRY SHOWERS QUICKLY
DISSIPATING AROUND SUNSET WITH CLEARING NOT LONG AFTER THAT.
OTHERWISE REST OF THE CWA CAN EXPECT CLEAR/MOSTLY CLEAR SKIES...
LIGHT DRAINAGE WINDS AND LOW TEMPS A FEW DEGS COOLER THAN LAST
NIGHT. TEMP MOS GUIDANCE LOOKS A BIT TOO WARM FOR HIGH MTN VALLEY
AND PLAINS RIVER VALLEY LOCATIONS WITH THE CALM...DRY AND CLEAR
CONDITIONS EXPECTED OVERNIGHT. SO IN THESE AREAS WENT WITH MIN
TEMPS 1-3DEG C LOWER THAN THOSE OFFERED BY THE MODELS. OTHERWISE...
SHOULD SEE UPPER 30S/LOWER 40S AT LOWER ELEVATIONS..AND UPPER
20S/30S ACROSS THE HIGH COUNTRY.

ON MONDAY...THE NORTHERN STREAM UPPER RIDGE SHIFTS EAST OF THE
NORTHERN AND CENTRAL ROCKIES WHICH PLACES COLORADO BACK INTO A
SLIGHTLY WARMER SOUTHWEST FLOW REGIME. MODELS INDICATE A 1-1.5DEG
C WARMUP IN 700 MB TEMPERATURES OVER THE FCST AREA WHICH WOULD
EQUATE TO MAX TEMPS 1-3 DEG F WARMER THAN THOSE TODAY. AS FOR
WINDS...LIGHT DOWNSLOPE/DOWNVALLEY BREEZES EARLY TO MID MORNING
SHOULD BECOME PREDOMINANTLY SOUTH-SOUTHWESTERLY LATER IN THE DAY
WITH SUSTAINED WIND SPEEDS ON THE PLAINS APPROACHING 20KTS BY
MID-AFTERNOON. MODELS ALSO SHOW THE SOUTHWESTERLY FLOW ALOFT
ADVECTING HIGHER SPECIFIC HUMIDITIES INTO SRN COLORADO...POSSIBLY
AS FAR NORTH AS SWRN PORTIONS OF THE CWA. THIS MAY AGAIN RESULT
IN A FEW LATE DAY SHOWERS/T-SHOWERS OVER THE HIGH TERRAIN OF PARK
AND SUMMIT COUNTIES. OTHERWISE SHOULD SEE DRY DAY WITH PLENTY OF
SUNSHINE.

.LONG TERM...(MONDAY NIGHT THROUGH SUNDAY)
ISSUED AT 326 PM MDT SUN OCT 19 2014

MONDAY NIGHT WILL BE QUITE WARM AS WARMER AIR MOVES ALOFT AND A
SURFACE LEE TROUGH DEEPENS OVER THE EASTERN PLAINS KEEPING WINDS
BREEZY AT TIMES. A SURGE OF HIGHER DEWPOINTS OVER THE EASTERN
PLAINS MAY CREATE SOME PATCHY FOG OVER LINCOLN AND WASHINGTON
COUNTIES AFTER MIDNIGHT.

A PACIFIC TROUGH WILL MOVE OVER THE WESTERN US TUESDAY AND INTO
THE STATE TUESDAY NIGHT. MODELS HAVE BEEN SPEEDING THIS SYSTEM UP
AS WELL AS SPLITTING THE SYSTEM. AS THE SYSTEM AS SPED UP...UPWARD
QG VERTICAL VELOCITIES ARE NOW PRETTY WEAK TUESDAY THEN TURN
DOWNWARD WEDNESDAY. THIS SHOULD NOW BRING THE BETTER CHANCE OF
SHOWERS OVER THE MOUNTAINS TUESDAY AFTERNOON AND INTO EARLY
WEDNESDAY MORNING WITH A CHANCE OF SHOWERS OVER THE PLAINS MAINLY
LATE TUESDAY NIGHT INTO WEDNESDAY MORNING. WEAK CAPE MAY PRODUCE
ISOLATED THUNDERSTORMS IN THE TUESDAY AFTERNOON AND EARLY
WEDNESDAY AFTERNOON...BUT LIKELY QUITE SPARSE IN COVERAGE.
TUESDAY TEMPERATURES WILL CONTINUE TO WARM OVER THE PLAINS WITH
SLIGHT COOLING OVER THE MOUNTAINS WITH THE MOISTURE AND SHOWERS
MOVING IN. THE COLD FRONT IS THEN EXPECTED TO PUSH THROUGH LATE
TUESDAY NIGHT TO EARLY WEDNESDAY MORNING. THIS WILL HELP KICK OFF
MORE SHOWERS OVER THE PLAINS AND COOL TEMPERATURES ABOUT 10
DEGREES. SHOWERS AND CLOUDS SHOULD BE ON THE DECREASE BY THE LATE
AFTERNOON AS THE SYSTEM EXITS QUICKLY. THE HIGH
TERRAIN...GENERALLY ABOVE 9000 FEET MAY PICK UP A COUPLE INCHES OF
SNOW THROUGH THE EVENT. SKIES ARE EXPECTED TO CLEAR QUICKLY WITH
TEMPERATURES COOLING QUICKLY WEDNESDAY NIGHT.

THURSDAY THROUGH SATURDAY...THE UPPER RIDGE WILL BUILD BACK OVER
THE STATE WITH A LEE SURFACE TROUGH DEVELOPING AGAIN. THIS WILL
BRING WARMER AND DRIER WEATHER EACH DAY WITH TEMPERATURES REACHING
WELL ABOVE NORMAL AGAIN...INTO THE UPPER 70S OVER THE PLAINS. THE
GFS HAS FOR THE LAST THREE RUNS BROUGHT IN THE NEXT UPPER TROUGH
QUICKLY FOR SUNDAY...WITH THE EC AND GEM HOLDING OFF UNTIL
TUESDAY AT LEAST. HOWEVER JUST RECENTLY THE EC AND GEM HAVE NOW
BEEN BRINGING IT IN SLIGHTLY FASTER. THIS LOOKS LIKE A STRONGER
AND COLDER SYSTEM...FOR A POSSIBLE CHANCE TO SEE SNOW SOMETIME
EARLY NEXT WEEK. WILL CONTINUE TO MONITOR THE MODEL TRENDS.

&&

.AVIATION...(FOR THE TAFS THROUGH 06Z MONDAY EVENING)
ISSUED AT 748 PM MDT SUN OCT 19 2014

WINDS HAVE BECOME SELY AND SHOULD BECOME SLY BY 03Z AND THEN MORE
SSW AFTER 06Z.

&&

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

$$

UPDATE...RPK
SHORT TERM...BAKER
LONG TERM...KRIEDERMAN
AVIATION...BAKER/RPK



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