Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 280911
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
311 AM MDT TUE JUL 28 2015

.SHORT TERM...(TODAY THROUGH TONIGHT )
ISSUED AT 311 AM MDT TUE JUL 28 2015

A STRONG UPPER LEVEL TROUGH MOVING ACROSS THE NORTHERN PART OF THE
COUNTRY WILL BRING A DRY WEST-SOUTHWEST FLOW ALOFT TODAY. THIS
SYSTEM ALSO PUSHED A COLD FRONT SOUTH ACROSS COLORADO OVERNIGHT.
BEHIND IT DEW POINTS HAVE FALLEN INTO THE 30S. SUNNY SKIES WILL
PREVAIL FOR A GOOD PART OF THE DAY. WILL SEE CUMULUS CLOUDS BUILD UP
OVER THE HIGHER TERRAIN THIS AFTERNOON. A SURFACE HIGH OVER THE
NORTHERN ROCKIES WILL PRODUCE EASTERLY WINDS TODAY. EVENTUALLY THESE
EASTERLY WINDS WILL INCREASE MOISTURE. THIS MOISTURE COMBINED WITH
AN UPSLOPE FLOW SHOULD PRODUCE CLOUDS ALONG THE FRONT RANGE TONIGHT.
AIRMASS WILL BE JUST SLIGHTLY UNSTABLE OVER THE HIGHER TERRAIN...SO
WILL KEEP THE SLIGHT CHANCE FOR THUNDERSTORMS IN THE FORECAST FOR
THE FRONT RANGE MOUNTAINS LATE THIS AFTERNOON AND TONIGHT. A WEAK
WAVE EMBEDDED IN THE FLOW ALOFT WILL BRING CLOUDS TO SOUTHERN PARTS
OF THE AREA TONIGHT. JUST A SLIGHT CHANCE FOR SHOWERS AND STORMS
WITH THIS SYSTEM. THERE WILL BE A BETTER CHANCE TO THE SOUTH AND
EAST OF THE AREA.

COOLER AIR BEHIND THE FRONT WILL DROP HIGHS IN THE 80S TODAY. FOR
TONIGHT...THE COOL DRY AIRMASS SHOULD ALLOW MOST LOCATIONS TO FALL
IN THE 50S. WHERE IT CLEARS IN THE MOUNTAINS VALLEY...30S WILL BE
POSSIBLE.

.LONG TERM...(WEDNESDAY THROUGH MONDAY)
ISSUED AT 311 AM MDT TUE JUL 28 2015

AN UPPER LEVEL HIGH WILL GRADUALLY EXPAND FM TEXAS ACROSS THE SRN
ROCKIES THRU THU WITH WLY FLOW ALOFT.  BOTH THE ECMWF AND GFS KEEP
THE BRUNT OF SUBTROPICAL MOISTURE TO THE SOUTH OF THE AREA ON WED
HOWEVER THERE WILL BE SOME RETURN OF LOW LVL MOISTURE IN SELY FLOW.
OVERALL WILL KEEP ISOLD TO WDLY SCT TSTMS OVER THE HIGHER TERRAIN
AND ACROSS THE PALMER DIVIDE.  AS FOR HIGHS WILL KEEP READINGS IN
THE 80S OVER NERN CO.

BY THU THE ECMWF BEGINS TO SHIFT SOME OF THE SUBTROPICAL MOISTURE
FURTHER NORTH WHILE THE GFS DOES NOT.  IF THIS MOISTURE DOES END UP
FURTHER NORTH LIKE ECMWF SHOWS THEN THERE WOULD BE A SLIGHT INCREASE
IN TSTM ACTIVITY OVER THE HIGHER TERRAIN ESPECIALLY SOUTH OF I-70.
MEANWHILE AT THE SFC THERE WILL BE A WK CONVERGENCE ZONE SETTING UP
OVER THE PLAINS WHICH MAY LEAD TO SOME ISOLD TSTM ACTIVITY WHERE
DEEPER LOW LVL MOISTURE WILL EXIST.  AS FAR AS HIGHS 850-700 MB
TEMPS BEGIN TO RISE A FEW DEGREES SO WILL KEEP READINGS IN THE UPPER
80S TO LOWER 90S OVER NERN CO.

BY FRI INTO SAT THE UPPER LEVEL HIGH WILL SHIFT A BIT FURTHER WEST
WITH THE FLOW ALOFT BECOMING MORE WNW.  BOTH THE ECMWF AND GFS SHOW
SOME SUBTROPICAL MOISTURE EMBEDDED IN THE FLOW WHICH MAY AFFECT THE
HIGHER TERRAIN LEADING TO AT LEAST A SLIGHT CHC OF STORMS.  OUTFLOW
BOUNDARIES FM MTN STORMS COULD TRIGGER SOME ISOLD STORMS ALONG THE
FRONT RANGE SO WILL KEEP IN LOW POPS BOTH DAYS.  HIGHS BOTH FRI AND
SAT WILL BE IN THE LOWER TO MID 90S OVER NERN CO.

FOR SUN INTO MON THE CENTER OF THE UPPER LEVEL HIGH WILL BE NEAR THE
FOUR CORNERS WITH WNW FLOW ALOFT REMAINING OVER NRN CO.  ONCE AGAIN
THERE MAY BE SOME SUBTROPICAL MOISTURE EMBEDDED IN THE FLOW ALLOWING
FOR A SLIGHT CHC OF STORMS OVER THE HIGHER TERRAIN.  ACROSS NERN CO
WILL KEEP IN LOW POPS BOTH DAYS AS BOUNDARIES FM STORMS OVER THE
HIGHER TERRAIN MAY TRIGGER A FEW STORMS.  MEANWHILE BOTH THE ECMWF
AND GFS SHOW SOME TYPE OF WK BNDRY NR THE WY-NE BORDER SUN NIGHT
THRU MON WHICH COULD ACT AS A FOCUS FOR TSTM DEVELOPMENT AND HIGHER
POPS. HOWEVER SINCE THIS IS WAY OUT IN DAY 6 AND 7 WILL JUST
MENTION LOW POPS FOR NOW. AS FOR HIGHS OVERALL THERE IS NOT MUCH
CHANGE IN THE 850 TO 700 TEMP FIELDS EITHER DAY SO READINGS WILL
LIKELY STAY IN THE LOWER TO MID 90S ACROSS NERN CO.

&&

.AVIATION...(FOR THE TAFS THROUGH 12Z WEDNESDAY MORNING)
ISSUED AT 311 AM MDT TUE JUL 28 2015

VFR CONDITIONS WILL PREVAIL THE NEXT 24 HOURS. MID AND HIGH CLOUDS
ARE EXPECTED TO INCREASE AFTER 00Z WITH CEILINGS STAYING ABOVE 8000
FEET. EASTERLY WINDS WILL PREVAIL TODAY...MAY SEE GUSTS TO 25 KNOTS
BETWEEN 21Z AND 03Z. WINDS WILL DECREASE AFTER 03Z AND TURN
SOUTHERLY.

&&

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

$$

SHORT TERM...MEIER
LONG TERM...RPK
AVIATION...MEIER


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