Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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931
FXUS65 KBOU 160251
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
851 PM MDT FRI MAY 15 2015

.UPDATE...
ISSUED AT 850 PM MDT FRI MAY 15 2015

SEVERE CONVECTION HAS MOVED OFF INTO NEBRASKA WITH A MORE STABLE
ENVIRONMENT LEFT BEHIND IN COLORADO. THERE ARE STILL SCATTERED
SHOWERS AND ISOLATED THUNDERSTORMS OVER THE FORECAST AREA...MAINLY
OVER THE MOUNTAINS. SOME OF THE MODELS ARE SHOWING A REDEVELOPMENT
OF PRECIPITATION OVERNIGHT...AND THIS LOOKS GOOD AS LARGE SCALE
ASCENT OCCURS AHEAD OF APPROACHING TROUGH. HAVE ADJUSTED POPS FOR
LATEST TRENDS. STILL LOOKS WET SATURDAY WITH NUMEROUS SHOWERS AND
A FEW STORMS. DEPENDING ON SPEED OF SURFACE TROUGH COULD SEE
ANOTHER RISK OF SEVERE STORMS ON THE FAR EASTERN PLAINS BY MID
DAY.

&&

.SHORT TERM...(THIS AFTERNOON THROUGH SATURDAY)
ISSUED AT 1135 AM MDT FRI MAY 15 2015

PRETTY DECENT CONVECTION GOING RIGHT NOW...ALL INITIATED ON THE
BOUNDARIES BEFORE THE NOON HOUR. THERE HAS BEEN SEVERE SIZED HAIL
AND A NUMBER OF FUNNELS AND TORNADOES ALREADY. MODELS HAVE THE
BROAD UPPER TROUGH AND CLOSED LOW TO MOVE FROM THE GREAT BASIN
EASTWARD TO OVER THE WESTERN COLORADO BORDER BY 12Z SATURDAY
MORNING...THEN TO OVER THE CWA BY SATURDAY AFTERNOON. THERE IS
UPWARD QG VERTICAL VELOCITY PROGGED OVER THE FORECAST AREA TONIGHT
AND SATURDAY. IT IS MODERATELY STRONG BY SATURDAY AFTERNOON. THE
LOW LEVEL PRESSURE GRADIENT IS PRETTY WEAK OVERNIGHT AND SATURDAY
...AND MOSTLY THE BOUNDARY LAYER FLOW FOR THE PLAINS HAS AN
UPSLOPE COMPONENT TO IT. BY 00Z SATURDAY AFTERNOON...WEST-
NORTHWESTERLIES ARE PROGGED. FOR MOISTURE...THERE IS A LOT AS THE
SLOWLY MOVING BROAD UPPER FEATURE MOVES ACROSS. THE CONVECTION
THIS AFTERNOON/EVENING SHOULD DECREASE MY MID EVENING...BUT AS THE
NIGHT WEARS ON THE PRECIPITATION WILL LIKELY BE MOVING INTO THE
WESTERN CWA ASSOCIATED WITH MORE OF THE SYNOPTIC SCALE UPPER
TROUGH. ON SATURDAY...FROM LATE MORNING THROUGH THE AFTERNOON
...WET...COOL WEATHER SHOULD COVER ALL THE CWA WITH AN UPPER LOW
OVER US. THE SNOW LEVEL WILL LIKELY GET DOWN TO AROUND 8500-9000
FEET AFTER MIDNIGHT THROUGH 15Z SATURDAY MORNING. WILL GO WITH
50-80% POPS SATURDAY AFTERNOON FOR ALL THE CWA. WILL ALSO KEEP
"SLIGHT CHANCE" OF THUNDER MOST OF OVERNIGHT AND SATURDAY...IN
SPITE OF THE LACK OF DECENT HEATING. FOR TEMPERATURES...SATURDAY
HIGHS LOOK TO BE 3-7 C COLDER THAN TODAY`S.

.LONG TERM...(SATURDAY NIGHT THROUGH THURSDAY)
ISSUED AT 1135 AM MDT FRI MAY 15 2015

ON SATURDAY EVENING...THE UPPER TROF WILL MOVE NORTHEAST INTO
NEBRASKA WITH STRONG SUBSIDENCE MOVING IN BEHIND IT ACROSS CENTRAL
AND SOUTHERN COLORADO. SHOWERS WILL DIMINISH RAPIDLY OVER FAR
NORTHEAST COLORADO WITH SOME CLEARING FURTHER WEST OVERNIGHT. CROSS
SECTIONS SHOW FAIRLY HEALTHY DOWNSLOPE FLOW WITH CROSS BARRIER
FLOW OF AROUND 30KT SO WOULD EXPECT SOME GUSTS AROUND 40KT OVER
FRONT RANGE FOOTHILLS.

THERE WILL BE RIDGING ALOFT BUILDING OVER COLORADO ON SUNDAY AND
MONDAY WITH SOME DRYING. HOWEVER ENOUGH MOISTURE AND INSTABILITY
FOR AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS OVER MOUNTAINS AND
PALMER DIVIDE. THERE IS A COLD FRONT WHICH MOVES OVER NORTHEAST
COLORADO SUNDAY NIGHT WITH A BIT COOLER TEMPERATURES ON MONDAY AND
PLAINS LOOK TO BE MORE STABLE ONLY MINIMAL SHOWER ACTIVITY. NEXT
STRONGER TROF WILL ROTATE ACROSS COLORADO ON TUESDAY AND TUESDAY
NIGHT WITH THE NEXT GOOD CHANCE OF SHOWERS AND THUNDERSTORMS ALONG
WITH COOLER TEMPERATURES.

&&

.AVIATION...(FOR THE TAFS THROUGH 06Z SATURDAY EVENING)
ISSUED AT 850 PM MDT FRI MAY 15 2015

MAINLY VFR CONDITIONS WILL PREVAIL BUT AT THE SAME TIME A RATHER
MOIST BOUNDARY LAYER WILL BRING A CHANCE OF LOWER IFR/MVFR
CEILINGS LATE TONIGHT THROUGH SATURDAY. SCATTERED SHOWERS ARE
EXPECTED TO REDEVELOP OVERNIGHT AND BECOME MORE WIDESPREAD BY
15Z-18Z SATURDAY. SOME THREAT OF THUNDER AS WELL SO WILL HAVE
TEMPO RAIN SHOWERS AND LOWER CEILINGS IN THE FORECAST MOST OF
SATURDAY WITH BETTER POTENTIAL OF A FEW EMBEDDED STORMS 18Z-23Z.

&&

.HYDROLOGY...
ISSUED AT 1135 AM MDT FRI MAY 15 2015

RIVER LEVELS ON THE SOUTH PLATTE WILL CONTINUE TO SLOWLY RECEDE
WITH THE EXCEPTION OF ITS COURSE THROUGH SEDGWICK COUNTY. IT IS
STILL EXPECTED TO RISE IN SEDGWICK COUNTY INTO MID DAY SATURDAY
WITH THE CREST AT JULESBURG FORECAST TO BE BELOW FLOOD STAGE. IT
SHOULD START TO RECEDE AT JULESBURG BY SATURDAY AFTERNOON.

THE CACHE LA POUDRE RIVER IN WELD COUNTY IS JUST ABOVE FLOOD
STAGE AND THIS WILL CONTINUE INTO SATURDAY.

&&

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

$$

UPDATE...BARJENBRUCH
SHORT TERM...RJK
LONG TERM...ENTREKIN
AVIATION...BARJENBRUCH
HYDROLOGY...RJK



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