Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 290253
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
853 PM MDT THU MAY 28 2015

.UPDATE...
ISSUED AT 853 PM MDT THU MAY 28 2015

THERE HAVE BEEN A COUPLE OF ROUNDS OF CONVECTION THAT FIRED
BEHIND THE MAIN BATCH OF SEVERE STORMS ON THE EASTERN
PLAINS...BUT OVERALL STORM INTENSITY AND COVERAGE WILL CONTINUE TO
DECREASE THROUGH THE COURSE OF THE EVENING AS AIRMASS STABILIZES.
SOME WEAK LIFT SHOULD RESUME LATER TONIGHT INTO FRIDAY MORNING PER
LATEST WATER VAPOR IMAGERY AND SHORT WAVE DROPPING SOUTHEAST FROM
WYOMING. THIS WILL HELP TO BRING A FEW MORE RAIN SHOWERS BACK TO
THE HIGH COUNTRY AND NORTHERN BORDER AREA...WITH SNOW LEVELS
PERHAPS DROPPING INTO THE HIGH MOUNTAIN VALLEYS BY DAYBREAK.
CHANCE OF RAIN WILL INCREASE BEHIND A WEAK FRONT EARLY FRIDAY
MORNING...BUT MORE WIDESPREAD SHOWERS AND A FEW THUNDERSTORMS
EXPECTED BEHIND A STRONGER FRONTAL SURGE BY LATE MORNING THROUGH
THE AFTERNOON.

&&

.SHORT TERM...(THIS EVENING THROUGH FRIDAY)
ISSUED AT 252 PM MDT THU MAY 28 2015

THERE IS PRETTY GOOD CONVECTION GOING OVER THE PLAINS RIGHT NOW.
HAIL OVER AN INCH HAS BEEN REPORTED WITH SOME OF THE CELLS. THERE
ARE BOUNDARIES ALL OVER THE PLACE. THE WATER VAPOR PICTURES ARE
SHOWING ANOTHER DECENT BATCH OF CONVECTION UPSTREAM IN EASTERN
UTAH AND WESTERN COLORADO...AGAIN ASSOCIATED WITH THE APPROACHING
TROUGH AXIS. MODELS SHOW THE WEAK UPPER TROUGH AXIS TO PUSH ACROSS
THE CWA THIS EVENING AND TONIGHT. BY FRIDAY AFTERNOON...A WEAK
UPPER RIDGE IS MOVING ACROSS COLORADO. THE FLOW ALOFT IS PRETTY
WEAK TONIGHT AND WEAK NORTHERLY ON FRIDAY. MODELS HAVE A TAD OF
WEAK UPWARD QG VERTICAL VELOCITY FOR THE NORTHEAST QUARTER OF THE
CWA TONIGHT INTO FRIDAY MORNING...THEN ALL DOWNWARD FOR ALL THE
CWA FOR THE FIRST TWO PERIODS. THE BOUNDARY LAYER FLOW IS MAINLY
NORTH AND NORTHEASTERLY TONIGHT AND FRIDAY FOR MUCH OF THE CWA.
CONCERNING MOISTURE...THERE IS A LOT TONIGHT AND FRIDAY. THE DEW
POINTS ARE IN THE MID 40S TO MID 50S F THIS EVENING...THEN MOSTLY
THE 40S F OVERNIGHT AND FRIDAY. THERE IS SOME CAPE AROUND THIS
EVENING...MOSTLY OVER THE EASTERN HALF OF THE CWA. VALUES ARE OVER
1000 J/KG OVER THE FAR EASTERN BORDER AREAS. THERE IS CAPE FOR
ALL THE CWA ON FRIDAY...BUT NOTHING OVER 1000 J/KG. IT WILL LIKELY
NOT GET VERY WARM ON FRIDAY WITH ALL THE CLOUDINESS EXPECTED.
THERE IS SOME MEASURABLE PRECIPITATION OVER ALL THE CWA MOST OF
TONIGHT AND FRIDAY TOO. THE GREATEST AMOUNTS ARE PROGGED THIS
EVENING OVER THE EASTERN CWA. WILL KEEP POPS GOING OVERNIGHT...BUT
LOW AFTER 06Z. BY LATE MORNING FRIDAY WILL GO WITH "LIKELY"S FOR
MUCH OF THE CWA. FOR TEMPERATURES...FRIDAY`S HIGHS LOOK TO BE 3-7
C COOLER THAN TODAY`S.

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 252 PM MDT THU MAY 28 2015

TROUGH WILL MOVE EAST OF COLORADO FRIDAY NIGHT. SOME DISAGREEMENT
ABOUT HOW FAST THE CLEARING/DRYING WILL COME. NAM CONTINUES TO BE
FASTER SUGGESTING LOTS OF CLEARING EARLY MONDAY MORNING...WHILE
THE OPERATIONAL GFS REMAINS SLOWEST/WETTEST AND STILL HAS
SIGNIFICANT RAIN IN THE FOOTHILLS FRIDAY EVENING. WILL STICK WITH
THE IDEA OF A COMPROMISE SHADED TOWARD THE DRIER SOLUTIONS...I
LEFT THE EVENING POPS AS THEY WERE BUT SPED UP THE DEPARTURE OF
THE WEATHER BY A FEW HOURS. THIS HAS ONLY MINIMAL POPS ON THE
SOUTHERN BORDER AND IN THE MOUNTAINS EARLY SATURDAY MORNING. AFTER
THAT IT WILL BE WARMING AND DRYING ALOFT AND SHOULD BE TOO STABLE
FOR MUCH AFTERNOON CONVECTION...THOUGH I DID LEAVE SOME LOW
AFTERNOON POPS IN THE MOUNTAINS. MODELS HAVE TRENDED WARMER FOR
SATURDAY WHICH FITS THE SLIGHTLY EARLIER TIMING AND MORE SUNSHINE.

FOR SUNDAY THROUGH TUESDAY A WARM DRY RIDGE WILL MOVE OVER. THERE
HAS BEEN A TREND TOWARD WARMER TEMPERATURES WHICH LOOKS ALRIGHT
THOUGH I DID HOLD BACK A FEW DEGREES DUE TO THE MOIST GROUND.
WE WILL BE NEAR 80 ON SUNDAY WHICH COULD BE THE FIRST 80 IN
MAY...THEN LOW TO MID 80S FOR MONDAY AND TUESDAY LOOK GOOD. MODELS
HAVE FLIPPED FOR THE MID TO LATE WEEK TROUGH...BUT THE CONSENSUS
IS THE SAME. SOME MODELS SHOW A WEAK LEAD TROUGH MOVING THROUGH
ABOUT WEDNESDAY WHICH WOULD BRING A LITTLE COOLING AND PERHAPS A
BIT MORE LOW LEVEL MOISTURE FOR SOME INCREASE IN THUNDERSTORM
ACTIVITY. OTHERS LACK THIS AND WOULD HAVE LITTLE CHANGE THROUGH
THE END OF THE WEEK. MAIN FEATURE IS THE UPSTREAM TROUGH WHICH
WILL KEEP A WARM AND MAINLY DRY SOUTHWEST FLOW ALOFT OVER US.
CONSENSUS FORECAST IS FINE WHICH SHOWS A LITTLE COOLING AND SLIGHT
INCREASE IN POPS STARTING WEDNESDAY...BUT PROBABLY NOT A BIG
CHANGE.

&&

.AVIATION...(FOR THE TAFS THROUGH 06Z FRIDAY EVENING)
ISSUED AT 853 PM MDT THU MAY 28 2015

THUNDERSTORM THREAT IS SHIFTING TO THE SOUTHEAST OF THE FRONT
RANGE AIRPORTS AT THE PRESENT TIME. COULD STILL SEE A FEW RAIN
SHOWERS IN THE OVERNIGHT HOURS BUT MAIN PERIOD OF SHOWERS AND A
FEW STORMS SHOULD OCCUR FROM AROUND 16Z FRIDAY TO 01Z SATURDAY.
INSTRUMENT LANDINGS EXPECTED THROUGH THAT TIME PERIOD DUE TO LOWER
CEILINGS...AS WELL AS POSSIBLE MVFR CONDITIONS IN AND NEAR
SHOWERS. WINDS SHOULD TREND LIGHT SOUTHERLY TONIGHT AND THEN TO
NORTHERLY BY 12Z-16Z FRIDAY WITH PASSAGE OF COLD FRONT.

&&

.HYDROLOGY...
ISSUED AT 853 PM MDT THU MAY 28 2015

HEAVY RAINFALL THREAT THIS EVENING IS QUICKLY DIMINISHING AS
AIRMASS STABILIZES. MORE WIDESPREAD RAINFALL IS EXPECTED
FRIDAY...BUT AGAIN IT SHOULD MAINLY BE LIGHT WITH A LOW RISK OF
LOCALIZED FLOODING AND LITTLE EFFECT ON THE LARGER RIVERS. THE
CACHE LA POUDRE RIVER IN GREELEY WILL REMAIN RIGHT NEAR FLOOD
STAGE THIS WEEKEND...WHILE THE SOUTH PLATTE DOWNSTREAM WILL BE
SLOWLY FALLING.

BY EARLY NEXT WEEK WARM TEMPERATURES WILL LEAD TO INCREASING
SNOWMELT...LEADING TO HIGH FLOWS ON RIVERS AND STREAMS IN THE
MOUNTAINS. THIS WATER WILL PROGRESS DOWNSTREAM DURING THE NEXT
WEEK SO HIGH FLOWS WILL CONTINUE ON THE SOUTH PLATTE.

&&

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

$$

UPDATE...BARJENBRUCH
SHORT TERM...RJK
LONG TERM...GIMMESTAD
AVIATION...BARJENBRUCH
HYDROLOGY...BARJENBRUCH/GIMMESTAD/RJK



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