Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 252255
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
355 PM MST WED FEB 25 2015

.UPDATE...
ISSUED AT 349 PM MST WED FEB 25 2015

MODERATE TO HEAVY SNOW NOW ENCOMPASSES MOST OF THE URBAN CORRIDOR
FROM LONGMONT SOUTH THROUGH BOULDER...DENVER AND CASTLE ROCK. THE
HEAVY SNOW HAS ALSO STRETCHED FURTHER EAST ACROSS SOUTHWEST WELD
COUNTY SO HAVE ADDED A WINTER ADVISORY FOR THOSE SECTIONS AS WELL.
DOES APPEAR TO BE A BACK EDGE OF THIS HEAVY SNOW ACROSS SOUTHERN
LARIMER COUNTY WITH DECREASING INTENSITIES NOTED FURTHER NORTH.
WILL STILL HAVE TO WATCH CLOSELY IF THE HEAVIER SNOW DOES STICK
AROUND LONGER THAN EXPECTED THEN THE ADVISORIES WOULD NEED TO BE
UPGRADED TO WARNINGS.

&&

.SHORT TERM...(THIS AFTERNOON THROUGH THURSDAY)
ISSUED AT 1023 AM MST WED FEB 25 2015

A MOIST NORTHWESTERLY FLOW ALOFT WILL REMAIN OVER THE REGION
THROUGH THURSDAY. A COLD FRONT RACED INTO THE FRONT RANGE MUCH
EARLIER THAN EXPECT THE SNOW SHOWERS INCREASING IN COVERAGE AND
INTENSITY ALONG THE FRONT RANGE. AS A RESULT...WE STARTED TO THE
HIGHLIGHTS A LITTLE SOONER. THE BEST COMBINATION OF UPSLOPE/INSTBY
WILL BE THE REST OF THIS AFTN INTO EARLY EVENING...03-04Z. RUC
SOUNDINGS THIS AFTN HAD CAPES OF 200-300 J/KG. SOME ADDITIONAL
EHHANCEMENT UPSTREAM OVER WYOMING AND SOME OF THIS WILL BE MOVING
INTO NORTHEASTERN COLORADO THROUGH THIS EVENING.  WEAK MID AND
UPPER QG ASCENT IS PROGGED TO OCCUR AROUND THE SAME TIME AS THE
SYSTEM PASSES OVERHEAD. WL KEEP THE HIGHLIGHTS AS IS FOR NOW. THE
HRRR DOES NOT KEEP HEAVY SNOW AROUND VERY LONG...HIGHER AMOUNTS
MAY BE MORE LOCALIZED IN ZONES 39>41 SO WL KEEP THE WINTER WEATHER
ADVISORY THERE. AS FOR THURSDAY...SPATIAL CROSS-SECTIONS KEEP A
FAIRLY PERSISTENT LAYER OF LOW LEVEL WEAK UPSLOPE ALONG THE FRONT
RANGE SO SOME LIGHT SNOW MAY PERSIST ON AND OFF THROUGH THE DAY.
IN THE MOUNTAINS LIGHT SNOW THERE AS WELL. SINCE THE HEAVIER SNOW
IS EXPECTED TO OCCUR THROUGH THE EVENING...WL NOT EXTEND THE
HIGHLIGHTS ANY FURTHER THAN 6 AM MST THURSDAY.

.LONG TERM...(THURSDAY NIGHT THROUGH TUESDAY)
ISSUED AT 1023 AM MST WED FEB 25 2015

...VERY ACTIVE PATTERN WITH CONTINUED SNOW FOR THE LONG RANGE
FORECAST...

FOR THURSDAY NIGHT INTO FRIDAY UPPER LEVEL FLOW CONTINUES TO BE
STRONG OUT OF THE NW. UPSLOPE FLOW ALONG THE FOOTHILLS BEGINS TO
BREAK DOWN EARLY FRIDAY AS DOWNSLOPING TAKES OVER AND HELPS TO
CLEAR OUT PRECIPITATION BY FRIDAY AFTERNOON FOR AREAS CLOSER TO
THE FOOTHILLS AND URBAN CORRIDOR. THE MOUNTAINS HOWEVER WILL
MAINTAIN DECENT MOISTURE SO LIGHT SNOW WILL REMAIN POSSIBLE
THROUGH FRIDAY. WITH THE COLD AIR USHERED IN BY THE PASSING FRONT
MID WEEK HIGH TEMPERATURES ON FRIDAY WILL BE IN THE MID TEENS TO
LOWER 20S WITH LOW TEMPS OVERNIGHT IN THE SINGLE DIGITS.

THE UPPER LEVEL PATTERN CHANGES AS ANOTHER TROUGH OVER THE
NORTHWEST ON FRIDAY AFTERNOON DROPS SOUTH BRINGING FLOW MORE
WESTERLY. THIS IS ACCOMPANIED BY A DEEP SURFACE LOW PRESSURE
SYSTEM CENTERED OVER THE GREAT BASIN THAT WILL HELP TO CYCLE IN
MOISTURE FROM THE SOUTHWEST WITH ITS CONTINUED CYCLONIC FLOW
PATTERN. WITH INCREASED MOISTURE ALONG WITH LIGHT UPSLOPE WILL
MAINTAIN A SLIGHT CHANCE OF SNOW FOR THE PLAINS ON SATURDAY BUT
CHANCES WILL INCREASE INTO SUNDAY AS THE SURFACE LOW MOVES INTO
SW CO BRINGING INCREASED UPSLOPE TO THE FOOTHILLS AND PALMER
DIVIDE AREA.

FOR SUNDAY THE UPPER LEVEL JET MOVES NORTH INTO NE CO INCREASING
CHANCE FOR SOME CONVECTION OR BANDING SNOW. THIS COMBINED WITH
DECENT QG ASCENT THROUGH THE WEEKEND ALONG WITH SURFACE HIGH
PRESSURE OVER THE EASTERN PLAINS WITH AID IN THAT DEVELOPMENT AS
WELL. BY LATE SUNDAY THE UPPER LEVEL TROUGH WILL SINK INTO THE
DESERT SOUTHWEST PLACING CO IN THE DEFORMATION ZONE DOWNSTREAM OF
THE MAIN BRANCH OF CIRCULATION. THIS WILL MAINLY IMPACT THE
SOUTHERN PORTIONS OF THE STATE BUT WILL MAINTAIN LIGHT SNOW FOR
OUR REGION IN THIS PATTERN. TEMPERATURES FOR SAT AND SUN WILL
REMAIN BELOW NORMAL STAYING IN THE LOWER TO MID 20S FOR HIGHS AND
SINGLE DIGITS FOR OVERNIGHT TEMPERATURES.

SNOWFALL AMOUNTS AT ANY PARTICULAR PERIOD WILL NOT BE
HEAVY...HOWEVER LIGHT SNOW OVER A LONGER PERIOD OF TIME WILL
ACCUMULATE UNDER COOLER TEMPERATURES.

FOR THE BEGINNING OF NEXT WEEK THE MODELS BEGIN TO DIVERGE ON THE
PLACEMENT AND MOVEMENT OF THE UPPER LEVEL LOW PRESSURE SYSTEM OVER
THE GREAT BASIN. WITH BOTH MODELS MOISTURE AND COOLER TEMPERATURES
WILL REMAIN WITH LIGHT SNOW POSSIBLE THROUGH THE EXTENDED PERIOD.
TEMPERATURES WILL START TO IMPROVE TUESDAY INTO WEDNESDAY WITH
ABOVE FREEZING BEING A POSSIBILITY.

&&

.AVIATION...(FOR THE TAFS THROUGH 18Z THURSDAY MORNING)
ISSUED AT 1023 AM MST WED FEB 25 2015

IFR CONDITIONS AND HEAVIER SNOW SHOWERS POSSIBLE THROUGH 02Z OR
SO...WITH POTENTIAL FOR 1-2 INCH PER HOUR SNOW RATES AND TEMPO
1/4SM VISIBILITY. HIGHEST THREAT WOULD BE AT KBJC AND KAPA...BUT
SOME THREAT AT KDEN TOO. OVERALL INTENSITY SHOULD DECREASE AFTER
04Z BUT IFR CONDITIONS WILL LIKELY LINGER WITH LIGHT SNOW THROUGH
THURSDAY MORNING...WITH SOME IMPROVMENT IN CIGS/VSBYS IN THE
AFTN WITH MVFR PREVAILING.


&&

.BOU WATCHES/WARNINGS/ADVISORIES...
WINTER WEATHER ADVISORY UNTIL 6 AM MST THURSDAY FOR COZ033-034-
039>041-043.

WINTER STORM WARNING UNTIL 6 AM MST THURSDAY FOR COZ035-036.

&&

$$

UPDATE...ENTREKIN
SHORT TERM...COOPER
LONG TERM...BOWEN
AVIATION...COOPER


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