Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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FXUS65 KBOU 180351
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
951 PM MDT FRI APR 17 2015

.UPDATE...
ISSUED AT 942 PM MDT FRI APR 17 2015

ALTHOUGH ADDITIONAL SHOWERS WILL BE MOVING INTO THE URBAN CORRIDOR
FROM DENVER SOUTHWARD AT THIS TIME...AND THEN INTO FRONT RANGE
FOOTHILLS OVERNIGHT...THE COVERAGE DOES NOT APPEAR TO BE
SUFFICIENT ENOUGH TO CONTINUE WITH THE WINTER STORM
WARNING...THEREFORE IT HAS BEEN CANCELLED. THE WRAP AROUND
SNOWFALL IS EXPECTED TO MOVE INTO THE MOUNTAINS BUT MOST OF THIS
WILL OCCUR ON SATURDAY. HAVE ALSO CANCELLED TORNADO WATCH 69 FOR
OUR NORTHEAST PLAINS. IF SOME CLEARING DOES OCCUR OVERNIGHT THEN
FOG MAY AGAIN RETURN FROM AROUND DENVER EASTWARD...WILL KEEP
PATCHY COVERAGE ALONG THE URBAN CORRIDOR...WITH A BIT MORE
COVERAGE FURTHER EAST.

UPDATE ISSUED AT 613 PM MDT FRI APR 17 2015

LATEST HRRR IS MOVING THE PCPN OVER SERN CO INTO THE PALMER
DIVIDE SHORTLY THEN NORTHWEST INTO THE URBAN CORRIDOR. HAVE
INCREASED THE POPS THIS EVENING. PCPN WILL BE RAIN OR A RAIN/SNOW
MIX. DUE TO THE CONVECTIVE NATURE OF THIS SYSTEM...AREAS OVER THE
PALMER DIVIDE AND THE CHEYENNE RIDGE COULD PICK UP AN INCH OR TWO
OF SNOW. ANY SNOWFALL THAT DEVELOPS ELSEWHERE ALONG THE URBAN
CORRIDOR SHOULD BE AN INCH OR LESS. TORNADO WATCH REMAINS IN
EFFECT FOR MORGAN....WASHINGTON...LOGAN...SEDGWICK AND PHILLIPS
COUNTIES UNTIL MIDNIGHT.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 124 PM MDT FRI APR 17 2015

UPPER LEVEL LOW CENTERED OVER SOUTH CENTRAL COLORADO WILL SLOWLY
SPIN NORTHEAST ACROSS THE STATE AND END UP OVER THE NORTHEAST CORNER
SATURDAY AFTERNOON. DRIER AIR HAS ROTATED NORTH ACROSS THE AREA THIS
AFTERNOON AND BROUGHT THE WIDESPREAD RAIN AND SNOW TO AN END.
CLEARING DUE TO THE DRIER AIR HAS ALLOWED SOME WARMING. HIRES MODELS
SHOWING SCATTERED CONVECTION FILLING IN DURING THE LATE AFTERNOON
AND EVENING. WILL KEEP SCATTERED TO LIKELY POPS IN THE FORECAST THIS
EVENING FOR THIS. ALREADY CANCELED THE ADVISORY WHERE THE SNOW ENDED
IN PARK COUNTY AND THE PALMER DIVIDE. MAY BE ABLE TO CANCEL THE
WINTER STORM WARNING AS WELL. WILL HOLD OFF FOR NOW AND SEE HOW MUCH
CONVECTION FORMS. OUTSIDE OF CONVECTION...ADDITIONAL SNOWFALL ONCE
THE DRY AIR MOVES THROUGH SHOULD BE LIGHT.

COOLED HIGH TEMPERATURES ARE FEW DEGREES FOR SATURDAY WITH COOL AIR
OVER US FROM THE UPPER LEVEL LOW. NORTHWEST FLOW BEHIND THE LOW
COMBINED WITH STEEP LAPSE WILL PRODUCE SNOW SHOWERS OVER THE
MOUNTAINS. INCREASED POPS FOR THIS. NEW SNOWFALL FOR THE MOUNTAINS
SATURDAY WILL GENERALLY BE LESS THAN 4 INCHES...THOUGH A FEW FAVORED
OROGRAPHIC AREAS COULD SEE A LITTLE MORE. FOR THE FRONT
RANGE...DOWNSLOPE FLOW WILL LIMIT PRECIPITATION CHANCES...THOUGH IT
SHOULD BE UNSTABLE ENOUGH FOR SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS. THE BEST CHANCE WILL BE OVER THE PLAINS CLOSER TO THE
LOW AND AWAY FROM DOWNSLOPE. AIRMASS WILL BE WARM ENOUGH FOR RAIN
SATURDAY WITH SNOW CONFINED TO THE FOOTHILLS AND MOUNTAINS.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 124 PM MDT FRI APR 17 2015

THE ACTIVE PATTERN CONTINUES THROUGH THE WEEKEND AND INTO EARLY
NEXT WEEK. SATURDAY NIGHT INTO SUNDAY THE UPPER LEVEL LOW CENTER
WILL MAKES ITS WAY EAST OVER THE CO AND KS BORDER. THIS WILL BRING
INCREASED NORTHERLY FLOW OVER NE COLORADO WITH A TROUGH OVER THE
WEST WILL HELP BRING A SURGE OF COOLER AIR THAT WILL SPREAD SNOW
SHOWERS OVER THE MOUNTAINS AND FOOTHILLS. THE TROUGH WILL PUSH
EAST HELPING TO DRY OUT THE PLAINS KEEPING THE REGION COOLER UNDER
MOSTLY CLOUDY SKIES. TEMPERATURES FOR SUNDAY WILL CONTINUE TO BE
BELOW SEASONAL NORMALS WITH HIGHS IN THE UPPER 40S TO LOWER 50S.

SUNDAY NIGHT INTO MONDAY STRONG NW WILL PREVAIL WITH A NW ORIENTED
JET MOVING INTO NE COLORADO. INCREASED MOISTURE IN THE MID LEVELS
WITH A SURFACE TROUGH WILL HELP TO KEEP SNOW IN THE MOUNTAINS AND
SCATTERED RAINSHOWERS OVER THE PLAINS THROUGH MONDAY NIGHT INTO
TUESDAY MORNING. WILL KEEP A SLIGHT CHANCE WITH THIS SYSTEM WITH A
CHANCE IN THE MOUNTAINS WITH DECENT ASCENT. TEMPERATURES FOR
MONDAY AND TUESDAY WILL SLOWLY INCREASE TO SEASONAL NORMALS BY
TUESDAY AFTERNOON AS THE UPPER LEVEL RIDING MOVES IN ALONG WITH
SURFACE HIGH PRESSURE. DOWNSLOPING WINDS OFF THE FOOTHILLS WILL
HELP TO WARM TEMPERATURES OVER THE PLAINS INTO WEDNESDAY WHERE
MODELS HAVE HIGH TEMPERATURES REACHING INTO THE UPPER 60S AND
LOWER 70S.

UPPER LEVEL FLOW TURNS SOUTHWESTERLY AHEAD OF THE NEXT DISTURBANCE
OVER SOUTHERN CA. THE MODELS DIVERGE AT THIS POINT WITH THE GFS
BRINGING PRECIPITATION BACK INTO THE MOUNTAINS BY WEDNESDAY
EVENING AND THE EC 24 HOURS BEHIND. WILL KEEP A SLIGHT CHANCE IN
THE GRIDS OR THIS PERIOD BUT WILL CONTINUE TO MONITOR MODEL
TRENDS.

&&

.AVIATION...(FOR THE TAFS THROUGH 06Z SATURDAY EVENING)
ISSUED AT 942 PM MDT FRI APR 17 2015

A MIX OF RAIN AND SNOW SHOWERS MOVING THROUGH DENVER AT THIS
TIME...MVFR WITH THE POTENTIAL FOR IFR CIGS/VSBYS AT KAPA SHORTLY
AND KBJC IN ANOTHER HOUR OR TWO. DURATION FOR THE IFR CONDITIONS SHOULD
BE A LITTLE SHORTER AT KDEN. POTENTIAL FOR FOG DOES EXIST EARLY
SATURDAY MORNING...12Z-15Z...SO WL KEEP THIS POSSIBILITY IN THE
TAFS AS WELL. CONVECTION MAY BE PRODUCING VARIABLE WINDS FOR A
TIME...BUT SHOULD SETTLE ON A LIGHT WNWLY WIND COMPONENT AFTER 06Z
AND THIS SHOULD CONTINUE INTO SATURDAY.

&&

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

$$

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



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