Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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953
FXUS65 KBOU 130352
AFDBOU

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE DENVER/BOULDER CO
852 PM MST FRI FEB 12 2016

.UPDATE...
ISSUED AT 834 PM MST FRI FEB 12 2016

LATEST SATELLITE IMAGERY SHOWING STRATUS AND FOG ADVANCING
WESTWARD OVER THE NORTHEAST PLAINS AND NOW IS INTO CENTRAL WELD
COUNTY. LATEST SHORT RANGE MODELS BRING THE STRATUS INTO LARIMER
COUNTY BUT CONTINUE TO KEEP MUCH OF THE DENVER AREA FREE OF
STRATUS AS DRAINAGE FLOW EXPECTED TO STRENGTHEN DURING THE NIGHT.
HAVE ALREADY UPDATE THE FORECAST WITH A BIT MORE CLOUDS/FOG
ESPECIALLY NORTH AND EAST OF DENVER. STILL SOME LOWER PROBABILITIES
THAT STRATUS MAY SPILL IN FROM THE NORTH OVER THE DENVER AREA
UNDER A WEAK DENVER CYCLONE. NO OTHER CHANGES NEEDED FOR TONIGHT.

UPDATE ISSUED AT 538 PM MST FRI FEB 12 2016

FOG SHOWING UP IN SIDNEY NEBRASKA CURRENTLY...FURTHER WEST THAN
HIRES MODELS HAD IT. MODELS ALSO SHOWING SLIGHTLY MORE POTENTIAL
FOR FOG PUSHING FURTHER WEST OVER THE PLAINS...MAINLY INTO WELD
COUNTY AND POSSIBLY CYCLONING DOWN INTO THE DENVER AREA. FOR NOW
WILL SPREAD FOG WEST INTO MORGAN AND WELD COUNTIES. WILL KEEP
WATCH ON MODEL AND OBSERVATIONAL TRENDS TO SEE IF IT NEEDS SPREAD
FURTHER WEST AND SOUTH.

&&

.SHORT TERM...(THIS EVENING THROUGH SATURDAY)
ISSUED AT 1258 PM MST FRI FEB 12 2016

MAIN ISSUE IS THE COLD AIR OOZING INTO COLORADO FROM THE EAST
TONIGHT AND THEN WASHING BACK OUT ON SATURDAY. THIS HAS BEEN A BIT
SLOW COMING IN TODAY...BUT IT IS COMING AND SHOULD SPREAD STRATUS
AND FOG AND COLDER AIR INTO THE EASTERN PORTION OF THE PLAINS BY
MIDNIGHT. LOW LEVEL FLOW SHOULD BE TURNING SOUTHERLY THIS EVENING
WHICH SHOULD ARREST THE WESTWARD MOTION. EXPECTING A WEAK DENVER
CYCLONE TO FORM BY MORNING BUT EXPECTING AREAS NORTH AND NORTHWEST
OF DENVER TO BE FOG FREE...SO EXPECT THE THREAT OF STRATUS/FOG
WRAPPING INTO DENVER TO BE LOW.

COOL AIR WASHES BACK OUT ON SOUTHERLY FLOW SATURDAY...THOUGH THERE
WILL STILL BE QUITE A GRADIENT FROM DENVER TO THE EASTERN BORDER.
OVERALL TEMPERATURES A FEW DEGREES WARMER. COULD BE SOME MOISTURE
APPROACHING FROM THE WEST...BUT NO POPS YET.

.LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY)
ISSUED AT 1258 PM MST FRI FEB 12 2016

FOR SATURDAY NIGHT...THE FLOW ALOFT WILL BE ZONAL AS THE RIDGE
SHIFTS TO THE EAST AND A WEAK SYSTEM APPROACHES COLORADO FM THE
NORTHWEST...AND BRUSHES NORTHERN COLORADO AROUND 06Z SUNDAY.
NAM12 SPATIAL CROSS-SECTIONS SHOW AN AMPLIFIED MOUNTAIN WAVE
DEVELOPING. STRONGEST WINDS APPEAR TO BE 06Z TO 15Z SUNDAY. COULD
SEE GUSTS IN EXCESS OF 60 MPH ABOVE TIMBERLINE. ALTHOUGH
WINDY...THE SHEAR ALOFT MAY BE TOO STRONG ALOFT TO SUPPORT WARNING
CRITERIA WINDS...SO WILL KEEP GUSTS IN THE FOOTHILLS IN THE 50-60
MPH RANGE. FOR SUNDAY AND SUNDAY NIGHT...STRONG NORTHWESTERLY FLOW
ALOFT. IN THE MOUNTAINS MOISTURE DEEPENING. MID LEVEL LAPSE RATES
IN THE 7-8C KM RANGE IN THE AFTN. MOISTURE IN THE MOUNTAINS WILL
BE DEEPEST SUNDAY AFTN AND EVENING. GOOD INSTABILITY AND FAVORABLE
OROGRAPHICS WILL FAVOR THE HIGHER NORTHWEST FACING SLOPES. COULD
SEE 1 TO 4 INCHES OF SNOWFALL THERE. DOWNSLOPE WILL NEGATE THE
SNOWFALL EAST OF THE CONTINENTAL DIVIDE...SO POPS WILL DROP OFF
QUICKLY THERE. AS FAR THE THE NORTHEAST PLAINS IN CONCERNED...WILL
SEE LITTLE IF ANY SHOWERS ALONG THE URBAN CORRIDOR NEAR THE
FOOTHILLS. FURTHER EAST ACROSS THE PLAINS AWAY FM THE
DOWNSLOPE...ENOUGH MID LEVEL MOISTURE COUPLED WITH MODERATE LAPSE
RATES TO PRODUCE A SLIGHT CHANCE OF RAIN SHOWERS IN THE LATE
AFTN/EVNG OR A BRIEF MIX OF RAIN/SNOW SHOWERS BY LATE SUNDAY
EVENING. AN UPPER LEVEL RIDGE WILL BUILD OVER THE WEST FOR THE
FIRST PART OF NEXT WEEK. ASIDE FM SOME DIMINISHING SNOW SHOWERS IN
THE MOUNTAINS ON MONDAY...IT WILL BE WARMER AND DRIER THROUGH THE
WEEK. TEMPERATURES ACROSS THE URBAN CORRIDOR AND NORTHEAST PLAINS
WILL BE WELL ABOVE NORMAL...CLIMBING INTO THE 60S. &&

.AVIATION...(FOR THE 18Z TAFS THROUGH 18Z SATURDAY AFTERNOON)
ISSUED AT 1258 PM MST FRI FEB 12 2016

VFR THROUGH SATURDAY. AREAS OF LOW CLOUDS ON FOG ON THE PLAINS
EAST OF DENVER SATURDAY MORNING...BUT LESS THAN A 20 PERCENT
CHANCE OF FOG OR LOW CLOUDS IN THE DENVER AREA. LIGHT EAST WINDS
WILL BECOME SOUTHERLY AT KDEN/KAPA THIS EVENING...THEN LIKELY
TURN NORTHWEST AS A DENVER CYCLONE DEVELOPS EARLY SATURDAY. SOME
UNCERTAINTY ABOUT THE LAST PART.

&&

.AVIATION...(FOR THE 06Z TAFS THROUGH 06Z SATURDAY NIGHT)
ISSUED AT 834 PM MST FRI FEB 12 2016

MAIN CONCERN IS POTENTIAL FOR STRATUS AND FOG INTO KDEN TONIGHT.
LATEST SATELLITE IMAGERY HAS STRATUS INTO SOUTHEAST WELD COUNTY
NEARING HUDSON. DRAINAGE WINDS ARE DEVELOPING NOW SO THIS WILL
KEEP MUCH OF THE LOW CLOUDS NORTH OF KDEN. THERE IS STILL A LOWER
PROBABILITY THAT DRAINAGE FLOW MAY NOT BE STRONG ENOUGH TO KEEP
OUT THE STRATUS. WILL MONITOR CLOSELY. LESSER CHANCES FOR LOW
CLOUDS AT BJC/APA TNT.

&&

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

$$

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



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