Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

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000 FXUS65 KBOU 141656 AFDBOU AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER/BOULDER CO 956 AM MST SUN FEB 14 2016 .UPDATE... ISSUED AT 955 AM MST SUN FEB 14 2016 W/NWLY SFC WINDS HAVE BEEN QUITE STRONG ABOVE TIMBERLINE THIS MORNING WITH LOCALIZED GUSTS UPWARDS OF 70 MPH. HIGH MTN CAMS INDICATED CONSIDERABLE BLOWING SNOW MAINLY ABOVE TIMBERLINE. HOWEVER IN THE PAST HOURS...THESE SAME WIND SENSORS HAVE SHOWN A DROP OFF IN WIND SPEEDS. THIS MATCHES WELL WITH MODEL GUIDANCE AS IT INDICATES A REDUCTION IN MTN TOP FLOW DURING THE NEXT 2-4 HRS... THEN A STEADY INCREASE AS THE NOSE OF A 120-130KT JET PASSES OVER NRN COLORADO. AS FOR THE SNOW POTENTIAL IN THE HIGH COUNTRY... SLOW GOING NEXT FEW HOURS...THEN A STEADY INCREASE IN BOTH COVERAGE AND INTENSITY AS 700-500MB QUASI-GEOSTROPHIC ASCENT INCREASING AND COLD AIR ADVECTION KICKS IN THE WAKE OF A WEAK SHORTWAVE TROUGH MODELS SHOW SWEEPING ACROSS N-CNTRL/NERN COLORADO LATER THIS AFTERNOON. THE CONVEYOR PACIFIC MOISTURE UPSTREAM OF NWRN COLORADO DOES NOT LOOK TERRIBLY DEEP...BUT COMBO OF LARGE SCALE LIFT AND OROGRAPHIC FORCING SHOULD HAVE LITTLE TROUBLE GENERATING THE SNOW AMOUNTS INDICATED IN THE WINTER WEATHER ADVISORY ISSUED FOR THE NRN MTN ZONES 31..33-34 STARTING AT 19Z TODAY. STG WINDS...BITTER COLD WIND CHILLS AND CONSIDERABLE BLOWING SNOW MAY POSE MORE OF A PROBLEM FOR MTN RESIDENTS AND HIGH COUNTRY TRAVELERS ESPLY THOSE CROSSING THE HIGH PASSES LATER THIS AFTERNOON AND EVENING. ELSEWHERE...WESTERLY WINDS IN THE FRONT RANGE FOOTHILLS ARE ALSO EXPECTED TO STRENGTHEN THIS AFTERNOON. COULD SEE GUSTS IN THE 45-55 MPH RANGE. NEARBY PLAINS ALREADY SEEING THESE GUSTY WLY WINDS WITH THE STNRY MTN WAVE HELPING TO MIX DOWN STRONGER FLOW ALOFT. SHOULD SEE THE STRONGER GUSTY WLY WINDS FIRST WITHIN THE I-25 CORRIDOR AND THEN OUT ACROSS THE NERN PLAINS THIS AFTERNOON. IN ADDITION...MODEL CROSS SECTIONS SHOW CLOUD BASES LOWERING OVER THE NERN PLAINS THIS AFTERNOON WITH PASSAGE OF THE WEAK SHORTWAVE. ITS POSSIBLE WE COULD SEE A FEW LIGHT RAIN SHOWERS OR RAIN/SNOW SHOWERS OUT THERE...BUT MEASURABLE PRECIP NOT LIKELY AS THE SUB- CLOUD LAYER APPEARS QUITE DRY. && .SHORT TERM...(TODAY AND TONIGHT) ISSUED AT 335 AM MST SUN FEB 14 2016 RATHER STG WNW FLOW ALOFT WILL CONTINUE OVER NRN CO THRU TONIGHT. MOISTURE WILL GRADUALLY INCREASE IN THE MTNS BY MIDDAY WITH BETTER LAPSE RATES BY AFTN. THUS SHOULD SEE A GRADUAL INCREASE IN SNOW BY AFTN WHICH WILL CONTINUE THRU THE EVENING HOURS ESPECIALLY ALONG AND NORTH OF I-70. AFTER MIDNIGHT MOISTURE WILL DECREASE SOMEWHAT HOWEVER WILL STILL SEE PERIODS OF LIGHTER OROGRAPHIC SNOW IN MOST MTN AREAS. MEANWHILE GUSTY WINDS WILL PRODUCE AREAS OF BLOWING SNOW ABV 10000 FT. WILL ISSUE AN ADVISORY FOR MTN AREAS ALONG AND NORTH OF I-70 THIS AFTN THRU TONIGHT. PORTIONS OF ZN 31 COULD GET CLOSE TO WARNING CRITERIA IF LATEST HRRR IS CORRECT. AT LOWER ELEVATIONS A PACIFIC FNT WILL MOVE ACROSS THIS AFTN WITH GUSTY NWLY WINDS DEVELOPING FM THE FOOTHILLS ACROSS THE PLAINS. WITH STG DOWNSLOPE COMPONENT IN PLACE PCPN POTENTIAL OVER NERN CO LOOKS TO BE RATHER LOW HOWEVER THERE WILL BE SOME MID LVL QG ASCENT LATER THIS AFTN INTO THE EARLY EVENING HOURS SO WILL KEEP IN A SLIGHT CHC OF SHOWERS. AS FOR HIGHS READINGS WILL BE COOLER THIS AFTN WITH TEMPS IN THE UPPER 40S TO LOWER 50S ACROSS NERN CO. AS FOR HIGH WIND THREAT OVERALL THERE IS NEVER REALLY MUCH OF A MTN WAVE FOR ANY EXTENDED PERIOD OF TIME TODAY OR TONIGHT. THUS DON`T EXPECT ANY WIDESPREAD HIGH WINDS ALTHOUGH THERE COULD BE A FEW BRIEF HIGHER GUSTS IN THE NORMAL WINDY AREAS IN AND NR THE FOOTHILLS. .LONG TERM...(MONDAY THROUGH SATURDAY) ISSUED AT 335 AM MST SUN FEB 14 2016 MODELS HAVE STRONG NORTHWESTERLY FLOW ALOFT FOR THE FORECAST AREA MONDAY THROUGH TUESDAY NIGHT. JET LEVEL SPEEDS ARE 80 TO 110 KNOTS ALL FOUR PERIODS. THE QG VERTICAL VELOCITY FIELDS HAVE WEAK DOWNWARD SYNOPTIC SCALE ENERGY FOR THE CWA ALL FOUR PERIODS. THE BOUNDARY LAYER FLOW LOOKS TO BE DOMINATED BY DOWNSLOPING THROUGH TUESDAY NIGHT. FOR MOISTURE...THERE IS SOME PROGGED OVER THE HIGH MOUNTAINS MONDAY INTO MONDAY EVENING...THEN IT DECREASES. THERE IS SOME OVER THE PLAINS...MOSTLY IN THE UPPER AND MID LEVELS MONDAY. TUESDAY AND TUESDAY NIGHT ARE PRETTY DRY IN ALL AREAS. THE QPF FIELDS SHOWS LIMITED SNOWFALL IN THE HIGH MOUNTAINS MONDAY AND MONDAY NIGHT. FOR POPS...NOTHING FOR THE PLAINS...TO DRY AND DOWNSLOPING. FOR THE MOUNTAINS...THERE IS SOME MOISTURE MONDAY AND MONDAY NIGHT AS WELL AS HELP WITH OROGRAPHICS...HOWEVER... MOISTURE DECREASES SLOWLY THROUGH THOSE TWO PERIODS...THERE IS SLIGHT WARM AIR ADVECTION...AND NO HELP FROM SYNOPTIC SCALE LIFT. CURRENT GFE GRIDS HAVE 50-80% POPS IN THE HIGH MOUNTAINS MONDAY AND MONDAY NIGHT...THIS LOOK REASONABLE. SNOWFALL AMOUNTS WILL BE HIGHEST IN ZONE 31...BUT HIGHLIGHT CRITERIA AMOUNTS ARE UNLIKELY. FOR TEMPERATURES...MONDAY`S HIGHS ARE 1-3 C WARMER THAN TODAY`S. TUESDAY HIGHS ARE 1-2 C WARMER THAN MONDAY`S. FOR THE LATER DAYS ...WEDNESDAY THROUGH SATURDAY...AN UPPER RIDGE MOVES ACROSS WEDNESDAY INTO EARLY THURSDAY. A WEAK UPPER TROUGH THEN PUSHES THROUGH BY FRIDAY MORNING. FLAT UPPER RIDGE RETURNS THROUGH EARLY SATURDAY. ZONAL FLOW IS PROGGED DON SATURDAY. THERE MAY BE ENOUGH ENERGY AND MOISTURE FOR LIMITED MOUNTAIN POPS THURSDAY AFTERNOON INTO EARLY FRIDAY. TEMPERATURES WILL STAY ABOVE SEASONAL NORMALS ALL FOUR DAYS. && .AVIATION...(FOR THE 18Z TAFS THROUGH 18Z MONDAY AFTERNOON) ISSUED AT 955 AM MST SUN FEB 14 2016 WESTERLY WINDS HAVE FINALLY TAKEN HOLD OF THE DENVER METRO AREA WITH THE MTN WAVE AND LEE TROUGH MOVING OFF AND AWAY FROM THE FRONT RANGE. CANNOT DISCOUNT OCCASIONAL S-SELY WINDS AT KAPA AND KDEN NEXT HOUR OR TWO...BUT PREVAILING WIND SHOULD BE W-NWLY. CLOSE TO THE FOOTHILLS...WINDS AT KBJC SHOULD STAY W-NWLY REST OF THE DAY AND AT TIMES QUITE STRONG WITH PEAK GUSTS POTENTIALLY TO AROUND 40KTS. WIND SPEEDS NOT LIKELY TO BE AS STRONG AT KDEN AND KAPA BUT GUSTS TO 30 KTS OR SO NOT OUT OF THE QUESTION THIS AFTERNOON. NO PRECIP TODAY AND CIGS SHOULD REMAIN ABOVE 7000 FEET AGL. && .BOU WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY UNTIL 6 AM MST MONDAY FOR COZ034. WINTER WEATHER ADVISORY UNTIL 5 PM MST MONDAY FOR COZ031-033. && $$ UPDATE...BAKER SHORT TERM...RPK LONG TERM...RJK AVIATION...BAKER

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