Area Forecast Discussion
Issued by NWS Denver/Boulder, CO

Current Version | Previous Version | Text Only | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS65 KBOU 192107 AFDBOU AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DENVER/BOULDER CO 207 PM MST FRI DEC 19 2014 .SHORT TERM...(THIS EVENING THROUGH SATURDAY) ISSUED AT 109 PM MST FRI DEC 19 2014 A SHORT WAVE RIDGE OF HIGH PRESSURE WILL SHIFT OVER NORTHERN COLORADO TONIGHT WITH THE RIDGE AXIS SHIFTING TO THE EASTERN BORDER BY LATE SATURDAY. SOME UPPER LEVEL MOISTURE WILL INCREASE OVER NORTHWESTERN COLO LATE TONIGHT...THEN SHIFTS EAST ACROSS THE NORTHEAST PLAINS ON SATURDAY. IN THE MOUNTAINS...SOME MID LEVEL MOISTURE DEVELOPS DURING THE DAY WL ALLOW FOR THE CHANCE OF SNOW TO REDEVELOP...ESPECIALLY IN THE MOUNTAINS NORTH OF INTERSTATE 70 BY LATE AFTERNOON. THE FLOW ALOFT WILL REMAIN FAIRLY WEAK SO WIND SHOULD NOT BE AN ISSUE IN THE HIGH COUNTRY. ACROSS THE NORTHEAST PLAINS...THE PRESSURE GRADIENT REMAINS FAIRLY RELAXED WHICH WL TRANSLATE TO CONTINUED LIGHT WINDS. THERE WILL BE SOME MODIFICATION OF TEMPERATURES WITH HIGHS GENERALLY IN THE MID TO UPPER 40S...A LITTLE COOLER WHERE SNOWFIELD STILL EXISTS NORTH AND EAST OF AKRON. .LONG TERM...(SATURDAY NIGHT THROUGH FRIDAY) ISSUED AT 109 PM MST FRI DEC 19 2014 ...MOIST AND COLD FOR THE WEEK AHEAD WILL LEAD TO MULTIPLE OPPORTUNITIES FOR SNOW... THE NEXT MAJOR SNOW PRODUCER WILL MOVE INTO THE MOUNTAINS ON SUNDAY. STRONG NW FLOW DOMINATES IN THE UPPER LEVELS WITH INCREASED MOISTURE FROM THE APPROACHING TROUGH IMPACTING THE PARK AND GORE RANGES. ANOTHER IMPORTANT INGREDIENT FOR A GOOD SNOW PRODUCER IS THE UPPER LEVEL JET. THE LATEST GFS HAS THE JET DIPPING INTO THE WESTERN PORTIONS OF THE STATE LEAVING OUR WESTERN BORDERS EXPOSED TO THE COLDEST AND MOST UNSTABLE PORTION OF THE CURRENTLY 160 KT JET STREAK. THIS WILL AID WITH GETTING SNOW IN THE BEST LAYER IN THE ATM. QG IS NOT IMPRESSIVE WITH THIS SYSTEM BUT WITH THE JET AS WELL AS MID LEVEL LAPSE RATES FROM 7-8 C/KM THE INSTABILITY WILL BE SUFFICIENT. THE ONLY POSSIBLE HITCH TO THE SYSTEM ARE THE TEMPERATURES. CURRENT CROSS SECTIONS SHOW TEMPERATURES NEAR MOUNTAIN TOP IN THE UPPER TEENS TO LOW 20S WHICH WILL CREATE A MORE SLUSHY AND HEAVY SNOW MIX TO START. ONCE THE COOLER AIR MOVES IN WITH THE FRONT EARLY MONDAY THE SNOW WILL BECOME MORE DRY AND ACCUMULATIONS WILL INCREASE. CURRENT MODELS ARE INDICATING POSSIBLE AMOUNTS OF 12 TO 20 INCHES FOR HIGHER ELEVATIONS IN THE NORTHERN MOUNTAINS AND PASSES AND POSSIBLE 4 TO 8 INCHES IN THE VALLEYS. IN ADDITION TO THE SNOW CROSS SECTION COMPONENT ALONG FLOW IS INDICATING HIGH WINDS FOR THE MOUNTAINS AS WELL THANKS TO THE APPROACHING JET. CURRENT MODELS ARE INDICATING 60-70 KTS AT MOUNTAIN TOP EARLY MONDAY. THIS WILL CREATE AREAS OF BLOWING SNOW FURTHER COMPLICATING MOUNTAIN TRAVEL ALONG AND NORTH OF I-70 FROM SUNDAY AFTERNOON THROUGH MONDAY. A WATCH WILL ACCOMPANY THIS FORECAST PACKAGE FOR THE MOUNTAINS AND BE VALID FROM SUNDAY AFTERNOON TO MONDAY EVENING. FOR THE PLAINS DOWNSLOPING DOWN THE FOOTHILLS WILL KEEP SNOW AT BAY FOR SUNDAY INTO EARLY MONDAY BEFORE A COLD FRONT PUSHES THROUGH AND INSTABILITY AND MOISTURE INCREASE. CLOUDY CONDITIONS WILL PREVAIL ON SUNDAY WITH TEMPERATURES IN THE MID 50S FOR NE CO. MODELS ARE INDICATING MEASURABLE SNOW FOR THE PLAINS MOST LIKELY MONDAY AFTERNOON INTO THE EVENING BUT EXACT AMOUNTS ARE DIFFICULT DUE TO POSSIBLE BANDING. AN ADVISORY MIGHT BE NEEDED AS SNOW AMOUNTS BECOME CLEARER...ESPECIALLY AROUND DIA. TEMPERATURES WILL COOL BEHIND THE COLD FRONT BRINGING OVERNIGHT TEMPS INTO THE LOWER 20S. ON TUESDAY FLOW ALOFT WILL BECOME MORE NORTHERLY AS THE LOW PRESSURE CENTER MOVES OFF TO THE EAST. MOISTURE WILL DECREASE THROUGH THE DAY BUT WILL MAINTAIN POPS IN THE MOUNTAINS DUE TO LINGERING MOISTURE AND DECENT LOW LEVEL LAPSE RATES. TEMPERATURES WILL BE COOLER WITH HIGHS ONLY ABLE TO GET INTO THE LOWER 40S FOR THE PLAINS AND SINGLE DIGITS FOR THE HIGHER MOUNTAINS. ON WEDNESDAY INTO THURSDAY MORNING AN APPROACHING RIDGE MOVES INTO THE REGION BRINGING WINDS BACK TO A MORE NORTHWESTERLY DIRECTION. MOISTURE IS WEAK SO CLOUDS WILL SCATTER OUT AND TEMPERATURES WILL BOUNCE BACK INTO THE LOWER 50S FOR THE PLAINS. KEPT SOME LOW POPS IN THE MOUNTAINS DURING THIS TIME MAINLY DUE TO OROGRAPHICS BUT THERE IS LITTLE MOISTURE TO PRODUCE MUCH ACCUMULATION. THE NEXT MAJOR SYSTEM IS CURRENTLY FORECASTED AS A WEAK UPPER LEVEL TROUGH THAT WILL BE OVER UTAH BY 18Z THURSDAY. BOTH THE EC AND THE GFS CURRENTLY HAVE A AN OPEN WAVE THAT IS LESS FAVORABLE FOR SNOW. I HAVE KEPT CHANCE POPS FOR THE MOUNTAINS INCREASING SLIGHTLY OVERNIGHT THURSDAY DUE TO STRONG SW FLOW ALOFT COMBINED WITH DECENT MOISTURE AHEAD OF THE TROUGH THURSDAY MORNING AND CONTINUED QG ASCENT OF -35 TO -40 FROM THE EC. FOR THE PLAINS ON THURSDAY CLOUDS WILL MOVE IN WITH INCREASING MOISTURE THURSDAY MORNING AND AFTERNOON WITH TEMPERATURES IN THE UPPER 40S FOR CHRISTMAS DAY COOLING OVERNIGHT WITH THE NEXT TROUGH. MODELS DIVERGE ON THE POSSIBILITY OF SNOW OVER THE PLAINS WITH THIS SYSTEM AS THE MAIN ENERGY ACCORDING TO THE GFS SITS TO OUR NORTH...GREATLY REDUCING SNOW CHANCES WITHOUT UPPER LEVEL INSTABILITY AND JET SUPPORT. WILL CONTINUE TO WATCH MODELS AND FINE TUNE FORECAST OVER THE NEXT FEW DAYS. && .AVIATION...(FOR THE TAFS THROUGH 00Z SATURDAY LATE AFTERNOON) ISSUED AT 109 PM MST FRI DEC 19 2014 VFR CONDITIONS OVER THE NEXT 24 HOURS. SFC PRESSURE GRADIENT REMAINS WEAK SO DIURNAL WIND PATTERN WILL PREVAIL WITH SELY WINDS SWITCHING TO SSWLY THIS EVENING. AMS WILL REMAINS HAZY WITH LIMITED MIXING BUT DO NOT ANTICIPATE FOG LATE TNGT INTO SAT MORNING. THE LATEST SIMULATED STLT IMAGERY PAINTS SOME FOG RIGHT ALONG THE PLATTE RIVER NORTHEAST OF DENVER AROUND 12Z...BUT THAT IS IT. AS A RESULT...WL KEEP FOG OUT OF DIA AT THIS TIME. && .BOU WATCHES/WARNINGS/ADVISORIES... WINTER STORM WATCH FROM SUNDAY AFTERNOON THROUGH MONDAY EVENING FOR COZ030>034. && $$ SHORT TERM...COOPER LONG TERM...BOWEN AVIATION...COOPER

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.