Scientific Forecaster Discussion
000 FXUS65 KPUB 122245 AFDPUB Area Forecast Discussion National Weather Service Pueblo CO 345 PM MST Thu Dec 12 2019 .SHORT TERM...(This evening through Friday) Issued at 345 PM MST Thu Dec 12 2019 Leading edge of the upper level jet pushing into Colorado this afternoon, bringing some very light snow to the central mountains from Cottonwood Pass northward. Jet and associated moisture will continue to plow into the state overnight and through the day on Fri, leading to a gradual ramp up of snow intensity and coverage along the Continental Divide. Snow accumulations through Friday afternoon won't be too extreme (5-10 inches over the Sawatch and Mosquito Ranges), but with strong west winds producing widespread blowing snow, especially near/above timberline, winter storm warning looks warranted for higher mountain zones, with advisory for lower elevations of Lake County. Farther south along the Divide, snow looks much lighter, with just a few inches expected over the La Garitas/San Juans. Some mainly light spillover showers expected in upper Arkansas Valley and over the eastern mountains, through Friday, while plains and bulk of the San Luis Valley stay dry and fairly mild under westerly flow aloft. .LONG TERM...(Friday night through Thursday) Issued at 345 PM MST Thu Dec 12 2019 Active meteorological conditions are expected over the CWA from Friday night into Monday morning in advance of improving conditions from later Monday into next Thursday. Initially, snow, heavy at times(with incoming system/PV analysis/etc.)in combination with gusty winds will be ongoing over the Central Mountains Friday evening, with snow expanding into the majority of our Continental Divide locations into Saturday night and then continuing into Sunday, therefore have expanded inherited Winter Storm Watch to also include the La Garita Mountains in addition to the eastern San Juan mountains from late Saturday afternoon into Sunday afternoon. Elsewhere, locations east of the I-25 corridor should experience generally dry and cooler conditions in combination with gusty winds at times from Friday evening into Saturday evening(with encroaching showers possible from the west as Saturday progresses). Recent longer range computer simulations, ensembles, PV analysis, forecast model soundings/etc. still indicate that the highest potential for more widespread and possibly moderate to heavy precipitation/snow over eastern locations should be realized from Sunday into Sunday night and have issued a Winter Storm Watch over many eastern locations to account for this potential as healthy upper disturbance interacts with northerly component surface surge during this time-frame. Coolest temperatures during the longer term should be realized from Saturday into Tuesday, with warmer conditions returning by next Wednesday and Thursday as upper ridging moves across New Mexico. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 345 PM MST Thu Dec 12 2019 VFR at all taf sites the next 24 hours, with increasing west winds after 15z-18z Thu. Higher terrain surrounding the San Luis Valley will see occasional snow showers overnight and through the day on Thu, but expect this activity to stay away from KALS until Thu night. && .PUB WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 5 PM MST Friday for COZ059. Winter Storm Watch from Friday afternoon through Sunday afternoon for COZ058>060. Winter Storm Watch from late Saturday night through late Sunday night for COZ061>063-072>087. Winter Storm Warning until 5 PM MST Friday for COZ058-060. Winter Storm Watch from Saturday afternoon through Sunday afternoon for COZ066-068.