600 FXUS65 KPUB 172224 AFDPUB Area Forecast Discussion National Weather Service Pueblo CO 324 PM MST Thu Dec 17 2020 .SHORT TERM...(This evening through Friday) Issued at 324 PM MST Thu Dec 17 2020 Currently...widespread cloud cover ahead of an upper trough over Utah have spread across much of southern Colorado early this afternoon. Temperatures have been highly dependent on both cloud cover, and snow cover. Areas along the lower Arkansas River Valley are cold with lower to mid 20s due to snow cover. The warmest areas are along the Eastern Mountain lee slopes where westerlies have allowed for better mixing and temperatures in the upper 40s. The San Luis Valley also remains cold, with 20s for far this afternoon. Tonight...the upper level trough over Utah is forecast to shift southeast into the Four Corners area by morning. Strong energy embedded in the southwest flow will lead to snow development this evening along the Continental Divide. The heaviest snow is forecast over the San Juan Range, where southwesterly flow is favored. Snow accumulations through Friday morning will range from 3 to 6 inches. Further north, lesser amounts are expected with around 1 to 3 inches possible. Snow will also begin to spread east into the Eastern Mountains by morning. Winds will be on the increase as well over the Mountains, with southwesterly flow on ridgetops gusting to near 40 mph. As for the Plains, expect dry conditions to prevail overnight. Temperatures will bottom out in the 20s for most areas by morning. Friday...the upper trough will continue to track south and east across Colorado and northern New Mexico. A cold front will drop south across the Plains by midday with winds shifting northerly for the afternoon. There could be a gusty winds with the front, with gusts near 30 mph possible. Expect snow over the Mountains to spread east into the Palmer Divide during the morning hours, then spread south and east with the cold front. Temperatures ahead of the front will likely warm into the 30s, but quickly fall back into the 20s by evening. Expect precipitation to develop with the front as well, with highest probabilities banked along the Eastern Mountains and lee slopes. Further east on the Plains, the northerly winds and quick movement of the upper trough will likely limit snow potential, with a dusting to inch through the late afternoon hours. A few raindrops may fall as the front passes, but everything should be snow by mid afternoon and colder air advects into the region. Mozley .LONG TERM...(Friday night through Thursday) Issued at 324 PM MST Thu Dec 17 2020 Friday night-Saturday night...Moderate to strong northwest flow continues behind Friday's passing system with secondary energy progged to dig across the Northern Rockies through the day Saturday, which then continues out across the High Plains Saturday night. At any rate, should see precipitation winding down across the region from northwest to southeast late Friday afternoon and evening with slowly decreasing clouds through the overnight hours. This, with decoupling winds, will lead to below seasonal lows Friday night, coldest across the valley locales and portions of the snowcovered southeast plains. With some modest increase in moisture and continued northwest flow aloft, there could be some spotty snow showers across the central mountains Saturday and into Saturday night, however, any accumulations are expected to light. Temperatures to warm back to near seasonal levels on Saturday, though did lower highs across the far southeast plains with continued slow melting of current snowpack. Sunday-Monday...Northwest flow aloft progged to weaken and become more westerly Sunday into Monday, leading to mainly dry and warmer weather areawide. Highs on Monday look to be back above seasonal levels in the lower to mid 50s across the plains, and mainly 30s and 40s across the higher terrain. Tuesday-Thursday...Latest long term models do indicate a broad upper level trough translating across the region in the Tuesday and Wednesday timeframe, though are still struggling on its location, with the GFS continuing to be the furthest south and west with the system, as compared to the EC. With that said, have not strayed from the blended model solution which does indicate slight and chance pops spreading from north to south across the region Tuesday night and Wednesday, along with a strong frontal passage with gusty northerly winds and much cooler temperatures (as compared to Tuesday) across the area on Wednesday. Tuesday temperatures look to be the proverbial "warm before the storm" with highs into the 50s once again on the plains. Despite the location differences with the mid week system, models are seemingly on board with upper level ridging building back across the Rockies for the Thursday (Christmas Eve Day) and Friday (Christmas Day) timeframe. Time well tell. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 324 PM MST Thu Dec 17 2020 KALS...VFR conditions through much of the forecast period with mid and high clouds continuing through Friday morning. Spotty snow showers may be possible over the San Luis Valley Friday afternoon. If one should hit the terminal, reduced CIGS and VIS would be possible, mainly after 20z. KCOS and KPUB...VFR conditions will passing mid and high clouds through Friday morning. A cold front will arrive Friday morning with winds shifting northerly behind the front. Gusts to near 30 kts are possible through the afternoon. Snow will likely impact the terminals from midday into the evening hours with reduced CIGS and VIS possible. Mozley && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...MOZLEY LONG TERM...MW AVIATION...MOZLEY