617 FXUS65 KPUB 241721 AFDPUB Area Forecast Discussion National Weather Service Pueblo CO 1021 AM MST Tue Jan 24 2023 .SHORT TERM...(Today and tonight) Issued at 402 AM MST Tue Jan 24 2023 Key Messages: 1) Light snow begins this afternoon over the Continental Divide, and spreads across the rest of our higher terrain this evening. 2) Cooler temperatures and gusty northerly winds are expected for this afternoon on our plains. Currently.. Water vapor imagery depicts a low pressure system to our south, centered over New Mexico. Patchy fog and low ceilings have developed across portions of the forecast area this morning, especially across the San Luis Valley, the Lower Arkansas River Valley, and the Raton Mesa area. A trough is approaching from our north, which should help to clear out any remaining fog through the early morning hours. As of 3am, we're already seeing clearing across the Palmer Divide, with the trough axis still just off to our north. Temperatures have fallen into the low to mid teens across clear areas, with the exception of our far southeastern plains, where extensive mid and upper level cloud cover is keeping temperatures in the 20s. Today and Tonight.. Behind the passing trough axis we'll see gusty northerly winds and cooler temperatures, with daytime highs topping out near freezing for most of our plains and mountain valleys, and teens to 20s for our mountain locations. Winds could gust up to 35 mph at times this afternoon, especially on our far eastern plains. As the low continues to push off to our south and east, we'll see increasing mid-level moisture and northerly to northwesterly flow aloft. Increasing moisture, along with shortwave energy should provide enough support to develop light snow showers this morning across the Continental Divide, which will likely spread into our eastern mountains, the Palmer Divide, and Teller county by this afternoon. Snow looks to spread into the rest of the I-25 corridor very late tonight into tomorrow morning. New snowfall amounts are expected to be light, generally 1-3 inches for our higher terrain, and less than 1 inch for our lower terrain, through the overnight hours tonight. .LONG TERM...(Wednesday through Monday) Issued at 402 AM MST Tue Jan 24 2023 Key Messages: 1) Light snow is expected across the mountains, mountain valleys, and even parts of the I25 corridor throughout the day Wednesday. 2) Drier and warmer conditions expected for the end of the week and into the weekend. 2) Inclement weather quickly returns late Saturday and into next week. Wednesday... The midweek period will bring some active to southern Colorado. Synoptically, a long wave trough will be digging across the central US, with embedded short waves within that flow. One of these short waves will pass over the region Wednesday, which is supported in GEFS and EPS ensemble models, leading to greater confidence in the pattern. With the long and short wave troughs over the southern Colorado region, synoptic ascent is expected to increase Wednesday. Along with that, an uptick in orographic forcing is anticipated given stronger winds aloft from the short wave. Given the synoptic and orographic forcing in place, scattered to numerous pockets of light snow are expected along the mountains and mountain valleys. At lower elevations across the I25 corridor and eastern plains, less precipitation and dry conditions are expected. Most of the eastern plains are expected to remain dry throughout Wednesday, though an increase in cloud cover is expected given the forcing over the region. As for the I25 corridor and immediate areas around it, northerly and easterly winds behind a weak cold front will help to provide enough surface upslope to allow for isolated to scattered pockets of light snow to develop throughout the day Wednesday. As for temperatures, a cold day is anticipated for southern Colorado. Given the reinforcement of colder air from the troughs and the increased cloud cover, temperatures will be around 10-15°F below average for this time of year. Thursday - Saturday... For the end of the week and start of the weekend, a quieter stretch of weather is expected for southern Colorado. Ensemble model guidance is in good agreement about building a ridge to the west and troughing to the east. This will put the Colorado region more in a northwesterly flow regime. Overall, this pattern will keep much of southern Colorado dry. The exception to this will be along the central mountains, where modest orographic forcing will help to spark isolated pockets of light snow throughout this timeframe. Looking at temperatures, a warmup is expected for much of southern Colorado. Westerly winds will become reestablished across the region and compressional warming will help to warm the area closer to average values for this time of year. Saturday Night - Monday... Starting late Saturday and into the start of next week, an uptick in active weather is expected. Ensemble model guidance starts to develop another long wave trough, which is anticipated to have additional short waves embedded within that flow. This pattern will bring increased precipitation chances to much of southern Colorado, especially for the mountain areas. This troughing pattern is also anticipated to push colder air into the region. The first batch of colder air is likely to arrive late Saturday as a cold front races southward and reinforcement of colder is expected thereafter, with below average temperatures expected for && .AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon) Issued at 1021 AM MST Tue Jan 24 2023 A short wave will be moving over the region today, this could bring snow showers in the Continental Divide and may bring snow to the San Luis Valley. So KALS will have a chance of intermittent snow showers throughout the day today. All three TAF stations, KALS, KCOS, KPUB will have VFR conditions with periods of MVFR due to snow showers. KALS will be MVFR from around 00Z to 15Z tomorrow morning. KCOS and KPUB will possibly be MVFR after 12Z tomorrow morning through the end of the forecast period due to snow showers. For winds, KALS will be light under 10 KTS throughout the forecast period. KCOS will start out gusty with winds out of a northwest component with gusts as high a 24 KTS, then from around 00Z through the rest of the forecast forecast period, winds will be light under 10 KTS. KPUB will start out gusty out of a northwest component, shifting to a northeast component with winds ups to 25 KTS around 20Z. From 01Z to the end of the forecast period, winds at KPUB will remain light under 10 KTS. -Riser && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...EHR LONG TERM...SIMCOE AVIATION...RISER