339 FXUS65 KPUB 092143 AFDPUB Area Forecast Discussion National Weather Service Pueblo CO 343 PM MDT Tue Oct 9 2018 .SHORT TERM...(This evening through Wednesday) Issued at 341 PM MDT Tue Oct 9 2018 ...Rain ending across the plains with a freeze expected tonight... ...Snow will ramp up for the mountains again tonight... The upper trough will continue to lift northeastward across CO this evening with the next kicker system expected to drop into northern UT tonight. Deformation band precipitation across the plains will continue to lift northeastward this evening with a quick decline in precipitation expected through 6-7 PM. Showers are more spotty and convective in nature across the mountains this afternoon and will also decrease in coverage through the evening with the loss of heating/instability. Snow ramps up again across the central mountains after 06z tonight as the next system opens up and moves across northern CO through mid day Wed. The central mountains will see the main impact from this system with a combination of dynamics and more favorable west to northwest orographics expected to produce advisory level snow amounts across the higher elevations of the eastern Sawatch and western Mosquito ranges. Per coordination with surrounding offices will hoist a winter weather advisory with this package for higher elevations of the Sawatch and Mosquito ranges. Snowfall amounts of 4 to 8 inches will be possible above 10000 feet with around 1-3 inches across the lower elevations by late Wednesday afternoon. While primary impacts will be across the central mountains, there will be a brief round of snow for the remainder of the southern mountains, valleys and adjacent plains this evening due to some lingering instability behind the departing system, and again late tonight through tomorrow morning with the next system...though this second round will stay mainly confined to the mountains. Snow levels will be low enough that all of these areas could see a switch over to snow tonight. Snow accumulations for the remainder of the mountains will be in the 2 to 4 inch range for the higher elevations above 10000 feet though some spotty areas could see up to 6 inches. Lower elevations of the mountains could see around 1 to 3 inches. Up to an inch will be possible on grassy surfaces along the I-25 corridor, particularly along the Palmer Divide. Another concern tonight will be the potential for freezing temperatures across the plains. Although clouds are progged to hang in tonight, current readings are already in the 30s with some light snow mixing in at times. While ground temperatures will remain too warm for accumulations, the likelihood for the first freeze of the season remains high in spite of the cloud cover and guidance temps agree with this. Will upgrade the freeze watch to a warning for all of the plains. This will not likely be a killing freeze for all areas, but it will be cold enough to harm more tender vegetation. For Wednesday, the system will exit the area during the afternoon and expect to see gradually improving conditions with snow decreasing during the late afternoon across the mountains. Plains are expected to remain largely dry with temperatures remaining below normal. Should finally see some sun breaks towards afternoon across the plains. -KT .LONG TERM...(Wednesday night through Tuesday) Issued at 341 PM MDT Tue Oct 9 2018 Wednesday night through Thursday night... The start of the long-term forecast period will bring continued unsettled weather to the forecast area, particularly in the mountains, as a series of disturbances move through the region. The first disturbance, a dampening shortwave trough in WSW flow, will bring rain and snow showers to the mountains starting Thursday morning after a brief respite in activity Wednesday evening. Showers will continue in the mountains through late Thursday night as another shortwave drops into the region from the northwest. The greatest precip totals will fall along the continental divide, especially in the central mountains. Snow levels will generally stay above 9,000 ft, with 3-6 inches total accumulation expected in the central mountains and 1-3 inches in the southwest mountains. Locally higher totals may be experienced. Totals in the eastern mountains should stay around or less than 1 inch. Over the plains, surface lee troughing near the Raton Mesa and broad high pressure over the central US plains will lead to strengthening southeast flow into the southeast Colorado plains Thursday into the evening. Increasing moisture and upslope flow combined with large scale lift could lead to the development of isolated showers and weak elevated thunderstorms over the far eastern plains Thursday afternoon/evening. Light rain/snow will be also be possible over the Palmer Divide Thursday night. Precip on the plains will come to an end late Thursday evening. As for temperatures, Wedensday night lows are currently forecast to be around or just above freezing across much of the plains, and slightly below freezing in Colorado Springs and the Palmer Divide. High temperatures on Thursday will generally be in the 50s across the plains and much of the high valleys. Thursday night will be slightly warmer than the previous night. Low stratus clouds should develop across much of the plains both Wedensday and Thursday night under the influence of moist upslope flow and weak synoptic lift. Friday through Saturday... Aside from some lingering early Friday showers over the mountains or far eastern plains, Friday through Saturday should be dry across most of the forecast area as large scale subsidence takes hold behind the previous storm system. The main forecast concern will be the approach of Sergio remnants. Models currently agree to bring the low and associated precip shield from southwest to northeast through southwest Texas Saturday morning and into south- central Oklahoma by the evening, well southeast of Colorado. The far southeast corner of the state may see associated rain and cloud cover from the system, but most other areas will remain dry. High temperatures on both Friday and Saturday will be around 60 across the plains and high valleys, and mid 50s in Colorado Springs. Winds will generally remain light both days. Saturday night through Tuesday... The next significant weather maker begins to impact southern Colorado Saturday night as a fairly strong shortwave trough approaches Colorado from the northwest. The shortwave will send a surface cold front down the eastern Colorado plains Saturday night, as well as spread QG forcing for ascent across most of the forecast area. Forecast models are in very good agreement currently on the timing of the features. Guidance spreads precip across the plains and eastern mountains along and behind the front Saturday night through Sunday evening. The airmass behind the front is expected to be very cold with snow levels dropping considerably, including across the plains. Therefore, it is looking more and more likely this could be the first decent snow event of the season for much of the plains, including the I-25 corridor. It is still too early to specify exactly how much snow will fall at any given location, however. The front will also be accompanied by gusty north winds. Behind the storm system, forecast models look dry for the start of the work week. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 341 PM MDT Tue Oct 9 2018 MVFR to IFR conditions will linger across the plains tonight with the possibility of seeing some local IFR cigs/vis develop along the southern slopes of the Palmer Divide as winds shift from the southeast providing a more favorable upslope component. Some -SHRASN will be possible at times tonight...though any accumulations will be light and remain confined to grassy surfaces at best. Should see cigs rise at both KCOS and KPUB Wednesday afternoon with some breaks possible at KPUB by late afternoon. Its quite possible KCOS will see MVFR cigs linger through most of the day. KALS will see a chance of showers this evening with cigs/vis remaining VFR. Skies will clear by afternoon with breezy southwest winds expected by afternoon. -KT && .PUB WATCHES/WARNINGS/ADVISORIES... Freeze Warning from midnight tonight to 10 AM MDT Wednesday for COZ069-083>089-093>099. Winter Weather Advisory from midnight tonight to 6 PM MDT Wednesday for COZ058-060. && $$ SHORT TERM...KT LONG TERM...LINE AVIATION...KT