976 FXUS65 KRIW 300411 AFDRIW Area Forecast Discussion National Weather Service Riverton WY 911 PM MST Mon Dec 29 2025 .KEY MESSAGES... - Another night of chilly temperatures for western valleys with mostly clear skies. - Temperatures continue their gradual warming trend through mid- week, becoming above normal by New Years Eve Day (Wednesday). - Dry conditions prevail for the rest of the year across the state. The next system moves in Thursday, and western Wyoming has a 60 to 80% chance for precipitation by the afternoon hours, with rain for valley bottoms and snow above 7000 ft. && .UPDATE... Issued at 1212 PM MST Mon Dec 29 2025 Nothing to update regarding the previous discussion as the overall pattern remains quiet and mild through the next few days. Chilly temperatures are forecast across the state today with highs in the 30s east of the Divide and 20s to low 30s west of the Divide. Colder air is persisting in some western valleys where recent snowfall occurred such as Star Valley, where highs may struggle to get into the 20s today. Otherwise, not much more to add in terms of the short term forecast. The next chance for precipitation looks to possibly arrive by the second half of the week with chances favoring western WY. Models are not showing all the impressive of a system so impacts at this time are looking minimal. && .DISCUSSION... Issued at 132 AM MST Mon Dec 29 2025 High pressure will be holding control along the northern Rockies during the next several days, deflecting the storm track back into Canada and keeping mild temperatures going for Wyoming. Lows this morning have been cold, with temps well below zero for the western valleys, and in the single digits above zero east of the Divide. Southwest flow returns today, helping to carve out some of the cold pool that has settled in the region. With the cold pool not overly strong and not reinforced by any snowpack, expect a good recovery of temperatures into the 30s this afternoon. Western valleys that do have snowpack and are starting a lower temperatures will have more trouble getting out of the teens this afternoon. This pattern will continue through the remainder of the week, as the ridge holds in place, pushing systems off to the north and continuing to carve up any remaining cold pool. Most areas will be back in the 40s by Wednesday, with Jackson Hole and Star Valley holding back a bit depending on how fast surface snow thins out. The ridge tries to shift more east late in the week, opening the door for some moisture to get back into the western mountains, but a lack of significant supporting storm systems will keep any snowfall on the lighter side for the time being. && .AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/... Issued at 906 PM MST Mon Dec 29 2025 VFR conditions prevail across the region over the next 24 hours with minimal aviation weather impacts expected. High clouds increase during the morning hours Tuesday, and could obscure the highest peaks of the Absaroka and Bighorn Ranges. Generally light winds are forecast for all areas, with typical windy spots like KCPR seeing gusts to around 20 kt during the afternoon hours Tuesday. No precipitation is in the forecast. && .RIW WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Dziewaltowski DISCUSSION...Straub AVIATION...VandenBoogart