774 FXUS65 KRIW 100601 AFDRIW Area Forecast Discussion National Weather Service Riverton WY 1201 AM MDT Wed Oct 10 2018 .SHORT TERM...(This evening through Friday) Issued at 100 PM MDT Tue Oct 9 2018 The next system is already spreading some light snow into the far west with the main upper low edging towards far wrn Idaho. Satellite pictures still show a pretty potent system but morning analysis of the thermal profile aloft was not that impressive so I still expect the system to pack quite a punch as it enters southwest WY but it should weaken and open up quickly by Wed aftn. Dynamics are still pretty solid for the swrn corner with Kemmerer seeming to be in the center of the best dynamics and upslope along the Bear River Divide. Potential for some warning amounts around Kemmerer so that area the hardest. Sweetwater looks like a decent advisory when combined with the gusty ene winds of 20 to 35 mph. South Pass is near the nrn edge of the better forcing but hopefully combination of ne winds to 40 mph along with at least a short period of moderate snow will make it quite dicey for a few hours. Lander is even more on the edge. Upslope looks decent for a while but forcing from this system is weak since the low is opening up so quickly. Keeping amounts in the 2 to 3 inch range but confidence is not high on those amounts. Much less the farther north you go in the basin. Some areas may see nothing or just flurries in the north half. I80 could be quite interesting for a few hours Wednesday morning with the band of heavier snow expected and gusty ene winds. This system falls apart quickly but a moist, cyclonic flow will keep snow going in the mountains through Thursday, mainly the nw mtns with additional accumulation. Depending on cloud cover which still looks like a lot, a season ending freeze may hit areas east of the divide Wed ngt. Next shift can look at this again. Friday is our 'quiet' day before the next system arrives Saturday. More on that below. .LONG TERM...(Friday night through Tuesday) Issued at 100 PM MDT Tue Oct 9 2018 The next weather system and cold front moves into northern WY after midnight Fri night and into central WY during Saturday morning. The front pushes into the south during Saturday afternoon. There is usually a period of moderate snow for a few hours with a system of this nature along with a gusty north wind and falling temps behind the cold front. Models have come into closer agreement in terms of timing and placement so snow is forecasted across a wider area during the day Saturday east of the divide. West of the divide, scattered snow will occur with the cold front passage with lesser impact. Snow will decrease and end from north to south Saturday night leading to a cold start to Sunday. Sunday should be dry for most locations with a few mountain snow showers possible over the higher peaks. Cold day on Sunday. Monday will be dry and milder for all areas. Then there is the potential for another weather system and cold front passage next Tuesday, but as far out as it is will keep and pops in the northern mountains. Colder highs next Tue. && .AVIATION...(For the 06Z TAFS through 06Z Wednesday night) Issued at 1140 PM MDT Tue Oct 9 2018 West of the Continental Divide...(KJAC, KRKS, KBPI, KPNA) IFR to LIFR will occur at the KRKS terminal through about 18Z. Through about 10Z the IFR conditions will likely be only from low ceilings, but snow and blowing snow should develop between 10Z and 12Z and last through about 18Z. RKS terminal airfield minimums is also a good possibility. Improving conditions are expected at KRKS between 18Z and 21Z with VFR conditions possible by around 00Z Thursday. Elsewhere, MVFR conditions are expected to impact the Upper Green River Basin Wednesday with the best chance at KBPI. Periods of light snow (MVFR conditions) could begin to impact KJAC in the afternoon, and last off and on Wednesday night. East of the Continental Divide...(KCPR, KCOD, KRIW, KLND, KWRL) MVFR to IFR ceilings are likely through the morning for much of the area except for the eastern Big Horn Basin where ceilings are expected to be VFR. The best chance of snowfall will be across the Lander Foothills. Ceilings will be slow to improve Wednesday afternoon, but current forecast has most areas lifting to VFR by late afternoon into early afternoon. Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for the latest information on icing and turbulence forecasts. && .FIRE WEATHER... Issued AT 100 PM MDT Tue Oct 9 2018 A cool and moist pattern will persist through at least Thursday. The next new storm system will spread another round of snow into the southwest and west this afternoon and evening then rapidly spread across the south and central portions overnight and continue into Wednesday before exiting the area. This next system will be a quick hitting, potent system with widespread snow across the Salt/Wyoming Range, Wind River Mountains and most of southwest and south central Wyoming up into parts of Fremont and Natrona Counties. && .RIW WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until noon MDT Wednesday for WYZ030. Winter Weather Advisory until noon MDT Wednesday for WYZ026>029. Winter Weather Advisory until 3 PM MDT Wednesday for WYZ014-015- 024. && $$ SHORT TERM...Skrbac LONG TERM...Hulme AVIATION...Murrell FIRE WEATHER...Skrbac