159 FXUS63 KUNR 100521 AFDUNR Area Forecast Discussion For Western SD and Northeastern WY National Weather Service Rapid City SD 1121 PM MDT Tue Oct 9 2018 .DISCUSSION...(This Evening Through Tuesday) Issued at 308 PM MDT Tue Oct 9 2018 Current surface analysis shows low pressure now centered over eastern KS, with high pressure over south central Canada. Upper level analysis shows weakening low pressure system over CO, with another low in place over the Pacific NW. Strong jet ahead of the CO low extends across the Plains into the upper midwest. KUDX radar shows very light rain/snow in spots across western SD, with regional radars showing bulk of pcpn over NE and moving through south central into eastern SD at this time. Skies remain cloudy with cold temperatures, 30s and lower 40s. Winds are northerly at 10 to 20 mph in most places. Weakening upper system to the south will move quickly through mainly eastern portions of the forecast area tonight. The heaviest pcpn will remain south and east of the CWA, but a band of moderate pcpn is forecast to clip central SD. Enough cold air will build into the area tonight to gradually turn rain to snow across south central SD. Snow could be moderate to briefly heavy at times overnight before gradually diminishing late tonight/early Wednesday. Will keep winter wx advisories going for south central SD up to Ziebach County tonight for 2 to 5 inches of snowfall. Have added Oglala Lakota County to the advisory, where some higher snowfall amounts are possible across the Pine Ridge. The highest amounts will generally be over the higher terrain of south central SD. Further west, amounts of an inch or two are possible across the rest of western SD, with an inch or less into northeast WY. The rest of Wednesday through Thursday looks mainly dry, but still cold as system over the Pacific NW likely weakens as it moves southeast through the Rockies. As it eventually moves through the Central Plains later Thursday to early Friday, there could be a few rain/snow showers across southern portions of northeast WY, the Black Hills, and southern SD. Friday looks to be the nicest day of the week, at least with regard to temperatures. Highs will be in the upper 40s and 50s. A clipper system will then move southeast across the Northern Plains on Saturday, with gusty winds and some rain/snow showers expected, especially across northeast WY and the Black Hills area. Temperatures will drop well below average again behind the front, with highs in the 30s and lower 40s on Sunday. Another clipper system could impact the area early next week. At this point, there appears to be no mild weather in sight until at least the middle or latter part of next week. && .AVIATION...(For the 06Z TAFS Through 06Z Wednesday Night) Issued At 1117 PM MDT Tue Oct 9 2018 Widespread IFR/LIFR conditions will continue Wednesday morning. Another disturbance will bring snow overnight, with the heaviest snow through south central South Dakota. Conditions will be slow to improve Wednesday afternoon. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...Winter Weather Advisory until noon MDT /1 PM CDT/ Wednesday for SDZ014-032-042>044-046-047-049. WY...None. && $$ DISCUSSION...26 AVIATION...7