675 FXUS63 KBIS 091754 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 1254 PM CDT Tue Oct 9 2018 .UPDATE... Issued at 1254 PM CDT Tue Oct 9 2018 Little change through the remainder of the afternoon and evening outside of observed trends through 17 UTC. At this time, no change to the Winter Weather Advisory or any significant changes to forecast snowfall amounts for tonight through Wednesday evening. There is a large range in potential snowfall, largely influenced by what snow ratio technique is used. Given the near freezing temperatures, favoring smaller ratios fairly close to the SFC-T based snow ratio technique. Thus, rain may begin to mix with snow across the glacial hills west of the James River Valley between 03-06 UTC, and potentially not a complete change over to snow across the James River Valley itself until 09-11 UTC. UPDATE Issued at 832 AM CDT Tue Oct 9 2018 Quick update for radar trends through 1315 UTC. Expect precipitation intensity to begin to decrease over the next 1-2 hours. A very light rain and snow mix may continue into the afternoon southwest and far south central aided by forcing in the right entrance region of the mid level jet and a slowly propagating shortwave. && .SHORT TERM...(Today and tonight) Issued at 525 AM CDT Tue Oct 9 2018 Rain and some snow over the forecast area continued as of this writing with snow in southwest North Dakota, south of Dickinson. Radar returns were weakening over western South Dakota so the very high pops I have in through this morning may be overdone as precipitation looks like it would end, based on current trends, a little before my timing. Regardless, a cold and damp day, compared to normals, is in the offing for this October 9. Models are in nice agreement on bringing the next wave in the parade up into the south and east parts of the forecast area this evening. The surface low moves from Iowa, north into Minnesota, and keeps strong cyclonic surface flow over the eastern half of the state through the day Wednesday, with increasing northeast winds, pulling far enough east to end precipitation on Wednesday night, but not before then. Model differences exist in cooling aloft and timing of change from rain to snow, and amounts, but regardless, several inches of snow is agreed upon, mainly east of Bismarck. With that have opted to post a Winter Weather Advisory for three to as much as six inches of snow for the area south of Bismarck through the James River Valley. Will also compose a Situation report that will be posted to NWS BIS web page before 630 AM. .LONG TERM...(Wednesday through Monday) Issued at 525 AM CDT Tue Oct 9 2018 Models agree on a break in the parade of systems for Thursday and Friday, and with at least weak ridging surface and aloft it is possible we could see some sunshine each of those days. That solar would take us back into the 40s for highs, maybe touching 50 west. A return to unsettled and cold weather looks likely for the weekend. && .AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon) Issued at 1254 PM CDT Tue Oct 9 2018 Widespread IFR/MVFR stratus will continue across western and central North Dakota for the 18 UTC TAF cycle. A light rain and snow mix will continue southwest this afternoon, with light rain or drizzle south central and the across the James River Valley. The next round of precipitation will spread across southwest and south central North Dakota this evening, and continue into Wednesday morning, decreasing from west to east Wednesday afternoon and evening. Precipitation is expected to be mostly snow southwest, with a mix of rain and snow further east, transitioning to all snow late tonight into Wednesday morning. IFR/LIFR visibility in snow is expected. Strong northerly winds with gusts around 25-30kts will develop south central, through the Turtle Mountains and James River Valley Wednesday. && .BIS WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory from 9 PM CDT /8 PM MDT/ this evening to 1 AM CDT /midnight MDT/ Thursday for NDZ023-025-036-037-045>048- 050-051. && $$ UPDATE...PA SHORT TERM...JPM LONG TERM...JPM AVIATION...PA