994 FXUS63 KBIS 200632 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 1232 AM CST Wed Feb 20 2019 .UPDATE... Issued at 1229 AM CST Wed Feb 20 2019 For this update, made some adjustments to PoPs based on observations and high-resolution model guidance. Snow will continue to increase over southeast parts of our forecast area through the night, with widespread light snow/flurries continuing across much of central and southwest North Dakota. Also decreased low temperatures to near 15 below zero in far northwest North Dakota. Williston has already reached 13 below, though has since risen. UPDATE Issued at 937 PM CST Tue Feb 19 2019 Increased PoPs across the south central and James River Valley with a high PoP-low QPF scenario in snow per radar and surface observation trends. Otherwise, the forecast was blended to observed trends through 03 UTC. UPDATE Issued at 552 PM CST Tue Feb 19 2019 No significant change to the forecast at this time. Expect a quick drop off in temperatures this evening, with near steady to slowly rising temperatures thereafter as cloud cover continues to increase. A Wind Chill Advisory may be needed across the northwest and far north central where skies will remain clear the longest and temperatures as a result the coldest. Otherwise, light snow will slowly spread across far south central North Dakota and the James River Valley this evening and through the night with a series of mid level impulses and low level warm air advection. Did add fog to the west per the visibility forecasts on the HRRR/RAP/NBM/GFSLamp through their 23 UTC iterations. && .SHORT TERM...(This evening through Wednesday) Issued at 214 PM CST Tue Feb 19 2019 Concerns for the short term include the developing snow for tonight and Wednesday across portions of south central and southeast North Dakota. Temperatures will also be challenging with recent deep snow cover in any location that has clear skies tonight. Global models agree in tracking an h500 wave from the intermountain region east northeast through the central and northern plains tonight and Wednesday. Overall, weak forcing should result in light precipitation and 1 to 3 inches of snow generally south of I-94 and east of highway 83, beginning this evening and ending Wednesday evening. Temperatures this evening will very likely fall quickly as the sun sets. So have dropped low temperatures about 5 to 10 degrees from previous forecast and current guidance. Although this will set the wind chills around -25 below for a few hours tonight, will not issue any headlines at this time. .LONG TERM...(Wednesday night through Tuesday) Issued at 214 PM CST Tue Feb 19 2019 The H500 flow continues to exhibit h500 troughiness across the western US through the period. This will keep the cold air in place over the region with below normal temperatures for what will likely be the remainder of February. It also suggests any weak waves exiting from the western trough will impact the northern plains, resulting in several episodes of snow. && .AVIATION...(For the 06Z TAFS through 06Z Wednesday night) Issued at 937 PM CST Tue Feb 19 2019 MVFR stratus will spread across most of southern North Dakota this evening and tonight, with light snow across south central North Dakota and the James River Valley. Fog may develop across portions western North Dakota tonight into early Wednesday morning, possibly impacting KDIK. However,this development is somewhat uncertain. Widespread MVFR/IFR conditions in stratus and snow are expected across central North Dakota on Wednesday. KJMS will be the terminal impacted the most by the snow. MVFR/IFR stratus is expected across the west on Wednesday. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Hollan SHORT TERM...WAA LONG TERM...WAA AVIATION...PA