FXUS63 KBIS 040604 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 1204 AM CST Wed Dec 4 2024 .KEY MESSAGES... - Northwest winds gusting as high as 45 mph will produce areas of blowing snow tonight through Wednesday. A Winter Weather Advisory for blowing snow has been issued for most of central North Dakota. - There could be a brief period of light mixed precipitation tonight, followed by rapidly falling temperatures. - After a brief period of cold temperatures tonight through Wednesday night, temperatures will then moderate through the weekend. - Mainly dry conditions are expected Thursday through Saturday, with widespread low to medium chances (20 to 50 percent) for precipitation returning Sunday into early next week. && .UPDATE... Issued at 1158 PM CST Tue Dec 3 2024 A cold front continues to move southward into northern North Dakota so far. Temperatures continue to drop rapidly behind the frontal passage. No updates are needed at this as the forecast remains on track. UPDATE Issued at 1003 PM CST Tue Dec 3 2024 Low clouds continue to quickly pour into the area while winds continue to increase. So far observations have been rather limited in reducing visibility, but with the increasing winds am reluctant to delay any of the advisory headlines as drifting may be occurring in rural areas. So far temperatures over the area have been steady to slightly rising over the past few hours, but this is to change after midnight with the front working its way in when temperatures are expected to drop. UPDATE Issued at 637 PM CST Tue Dec 3 2024 Cold front remains about 200 miles north of the International Border, recently passing through Saskatoon, with low over south central Manitoba. Winds are still on the increase, though, ahead of the front in the tightening pressure gradient, with gusts in the 30s starting to show up in a couple observations in far northern North Dakota. Thus, winds will continue its increase this evening, though the temperature drop will not show up until late tonight. As for precipitation chances, did drag out low chances for precipitation a little longer late tonight into Wednesday morning based on latest guidance that shows some precipitation may linger. && .DISCUSSION... Issued at 144 PM CST Tue Dec 3 2024 The main forecast issue will be the potential for blowing and drifting snow tonight through Wednesday behind an Arctic cold front that drops south through the area tonight. As mentioned in the early afternoon update, if there were no snow involved, eastern portions of central North Dakota could expect near advisory to low advisory criteria winds, with lower probabilities of advisory criteria winds as you go west. West of the Highway 83 corridor, uncertainties increase both due to the lack of snow and also the extent of warm temperatures today. The southwest would definitely not need winter weather highlights with temperatures around 50 in the far southwest, which will melt or crust any remaining snow. The northwest into the south central are a bit more uncertain. There are some areas in both these areas, which may yield some blowing snow at times. In central ND, temperatures have already reached the mid 30s which could really put a crust to the snowpack. Prior to today there was little or no crust on the latest snow. Our best guess was to include areas along and east of the Highway 83 corridor in a winter weather advisory for blowing snow. Confidence is highest over eastern portions of central ND from the Turtle Mountains into the James River Valley. over western portions of the advisory, for the most part winds look like they would be below wind advisory criteria, but would be concerned not having any highlights. With the initial surge of cold air tonight, it looks like there could be a brief period of a wintry mix, possibly even a brief snow squall. It appears that the temperature of the entire column will quickly drop, but surface temperatures will be warm initially, resulting in a possible flash freeze scenario. We did keep a mention of a slight chance of freezing rain tonight but think if it does occur it would be very brief. Wednesday afternoon, the winds diminish from west to east across central North Dakota. We kept the Advisory going through 6 PM, but do think it's possible that at least western portions of the Advisory may be able to be cancelled early. A lot of that will also depend on the resulting temperatures this afternoon and the influence of the warm temperatures on the snowpack. Wednesday night into Thursday another shortwave dropping southeast congruent with an area of isentropic upglide over eastern Montana into wester ND, will produce an area of light snow or flurries over western and south central ND. Cold temperatures behind the Arctic cold front will remain over the area through early Thursday. Moderating temperatures are then expected later in the day Thursday and Through the weekend. After the small chances (20 to 30 percent) of snow west and south central Wednesday night into early Thursday, mainly dry conditions are expected through Saturday. Low to medium chances (20 to 50 percent) for precipitation then return on Sunday into early next week. && .AVIATION /06Z TAFS THROUGH 06Z THURSDAY/... Issued at 1158 PM CST Tue Dec 3 2024 A cold front will move through the region tonight with a quick burst of snow with strong north to northwest winds, although winds may already be gusty ahead of the front. MVFR ceilings will also spread north to south ahead and behind the cold front and likely remain at least through the morning hours. After the initial cold frontal passage we expect little if any additional snow, but periods of blowing snow, especially at KMOT, KBIS and KJMS through the daytime hours. Winds will diminish from west to east Wednesday afternoon. && .BIS WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 6 PM CST Wednesday for NDZ003>005-011>013. Winter Weather Advisory until 6 PM CST Wednesday for NDZ021>023-025-035>037-046>048-050-051. && $$ UPDATE...Johnson DISCUSSION...TWH AVIATION...JJS