FXUS63 KBIS 030615 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 115 AM CDT Fri Apr 3 2026 .KEY MESSAGES... - A winter storm will impact the region late tonight through Saturday. There are high chances for exceeding 6 inches of snow and low to medium chances for exceeding 12 inches across the southern half of the state. - Gusty north to northwest winds could cause areas of blowing snow in south central and eastern North Dakota on Saturday. - Dry and seasonably cool Saturday night through Monday. && .UPDATE... Issued at 114 AM CDT Fri Apr 3 2026 So far, the forecast is mostly unfolding as expected. Scattered snow showers are now spreading across southwest North Dakota and may soon enter Sioux County, which is slightly farther to the east than was expected at this hour. Some models and ensembles continue to hint at possible mixed precipitation in the southwest overnight, but so far have only seen snow on webcams and in automated surface observations. The latest NBM maintained freezing rain probabilities in the southwest, which we kept but limited to a maximum of 15 percent. As for the rest of the forecast for the storm system, there was a slight but noticeable southward shift in snow totals/probabilities in the 00Z suite of guidance. The decrease in most likely snow amounts is most pronounced from Dunn to Sheridan Counties. Despite this southward shift, there are no planned changes to any headlines until the event is well underway, as there is still at least a 25 percent chances for at least 6 inches in parts of the aforementioned counties. UPDATE Issued at 936 PM CDT Thu Apr 2 2026 There were no major edits to the forecast with this product issuance. All remains on track for snow developing into the region tonight into Fri AM. No changes to headlines. UPDATE Issued at 658 PM CDT Thu Apr 2 2026 An area of light snow, likely associated with a mid level vort max interacting with a mid level cloud deck, continues to slowly move to the east-northeast over central ND east of Highway 83, and will continue to do so for a few more hours this evening. POPs were adjusted for this. Otherwise, there were no major changes to the forecast other than letting the Winter Weather advisory over the southeast expire at 00Z. Incoming storm system will be the next focus, and will be interesting to see how the blended models trend now that more of the higher resolution data will be included later this evening. && .DISCUSSION... Issued at 152 PM CDT Thu Apr 2 2026 We have had a few reports of freezing drizzle late this morning and some fog remains southwest. Expect only some minor impacts but will leave the Winter Weather advisory going south central. Think the evening shift can cancel late afternoon or early evening. Attention then turns to late tonight through Saturday morning and into Saturday afternoon. Overall there was little change in our thinking for the area of highest impact snowfall. We issued the Winter Storm Warning for the same counties as the Winter Storm Watch. We also issued a Winter Weather Advisory going another row of counties north of the Warning. There is a slight chance of a period of light freezing rain along the far southern tier counties late tonight into Saturday morning, but by a large, the threat for freezing rain has pushed farther south. All Snow is expected across most of the forecast area. Easterly winds pick up Friday, especially across the south and east with wind speeds mainly 15 to 25 mph here, with a few higher gusts. winds are lighter as you go north and west. There could be some significant reductions in visibility Friday afternoon and into Friday night where the strongest winds match up with areas of moderate to heavy snow. Winds also turn more northerly Friday night into Saturday morning, with the favored areas for blowing snow shifting to the far south central and into the James River Valley. Heavy snow produce the main impacts with this system. There was a bit of wobbling north and south, but in general the axis of heaviest snow remains over the far south central and into the James River Valley. NBM 48 hour probabilities for 6 inches of snow are high in the far southwest, much of south central and into the James River Valley. There is a pretty quick drop off in these probabilities as you go north of a line from Baker Mt, to Dickinson, Beulah/Hazen, and Carrington. Probabilities are highest (greater than 90 percent) in the far south central into the James River Valley. Bismarck currently sets at 85 percent. The probability of 12 or more inches during the same timeframe, ending at 18Z Saturday is low to medium across much of the south central and James River Valley, and in the far southwest, northeast towards the east end of Lake Sakakawea, and east to around the Harvey area. Deterministically, early on in the shift when some of the higher resolution guidance was coming in, including the NAM, there looked to be a southward shift in the track of higher amounts. Then as the GEFS/ECMWF arrived there was a distinct northward shift in the placement of the 70H low with these models. Both showed a 70H low tracking from west cental SD into north central SD on Friday, with the EC poking into far south central ND. Even though the forecast qpf looks to remain farther south, there may be enough forcing with the 70H low lifting farther north to support higher amounts a bit farther north of the qpf footprint. Also, looking at the GFS Bufkit soundings, specifically at Bismarck and Jamestown, the column has cooled from earlier soundings and you see a larger percentage of the sounding near or within DGZ, whereas earlier soundings had a majority of the sounding above the DGZ. There is also moderate to strong forcing throughout a larger portion of the DGZ. This would lead to some higher snowfall rates. Thus we kind of backed off a southward shift in the snow totals and went with the straight NBM guidance. We did knock back the snow ratios a bit compared to our given NBM guidance. Thus overall, there was a bit of a drop in snow amounts, but the overall placement of the heavy snow was very close to the previous shift. Confidence in these snow amounts remains highest in the far south central and into the James River valley. Confidence is not as high from the Amidon, Beach and Dickinson areas north and east towards Washburn and Harvey. However they do remain high enough here to keep issue a Winter Storm Warning. North of the Highway 200 corridor confidence in snow totals drops quickly, but we did include a buffer of counties north of the Warning, for the transition of Warning criteria snow to the south, and sub advisory criteria north. Once the precipitation ends from west to east on Saturday, we dry out Saturday night through the remainder of the weekend and into early next week, although temperatures remain at or below seasonable normals. && .AVIATION /06Z TAFS THROUGH 06Z SATURDAY/... Issued at 114 AM CDT Fri Apr 3 2026 Snow will increase over southwest North Dakota late tonight and spread eastward across the southern two thirds of the state through Friday. The snow will be moderate to heavy at times, with prevailing IFR to LIFR visibility. KXWA and KMOT will be near the northern edge of lighter snowfall at times throughout the forecast period. Mostly IFR ceilings through tonight, with some intermittent periods and areas of both MVFR and LIFR. Then on Friday, expecting MVFR ceilings across the north and IFR across the south. Winds will gradually turn from easterly to northerly through the forecast period, sustained around 10-15 kts. && .BIS WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory from 1 PM CDT /noon MDT/ this afternoon to 1 PM CDT /noon MDT/ Saturday for NDZ005-010>013- 017. Winter Storm Warning until 1 PM CDT /noon MDT/ Saturday for NDZ018>020-031>034-040>045. Winter Storm Warning from 7 AM this morning to 4 PM CDT Saturday for NDZ021>023-025-035>037-046>048-050-051. && $$ UPDATE...Hollan DISCUSSION...TWH AVIATION...Hollan