FXUS63 KBIS 131132 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 632 AM CDT Fri Mar 13 2026 .KEY MESSAGES... - Chance (30-70 percent) of snow west and south central today, then a chance of snow southwest and south central tonight. An inch or two of snow accumulation possible southwest through tonight. - Snow develops over much of the area Saturday into early Sunday, with moderate to heavy snow and the greatest impacts possible along and south of Interstate 94. Gusty winds developing may create blowing snow impacts Saturday night into Sunday. - Well below normal temperatures this weekend into early next week, followed by a moderate to strong warming trend through the middle to later portions of next week. && .UPDATE... Issued at 629 AM CDT Fri Mar 13 2026 No major changes to the forecast for this morning. See below for more detailed discussion and updated Aviation section. && .DISCUSSION... Issued at 440 AM CDT Fri Mar 13 2026 Currently, strong northwest flow with a 150kt upper level jet aloft. Ridge of surface high pressure building south-southeast across the western and central Dakotas this morning, with diminishing winds across the local region. Earlier dropped the remaining High Wind Warning and Winter Weather Advisory with the improving conditions. A cloudy sky across the region, with both low and mid level BKN-OVC clouds over western and central ND to start the day. Embedded wave and its associated subtle surface low track east- southeast across Montana and through western ND into northern South Dakota today and this evening. Coupled with upper level jet dynamics we expect snow to develop across western into south central areas of the state, focused over the southwest where the best forcing combo is projected over the next 12-24 hours. Up to an inch or two of snow is currently forecast over southwest ND through tonight, with lesser amounts as you head north and east. More widespread snow chances then quickly develop Saturday/Sat night, when an upper level trough digs/amplifies into the Northern and Central Rockies in response to favorable right entrance/left exit region jet dynamics. An associated lee side sfc low develops over eastern Wyoming/Colorado Sat AM, then develops/deepens east into the Central Plains by Sat night. A broad area of strong DivQ forcing and low/mid level frontogensis sets up on the north side of the sfc low track during the day Sat into Sat evening, with models showing a notable northward shift to bringing decent accumulating snowfall to southern areas of the state. GEFS and EC ensembles def shifting north, with percent chance of at least 3" of snow now close to 90% along and south of I-94, and probabilities for at least 6" also increasing, with NBM now at 50-80% chance over my southwest and far south central and southern James Valley (40-60% chance for at least 8" for this same area). Given the above mentioned co-forcing, some banded snow is likely, which may be what is driving some of the higher advertised amounts. Also expect to see winds increasing as the sfc low organizes into the Central Plains, increasing the potential for blowing snow impacts. With the above info and after collaboration with surrounding offices and WPC, we opted to issue a Winter Storm Watch for all of southwest ND, and across far south central and the southern James River Valley south of I-94 Sat morning through Sunday morning. Future adjustments to the watch are possible, and/or upgrades in the near future. Thereafter, a large and broad upper level ridge of high pressure is favored by ensembles to develop over the western CONUS next week, gradually moving east through the week. Rain and snow chances remain forecast Monday and Tuesday during the transition from the colder airmass this weekend to the warmer airmass associated with the upper ridge, followed by mainly dry weather for the rest of the week. Temperatures will moderate nicely after Monday, with a strong warming trend favored Tue-Thu (widespread highs in the 50s and 60s next week Wed and Thu). && .AVIATION /12Z TAFS THROUGH 12Z SATURDAY/... Issued at 629 AM CDT Fri Mar 13 2026 Areas of mainly MVFR to low VFR ceilings are expected over western and central ND this morning, but improving towards 15-18Z with a lowering mid level cloud deck. Winds continue to diminish over central and eastern ND this morning, shifting to the southeast from west to east during the day today. Next round of winter weather enters southwest North Dakota later this morning, then slowly expands east into south central ND during the day. MVFR to possibly IFR ceilings and visibility in falling snow forecast for southwest and south central terminals, including KBIS and KDIK. && .BIS WATCHES/WARNINGS/ADVISORIES... Winter Storm Watch from Saturday morning through Sunday afternoon for NDZ031>034-040>048-050-051. && $$ UPDATE...NH DISCUSSION...NH AVIATION...NH