753 FXUS63 KBIS 060937 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 437 AM CDT Sat Jun 6 2026 .KEY MESSAGES... - Highs in the mid 80s to mid 90s today. Becoming windy to very windy this afternoon into this evening. - A Wind Advisory is in effect for portions of western and south central North Dakota south and west of the Missouri River. - Isolated to scattered severe thunderstorms are possible over western North Dakota tonight. - Isolated to scattered severe thunderstorms over much of western and central North Dakota Late Sunday afternoon and Sunday night. - Except for a brief break on Monday, a more active severe weather pattern looks to continue next week. && .DISCUSSION... Issued at 250 AM CDT Sat Jun 6 2026 An upper level low pressure system currently just of the coast of the Pacific Northwest will influence the weather over the Northern Plains this weekend. Currently, upper level ridging downstream of the low is propagating across the forecast area. Skies were mostly clear across western and central ND as of 4 AM this morning. Back to hour west, surface low pressure was located over the northern High Plains of Wyoming and southeast Montana. North of the low, over northeast Montana, an area of scattered thunderstorms has developed within an area of warm advection combined with weak shortwave energy tracking through a broad southwest upper flow. This was noted yesterday and will monitor but may need to add some low pops over the far northwest early this morning. One this passes, the daytime is expected to be dry. It will be hot, with an increasing southeast surface flow across the west and central. Areas to the south and west of the Missouri River look to have the greatest potential for Advisory level winds this afternoon. We have issued a Wind Advisory for this area, expecting sustained winds around 30 mph with gust to 45 mph. There are some indicating the strong winds may linger into the evening so we kept the advisory going through much of the evening as a very strong low level jet develops across western and central ND. If we lose the strong winds this evening, we can always cancel, but there was enough of a signal to keep it going beyond the loss of daytime heating. Convection tonight will be the next concern in the west, and possibly into the north central late. There was little change in the new Day 1 SPC outlook, compared to yesterday's Day 2 outlook across western North Dakota. Convection is expected to develop over the High Plains of Wyoming and Montana today and track northeast. A surface trough is expected to extend from the surface low over southeast Montana, northeast into far northeast Montana at 00Z. Forecast soundings around Williston at this time indicate a very unstable but capped environment. There a few CAMs that do develop convection at this time. Given the forecast highs are in the mid 90s and if we exceed that, maybe we do get some convection trying to go. If convection would develop, we could get some rapid development with large hail possible. The consensus though is favoring later convection, behind the surface trough, skirting far northwest North Dakota. There are indications of higher end winds with DCAPE and 0-3km bulk shear, but the DCAPE is stronger earlier in the day, but wanes in the evening. 0-3km shear increases in the evening but becomes strongest possibly after convection moves through. Very steep lapse rates slowly diminish through the evening, but with a max remaining over far northeast MT into northwest ND, near the Missouri River on the Williams McKenzie county line. A very strong llj will also be developing in the evening, and a large hail parameter maximized over northeast Montana but poking into northwest ND in this same area. Although parameters done line up exactly, they are there. Outside of northwest ND, the parameters are not as impressive. Therefore we will stick with ping pong ball sized hail and up the winds to 70 mph for messaging, but limit this to northwest ND, pretty much within the Slight Risk area. The rest of western and north Central ND, we will mention 60 mph winds and quarter sized hail. Sunday will be another day of isolated to scattered severe storms. A cold front moves into the state with a very moist and unstable airmass, but will be capped. The question whether there will be enough convergence along the front to initiate convection. If so bulk shear is not overly strong, but is trending to more perpendicular to the surface boundary. Thus supercells with very large hail would be favored. If convection hold off until later, bulk shear is then more parallel to the front and upscale growth into a linear system would be favored, with strong winds more of a threat than large hail. At this time, see no reason to change our current messaging of golf ball sized hail and 70 mph winds. It's entirely possible that we will see some changes as the convective mode reveals itself as we get close to Sunday. However, there's too much uncertainty at this time. Whatever does take place, things should clear out late with Monday being a mostly dry and cooler day. We then get right back into the swing of things as we warm up and ratchet up the convection again on Tuesday. SPC is still maintaining a slight risk for much of western and central ND on Tuesday. && .AVIATION /06Z TAFS THROUGH 06Z SUNDAY/... Issued at 108 AM CDT Sat Jun 6 2026 VFR conditions are expected through the 06Z TAF period. The exception will be after 00Z Sunday over west central into northwest ND as a convection may develop/move into this area. Until then mostly clear skies tonight with increasing mid and high clouds Saturday in the west. Southeast winds will will also be increasing Saturday, becoming strong 25 to 35 knots with gusts to 40 knots in the afternoon and early evening, before slowly diminishing. Convection developing or moving into western ND around or after 00Z Sunday with gusty and erratic winds possible with any storms and MVFR ceilings and visibilities in any heavy downpours. && .BIS WATCHES/WARNINGS/ADVISORIES... Wind Advisory from 1 PM CDT /noon MDT/ this afternoon to midnight CDT /11 PM MDT/ tonight for NDZ017>020-031>033- 040>044-059>062. && $$ DISCUSSION...TWH AVIATION...TWH