FXUS63 KBIS 201738 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 1238 PM CDT Sat Jun 20 2026 .KEY MESSAGES... - Near to slightly below average temperatures today and below average temperatures Sunday. A few showers and thunderstorms in the southwest this evening through tonight. More widespread shower and thunderstorm chances expected Sunday. - A gradual warming trend through next week, along with near daily chances for showers and thunderstorms. - The severe weather threat is low this weekend through at least mid next week. && .UPDATE... Issued at 1238 PM CDT Sat Jun 20 2026 Diurnal cu has developed over most areas north and east of the Missouri River. With a more solid cloud deck incoming from the southwest, continued development further to the southwest will likely be limited. In addition, some of this diurnal cu may dissipate earlier than the traditional peak heating timeframe depending on how far north and east the mid to high cloud deck penetrates this afternoon. UPDATE Issued at 844 AM CDT Sat Jun 20 2026 Based on the latest satellite imagery and observations, patchy morning fog appears to have dissipated within the forecast area. The ongoing forecast looks to be in good shape. UPDATE Issued at 644 AM CDT Sat Jun 20 2026 Limited updates needed at this time. Some patchy shallow fog has formed in eastern portions and may linger for the next couple of hours. Added in some patchy fog mention for these areas this morning. Otherwise the forecast remains on track. && .DISCUSSION... Issued at 408 AM CDT Sat Jun 20 2026 Upper level ridge will keep conditions mainly dry through today. Developing surface low to our west will eventually bring a switch to east southeast flow, perhaps becoming breezy across the west. This southerly flow should bring slightly warmer near normal temperatures in the 70s today. Tonight, split lows will begin to form in the southern Canada and in the central plains. The low in the central plains could bring some showers and thunderstorms across mainly southwestern portions. SPC has a general risk for thunderstorms, mainly for tonight due to this feature, with the marginal risk not too far away. If the axis of higher instability can get into southwestern ND, then perhaps an isolated stronger storm is possible although this setup is fairly low confidence at this time. Otherwise look for a steady southeasterly wind through tonight with lows slightly warmer in the mid 40s to mid 50s. Sunday, the central plains low dives southward while the southern Canada low slowly progresses eastward. The result will be slightly cooler temperatures in the 60s west to 70s east, with chances for showers and thunderstorms mainly in the west and possibly central portions. There is some uncertainty how far into central ND this precipitation can get on Sunday, as dry easterly air main hold off these chances. Some breezy winds may also be found on Sunday. The Canadian low stalls in southern Saskatchewan Sunday night, bringing chances for showers and thunderstorms to most of western and central ND. Lows will be in the mid 40s to lower 50s. Given the lack of instability, the chance for severe weather is low on Sunday through Sunday night. Canadian low becomes more broad and progressive Monday. This could bring another push of widespread showers and thunderstorms to most of the state, with limited chances for severe weather. Temperatures will remain near 70 degrees, which is below seasonable normals. A south wind becoming a westerly wind may also be found as this low moves through on Monday. This slow moving low continues to progress across the region on Tuesday, lingering shower and thunderstorms chances and perhaps bringing breezy northwest winds. Temperatures will remain below normal as this low moves threat, and the chances for severe weather remain low given an overall lack of instability. Ridging aloft combined with a surface high then looks to diminish precipitation chances Tuesday night, and bring mainly dry conditions Wednesday and Thursday. Temperatures will also go on a gradual warming trend Wednesday and are forecast to continue through the rest of the week. There is some uncertainty on precipitation chances later in the week. Some clusters want to move another shortwave pattern through, while others hold on to a weak ridge pattern longer. Even if the weak ridge pattern holds out, placement of this ridge to our west could provide for some unsettled northwest flow at times. Thus the forecast introduces some slight PoPs later in the week. && .AVIATION /18Z TAFS THROUGH 18Z SUNDAY/... Issued at 1238 PM CDT Sat Jun 20 2026 Dry conditions are expected to continue this afternoon before shower and thunderstorm chances gradually begin to enter the southwest this evening. Precipitation chances will then continue to increase overnight and through Sunday morning, including in the northwest and south central. The terminals most likely to see precipitation before 18Z Sunday are KDIK and KXWA with lower chances at KBIS. A few rumbles of thunder are possible as well. However, with low confidence, maintained PROB30 and prevailing mentions as SHRA for now. Otherwise, MVFR ceilings associated with this system may encroach into the far southwest Sunday morning. Diurnal cu over most locations north and east of the Missouri River could produce low VFR ceilings at times this afternoon, though will gradually rise in height before dissipating soon after peak heating. && .BIS WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Telken DISCUSSION...Anglin AVIATION...Telken