FXUS63 KBIS 090903 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 403 AM CDT Thu Jul 9 2026 .KEY MESSAGES... - Isolated to scattered severe thunderstorms are possible this afternoon through this evening. - A strong warming trend is expected through the rest of the week, with very hot daily high temperatures around 95 to 105 forecast this weekend through early next week. An Excessive Heat Watch has been issued for Saturday through Monday. - Mainly dry conditions are expected the hot spell. && .DISCUSSION... Issued at 204 AM CDT Thu Jul 9 2026 A quasi-zonal flow will remain across the forecast area today and tonight. A shortwave trough and associated cold front will provide the potential for strong to severe storms this afternoon and this evening across the forecast area. Building upper height will then dominate through the weekend with an extended period of very hot temperatures and oppressive heat through the weekend and into next week. Currently skies ranged from clear east to mostly cloudy west as cirrus from Montana convection pushes into the state. Temperatures are mainly in the upper 50s to upper 60s early this morning. For today...A shortwave trough tracking through southern Canada will push an attendant cold front into northwest ND by this evening. Meanwhile, convection currently along the associated warm front over eastern Montana will push into North Dakota this morning. CAMS are in disagreement on how this convection will evolve this morning. Some keep convection along the International Border, some extend convection farther south and others bring convection almost to the South Dakota border this morning. There is also a lot of uncertainty in how far east convection spreads as well as the extent of this convection (isolated versus scattered). Forecast soundings indicate elevated instability over the area today. Currently there is some stronger effective shear over western ND with slightly unstable CAPE values pushing into the state from Montana. Through at least mid-morning, it looks like Effective shear will diminish but Cape will slowly increase. As mentioned earlier CAMS are in general disagreement, but most do at least bring some convection into the northwest this morning. How it evolves after this is uncertain. Also uncertain is how this will impact convection later today. In general, once the initial shortwave trough and associated convection moves through during the day, the forcing for ascent later in the day is not great. Medium range models indicate pressure falls in eastern Montana and western ND this morning, strongest early in the morning, then there are little if any pressure falls at all this afternoon, before meager falls this evening tracking through north central to northeast ND. At the surface today, low pressure moves into western ND around midday then slowly pushes east through the afternoon. By mid to late afternoon there is a pre-frontal trough over western ND pushing slowly into central ND and a Cold front that is pushing into northwest ND. A very unstable airmass will be situated over much of western and central ND with MLCAPE values around 3000 J/Kg. Although bulk shear is not great, there is sufficient shear (around 25 to 35 knots) orientated nearly perpendicular across the surface trough from southwest into north central ND. The question becomes, will there be enough forcing for ascent from the surface convergence along the trough and only weak waves moving through the broad upper level flow. If so, there will be the potential for rapidly developing supercells within the very unstable airmass and steepening lapse rates. Large hail to around 2 inches will be possible across central ND, along with winds gusts to 60 mph. Although parameters are not necessarily favorable for a tornado, given the slow moving boundary and supercell potential, a tornado can not be ruled out over central ND. Large hail looks to be the greatest hazard though. With all that said, currently cams do not look all that excited with convection later this afternoon through this evening. A few show convection developing southwest-south central and only a few show some convection developing over central ND. Wondering if this is due to at least in some extent to the CAMS showing convection tracking across the area today, associated with the ongoing Montana convection, thus CAMS are assimilating a slow recovery behind this convection. So a lot may depend on how things evolve this morning and early afternoon. If convection does not track across the area, perhaps there will be a better severe potential later today. Either way, if convection does develop later this afternoon, into the evening, there threat fore severe storms will remain. In addition, there is an approaching cold front. If convection does hold off until this evening, bulk shear increases significantly, and there may be more threat of clusters of storms (moreso north) as the shear vectors are more parallel to the approaching cold front. Will continue to monitor. Once convection ends tonight, attention turns to an extended period of very hot temperatures and oppressive heat indices. We have issued an Extreme Heat Watch beginning midday Saturday and continuing through Monday evening. Sunday still looks to be the day with the highest potential for Heat Impacts, but all three days (Saturday through Monday) will see highs mainly in the mid 90s to around 100 to 105. Hottest temperatures will be in the southwest, but humidity will be higher in the northwest and central. It's possible that southern portions of the forecast area will see another day of hot temperatures and heat related impacts on Tuesday, but the uncertainty increases a bit and the north does cool off a little. Beyond Monday there is a bit of a drop in NBM ensemble high temperatures, but the spread also increases significantly. In the Saturday through Monday timeframe, the NBM ensemble spreads have actually tightened up. This has increased confidence in the potential for an impactful heat wave this weekend into early next week, in addition to the warm overnight lows only dropping to around 70 degrees. Therefore we went ahead with the Excessive Heat Watch. Shower and thunderstorm chances remain minimal through the weekend and into early next week. && .AVIATION /06Z TAFS THROUGH 06Z FRIDAY/... Issued at 1149 PM CDT Wed Jul 8 2026 Mostly VFR conditions expected through the 06Z TAF period. Light southerly winds expected tonight and into Thursday morning. Southerly flow then increases to 10 to 20 mph over central ND Thursday afternoon and turns westerly over western ND. Winds then become light after 00Z Friday across the forecast area. Convection could push into western ND towards morning, but strong to severe storms are not anticipated with this activity. Isolated to scattered strong to severe storms are possible Thursday afternoon into Thursday evening across western and central ND. Any of these storms will contain gusty and erratic winds and hail, as well as the potential for MVFR ceiling and visibilities with any heavy downpours. && .BIS WATCHES/WARNINGS/ADVISORIES... Extreme Heat Watch from Saturday afternoon through late Monday night for NDZ001>005-009-010-012-013-017>020-022-023-025- 031>033-035>037-040>044-046>048-050-051-055>062. && $$ DISCUSSION...TWH AVIATION...TWH