FXUS63 KBIS 080347 AFDBIS Area Forecast Discussion National Weather Service Bismarck ND 1047 PM CDT Tue Jul 7 2026 .KEY MESSAGES... - A few scattered showers and thunderstorms remain possible through tonight, but severe weather and heavy rain are no longer anticipated. - Cooler temperatures continue through Wednesday, followed by a strong warming trend through the weekend. - Very hot this weekend and early next week, with daily high temperatures and maximum heat indices around 95 to 105. && .UPDATE... Issued at 1045 PM CDT Tue Jul 7 2026 The risk for excessive rainfall appears to have shifted into north central and northeast South Dakota. Showers and thunderstorms will remain possible though along the ND/SD border east of Lake Oahe into the overnight hours. Severe weather is also no longer anticipated this evening through tonight. A separate area of scattered showers across northwest and north central North Dakota may persist into the overnight hours. A mention of patchy fog was added to much of southwest and south central North Dakota from late tonight to mid Wednesday morning. Potential contributing factors to fog formation include fresh rainfall from earlier today, low dewpoint depressions, an east- northeast upslope flow, and existing low stratus. UPDATE Issued at 728 PM CDT Tue Jul 7 2026 Numerous thunderstorms are developing south of I-94 and east of Highway 83 early this evening. The main hazard from these storms will be torrential rainfall, which may cause localized flooding. Classic setup for excessive rainfall from training convection through this evening with 850 mb moisture transport vectors pointed into mid/low level frontogenesis and perpendicular to Corfidi vectors. Anomalously high precipitable water and deep warm cloud layers also support very high rainfall rates. Recent CAMs favor backbuilding convection as far west as Lake Oahe through late evening, but there is uncertainty which side of the ND/SD border this could fall on. && .DISCUSSION... Issued at 238 PM CDT Tue Jul 7 2026 Quasi-zonal flow aloft continues as a short wave digs across the main flow aloft this afternoon bringing chances for thunderstorms in North Dakota. There is a low chance of strong to severe thunderstorm possible this afternoon along the MUCAPE axis along the North and South Dakota border. Precipitable water around 1.5 inches will move across the region supporting high rainfall rates which have been observed in South Dakota this morning. Localized flooding is possible if thunderstorms train over an area for a couple of hours. Some of the CAMs show an area of strong thunderstorms developing in the southern James River Valley this afternoon. However the southern James River Valley had an MCV roll through the region so the environment may be a little worked over. The greatest risk for strong storms remain in South Dakota. Daily chances will continue across the state as multiple waves move across the region as Quasi-zonal flow persists. CSU ML program and NSSL ML Program does highlight a low chance of severe weather Thursday into the weekend. Thursday is now outlooked for a marginal risk for large hail and damaging winds. Severe weather chances will continue through the week due increased instability, due to warmer temperatures, low level moisture, and multiple waves. Temperatures are forecast to slowly decrease by tomorrow into the 70s and 80s before ramping back up into the 80s and 90s by the weekend. An upper level ridge is forecast to build back over the west this coming weekend supporting a round of hot weather. The NBM 25th to 75th on Sunday does range from the lower 90s to lower 100s for KBIS. The current NBM forecast for Sunday and Monday is 100 and 99. Thus, there is high confidence in hot temperatures for early next week leading to heat headlines. && .AVIATION /00Z TAFS THROUGH 00Z THURSDAY/... Issued at 1045 PM CDT Tue Jul 7 2026 Scattered showers will remain possible across northwest and north central North Dakota into the overnight hours, as will a few showers and thunderstorms along the ND/SD border. Other than possible brief MVFR visibility restrictions from rainfall at KXWA and KMOT, major terminals are no longer expected to see significant impacts from showers or storms. MVFR/IFR ceilings have developed over much of southwest North Dakota this evening. The low ceilings could spread eastward over south central North Dakota later tonight into Wednesday morning, while persisting in the southwest. There could also be patchy fog across southwest and south central North Dakota later tonight into early Wednesday morning. Confidence in the presence, coverage, and intensity of fog is not high enough to mention in TAFs at this time. Winds through the forecast period will generally be southeast to northeast around 5-10 kts. && .BIS WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Hollan DISCUSSION...Johnson AVIATION...Hollan