textproduct: Bismarck

KEY MESSAGES

- Medium to high chances of showers and thunderstorms spreading across much of western and central North Dakota today through tonight. There is a low risk of strong to severe storms along and south of the I-94 corridor with this activity.

- A cooling trend is expected through midweek, before a warming trend occurs late this week and into next weekend.

- Very hot this weekend and early next week with temperatures above 100 degrees possible, and heat index values of 100 to 105.

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 728 PM CDT Tue Jul 7 2026

Strong thunderstorms will impact south central and southeast North Dakota this evening, with heavy rain reducing visibility to IFR levels, gusty winds, and possibly some small hail. The strongest storms are likely to remain south of KJMS and KBIS. MVFR ceilings are possible across southwest and south central North Dakota through Wednesday morning, perhaps falling to IFR or even LIFR in the southwest. Outside of thunderstorms, winds will generally be easterly at around 5-10 kts.

BIS WATCHES/WARNINGS/ADVISORIES

None.