textproduct: Bismarck

KEY MESSAGES

- Scattered thunderstorms are expected in south central and eastern North Dakota this evening. Key potential hazards are hail up to 2 inches in diameter and 70 mph wind gusts.

- Mainly dry conditions then expected through mid-week, with low to medium precipitation chances returning late Thursday through the end of the week into early next week.

- Near critical conditions could return Tuesday over the far southwest.

UPDATE

Issued at 651 PM CDT Mon Aug 24 2026

A Severe Thunderstorm Watch has been issued across much of south central North Dakota, including the James River Valley, until 1 am CDT, though storms will likely exit to the east of the Bismarck WFOs County Warning Area a few hours prior. Currently, a cluster of supercells has developed over parts of Kidder, Foster, and Stutsman counties and are likely producing large hail. These storms may congeal into a line as they gradually move east this evening, which would then favor more of a wind threat. Storm coverage may also expand both further to the north and south across the watch area.

DISCUSSION

Issued at 222 PM CDT Mon Aug 24 2026

Current surface analysis places low near the Saskatchewan and Manitoba border, with trough dropping southward through central North Dakota, while high is over the Midwest. Upper level analysis places high over New Mexico with ridge stretching to the north, but top of ridge is being busted down by a compact low over southern Saskatchewan which is gradually meandering to the east. Over our area, aforementioned surface trough continues to push through, right now passing generally over and just east of the Highway 83 corridor, with high humidity ahead and drier air behind.

For the rest of this afternoon into this evening, aforementioned trough will continue to gradually meander east. Behind the trough, dry air continues to push in resulting in low relative humidity values. This is especially noted over southwest into parts of northwest North Dakota where, combined with a westerly breeze, near critical wildland fire conditions have developed.

To the east of the trough, elevated moisture remains in place with CAPE values around 3000 J/Kg, and 0-6 km shear values around 40 kts, plenty for rotating updrafts. The question is at what point as the trough pushes east will storms develop, given the forcing is not the strongest and there is some capping to deal with. Guidance has wavered some between the 5-7 PM CDT hours, but the later it goes the further east the initiation is expected. With that said, once initiation does occur, expect any storm to develop rapidly, with discrete development given deep layer shear vectors remain perpendicular to the boundary. With that all said, storms should then move quickly off to the east, with quiet weather then setting in for the rest of the night.

On Tuesday, mainly quiet weather is expected as the ridge axis re-focuses over the Rockies, though the aforementioned compact low/short wave will move through southern Manitoba which may lead to a few showers around the Turtle Mountains region. Northwest winds will be on the increase as the surface low with this system moves east through Manitoba into Ontario. Upper ridge gradually meanders east resulting in quiet weather for us through Thursday before pattern becomes more unsettled, bringing some low to medium precipitation chances to end the week into the weekend.

AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/

Issued at 651 PM CDT Mon Aug 24 2026

A cluster of severe thunderstorms has developed over parts of south central North dakota. These storms will move east this evening likely impacting KJMS within the next hour or two. Strong erratic winds, torrential rain, and large hail are the primary threats. Once storms move east of KJMS, VFR ceilings and visibility are expected through the period.

BIS WATCHES/WARNINGS/ADVISORIES

None.