textproduct: Bismarck

KEY MESSAGES

- Low chances (20-30%) for showers and thunderstorms today. Isolated severe storms (level 1 out of 5) are possible in the southern James River Valley this afternoon.

- Low to medium chances (20-40%) for showers and isolated thunderstorms tonight. Severe weather is not expected.

- Low to medium chances (20-40%) for hit and miss showers and thunderstorms continue Tuesday through Wednesday, then only low chances (20%) late in the work week. - Seasonable temperatures are expected this week.

UPDATE

Issued at 944 AM CDT Mon Aug 17 2026

The forecast for today remains on track. Main change was to trend SKY and POPs with latest imagery and latest model output.

UPDATE Issued at 552 AM CDT Mon Aug 17 2026

A small area of thunderstorms has developed just north of Minot, otherwise it was clear to partly cloudy across western and central ND early this morning. Made some minor adjustments to pops and sky cover based on latest radar and satellite imagery. Wouldn't be surprised to see at least a little more development through the morning as the cold front pushes farther south and upper level instability increases.

DISCUSSION

Issued at 221 AM CDT Mon Aug 17 2026

Currently, weak low pressure was located over the area, ahead of an approaching cold front dropping south from Canada. Skies were partly cloudy and last nights evening convection has mostly dissipated except for an isolated shower over northwest ND. We remain within a northwest upper level flow. Although modest at best, elevated instability remains over the area with modest shear as well. Short term guidance has been overdoing the overnight convection and continues so. May take a look and see how the northwest convection is going in a bit and if not much has changed, drop from chance to slight chance early this morning. With that said, think there is a chance of showers and isolated thunderstorms yet this morning, but probably more like mid to late morning as elevated instability and bulk shear aloft continue to increase. Forecast NAM soundings from Dickinson to Bismarck and Jamestown indicate 1000-1500 J/kg of SBCape with 30-40kts of bulk shear and little CIN, late this morning, then instability drop pretty quick this afternoon. If you go down to Ashley, instability increases to around 2000 J/kg with 35 to 40 knots of shear late morning, before also losing instability as drier air moves in this afternoon. SPC has pulled the marginal risk of severe storms (that was east of the forecast area) back west into the far southern James River Valley. Think there is a small window late morning into the early afternoon for a stronger to possibly severe storm here. The main hazards would be quarter sized hail and 60 mph winds.

After early this afternoon, the threat for severe storms looks to be over for a while. At the surface high pressure builds over the area tonight, but jet energy over the area may provide enough forcing for scattered showers and isolated thunderstorms tonight into Tuesday, with another wave bringing low chances for scattered showers and isolated thunderstorms on Wednesday. Severe storms are not expected at this time Tuesday through Wednesday.

Upper level ridging over the western U.S west amplifies and pushes east Wednesday through Friday. Northwest flow remains over the area so a low threat for a hit or miss thunderstorm will remain, but overall, precipitation chances will remain low for the second half of the work week.

Temperatures remain seasonable through the forecast period. High temperatures will generally range from the mid 70s to mid 80s. A little cooler on Tuesday and a little warmer on Thursday. Forecast lows are expected to range from the mid 40s to mid 50s. Again, a little cooler on Tuesday, and with some upper 50s to lower 60s later in the week.

AVIATION /12Z TAFS THROUGH 12Z TUESDAY/

Issued at 552 AM CDT Mon Aug 17 2026

A cold front will drop southeast through the area today. Winds will shift to the northwest 10 to 20 mph behind the cold front, with a slight chance of a shower or thunderstorm mainly at the southern TAF sites of KBIS and KJMS this afternoon. Current convection in the north central has moved east of KMOT and probabilities at KBIS and KJMS late this morning through this afternoon are too low for even a PROB30 at this time. Any thunderstorms that do develop would produce locally gusty and erratic winds and brief heavy downpours. Winds turn north to northeast later today then become light this evening. Another chance of showers and thunderstorms mainly west and south tonight, but again, probabilities too low attim for even a PROB30.

BIS WATCHES/WARNINGS/ADVISORIES

None.