textproduct: Bismarck

KEY MESSAGES

- Scattered showers and thunderstorms across northwest and central North Dakota this morning and afternoon. A few storms may be strong to severe, mainly in north central North Dakota.

- Critical fire weather conditions are possible in far southwest North Dakota on Friday.

- Temperatures warming to well above normal through Saturday, then cooling back to near or slightly below normal early to mid next week.

- Medium to high chances for showers and thunderstorms Sunday through Labor Day.

UPDATE

Issued at 711 AM CDT Thu Sep 3 2026

Thunderstorms continue over portions of northwest and central North Dakota this morning, with the strongest convection now over north-central North Dakota where a recent report of ping pong ball size hail was received. This is on the northern end of a low-level jet with plenty of elevated instability in place. Expect the severe threat with these storms to continue through this morning, along with the potential for locally heavy rainfall.

DISCUSSION

Issued at 535 AM CDT Thu Sep 3 2026

The Northern Plains lie under southwest flow aloft early this morning between a transient ridge exiting the Red River Valley and a deep longwave trough over the Pacific Northwest. A nearly- stacked low pressure system is depicted on water vapor imagery spinning northward through southern Alberta, with a separate surface low analyzed in southeast Montana. A broad expanse of low level warm air advection and moisture transport downstream of these features has ignited areas of showers and thunderstorms. One cluster of widely scattered showers and isolated thunderstorms has been migrating eastward across south central North Dakota into the James River Valley. Meanwhile, clusters of much stronger thunderstorms were moving through northwest and north central parts of the state as of 5 AM CDT. These strong to at times severe storms are moving through an environment with up to 2000 J/kg MUCAPE and effective bulk shear as high as 40-50 kts. Convective evolution through this afternoon is uncertain, and CAMs offer little consistency in potential outcomes. The ongoing convection may continue to lift northeastward into southern Canada by this afternoon. Some CAMs then hint at trailing redevelopment in north central North Dakota this afternoon as an upper level jet streak lifts northeast off the Rockies, but there are obvious questions on how the environment may be modified by morning convection. Model soundings and two-dimensional CIN fields suggest a capping inversion is likely to keep storms elevated through the day, but UH fields in the HREF broadly support strong to severe convection in north central North Dakota this afternoon with a similar CAPE/shear parameter space as mentioned above. Storm mode could be mixed or clustered as there is no well-defined surface boundary where convection is forecast, so will leave our projected hazards at hail up to ping pong ball size and winds up to 60 mph. Torrential rainfall could also caused localized flooding, as has already been observed in Williston and southwest Ward County early this morning.

Mid to upper level ridging is forecast to amplify over the Northern Plains on Friday as a deep upper low spins over the Pacific Northwest. This brings the high temperature forecast into the 90s along and to the south and west of the Missouri River, along with a strengthening southeast surface flow around 20 to 25 mph. In western North Dakota, RH is forecast to fall below 30 percent south of the Missouri River, with minimum values closer to 15 percent in the far southwest along the Montana border. The greatest overlap in strong winds and low RH is in Slope and Bowman Counties, where a Fire Weather Watch has been issued for Friday afternoon and early evening. Surrounding areas in west central and southwest North Dakota could see near- critical fire weather conditions on Friday.

The ridge is forecast to become even more amplified on Saturday, with forecast highs ranging from the mid and upper 80s north to lower and mid 90s south. The low level jet could induce convection over parts of the region late Friday night into Saturday morning, but mostly dry weather is otherwise anticipated from tonight until Saturday night when the deep western CONUS trough begins kicking shortwave energy into the Northern Plains. This culminates in widespread low to medium shower and thunderstorm chances Sunday through Labor Day as a more potent shortwave lifts northeastward over the region while the original Pacific Northwest low spins toward the Canadian Rockies. Temperatures are favored to trend cooler early to mid next week as the upper low crosses southern Canada.

AVIATION /12Z TAFS THROUGH 12Z FRIDAY/

Issued at 711 AM CDT Thu Sep 3 2026

Scattered showers and thunderstorms will continue over northwest and central North Dakota this morning and afternoon. A few stronger storms are possible, especially over north central into parts of northwest North Dakota, with erratic gusty winds and hail. Categorical flight restrictions to MVFR/IFR are possible with any thunderstorm, mainly from visibility reductions caused by heavy rainfall, but also possibly from lower ceilings. Outside of showers and storms, areas of fog over parts of southwest North Dakota will result in IFR to LIFR visibility through mid-morning. At this time, it appears the reduced visibility should remain south of the KDIK terminal.

BIS WATCHES/WARNINGS/ADVISORIES

Fire Weather Watch from Friday afternoon through Friday evening for NDZ040-043.