999 FXUS63 KBIS 150041 AFDBISArea Forecast Discussion National Weather Service Bismarck ND 741 PM CDT Sun Sep 14 2025
.KEY MESSAGES...
- Tornado threat through much of North Dakota continues through this evening.
- Shower and thunderstorm chances continue through much of the week.
- Highs mostly in the 70s through Tuesday, then cooling into the 60s by the end of the work week.
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.UPDATE... Issued at 723 PM CDT Sun Sep 14 2025
Thunderstorms continue to lift through central North Dakota into the James River Valley. Current tornadic storm lifting through McHenry County continues to run right along a gradient of around 30kts of 0-3km shear, which has been the general trend through this event. A line of storms has also blossomed on the southern end of an area of elevated instability, moving into a more unstable airmass. So far the main possible threat with these storms would be wind, though brief heavy rain fell in Jamestown leading to some street flooding. The expected general trend with this whole system is to continue to lift northward, and also expect a downward trend with the loss of daytime heating, especially on the eastern storms.
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.DISCUSSION... Issued at 231 PM CDT Sun Sep 14 2025
Surface low now lifting northward, centered between Pierre and Mobridge, SD, with warm front wrapping into the north side of the low. Broad area of showers and storms have developed over south central into southwest North Dakota. In this vicinity, more low-level SRH rich air in the vicinity of the warm front will bring a tornadic threat. This has been confirmed by multiple tornadoes that have already occurred over far south central North Dakota. There also is a limited large hail/wind threat. Another great concern given the moisture rich environment is heavy rain, thus the potential for flooding. The threat for the severe weather continues into this evening before dissipating.
System will meander north through the night. Models still show a bit of timing uncertainty with the departure of the low into Canada on Monday, now generally sometime in the afternoon/early evening. This keeps high chances for showers but comparatively lower chances for thunderstorms in the forecast on Monday, decreasing from south to north in the afternoon through the evening. Not long after the departure of the low late Monday, another wave deepening over the Northern Rockies will begin sending DCVA into the region on Tuesday, which keeps a 20 to 40 percent chance of rain in the forecast. Guidance then shows another shortwave digging down from Canada on Wednesday. This wave is likely to bring a cooler air mass into the region, which may hold through the end of the week as the wave interacts with the other aforementioned wave and meanders around the Upper Midwest. The NBM maintains a 30 percent chance of rain on Wednesday, followed by only a 20 percent chance Thursday through Saturday.
For Monday and Tuesday, high temperatures are mostly expected to be in the 70s, though parts of southwest and south central North Dakota could stay in the mid to upper 60s should it rain most of the day. Ensembles then show a distinct cool down for the second half of the week, with highs mostly in the 60s Thursday through Saturday. Forecast lows tonight remain closer to summertime values of mid 50s to lower 60s, then gradually cool to around 45 to 50 for the second half of the week.
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.AVIATION /00Z TAFS THROUGH 00Z TUESDAY/... Issued at 723 PM CDT Sun Sep 14 2025
Widespread showers and thunderstorms will continue to move through much of the area, especially over central into eastern North Dakota. Some storms may be severe over the northern and eastern portions of the area through about 02Z, including the KJMS and KMOT terminal. Later tonight, showers with a few thunderstorms may linger across much of the area along with some lower clouds. Widespread MVFR conditions are expected, with some IFR conditions possible. These same conditions may then continue into Monday morning. Southerly winds will be found across the eastern half of the state tonight into Monday, with westerly winds in the west.
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.BIS WATCHES/WARNINGS/ADVISORIES... None.
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UPDATE...JJS DISCUSSION...JJS AVIATION...Anglin
NWS BIS Office Area Forecast Discussion