798 FXUS63 KBIS 171047 AFDBISArea Forecast Discussion National Weather Service Bismarck ND 547 AM CDT Wed Sep 17 2025
.KEY MESSAGES...
- Patchy fog across the north early this morning.
- Showers and isolated thunderstorms remain in the forecast through Friday. The highest chances are late tonight through Thursday where much of the forecast area has a 70 to 90 percent chances of showers and a few thunderstorms.
- Cooler, but still seasonable temperatures are on tap to finish out the second half of the week.
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.UPDATE... Issued at 547 AM CDT Wed Sep 17 2025
The main update early this morning is that showers and a few thunderstorms have developed over much of the southwest and parts of the south central over the past couple hours. Most thunderstorms so far have been confined to a low instability gradient from approximately Dickinson to Hazen to Washburn. As forecast, fog has developed over parts of northern ND, however, appears to remain very patchy in nature at this time.
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.DISCUSSION... Issued at 249 AM CDT Wed Sep 17 2025
A fairly well stacked low pressure system will continue to organize over the Central Plains today before gradually churning into the Northern Plains tonight through Thursday, and lingering through Friday. This will bring numerous showers and isolated thunderstorms to the state today through Friday. Currently, most showers and thunderstorms are still down in Nebraska and western Iowa. However, northern periphery showers off an associated surface trough are present in northwestern South Dakota. While this is delayed from model runs in prior days, these will gradually work into the state today with additional development also expected.
Through the duration of this system, instability is generally expected to be fairly minimal, except for in the areas along, south, and west of the Missouri River this afternoon. But even then, little shear is is progged. So while occasional thunderstorms are expected, especially in the southwest this afternoon, strong to severe storms are not anticipated. The highest chances for widespread showers, and maybe a few rumbles of thunder, is late tonight through the day Thursday, where most of the forecast area will see a 70 to 90 percent chance of precipitation. The lowest overall chances for precipitation during this event will be west near the ND/MT border.
Once this system clears out, mostly dry conditions are expected for this weekend through the middle of next week. That said, deterministic models are fairly consistent in bringing a trough through late this weekend or Monday morning. While the NBM currently keeps conditions dry throughout the CWA, wouldn`t be surprised if at least a few showers occur in the end. By the middle of next week, the pattern becomes less certain, though an incoming ridge seems favored despite some models maintaining a more zonal flow pattern.
With periodic precipitation chances and ample cloud cover, much cooler temperatures are expected today through Friday with highs mostly in the 60s to low 70s. Thursday will be the coolest day, however, with temperatures forecast to range from the upper 50s to upper 60s. A slight warming trend is then favored this weekend and into early next week with highs returning into the 70s to around 80. Lows will be mostly in the upper 40s to mid 50s through at least this weekend, which is seasonable for this time of year. As a final note, a little patchy fog has begun to develop in northern parts of the state early this morning and should dissipate by late morning.
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.AVIATION /12Z TAFS THROUGH 12Z THURSDAY/... Issued at 547 AM CDT Wed Sep 17 2025
Showers and thunderstorms have developed over much of southwestern and parts of south central ND over the past couple hours. This includes lightning that has been observed recently just north of KDIK, or rather, mainly along and north of I94. Shower and thunderstorm chances are going to persist across most of western and central ND through the day today, with impacts expected at KDIK and KBIS at times. Uncertainty remains higher at KXWA, KMOT, and KJMS until tonight. Along with shower and thunderstorm chances, MVFR/IFR ceilings are expected to progress over most of the state tonight. On a related note, patchy fog has also developed over parts of the north early this morning though should dissipate by mid to late morning. Overall, winds are expected to remain light, though breezy winds out of the northeast are possible tonight mainly for south central ND.
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.BIS WATCHES/WARNINGS/ADVISORIES... None.
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UPDATE...Telken DISCUSSION...Telken AVIATION...Telken
NWS BIS Office Area Forecast Discussion