textproduct: Bismarck

KEY MESSAGES

- Cool today, with highs only in the 60s and lows tonight in the upper 30s to mid 40s.

- Below average temperatures favored to continue through next week.

- Mostly dry this weekend, then more frequent chances for showers and thunderstorms throughout the upcoming work week.

UPDATE

Issued at 923 AM CDT Sat Jun 13 2026

Broad area of light rain continues to settle through northern North Dakota. For morning update significantly increased rain chances and spread the chances further to the south through mid-day.

UPDATE Issued at 639 AM CDT Sat Jun 13 2026

The forecast remains in good shape. Some light rain is being observed just north of the border at Estevan, and MRMS radar imagery does indicate a broad swath of light rain preparing to cross into far northern North Dakota. Will leave forecast rain chances at 15 to 25 percent for now, as the probability of measurable precipitation remains low.

DISCUSSION

Issued at 333 AM CDT Sat Jun 13 2026

Early morning upper air analysis shows a closed low spinning over northern Ontario with an attendant trough extending westward through the Canadian prairie provinces. At the surface, a ridge axis extends from near Glacier National Park through southern North Dakota. Radar imagery suggests a west-to-east oriented band of persistent light rain just south of the ND/SD border, but unsure how much is actually reaching the ground given higher cloud bases. The Canadian upper trough will sag southward through the state today. There could be some light rain with its passage, but recent model guidance has backed off from this potential. A 15 to 25 percent chance of light rain was maintained across the north this morning into the afternoon, but measurable rainfall appears highly unlikely. The main story for today is how cool it will feel given the time of year. High temperatures this afternoon are only expected to reach the lower to mid 60s under a mostly cloudy sky and with northwest winds around 20 to 25 mph. The winds will taper off this evening, which combined with decreasing clouds should allow overnight temperatures to at least fall into the lower to mid 40s, with upper 30s likely in low-lying, sheltered areas across western North Dakota.

Flow aloft remains northwest on Sunday, but briefly becomes less active as a shortwave passes by to our south. But by late Sunday night, deterministic models show an increase in shortwave energy embedded in the northwest cyclonic flow, persisting through Monday. This will likely yield a period of isolated to scattered showers and thunderstorms, with peak coverage Monday afternoon. Forecast CAPE is only around 500 J/kg Monday afternoon, but there are mixed signals in deep layer shear, with 0-6 km values ranging from as low as 10 kts to as high as 50 kts. Severe weather is not expected, but a few stronger storms cannot be ruled out. High temperatures are forecast to bounce back into the 70s for most areas Sunday and Monday.

A potent shortwave is forecast to move from British Columbia on Tuesday into the Northern Plains and Upper Mississippi River Valley on Wednesday, all while deeper troughing persists from Hudson Bay to the Great Lakes. This shortwave has shown a southward trend over the past few model runs, but still looks to bring us the highest chances for precipitation next week. Tuesday could be a pleasant day prior to its arrival, with highs still mostly in the 70s and lighter winds. But there are still low chances for showers and thunderstorms in western North Dakota during the day Tuesday, and those chances increase and expand eastward Tuesday evening through Wednesday. With ensembles consolidating on the more southern track providing increased cloud cover and rain chances over the area, forecast highs on Wednesday are in turn trending cooler, now mostly around 65 to 70. This system also has potential to produce stronger winds, but the southward shift limits that potential to perhaps just southwest North Dakota.

High temperatures may be slower to recover with the mid week shortwave now favored to dig farther south. The NBM now keeps highs on Thursday in the mid 60s to lower 70s. While temperatures could begin to warm back closer to normal thereafter, there is still uncertainty on the persistence of the stalled upper low near Hudson Bay, with 3 out of 4 ensemble clusters showing a northwest flow pattern continuing over the Northern Plains through at least Friday. The NBM maintains medium rain chances on Thursday as the northwest flow aloft remains cyclonic and could feature a weaker trailing shortwave, with lower chances to close out next week.

AVIATION /12Z TAFS THROUGH 12Z SUNDAY/

Issued at 639 AM CDT Sat Jun 13 2026

MVFR ceilings are expected in parts of north central and eastern North Dakota this morning, but the probability of them reaching KMOT or KJMS remains low. VFR conditions are otherwise anticipated across western and central North Dakota through the forecast period. A few light rain showers are possible across the northern half of the state this morning into the early afternoon, with no expected impacts to aviation. Winds will become northwest and increase to 15- 20 kts with gusts to 25-30 kts by this afternoon, then diminish back to 5-10 kts this evening.

BIS WATCHES/WARNINGS/ADVISORIES

None.