textproduct: Bismarck

KEY MESSAGES

- Warmer today, with highs in the mid 60s to mid 70s. A few isolated showers or thunderstorms could develop this afternoon and early evening.

- Well above normal temperatures through the first half of next week, with near-record highs around 90 to 95 Memorial Day and Tuesday.

DISCUSSION

Issued at 200 PM CDT Sat May 23 2026

Cyclonic flow is found over the northern Plains this afternoon as two upper level lows merge in the southern Canadian Prairies. While mainly dry conditions are expected across the forecast area, the southward displacement of one of these lows further south will provide enough lift to promote low chances for isolated showers and storms across portions of the north central into the northern James River Valley this afternoon. The chance for severe weather remains very low. Otherwise, a partly to mostly cloudy sky can be anticipated across the forecast area through this afternoon and evening. Highs are forecast from the mid to upper 60s in the James River Valley north, to the mid 70s in the far west. Lows tonight are generally expected to drop into the 40s. There is a very low chance (<10%) for another round of patchy fog tonight into Sunday morning as winds become very weak and become clear, though poor near surface saturation would likely limit overall coverage. An interrogation of BUFKIT model soundings indicates that the most likely area of development would be across the north central into the northern James River Valley, though even here overall coverage is expected to be limited to mainly low lying areas.

Warming and mainly dry weather is then expected Sunday through the middle of the coming week as the merging low is displaced eastward by a building ridge moves in across the Great Plains. There is a low chance for some isolated showers and thunderstorms Sunday afternoon and evening as flow becomes more zonal during the transition, mainly in the north central and north east. As the departing low begins to retrograde over Hudson Bay, and as an incoming Pacific Trough closes off into a low over the desert southwest, the ridge is expected to amplify late Monday through Wednesday, setting the northern Plains up into a modified blocking pattern through this period. Highs are expected to rise from mainly the 80s on Sunday into mainly the lower to mid 90s Monday and Tuesday, potentially record record breaking heat for this time of year. Highs are forecast to remain elevated, but a little cooler on Wednesday as lee cyclogenesis spits out a low into central Montana. Winds during this period are expected to develop as the surface gradient tightens ahead of this surface system, becoming strong out of the south southeast around 20 to 25 MPH gusting up to 40 MPH Tuesday and Wednesday afternoons.

As we head into late Wednesday and the later of the week, the ensemble advertises the aforementioned closed low in the desert southwest to being displacing the amplified ridge off to the east. With this, chances for showers across portions of the forecast area would be expected to increase through the end of the workweek. Cluster analysis still reveals two broad scenarios at this time, with the displacement of the ridge possibly limited by the retrograding Hudson Bay low to our northeast. The majority solution (approximately 70 percent of ensemble members) favors a stubborn Hudson Bay Low, and thus more robust ridging across much of North Dakota. With this, the chances for precpitation would be more limited to the western and far southern portions of the forecast area. A comparably wet minority cluster (approximately 30 percent of members), is much more aggressive with the eastward displacement of the ridge, allowing for precpitation across much of western and central North Dakota. In either scenario, overall precpitation accumulation is expected to be light, with a low chance to exceed 0.25" of rain through the end of the workweek.

Looking further ahead, long term models broadly advertise the blocking pattern fully breaking down through the weekend into early next week, with the general trend to place the northern Plains under southwesterly flow during this period. We could expected a return of near daily chances for precpitation across portions of the forecast area with this pattern, while the 25th to 75th percentile highs fall broadly in the mid 70s to mid 80s.

AVIATION /18Z TAFS THROUGH 18Z SUNDAY/

Issued at 200 PM CDT Sat May 23 2026

Mainly VFR ceilings and visibility is expected at all terminals throughout the 18Z TAF period. Low stratus continues to erode as it lifts up to the northeast early this afternoon, which may briefly induce high MVFR ceilings at KMOT and KJMS. Otherwise, mainly mid level clouds are expected through the remainder of the period. Clearing skies overnight and weakening winds may allow for patchy fog to develop across portions of western and central North Dakota overnight, though confidence in this development remains low. Light west northwest winds this afternoon will diminish this evening, becoming very light and variable, before reorganizing out of the south early tonight through Sunday morning.

BIS WATCHES/WARNINGS/ADVISORIES

None.