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KEY MESSAGES

- Low chances for scattered light rain or freezing rain showers across central North Dakota this morning.

- Windy conditions expected Tuesday through Wednesday, with medium to high chances for light rain or snow.

- Except for western North Dakota on Tuesday, temperatures remain below normal through the work week.

DISCUSSION

Issued at 530 AM CDT Sun Apr 5 2026

A clipper system embedded in northwest flow aloft is passing through the Canadian prairie provinces early this morning. A southern extension of mid level differential cyclonic vorticity advection could provide enough forcing for light precipitation from central North Dakota to the James River Valley this morning, but there is uncertainty on whether there will be enough deep layer moisture to support precipitation. The past several runs of the HRRR and RAP have been very consistent with a completely dry vs. low QPF solution, respectively. Any precipitation that falls would likely be liquid on account of an above freezing layer from just above the surface inversion to around 1 km AGL. This would result in a conditional precipitation type of freezing rain at most locations, with surface temperatures broadly around 25 to 30. Given the aforementioned moisture uncertainty, we will continue to only advertise a 20 to 25 percent chance of light rain or freezing rain this morning, with very little no impacts anticipated.

A cold front attendant to the clipper will drop into the state from the northwest this morning, progressing southeastward through the day. Light precipitation is currently observed along the front from southeast Alberta through southern Saskatchewan, but while earlier CAMs did project this could extend into North Dakota, the cold front now appears more likely to outrun forcing aloft, keeping western North Dakota dry. The cold front is expected to bring gusty northwest winds across the state through this afternoon, strongest from north central North Dakota through the James River Valley where gusts could reach 35 mph. High temperatures this afternoon will be limited to the mid and upper 30s where a deeper snowpack remains, and 40s elsewhere. There is a low chance for a few afternoon and early evening rain or snow showers clipping the eastern fringes of our forecast area that would most likely produce only trace accumulations.

A strong surface ridge will begin extending into the region from the northwest tonight, setting up a baroclinic zone from central Montana to central South Dakota. Model guidance generally favors a narrow band of light snow developing along the baroclinic zone late tonight into Monday morning, but it is uncertain whether this would cut through southwest North Dakota. The northern most solutions of the current suite of guidance set the light snow up along the Highway 12 corridor. The rest of western and central North Dakota should see a quiet but chilly night with lows mostly in the teens to lower 20s. The upstream surface high pressure will slide into the Red River Valley on Monday, providing reinforcement for the unseasonably cold and dry air mass arriving later today. Forecast highs on Monday are limited to the mid and upper 20s over deeper snowpack (though there could be significant melting today) and only increase to around 40 along the Montana border. Monday night will remain chilly, with lows in the teens and 20s.

From Tuesday through Wednesday, a potent upper level shortwave/ closed low will dig into British Columbia and eject from the Northern Rockies into the Northern Plains. A preceding low- amplitude shortwave with strong isentropic ascent in the mid layers could bring a band of light snow across central and eastern North Dakota on Tuesday, with a short-duration at any given location yielding only a dusting of snow at most. By Tuesday afternoon, the surface pressure gradient will become squeezed by high pressure over the western Great Lakes and deepening low pressure over southern Alberta, resulting in southerly winds around 20 to 30 mph with gusts near 40 mph. Despite poor boundary layer mixing, the eastern fringes of the upstream thermal ridge could sneak into western North Dakota by late Tuesday afternoon, allowing temperatures to climb into the 50s, if not 60s. But elsewhere, it is more likely to be yet another cooler day of highs in the 30s and 40s.

The cold front and upper low are forecast to cross the region Tuesday night into Wednesday. Ensemble guidance is beginning to consolidate on a common solution, but there is still uncertainty in the latitudinal placement of the occluding low, with ECMWF members tending to favor a more northern solution along or just north of the Canadian border and the GEFS tending to favor a more southern solution directly through North Dakota. The northern solution would keep both chances for snow as a type and higher QPF of any type farther north. The southern solution would bring higher chances for snow farther south in the wrap- around deformation band on Wednesday. Both solutions would likely bring scattered rain showers and perhaps a thunderstorm or two across the state Tuesday evening and night, possibly mixing with or changing to snow on the back end, and with greater certainty would bring gusty northwest winds across the region through Wednesday. But the location of strongest winds and magnitude thereof would also be dependent on the aforementioned outcomes, with the southern solution favoring both stronger winds south and lighter winds north when compared to the northern solution. Despite the southern solution being both cooler and wetter, snow threshold probabilities are actually quite similar between the two outcomes, with only medium chances for exceeding 1 inch of snow in the Turtle Mountains area and low chances across the rest of northwest and north central North Dakota.

Ensembles are coming into better agreement on the synoptic pattern for the end of the work week, with a residual northwest flow over the Northern Plains on Thursday transitioning to more of a zonal flow on Friday as a cut-off low spins off the coast of California. This is trending the forecast toward a drier solution, with still well below normal temperatures favored on Thursday followed by the start of a warming trend on Friday. For next weekend, the big question is whether flow aloft will remain zonal or turn southwesterly. A warming trend is still favored in either case, with it just being a matter of near average vs. above. Both outcomes would still keep precipitation chances in the forecast over the weekend, but the southwest flow pattern would increase probabilities at higher QPF thresholds.

AVIATION /06Z TAFS THROUGH 06Z MONDAY/

Issued at 530 AM CDT Sun Apr 5 2026

Mostly VFR conditions early this morning, with patchy fog across southern North Dakota reducing visibility at times. A few light rain or freezing rain showers could develop in north central North Dakota early this morning ahead of a cold front moving down from Canada, and track southeastward through late morning. The arrival of the cold front will bring gusty northwest winds to all terminals and perhaps a period of MVFR ceilings. Confidence in the lower ceilings has decreased from previous forecasts, except in north central North Dakota. Northwest winds around 15-20 kts with gusts around 30 kts this afternoon will diminish and turn northerly in the evening.

BIS WATCHES/WARNINGS/ADVISORIES

None.