Bismarck (BIS) — the National Weather Service forecast in plain English · Plaincast

Messages

High rain chances (~70 to 100 percent) Sunday night into Monday.

Update

Cold front continues to settle through the area, and has now passed just to the south of Bismarck. This will continue through the morning, with northerly winds continuing to increase in its wake. Going forecast continues to be in good shape.

Discussion

Current surface analysis places low over northern Manitoba and Saskatchewan with secondary low over western South Dakota. Cold front continues to drop through northwest into north central North Dakota. Upper level analysis places broad ridge over the Midwest, with trough over the northwestern CONUS resulting in west/southwest flow over our area, though a few short waves swinging around low along the northern Manitoba/Saskatchewan border continue to be noted in the flow.

For today, cold front will continue to drop through the area with winds becoming northerly and breezy in its wake. In addition, notably cooler air will move in behind the front. High temperatures over our area will range from the mid 60s over northwestern North Dakota to the 80s over the southern James River Valley. A broad short wave swinging around the upper low to the north pushes into our area, which may result in some modest afternoon showers. Chances settle towards the south towards evening.

On Saturday, surface high pushes towards the area, with notably cooler temperatures (highs about 10-15 degrees below average). A short wave moving through overnight may result in some rain showers over southern parts of the area. In the meantime, a compact surface low pushes onshore over the Pacific Northwest.

On Sunday, modest ridging develops to the west ahead of the aforementioned low, quickly passing over the area as the upper low slides over the Rockies and a lee slide surface low develops. System then pushes east-northeast over the Northern Plains and Canadian Prairies, bringing widespread high rain chances (~70-100 percent) to our area Sunday night into Monday. Latest the blend-of-models forecast guidance shows a 50 percent or great chance of seeing a half inch of precipitation along and north/east of the Missouri River, with a 70 percent or greater over north central North Dakota.

System then exits the area late Monday with drier westerly flow for Tuesday. Thereafter, guidance is having trouble with some key features, but overall the pattern suggest occasional modest precipitation chances. As for temperatures, the blend-of-models forecast continues to express low confidence given the notable spread in possible highs/lows.