Messages

Isolated isolated to scattered severe thunderstorms will be possible over western and south central North Dakota this afternoon and evening. Potential hazards include hail up to the size of ping pong balls, damaging winds up to 70 mph, and torrential downpours.

Isolated severe thunderstorms possible Monday afternoon and evening primarily over central and eastern North Dakota. Potential hazards include large hail up to 2 inches in diameter and damaging winds up to 70 mph, but still some question if thunderstorms can develop.

Near-critical fire weather conditions expected over parts of western North Dakota on Monday, and the far southwest on Tuesday.

Discussion

Current surface analysis places trough stretching from western Saskatchewan through eastern Montana/Wyoming, with high over the midwest. Upper level analysis places high over New Mexico, with ridge stretching northward to the lee of the Rockies into the Plains. Over our area, low level moisture continues to be on the increase with south-southeasterly low level flow between the two aforementioned surface features. A line of showers with a few embedded thunderstorms continues to slide through western North Dakota affiliated with a short wave trough noted in the flow.

For the rest of this afternoon into this evening, a tricky forecast is on tap as some variables remain in play. It has been well advertised that with the returning moisture we will have an unstable atmosphere in place, particularly over southwest into south central North Dakota where storm energy values are already in excess of 2000 J/Kg at this time over a broad part of the area, and that plenty of deep layer shear in in place (40-50 knots 0-6km) to support rotating updrafts. With that said, the flies in the ointment continue to be rather modest forcing, along with forecast soundings showing a cap that may be difficult to overcome. Latest short term guidance continues to show a variety of solutions ranging from some light showers/a few weak storms to a variety of severe over the southwest and south central, possible nudging northward. So, the severe threat will remain conditional, but if a storm or storms were able to get going in earnest, large hail and damaging wind gusts remain a concern given the aforementioned shear/instability. A secondary wave pushes in from Montana later tonight, which may lead to some additional elevated storms, which would move through overnight.

On Monday, surface trough to the west pushes over western North Dakota in the morning, into central North Dakota before stalling mid-day. Behind the trough, drier air will move in with breezy conditions developing, which will lead to some near-critical fire weather conditions over the far west. Ahead of the trough, moist air remains in place. storm energy values will again be elevated over this area, along with similar deep layer shear as today. Again, though, the threat remains conditional as to whether enough forcing will be in place in order for storms to develop.

On Tuesday, quiet weather is expected as the ridge axis re- focuses over the Rockies, though a compact low/short wave will zip through southern Saskatchewan/Manitoba which may lead to a few showers or possibly a thunderstorm around the Turtle Mountains region. Northwest winds will be on the increase as the surface low with this system moves east through Manitoba into Ontario. Upper ridge gradually meanders east resulting in quiet weather for us through Thursday before a few weak waves move through the ridge, bringing some low precipitation chances to end the week.