Day 4-8 Convective Outlook

Issued:  ·  Valid: –

Summary

Organized severe thunderstorms may develop across parts of eastern Montana and the Dakotas next Tuesday or Wednesday. An increasing risk for thunderstorms with potential damaging wind gusts may also affect the lower Great Lakes through New England by next Thursday or Friday.

Product Text

000 ACUS48 KWNS 030904 SWOD48 SPC AC 030902 Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0402 AM CDT Fri Jul 03 2026 Valid 061200Z - 111200Z ...DISCUSSION... Medium-range guidance suggests that a modest mid-level ridge, along an axis from the eastern Great Basin into the Upper Midwest by early next week, may gradually become suppressed by a low-amplitude short wave trough emerging from the Great Basin by the middle of next week. It appears that this will occur as a much more substantive trough and embedded low, within the stronger westerlies confined to the higher latitudes, progress inland across British Columbia and the Canadian Rockies. This could be accompanied by some potential for organized severe thunderstorm development across parts of eastern Montana into the Dakotas by next Tuesday and/or Wednesday, but enough spread persists within latest model output to preclude 15 percent or greater severe probabilities at this time. A preceding trough within the stronger westerlies is forecast to slowly progress east of the Canadian Prairies through Hudson Bay, Ontario, Quebec and the remainder of the eastern Canadian Provinces by late next week. It is possible that a corridor of boundary-layer moistening and destabilization ahead of an associated cold front could support increasing risk for thunderstorms across parts of the lower Great Lakes through New England by next Thursday into Friday. However, the extent of this potential, and the degree to which it could pose a risk for damaging wind gusts remains uncertain at this time. Otherwise, severe potential in lower-latitudes, if any, will likely generally be associated with sub-synoptic developments yet to evolve and of rather low predictability at this time range. ..Kerr.. 07/03/2026