Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
780 ACUS48 KWNS 240854 SWOD48 SPC AC 240852 Day 4-8 Convective Outlook NWS Storm Prediction Center Norman OK 0352 AM CDT Mon Jun 24 2024 Valid 271200Z - 021200Z ...DISCUSSION... ...D4/Thursday: Northern High Plains... A rather amplified mid/upper-level shortwave trough is forecast to move from the Northwest toward the northern Rockies on Thursday, reaching the northern High Plains later Thursday night. A surface low is forecast to deepen across eastern MT during the day, and then move eastward across the Dakotas Thursday night. Some uncertainty remains regarding the magnitude and placement of organized severe-thunderstorm potential, due to the relatively late shortwave arrival and a tendency for stronger mid/upper-level flow to be displaced from the warm sector. However, modest low-level moisture return will support potential for moderate destabilization, in conjunction with some increase in deep-layer flow/shear. Some potential for strong to severe storms is evident from eastern MT into the western and possibly central Dakotas, and probabilities will likely be needed in subsequent outlooks. ...D5/Friday: Northern/central Plains into the upper Midwest... The shortwave trough and related surface low that affect the northern High Plains on Thursday will move eastward on Friday, as a trailing cold front moves across parts of the central Plains. A warm front will move northward in advance of the surface low across parts of MN/WI. Details regarding the northward extent of stronger destabilization remain uncertain, with some potential for rather extensive early-day convection within a warm-advection regime. However, an organized severe-thunderstorm threat could eventually evolve in conjunction with the surface low and warm front across MN/WI, and also potentially along the cold front into parts of Iowa and the central Plains. ...D6/Saturday - D8/Monday... Predictability begins to wane by D6/Saturday regarding evolution of the upper pattern and surface features across the CONUS. The cold front that moves across parts of the Great Plains and Midwest on Friday is generally forecast to move across parts of the Great Lakes and Northeast on Saturday. Guidance varies regarding the extent of prefrontal destabilization and strength of deep-layer flow, but strong to potentially severe storms could develop along the front by Saturday afternoon/evening. Another mid/upper-level trough may move from the Northwest across the northern Rockies and High Plains Sunday into Monday, though considerable uncertainty remains regarding the amplitude/timing of this trough and any related severe potential into early next week. ..Dean.. 06/24/2024