Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
572 ACUS02 KWNS 190536 SWODY2 SPC AC 190534 Day 2 Convective Outlook NWS Storm Prediction Center Norman OK 1234 AM CDT Sun Jul 19 2026 Valid 201200Z - 211200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS FAR SOUTHEAST MN...NORTHEAST IA...NORTHERN IL...WI...AND THE UPPER PENINSULA OF MICHIGAN... ...SUMMARY... Severe thunderstorms are probable across portions of the Upper Midwest and Great Lakes vicinity on Monday. Swaths of damaging winds will be the most likely hazard, with isolated large hail as well. Isolated strong to damaging gusts may occur over parts of the Carolinas. ...Upper Midwest/Great Lakes... An upper shortwave trough initially over the northern Plains early Monday will strengthen as it progresses east/southeast over the Upper Midwest/Great Lakes. As this occurs, mid/upper west/northwesterly flow will intensify, with most guidance showing 50-60 kt at 500 mb, and 850-700 mb potentially increasing to 40+ kt. At the surface, low pressure will deepen as it shifts east across Ontario and the northern Great Lakes. A trailing cold front will sweep east/southeast during the afternoon and evening, becoming positioned from northern Lower MI to northern MO by Tuesday morning. Ahead of the front, a very moist airmass characterized by 70s dewpoints will be in place. This moisture will modestly decrease east of Lake MI. Within the moist axis, strong to extreme instability is forecast (particularly from IA into WI). Some uncertainty remains concerning placement and extent of potential ongoing convection early Monday, and will depend on evolution of storms overnight in the Day 1/Sunday period, and the timing of a possible lead shortwave impulse. Morning convection could have implications for where corridors of greater severe potential will develop during the afternoon/evening. Nevertheless, the region will experience strong warm advection ahead of the cold front, and airmass recovery is likely. Supercell wind profiles are evident in forecast soundings. A favorable thermodynamic/kinematic environment could support initial supercells capable of all severe hazards, and possibly significant severe. However, given the progressive nature of the upper trough and surface cold front, along with intensifying 850 mb flow by late afternoon/evening, upscale growth into one or more bowing MCSs appears possible. Significant damaging wind potential will increase with a transition to linear storm mode. The south and east extent of severe potential is also uncertain, but if a mature MCS develops during the evening, it seems reasonable the severe wind risk could persist into portions of Lower MI, northern IN and northwest OH overnight. ...North Carolina vicinity... Weak northwest flow aloft will persist across the Mid-Atlantic on Monday. Modest lee troughing across the Piedmont will allow a surface front to lift north across part of NC into VA, and spreading rich boundary layer moisture across the region. Strong heating will result in moderate destabilization and scattered thunderstorms will develop during the afternoon. Deep-layer flow will remain modest, but sufficient clustering, high PW values, and steep low-level lapse rates will support isolated damaging wind potential. ..Leitman.. 07/19/2026 $$