Severe Storm Outlook Narrative (AC)
Issued by NWS
Issued by NWS
858 ACUS03 KWNS 220727 SWODY3 SPC AC 220726 Day 3 Convective Outlook NWS Storm Prediction Center Norman OK 0226 AM CDT Sat Jun 22 2024 Valid 241200Z - 251200Z ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS FOR PARTS OF MN...NORTHWEST WI...WESTERN UPPER MI... ...SUMMARY... Severe thunderstorms are possible on Monday across parts of the northern Great Plains into the upper Mississippi Valley and Great Lakes. ...Northern Great Plains into the upper MS Valley/Great Lakes... Uncertainty remains rather high regarding storm potential on Monday from the northern Great Plains into the upper MS Valley and Great Lakes. However, with some conditional significant-severe potential within a favorable environment, a Slight Risk has been added for parts of MN into northwest WI and western upper MI, where confidence is currently highest in isolated to widely scattered storm coverage. A mid/upper-level shortwave trough and related surface low are forecast to move eastward across parts of SK/MB on Monday. A secondary surface low is forecast to develop along a trailing surface trough/weak cold front across the Dakotas. A surface boundary initially draped roughly from the Ohio Valley northwestward through parts of IA and southeast SD is forecast to move northward as a warm front, potentially reaching parts of central MN and eastern ND by Monday evening. Storm development/evolution across the region remains unclear, with the stronger large-scale ascent expected to remain north of the international border. However, strong to locally extreme instability is expected to develop along/east of the surface trough across the Dakotas, and along and to the south/west of the northward moving warm front. While the warm sector may remain capped for much of the day, at least isolated storm development will be possible near the warm front, and also potentially near the surface trough/cold front. Elevated convection may also develop to the cool side of the warm front, especially during the evening when some intensification of a southwesterly low-level jet is expected. Deep-layer shear will be sufficient for organized convection. Any surface-based supercell development could pose a conditional risk of all severe hazards, including some potential for significant hail and/or wind given the very favorable thermodynamic environment. Depending on the evolution of initial storm development, an MCS could develop and move southeastward along the instability gradient, though this scenario remains rather uncertain at this time. ...Coastal Carolinas... Some guidance suggests a southeastward-moving cold front will slow down or stall across eastern NC/SC, resulting in the potential for scattered thunderstorm development during the afternoon, within a moderately unstable environment. Should this occur, modest northwesterly flow aloft could support sufficient storm organization for an isolated damaging wind and hail threat. This scenario remains uncertain, but severe probabilities may eventually be needed if confidence increases. ..Dean.. 06/22/2024 $$