Severe Storm Risk - Marine on Saint Croix, MN

There is a Slight Severe Storm Risk for your location. Continue reading for today's outlook from the National Weather Service's Storm Prediction Center. -------------------- National Severe Storm Outlook THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS SOUTHERN MINNESOTA...FAR NORTHERN IOWA...AND PARTS OF WISCONSIN THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE SOUTHERN PLAINS SUMMARY Severe thunderstorms are likely across the Upper Mississippi Valley and Great Lakes region with potential for large to very large hail, damaging wind, and tornadoes, mainly late this afternoon into tonight. A more isolated risk for severe storms is possible across portions of the southern Plains late this afternoon and evening. Upper Mississippi Valley/Great Lakes including MN/WI/IA Multiple lead mid-level disturbances over the northern High Plains will progress northeastward today toward the Upper Midwest, with strengthening winds aloft across this region particularly late today and tonight. A surface low will tend to deepen/develop east-northeastward from northeast Nebraska into far southern Minnesota and Wisconsin by tonight in vicinity of a slow-moving/stalled frontal boundary. Low/middle 60s F surface dewpoints will advect north-northeastward and become increasingly prevalent along/south of the aforementioned stationary/warm front this afternoon. MLCAPE values are forecast to reach 2000-2500 J/kg by around 21z/4pm CDT. Thunderstorm development will become increasingly probable through mid/late afternoon (21-00z) as isentropic ascent strengthens ahead of the approaching upper disturbance. This should especially be the case near the primary boundary. However, semi-discrete warm sector supercellular development, across areas such as southern Wisconsin, cannot be ruled out. Lingering inhibition coupled with 45-50 kt effective bulk shear should promote initially discrete supercells. Hodograph elongation appears favorable for a large hail threat, possibly as large as 2-3 inches in diameter with the more robust cells. Additionally, enhanced low-level SRH along the frontal zone is expected to result in a corridor of relatively higher tornado potential for storms that can remain rooted immediately along the boundary. While the overall environment appears very favorable for intense convection/supercells, east-northeasterly storm motions along or just north of the warm front will likely promote clustering/upscale growth through the evening, with an increasing damaging wind potential and a continued tornado risk via line-embedded circulations. Northern Illinois/northern Indiana and southern Lake Michigan See Mesoscale Discussion 395 for short-term details. There is the potential that a somewhat separate corridor of severe-weather potential today, potentially via a subtle mid-level wave and morning convection across northeast Missouri/northwest Illinois vicinity and/or additional development later today. The initially elevated storms are on the edge of the east/northeastward-advecting elevated mixed layer. Steep mid-level lapse rates and 35+ kt effective shear could support initially isolated hail potential, but a more organized surface-based severe risk could materialize later this afternoon, although the specific details remain uncertain. Southern Plains including Oklahoma/Texas Confidence/potential for isolated to widely scattered locally intense storms later this afternoon has incrementally increased, although specifics regarding the extent of convective initiation are still uncertain. A moist and potentially unstable air mass will persist regionally to the east of a dryline located around peak heating from east-central Kansas south-southwestward into west-central Oklahoma and western north Texas to the Texas Big Bend vicinity. Immediately east of the dryline, warm-sector dewpoints are expected to generally be in the middle 60s F, supporting MLCAPE values to 2500-3000 J/kg. A subtle disturbance over northern Mexico and the southern Rockies could approach the dryline/warm sector later today. Regardless, ample post-dryline mixing and near-dryline confluence/weak convergence should be sufficient for isolated deep convective initiation after 21z/4pm CDT. Forecast mass fields and some short-term guidance would imply that this is most probable across central/southwest Oklahoma into the north Texas Big Country, and perhaps somewhat separately across the Texas Big Bend and Rio Grande vicinity. If/where storms develop and mature, deep-layer shear on the order of 40+ kt will support supercells, potentially capable of all hazards including very large hail. Northern High Plains Generally isolated severe storms including a few low-topped supercells capable of hail/wind are possible late this afternoon into evening along/north of the surface front. This is where modest low-level moisture and vertical shear will be maximized, in the presence of steep low/mid-level lapse rates.