Severe Storm Risk - Jim Falls, WI

There is a Marginal 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 IOWA THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE UPPER MIDWEST AND CENTRAL/SOUTHERN PLAINS SUMMARY Severe thunderstorms capable of producing severe/damaging winds and large to very large hail are likely late this afternoon and evening centered across much of Iowa. Isolated to scattered severe hail and damaging winds are possible over a broader area from parts of the southern High Plains to the Upper Midwest. Central Plains into the Upper Midwest including Iowa A cyclonically influenced moderately strong belt of westerlies will exist over the northern Plains to Upper Midwest and upper Great Lakes. The primary surface low will remain in northern Ontario, with a trailing cold front extending southward into the Upper Midwest and northern/central Plains. A secondary surface low will exist across southwest Kansas and northwest Oklahoma around peak afternoon heating, with a dryline extending south-southwestward from this low across much of the southern High Plains. Continued expectations are for robust thunderstorm development along the cold front/surface trough from eastern Nebraska into Iowa to be delayed until late afternoon or early evening (around 22-00Z), as large-scale ascent will remain weak until a low-amplitude shortwave trough embedded within the westerly mid-level flow eventually overspreads the surface warm sector. Continued low-level warm/moist advection through the day and diurnal heating will contribute to the development of moderate to locally strong instability (2500+ J/kg MLCAPE) across this region by early evening. While low-level winds are forecast to remain fairly modest, enhanced mid/upper-level flow will support sufficient (35-50 kt) deep-layer shear for updraft organization. Initial supercells should pose a threat for large to isolated very large hail (2+ inches in diameter), before likely quick upscale growth this evening across Iowa with an increasing potential for scattered severe/damaging winds. Some of these gusts could exceed 75 mph on a localized basis given the expectation for an organized cluster and ample instability. A tornado or two could also occur this evening as low-level shear gradually increases with a strengthening low-level jet. Southern High Plains While clouds linger at midday, particularly with southward extent across west/southwest Texas, robust daytime heating will yield a very well-mixed/deep boundary layer near/south of the secondary surface low over southwest Kansas/northwest Oklahoma. Mid-level temperatures will remain cool enough to support at least weak instability, even with modest low-level moisture/surface dewpoints. A weak mid-level shortwave trough moving from the southern Rockies into the southern High Plains will enhance large-scale ascent late in the day. This should support the development of high-based thunderstorms, with occasional strong to severe wind gusts expected. Latest short-term guidance suggests a more probable zone of thunderstorm-related gust potential may focus across the Texas South Plains and Low Rolling Plains. Isolated gusts of 70+ mph may occur given the very deeply mixed boundary layer extending up to around 500 mb. Cells that develop in west/southwest Texas may also contain some hail, with elongated hodographs in mid/upper levels.