Severe Storm Risk - Neponset, IL

There is a Enhanced 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 FROM PORTIONS OF THE UPPER MIDWEST/UPPER GREAT LAKES INTO THE OHIO VALLEY THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PORTIONS OF SOUTHWEST SOUTH DAKOTA...WESTERN NEBRASKA...NORTHEAST COLORADO...AND FAR NORTHWEST KANSAS SUMMARY Severe storms capable of strong to severe wind gusts and large hail are possible across the Great Lakes into the Ohio Valley Monday into Monday night. More sporadic occurrences of damaging wind appear possible in the Mid-Atlantic, Tennessee Valley, central High Plains, and southeast Arizona. Upper Midwest/Great Lakes into the OH/TN Valleys A very moist airmass is in place from the Upper Midwest into the OH and TN Valley. This airmass is exists south of a diffuse cold front that extends from a surface low over far southeast Manitoba southeastward to far eastern Upper MI. One thunderstorm is currently ongoing near this boundary over eastern Upper MI. Most of the thunderstorms are ongoing just northeast another surface boundary demarcating the very moist (i.e. 70+ dewpoints) to it southwest. How this warm-air advection activity evolves early this morning will have a large impact on the severe potential farther downstream from the Mid MS Valley into the OH and TN Valleys through the late morning into the afternoon and evening. Much of the guidance is beginning to suggest the warm-air advection activity clusters early this morning over the MN Arrowhead vicinity before then tracking southeastward within the moisture/buoyancy gradient and organizing/intensifying significantly. Synoptically, the overall setup matches many characteristics of scenarios with strong, forward-propagating MCSs, including a surface boundary parallel to the deep-layer shear, at least modest mid-level warm advection, and very strong to extreme buoyancy. Given the trend within the guidance and favorable synoptics, confidence in the development of a strong forward-propagating MCS is high enough to adjust the 30% wind probabilities westward while also introducing a CIG1 area. There is a chance that both higher wind probabilities and a CIG2 may be needed, but predictability regarding convective evolution is too low at this time. Central High Plains into western/central NE and SD Moist, post-frontal surface flow is expected across much of NE and SD, shifting from northerly early in the day to more easterly by the afternoon. Dewpoints will initially be in the mid to upper 70s, although strong boundary-layer mixing will likely result in dewpoints ranging from the upper 50s/low 60s across the NE Panhandle to the low 70s across eastern NE. This reservoir of low-level moisture coupled with strong heating and steep mid-level lapse rates will result in a corridor of moderate to extreme buoyancy from eastern WY/northeast CO/southwest SD eastward across south-central SD and much of NE. Most of the guidance indicates a subtle, convectively augmented vorticity maximum will progress eastward through the northern periphery of the Four Corner upper ridge. This should contribute to thunderstorm development across the high terrain, which would then progress downstream into a more moist and unstable airmass. One or more clusters could evolve, but the overall predictability of the convective evolution is low. That being said, environmental conditions support the potential for strong to severe gusts, including the potential for some over 75 mph. Eastern extent of the wind threat will likely be limited by building convective inhibition associated with nocturnal cool, unless a more coherent and organized MCS were to evolve. If that occurs, the wind threat could extend farther east into more of eastern NE and north-central KS, and 5% wind probabilities were expanded eastward/southeastward to account for this potential. Depending on the strength of the MCS, the wind threat could extend eastward into more of OH and PA, and also farther southward into more of TN, during the late afternoon/evening. Mid-Atlantic States Some wind threat could exist during the afternoon/evening across the Mid-Atlantic, where marginal buoyancy and deep-layer shear could support a few stronger updrafts. Southeast Arizona Isolated severe gusts are possible over southeast AZ as mid-level moisture and daytime heating leads to scattered storms over the higher terrain, particularly far southeast AZ. Cells are expected to move westward into warmer temperatures and deeper boundary-layer mixing, with PWAT over 1.25" and steep low-level lapse rates supporting strong outflows.