Severe Storm Risk - Granite City, IL

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 A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF THE SOUTHERN AND CENTRAL PLAINS INTO THE LOWER MISSOURI VALLEY SUMMARY Scattered severe storms capable of large hail and severe gusts are expected this evening into tonight over parts of the central and southern Plains into the Lower Missouri Valley. Isolated large hail may also occur in the southern Great Lakes. Southern and Central Plains The latest water vapor imagery shows an anticyclonic flow pattern in place over the eastern two-thirds of the nation, with southwesterly mid-level flow from the Desert Southwest into the southern and central Plains. At the surface, a cold front is located from near the Oklahoma Panhandle northeastward into north-central Missouri. A 1007 mb low is analyzed over the northeastern Texas Panhandle. Low-convergence is maximized along the front over the central Plains, where scattered thunderstorms are ongoing. The convergence axis extends southward into the Low Rolling Plains of northwest Texas, where a cluster of storms is also ongoing. Ahead of the convergence axis, surface dewpoints are in upper 60s and lower 70s F over much of the southern and central Plains, which is contributing to moderate instability, with the RAP estimating MLCAPE mostly in the 2000 to 2500 J/kg range. In addition to the instability,the WSR-88D VWP at Wichita, KS has 0-6 km shear near 35 knots with 40 to 45 knots of southwesterly flow in the mid-levels. Some directional shear is present in the boundary layer. This environment will support a threat for supercells with cells that remain discrete. Supercells will be capable of large hail, severe wind gusts and perhaps a tornado or two. Severe wind gusts are expected to become the primary severe threat as the primary mode becomes linear, later this evening. Further south into western Oklahoma and northwest Texas, the latest WSR-88D VWP at Frederick has about 35 knots of 0-6 km shear. The RAP also has steep mid-level lapse rates in the 7 to 7.5 C/km range. This should support supercells with a potential for large hail and severe wind gusts. Southern Great Lakes A minor shortwave trough appears to be moving into the western Great Lakes early this evening. Ahead of this feature, thunderstorms have developed over far southern Wisconsin. The storms will track east-southeastward into the southern Great Lakes this evening into the overnight. The RAP currently shows an axis of instability analyzed from western Illinois northeastward into the southwestern Great Lakes. Along and near this axis, RAP forecast soundings late this evening have MUCAPE around 1500 J/kg with effective shear near 40 knots. This may be enough for an isolated large hail threat, with the stronger elevated storms.