Severe Storm Risk - Savanna, 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 FROM THE SOUTHERN GREAT LAKES INTO THE MID-ATLANTIC STATES SUMMARY A couple of organized thunderstorm clusters are expected to develop across the southern Great Lakes and mid/upper Ohio Valley through tonight, accompanied by the risk for damaging wind gusts. More widely scattered strong thunderstorms east of the Blue Ridge may also produce damaging wind gusts this evening. 20Z Update The northern portion of the Marginal Risk was expanded westward into portions of northeastern Iowa to account for recent convective development associated with a mid-level perturbation visible on water vapor satellite imagery. An unstable airmass and modest deep-layer shear will support loosely organized convection, capable of producing isolated occurrences of 60 MPH winds and 1-inch hail. Elsewhere, the western portion of the Slight Risk area was expanded across Illinois, Indiana, and portions of Ohio, where thunderstorms have developed along a surface boundary and may pose an increased threat for 55-70 MPH wind gusts and 1-inch hail. See MCDs #2234 and #2235 for more detail. Further downstream across North Carolina, the severe wind probabilities were extended southward to account for recent convective trends. A corridor of higher wind probabilities was considered across portions of Virginia, but uncertainty in the longevity of the convection moving across the Appalachians and overall convective organization precluded adding additional highlights at this time. The 30% wind threat area is expected to see convective development later this evening, as storms move from the Great Lakes into the region. There is some uncertainty in the northward extent of the area owing to the drop off in buoyancy, but continued spread in the high-resolution forecast guidance regarding the timing and placement of convection precludes additional adjustments at this time. Convection is also anticipated to develop across portions of north-central Nebraska into South Dakota during the early morning hours. These storms could produce isolated occurrences of hail, though uncertainty in the timing of convective initiation and maturation suggests this will primarily pose a threat in the Day 2 time frame.