Weather Alerts For Lake Forest, 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 CENTRAL PLAINS AND LOWER MISSOURI VALLEY SUMMARY Thunderstorms with severe wind gusts and hail will be possible this evening from parts of the central Plains into the lower Missouri Valley. Isolated severe gusts and hail will also be possible in parts of the central and northern High Plains, and from the Midwest into the Great Lakes. Central Plains/Lower Missouri Valley The latest water vapor imagery shows west-northwesterly mid-level flow over the central U.S. with a shortwave trough embedded in the flow over western Kansas. At the surface, a moist airmass is located from the mid Mississippi Valley westward into the central Plains, where surface dewpoints are mostly from the upper 60s and lower 70s F. Low-level convergence is maximized along and near a well-defined outflow boundary located across central Kansas. Isolated severe thunderstorms are ongoing near this boundary. In this area, moderate deep-layer shear and steep low to mid-level lapse rates will be favorable for isolated large hail and severe wind gusts over the next few hours. Further to the north across northern Kansas and southern Nebraska, the RAP has strong instability analyzed with MLCAPE in the 3000 to 3500 J/kg range. Thunderstorms are currently ongoing in western Nebraska and northeastern Colorado. These storms will move toward the stronger instability over the next few hours. As this happens, the storms may increase in intensity. If this were to occur, the strong instability and moderate deep-layer shear over northwest Kansas and southwest Nebraska would support a threat for hail and isolated severe wind gusts. A second severe threat area is expected to become active further east from northeast Kansas into west-central Missouri as low-level flow increases this evening. Thunderstorms are now developing in north-central Kansas and this convection should expand in coverage over the next couple of hours. The primary threat would be wind damage, especially if a short intense line segment can become organized. Along its path, severe wind gusts could exceed 70 mph...see MCD 2031. Midwest/Great Lakes The latest water vapor imagery shows a distinct shortwave trough over the mid Mississippi Valley within west-northwesterly flow aloft. At the surface, a moist airmass is located from the mid Missouri Valley east-northeastward into the lower Michigan, where surface dewpoints are mostly in the upper 60s and lower 70s F. An axis of low-level convergence is located from northern Iowa into far southern Wisconsin, along which thunderstorms are ongoing. A couple of cells have remained discrete across northwestern Iowa, where an axis of moderate instability is analyzed. As these cells move southeastward into north-central Iowa this evening, isolated large hail and a few severe wind gusts will be possible. Further east, the storms have organized into a line segment over far southern Wisconsin. These storms will have an isolated wind-damage threat over the next couple of hours. A marginal severe threat may also continue over parts of lower Michigan early this evening. Central and Northern High Plains West-northwesterly mid-level flow is currently located across the northern Rockies and northern High Plains, with a distinct shortwave trough moving through Montana. At the surface, an axis of low-level moisture is present from eastern Wyoming into eastern Montana, along which surface dewpoints are near 60 F. This is contributing to MLCAPE around 1000 J/kg along parts of the moist axis. Isolated strong to severe storms are ongoing near the moist axis in far northeast Wyoming and in northeast Montana. Moderate deep-layer shear and steep low to mid-level lapse rates will support a potential for isolated severe gusts and hail this evening.

Pollen Index: 9.8 Pollen Level: high Predominant Pollen: Ragweed, Nettle and Chenopods. The quantity of pollen grains in the air for Wednesday will be falling in the moderate range. This lowering of pollen concentrations is a result of falling temperatures, rising humidity, and expected precipitation in the morning and evening which tends to wash pollen out of the air. Relief is in sight.