Weather Alerts For Evanston, IL

# HEADLINE -------------------- HEAT ADVISORY IN EFFECT FROM NOON TODAY TO 9 PM CDT THIS EVENING # DETAILS -------------------- WHAT Heat index values of 100 to 105 expected. WHERE Boone, De Kalb, Lee, Ogle, Winnebago, Central Cook, DuPage, Kane, Lake IL, McHenry, and Northern Cook Counties. WHEN From noon today to 9 PM CDT this evening. IMPACTS Hot temperatures and high humidity may cause heat illnesses. ISSUED AT Wednesday, September 2, 2026 at 12:55 AM CDT ISSUED BY National Weather Service Chicago IL HEADER URGENT - WEATHER MESSAGE # PRECAUTIONARY/PREPAREDNESS ACTIONS -------------------- Take extra precautions when outside or consider altering outdoor plans. Wear lightweight and loose fitting clothing. Try to limit strenuous activities to early morning or evening. Take action when you see symptoms of heat exhaustion and heat stroke. # AREAS AFFECTED -------------------- Northern Cook, Boone, Central Cook, De Kalb, DuPage, Kane, Lake IL, Lee, McHenry, Ogle, Winnebago Including the cities of Palatine, Oak Park, Elgin, Buffalo Grove, Wheaton, Aurora, DeKalb, Naperville, Rockford, Rochelle, Woodstock, Oak Lawn, Cicero, Schaumburg, Northbrook, Belvidere, McHenry, Algonquin, Downers Grove, Waukegan, Lombard, La Grange, Byron, Dixon, Carol Stream, Sycamore, Des Plaines, Chicago, Mundelein, Crystal Lake, Oregon, Gurnee, and Evanston

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 PORTIONS OF THE CENTRAL PLAINS AND MIDWEST AS WELL AS THE MID ATLANTIC SUMMARY Scattered strong to severe thunderstorms remain likely into tonight across parts of the northern/central Plains and Upper Midwest, and parts of southern New York into the Mid-Atlantic. Large hail and damaging winds should be the main threats. Southern NY/The Mid Atlantic A mid-level shortwave trough and enhanced west-northwesterly flow were observed from the Northeast/Mid Atlantic States to the lower Great Lakes this evening. A front was draped from northwest to southeast across southern NY/New England, with numerous showers and storms ongoing along and south of it this evening. The air mass here is unstable and moderately sheared which is supporting organized supercells and short linear segments. Damaging gusts remain likely through this evening, along with some hail and perhaps a brief tornado, especially near the from across southeastern PA and NJ where low-level sear is maximized. Convection should eventually begin to weaken with the loss of diurnal heating and as it approaches the coast later this evening. Central Plains and Midwest Several supercells have developed ahead of a weak surface low along a stalled front from NE into SD. A very unstable air mass (MLCAPE of 3000+ J/kg) is in place and extended downstream of the cluster across eastern SD, northern IA and southern MN. A belt of strong mid-level westerly flow along the front will continue to support organized storms. Upscale growth is possible this evening with one or more clusters or an MCS expected to eventually develop and track across portions of northern IA and far southern MN. This will pose a threat for severe wind gusts and perhaps a tornado along the front through tonight. Farther southwest along the surface lee trough, scattered high-based storms were ongoing in eastern CO and western KS. Buoyancy and shear are much weaker, but steep lapse rates and T/TD spread of 30-40 degrees could support a sporadic severe gusts with these storms before they weaken near sunset. Great Lakes A secondary mid-level vort max and upper low, currently over the western Great lakes, may serve as a focus for additional storm development tonight across eastern WI and lower MI. The eastern portions of the quasi stationary front remain very warm and unstable. As ascent from the upper low/shortwave approach after midnight, they may support a modest enhancement of the southwestern low-level jet. Warm advection at the nose of this feature could allow for a cluster of thunderstorms to develop and intensify. The large elevated buoyancy and 40-50 kt westerly flow would favor a risk for hail and damaging gusts before moving into southern ON by 12z Wed. However, confidence in how this scenario evolves remains low and only 5% wind/hail probabilities will be maintained given the uncertainty in storm development. Coastal Southeast Texas/Southwest Louisiana Tropical Storm Edouard will continue tracking northwestward across southeast TX and southwest LA per latest NHC forecasts. Some enhancement to the low-level wind field and hodographs has been noted in outer bands along the northern portions of the circulation. This may support transient updraft rotation with any cells. A brief tornado or two may occur across parts of coastal southeast TX/southwest LA through tonight as the system weakens.

Pollen Index: 11.1 Pollen Level: high Predominant Pollen: Ragweed, Chenopods and Nettle. Pollen concentrations for Wednesday will be rising and extend even further into the extremely high range. This rise is a result of higher temperatures and the lower dewpoint.