Peoria, Ill (WMBD) – A very warm and humid air mass will bring very hot and humid conditions to Central Illinois this weekend with the worst heat arriving Saturday. A cold front and pre-frontal trough could bring a few strong storms to the region Saturday evening.
- Heat index values of 100-105° Saturday afternoon
- Severe storms possible Saturday evening
- Moderate confidence forecast
- Scattered storm coverage (Not everyone will see storms)
- Main window for severe weather: 6 pm to midnight
Temperatures will climb into the lower to mid 90s Saturday afternoon as a sprawling ridge of high pressure sits across the Central Plains. With dew points in the mid 70s heat index values will soar into the triple digits making it the hottest weather we’ve seen this year.
While Central Illinois is certainly no stranger to high heat, it can still prove to be dangerous to those spending time outdoors. When there’s a lot of moisture in the air (dew points in the low-mid 70s), sweat does not evaporate as quickly which makes it difficult for the body to cool off. This could cause heat related illness and heat exhaustion. If you must be outside remember to drink plenty of water and find shade or AC when you can.
Also, remember to never leave kids or pets in a locked vehicle. When the outside air temperature is at 90° the temperature inside the car can climb to 119° in as little as 20 minutes, and that’s not including the heat index.
Strong Storm Potential
With the exception of some spotty showers & storms most of the day will be dry. Scattered thunderstorms are expected to develop this evening and some may be severe as they move south through the region. The Storm Prediction Center has placed areas north and east of I-74 within a Slight Risk (Level 2 threat) while everyone else is in a Marginal Risk (Level 1 Threat).
A very warm and unstable airmass will be in place across Central Illinois, however when and where storms will develop is unclear. Storms will either develop along an outflow boundary or a cold front Saturday afternoon. Both features are expected to be in Wisconsin, but depending on which boundary acts as the focus for storms, will ultimately impact storm timing and strength.
While isolated pop-up showers and storms are possible throughout the afternoon, the greatest risk for strong to severe storms will be between 6pm and midnight. Any storms that move through Central Illinois during this time may produce locally damaging wind gusts, heavy rain and perhaps some hail. The risk of a tornado is low.
If storms develop later in the evening they may not move through Central Illinois until after 10 pm. In this scenario storms will likely continue past midnight but the risk of sever weather will be lower. Given the uncertainty in storm timing and strength, be sure to monitor the forecast for future updates.