Strong Storms Could Break The Heat Late Today
Those who like their summers a little cooler got to enjoy 3 days last week with highs in the 70s. Since then we have seen four days in a row with highs above average and today will make it 5 days in a row. While we will cool off a bit beginning Tuesday it doesn't appear we will see any 70s for highs at least through the weekend.
Temperatures today only tell part of the story. The HRRR model is forecasting highs near 90°.
High dew points today (in the 70s) will make it feel like the tropics have descend upon Chicago. That combination of heat and humidity will give us some of the highest heat index values we have seen all summer.
The irony is that with all the moisture in the air we still are well below average in terms of actual rainfall. So far this month we have only seen a paltry .05" of rain at O'Hare. The GFS total precipitation forecast through the end of the week is calling for anywhere between a quarter of an inch to an inch of rain total. That won't make up for the deficit though since we should have more than 2" of rain by this point in the month. August averages just under 5" of rainfall making it the wettest month of the year.
The Storm Prediction Center has placed us in an "enhanced risk" area for severe weather today and tonight. A cold front will push into the very hot and humid air that will be sitting over us most of the day. An "enhanced risk" means numerous severe storms possible. The greatest threat from these storms will be damaging winds. The most likely window for the storms to occur is between 3 pm and 9 pm.
The 6-10 day temperature probability outlook keeps the heat coming through the middle of the month. It has us outlooked for above average temperatures overall from the 15th through the 19th. The 8-14 day forecast has most of the Chicagoland area near normal from the 17th through the 23rd.
Looking longer range towards the end of the month it appears a warmer than average pattern will dominate. The Muli Model Ensemble air temperature anomaly forecast has northern Illinois outlooked for above average temperatures for the week ending on August 28th. In other words, our warm summer will sizzle on for the foreseeable future.
Here is my 7 day forecast: Today: Partly/mostly cloudy, thunderstorms mainly late (some strong) High: 90 (Heat index near 100) Tuesday: Partly to mostly sunny Low: 70 High: 83 (78 Lakefront) Wednesday: Partly to mostly sunny Low: 67 High: 84 (78 Lakefront) Thursday: Partly to mostly sunny Low: 68 High: 85 (79 Lakefront) Friday: Partly cloudy, isolated shower/t-storm possible Low: 69 High: 87 (80 Lakefront) Saturday: Partly cloudy, isolated shower/t-storm possible Low: 67 High: 848 Sunday: Partly cloudy, sct. showers/t-storms possible Low: 69 High: 88 #ilwx