Significant heat wave is expanding north & northeastward prompting widespread Heat Advisories & some Excessive Heat Watches & Warnings.
Newton, Jasper & Benton counties are under the Heat Advisory at the moment with likelihood Northern Indiana & Indianapolis offices will follow suite.
After patchy fog & 60s this morning, we are heating up quickly now with a very light south-southwest wind.
Temperatures are already 80-87 as of 12 p.m. with dew points 65-74 bringing heat indices up to as high as 94.
89-95 is expected today with heat indices 95-106. Skies should mostly sunny to partly cloudy.
Other than a small isolated shower/storm Saturday, we are dry with partly cloudy to mostly sunny skies & highs 91-97 with heat indices 97-109.
On Sunday, a complex of severe storms will make it to northern Illinois & Michigan then collapse in the morning hours. We may pick up some debri cloudiness, but cap will put the kabosh on this round of storms.
However, the big question is what happens along the complex's outflow boundary in the afternoon as we become boiling hot with up to 4000 J/kg of ML CAPE as temperatures surge to 94-100 with heat indices 100-115.
Strong cap will be in place, but we will be a pot of boiling water on a stove with a lid on & that lid will be bouncing on the pot with the boiling heating.
If enough surface convergence can develop on the outflow boundary & those updrafts completely overcome the stout cap, then some pulsey severe storms may develop after 4 p.m.
Given such heating & instability, isolated microburst & hail threat would occur.
Bigger risk would be northeast Ohio through southern Ontario to New England as MCV from the storm complex moves into hot, unstable environment.
Storms are possible at times Monday-Wednesday of next week & again the weekend of July 25-26.
The intense heat will decrease, but it will still be very warm to hot & humid with highs in the 80s to lower 90s with heat indices 90s to 104.
The hottest weather of next week is setting up for Friday & then next Saturday with widespread 90s with 100s heat indices.