Marcus’ 4 a.m. Thursday forecast INDIANAPOLIS (WISH) — Central Indiana is enjoying a stretch of quiet, fall-like weather that won’t last long. Heat and humidity return in force early next week, bringing heat indices near 100 degrees and increasing storm chances. Crisp Mornings, Comfortable Afternoons High pressure centered northwest of Indiana is keeping skies clear and the air remarkably dry. Temperatures dipped into the 50s overnight, with some rural northern counties even reaching the upper 40s. Expect another beautiful day today with highs in the mid-70s to low 80s. Humidity will remain exceptionally low as dry air continues to mix down to the surface once the day heats up. Overnight lows will once again dip into the comfortable 50s, making for perfect sleeping weather. Mostly Dry Through Friday Aside from a few passing clouds, the dry streak continues through Friday. Highs will stay comfortably below normal for late July, topping out in the upper 70s to low 80s. Friday will feature a few more clouds as a weak disturbance passes well to our south, but any meaningful rain should stay out of central Indiana. Heat and Humidity Return Sunday The transition begins this weekend. While Saturday remains mostly quiet with highs in the low to mid-80s, a ridge of high pressure will start building back in from the Rockies. This shift will pull warmer air and much deeper moisture back into central Indiana. You’ll notice the difference Saturday afternoon as southerly winds increase and humidity levels start to creep back up. By Sunday and Monday, high temperatures will climb into the upper 80s and low 90s. With dew points returning to the 70s, the heat index will likely approach 100 degrees by Monday afternoon. Storm Chances Loom Next Week As the heat returns, so do chances for rain. While widespread severe weather isn’t expected right now, we are watching for disturbances that could trigger storms starting late Sunday. There is significant uncertainty regarding how many storms will actually develop and how widespread the rain will be. A layer of warm air aloft—known as a “cap”—could limit how much rain actually reaches the ground, even as the atmosphere becomes more unstable. Think of the cap like a lid on a pot of boiling water. The atmosphere below wants to rise and form storms, but that warm layer acts as a barrier. If and when storms do break through that barrier, they can become quite strong. But if the cap holds, we just stay hot with little to no rain. This setup means we could see scattered strong storms, or we could see mostly dry conditions despite the oppressive heat. We’ll have a better handle on storm timing and coverage as we get closer to Sunday and Monday. 7-Day Outlook ...read more read less