Marcus’ 4 a.m. Friday forecast INDIANAPOLIS (WISH) — Southern portions of central Indiana need to prepare for heavy rainfall and potential flooding as a Flood Watch takes effect Friday afternoon through Saturday morning. Multiple rounds of thunderstorms are expected to produce 1 to 3 inc hes of rain, with locally higher amounts possible across already saturated ground. This Morning A stagnant frontal boundary positioned over the Ohio Valley is acting as a conveyor belt for Gulf moisture streaming into the region. While the heaviest rainfall has remained south of the Indianapolis metro area overnight, showers and embedded thunderstorms will continue expanding northeast through the morning hours. This Afternoon and Tonight The primary concern is torrential rainfall. An upper level disturbance moving in from the west this afternoon could serve as a catalyst for more organized severe weather development, particularly across south central Indiana. While extensive cloud cover may limit instability somewhat, any storms that do develop could produce damaging winds or even a brief tornado. The severe weather threat will be highest from mid-afternoon through early evening, especially in areas south of Bloomington extending toward the Kentucky border. Rainfall totals: Expect widespread 1 to 3 inches, with isolated amounts potentially exceeding 4 inches in areas where storms train repeatedly over the same locations. This is on top of already saturated soils from recent wet weather. The Flood Watch remains in effect for counties roughly west and south of a Terre Haute to Bedford line, though forecasters may expand coverage if storm development shifts farther north than currently expected. Saturday The frontal boundary will remain stalled across the region, keeping scattered showers and thunderstorms in the forecast Saturday afternoon and evening. High temperatures will climb into the low to mid-80s despite the cloud cover and storm activity. Sunday: Transitioning to Drier Weather A building high-pressure ridge from the west will finally nudge the frontal boundary northward and out of the state. Expect decreasing clouds and drier conditions to take hold by Sunday afternoon. This will mark the beginning of a significant pattern change as temperatures begin climbing. Highs Sunday will reach the upper 80s with increasing sunshine. Next Week: Dangerous Heat Wave Prepare for the most intense heat of the summer season. An upper-level ridge will dominate the weather pattern, bringing multiple consecutive days with high temperatures in the mid to upper 90s starting Monday. Combined with high humidity, heat indices will soar between 100 to 105 degrees during afternoon peak heating hours. Overnight lows will only drop into the mid to upper 70s, providing little relief from the heat stress. Isolated storms may develop late in the week as a weak disturbance passes through, but they will do little to break the heat’s grip on the region. 7-Day Forecast ...read more read less