AUSTIN — Central Texas is forecast to move from September heat into a cooler, wetter stretch late this week, with several inches of rain possible and a risk of flash flooding. Monday, Sept. 28, and Tuesday are expected to remain hot, with highs in the 90s. Humidity could push heat index readings to 100 degrees or higher in many areas Monday. A few isolated showers are possible, but most places are expected to stay dry. South winds could gust to 20 to 25 mph Tuesday. Rain chances are expected to grow late Wednesday as tropical moisture combines with a slow-moving low-pressure system moving in from the Pacific. The wet pattern is forecast to strengthen from Thursday into the start of the weekend, bringing the potential for heavy rainfall and flash flooding. The forecast calls for a marked cooldown alongside the rain: Austin’s projected high falls from 95 degrees Wednesday to 87 Thursday and 83 Friday. Showers and thunderstorms remain possible through the weekend. Specific rainfall totals and timing remain uncertain. Residents should follow updated forecasts and local weather alerts as the system approaches, particularly because heavy rain can cause flash flooding.