Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 338 PM EDT Tue Sep 24 2024 Valid 00Z Wed Sep 25 2024 - 00Z Fri Sep 27 2024 ...Tropical Storm Helene is forecast to intensify to hurricane strength and bring life-threatening impacts to Florida and the Southeast late Wednesday through Friday... ...Rainfall this week may help relieve drought conditions in the central/southern Appalachians, Tennessee/Ohio Valleys, and Mid-Atlantic but will also pose a risk of flash flooding... ...Much above average temperatures continue across the West into the Northern Plains... A deep amplified upper-level trough will move southeast across the Mississippi Valley today and will begin to interact with Tropical Storm Helene by late Wednesday. This feature will help to pull tropical moisture and Helene northwards into the eastern Gulf of Mexico over the next couple days. A frontal system will move into the eastern U.S. ahead of this upper-level trough, which will bring rainfall to portions of the central/southern Appalachians, Tennessee/Ohio Valleys, Great Lakes, and Mid-Atlantic through Wednesday. Though beneficial for areas experiencing drought conditions, locally heavy rainfall could lead to isolated to scattered instances of flash flooding, especially in urban areas. All attention will shift to Tropical Storm Helene late Wednesday and Thursday as it approaches the United States. Helene is forecast to intensify and be near hurricane strength when it reaches the far northwestern Caribbean Sea early Wednesday then rapidly intensify over the eastern Gulf of Mexico and become a major hurricane when it approaches the northeastern Gulf Coast on Thursday. The risk of impacts from life-threatening storm surge and damaging hurricane-force winds continues to increase along the coast of the Florida Panhandle and the Florida West Coast. Hurricane and Storm Surge Watches are in effect for much of that area and residents in those areas should follow advice given by local officials. Helene will bring heavy rain to portions of the western Caribbean, which will cause considerable flooding and mudslides across western Cuba. Heavy rainfall will likely result in locally considerable flash and urban flooding across portions of Florida, with isolated flash and urban flooding possible across the Southeast, Southern Appalachians, and the Tennessee Valley Wednesday through Friday. Additionally, minor to isolated moderate river flooding will be possible. Please refer to the National Hurricane Center for the latest updates on this system. In the West, an amplifying upper ridge across the interior will support much above average temperatures over the next few days across nearly all of the West and the Northern Plains. High temperatures across these regions are forecast to be as much as 10 to 20 degrees above average. Numerous record high minimum temperatures will be possible over the next few nights/early mornings, and a few record high maximum temperatures will be possible as well. A weak frontal system will move across the Northwest and into the northern Plains by Thursday evening, which may provide a little relief from the heat and trigger some showers in the Northwest on Wednesday. Dolan/Kong Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php