Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 400 AM EDT Mon Sep 23 2024 Valid 12Z Mon Sep 23 2024 - 12Z Wed Sep 25 2024 ...Threat of heavy rain and locally strong to severe thunderstorms will slowly shift from the southern Plains this morning to the Ohio Valley, central Appalachians and lower Great Lakes on Tuesday into early Wednesday... ...Watching the western Caribbean Sea for tropical cyclone formation that could bring strengthening winds and passing squally downpours into the Florida Keys Tuesday night into Wednesday morning... A low pressure wave consolidating over the southern Plains along a slow- moving front is forecast to move northeastward through the Mid-Mississippi Valley by tonight, then across the Midwest and Ohio Valley on Tuesday. Heavy showers and some severe thunderstorms this morning across the southern Plains are expected to taper off as today progresses but the threat of heavy rain and locally strong to severe thunderstorms will increase from the Mid-Mississippi Valley into the Midwest in the mean time. By Tuesday, the center of the low will pass through the Midwest toward the lower Great Lakes, the threat of heavy rain and embedded strong thunderstorms will then develop well ahead of the low across the Ohio Valley, mainly from Tuesday afternoon into Tuesday night. By early Wednesday, many areas across the lower Great Lakes and the interior East Coast will be enshrouded by showers and embedded thunderstorms. These showers and storms will extend farther southwest near/along the trailing front across the interior Gulf Coast states. Showers and periods of rain will also move across the lower Great Lakes into the central Appalachians and upstate New York in association with another wave of low pressure near the front. The upper-level low behind the slow-moving front will slide across the central Plains, allowing much of the western U.S. to remain dry along with a warming trend for the next couple of days. Meanwhile, colder air will remain entrenched across the Plains behind the front but 90s will be common in the afternoon across the South and into the interior Southeast today and Tuesday ahead of the front. The outer edge of a Pacific cyclone centered over the Gulf of Alaska will only bring some light rain into northwestern Washington State this morning. A weak frontal system will only deliver some passing showers across the northern Plains today into tonight. Farther south into the tropics, the National Hurricane Center continues to watch the western Caribbean Sea for potential tropical cyclone formation. Computer models now appear to be in good agreement for the system to move northwestward and reach the Yucatan Channel by the time the short-range forecast period ends Wednesday morning. This means that the Florida Keys could experience strengthening winds along with passing squally downpours from Tuesday night into Wednesday morning. Please refer to the National Hurricane Center for the latest updates on this system. Kong Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php