Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 400 PM EDT Sun May 12 2024 Valid 00Z Mon May 13 2024 - 00Z Wed May 15 2024 ...Risk for numerous instances of flash flooding will shift from eastern Texas/central Louisiana late Sunday to the central Gulf Coast Monday... ...Showers and storms expected ahead of a cold front across the Central Plains into the Mississippi Valley Monday, spreading into the Ohio Valley and Interior Northeast by Tuesday... ...Generally above average temperatures expected for the West... A southern stream upper-level wave and associated surface frontal system traversing the south-central U.S. this weekend/early next week will continue to bring extremely heavy rainfall and the threat for flash flooding, as well as severe weather, from the Southern Plains to the Southeast. The threat Sunday evening into early Monday morning will be focused on portions of eastern Texas into central Louisiana where a Moderate Risk of Excessive Rainfall (level 3/4) remains in place. Here, abundant moisture and strong CAPE will lead to very heavy downpours with additional rounds of storms focusing along a slow moving warm front leading to several inches of rain on top of wet antecedent conditions. Scattered to numerous instances of flash flooding remain possible overnight Sunday. The system will continue eastward Monday, with the threat of very to extremely heavy rainfall extending along the warm front through the central Gulf Coast. A Slight Risk of Excessive Rainfall (level 2/4) stretches from eastern Texas to the Florida Panhandle, with a more concentrated Moderate Risk centered on southeastern Louisiana to the far western Florida Panhandle where the greatest confidence in coverage of repeated storms producing intense downpours exist. The prospect of several inches of rain could lead to numerous additional instances of flash flooding Monday. Additionally, storms will also have the potential to become severe, with a Slight Risk of severe weather from the Storm Prediction Center stretching from central Texas to southwest Georgia and the Florida Panhandle for the threat of very large hail, damaging winds, and a few tornadoes. The warm front will begin to lift further northeastward on Tuesday, with showers and storms extending towards the Atlantic coast of the Carolinas and Georgia. Another Slight Risk of Excessive Rainfall exists across this region southwestward through the Florida Panhandle where a few additional scattered instances of flash flooding will be possible. Another frontal system to the north will bring additional showers and thunderstorms from the Central Plains late Sunday to portions of the Mississippi Valley and Midwest by Monday. The most concentrated focus for storms will be ahead of a southeasterly moving cold front through portions of the Middle Missouri and Mississippi Valleys. While rain rates wont be quite as intense as in the South due to a lack of greater moisture and instability, enough rain is still expected to lead to some threat for flash flooding, with a Slight Risk of Excessive Rainfall in place. Shower and storm chances will spread eastward ahead of the cold front into the Great Lakes/Ohio Valley by Monday evening and into the Appalachians/Interior Northeast into the day Tuesday. To the west, the next system dropping southeastward from western Canada will begin to spread into the Northern Rockies/Plains late Monday and into the day Tuesday, bringing a chance for some light to moderate showers and thunderstorms. Some snow will be possible for higher elevations into the mountains. Forecast temperatures will tend to be near or a bit below average for eastern portions of the country under the influence of the active pattern. Highs Monday and Tuesday generally range in the 60s and 70s from the Central Plains east through the Tennessee Valley to the Carolinas and northward, with more 80s possible from the Southern Plains into the Southeast. One exception will be south of the warm front along the Gulf Coast over portions of South Texas and Florida, where highs will be hot and into the 90s and low 100s. Some record-tying/breaking high temperatures will be possible. In the West, highs will be well above average over portions of the Northern Rockies/High Plains Monday, with temperatures into the upper 70s and low 80s, before the noted frontal system pushes in and drops temperatures into the 60s Tuesday. Conditions will also be well above average over central/northern California and the adjacent Great Basin, with 80s and even some 90s expected inland from the immediate Pacific Coast. While not as anomalous, temperatures will still be above average in the Pacific Northwest by Tuesday, with highs into the 70s, as well as in the Desert Southwest, with highs in the 90s to low 100s. Putnam Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php