Short Range Forecast Discussion NWS Weather Prediction Center College Park MD 245 PM EDT Mon Sep 15 2025 Valid 00Z Tue Sep 16 2025 - 00Z Thu Sep 18 2025 ...Slow moving coastal low to bring heavy rain potential along the Mid-Atlantic coast... ...Heavy rains possible across the Central to Northern Plains Tuesday and Wednesday... ...Tropical moisture from Mario to begin to push into Southern California... ...Below average temperatures likely where wet weather occurs next two days, otherwise above average temperatures expected across much of the CONUS... The large scale mid to upper level flow across the Lower 48 is becoming increasingly amplified, resulting in slow moving systems affecting the CONUS. Along the Mid-Atlantic coast, surface low pressure currently approximately 120 miles southeast of Cape Hatteras, will be moving slowly westward across the Outer Banks tonight/early Tuesday and then slowly north northeastward into southeast Virginia by Wednesday morning. The slow movement of the system will support potential for heavy rainfall amounts across northeast North Carolina into southeast Virginia and the southern Delmarva Peninsula with two day totals of 2-5" possible. These areas have been dry over the past month or two with much of the area in DO (abnormally dry) drought conditions. Heavy rains also possible Tuesday into Wednesday across large sections of the Central to Northern Plains. A mid to upper level system pushing out of the Northern Rockies will slow as it emerges into the Northern to Central Plains Tuesday. Showers and thunderstorms will increase in coverage Tuesday across the Central to Northern Plains, with these showers/thunderstorms continuing into Wednesday and Thursday. These rains will bring relief to areas of western Nebraska and southern South Dakota that are experiencing abnormally dry (D0)to moderate drought (D1) conditions. The remainder of the Central to Northern Plains that may receive heavy rains are not in drought conditions due to greater rains over the past few months. Tropical moisture associated with Mario, currently moving northwestward well off the west coast of the Baja, may being to impact Southern California Tuesday and Wednesday, before pushing farther north into Central California mid to late week. While Mario is forecast to weaken as it moves northwestward, this tropical moisture may bring showers into far southern coastal California and the offshore islands Wednesday, with these showers pushing farther north into much of Southern California on Thursday. Temperature wise across the lower 48, much of the CONUS will see above average temperatures over the next few days in the last full week of summer. Exceptions to this will be in the above mentioned regions where heavy precipitation is possible, across the Mid-Atlantic Tuesday and Wednesday, and across the Central to Northern Plains Wednesday into Thursday where below average temperatures are likely due to this heavy rain potential. Oravec Graphics available at https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php