Excessive Rainfall DiscussionNWS Weather Prediction Center College Park MD731 PM EDT Mon Jul 7 2025Day 2Valid 12Z Tue Jul 08 2025 - 12Z Wed Jul 09 2025...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR THE EASTERNMID-ATLANTIC STATES AND SOUTHERN NEW ENGLAND, AS WELL AS PARTS OFTHE SOUTHERN PLAINS......Mid-Atlantic and Northeast...Post-tropical cyclone Chantal will be exiting east of Cape Cod tostart the period as it continues to get caught up in increasingsouthwesterlies downstream of a trough approaching from the GreatLakes. This trough will continue to translate eastward through theday, but will be slow to advect due to downstream Bermuda-typeridging. Between these two features, SW flow will remain prevalentover the area, with 850-500mb winds being nearly unidirectionalfrom the W/SW at 15-20 kts. This will result in a continuedextremely moist environment with PWs likely eclipsing 2" fromeastern VA through southern New England Tuesday afternoon,coincident with a plume of SBCAPE exceeding 2000 J/kg.Into these impressive thermodynamics, a shortwave embedded withinthe mean flow will traverse northeast ahead of a cold front andalong a surface trough, providing additional ascent atop thealready impressive convergence on these boundaries. This suggestsshowers and thunderstorms will become widespread, which isadditionally supported by high-res CAM simulated reflectivity.Storms that develop will move very slowly, and Corfidi vectorscollapsed to just around 5 kts will support backbuilding andtraining echoes along the surface trough and front. With warm clouddepths potentially eclipsing 14,000 ft, this will support efficientwarm-rain processes and rain rates above 2"/hr at times. Wheretraining occurs, this could result in total rainfall in excess of3", with instances of flash flooding possible across much of theI-95 corridor from Richmond, VA to Portland, ME, and a slight riskhas been added for this area.