A developing low pressure over an upper-level low will be the culprit for bringing rain from the South this Thursday, then to portions of the Northeast on Friday as the low pressure moves up the East Coast, similar to the storm on Wednesday.
This Thursday, rain will be falling across portions of the Mid-Mississippi and Tennessee River Valleys during the morning hours. A line of rain and thunderstorms ahead of a cold front will also extend down toward the central Gulf Coast. Then into the afternoon, as the heat and instability increases across the Southeast, there will be the marginal risk for a few strong to severe thunderstorms from east-central Alabama through much of Georgia and into the western Carolinas. This threat will begin once the storms move in to this area during the afternoon and evening. Showers and embedded thunderstorms will also be possible during this time period in the Tennessee River Valleys as well as in the southern Appalachian Mountains.
Thursday night, the storm will begin to take a northerly turn as the trough begins to lift. A couple rounds of rain and thunderstorms will move into the Carolinas and Virginia while several hours of a steady rain impact the central Appalachians and a large portion of the Mid-Atlantic.
By Friday, it will be the Northeast’s turn for the rain. During the morning hours, a steadier rain will still be impacting the I-95 corridor and surrounding hours from Washington, DC up through New York City. Then into the afternoon, a widespread rain will move into most of New England by the end of the day, beginning from south to north. Also eastern New York will be in the rain as well while the rain clears the Mid-Atlantic by the mid-afternoon.
Friday night, rain will clear out of northern New England during the first half of the night while an approaching cold front from the west brings a brief rounds of showers to the Great Lakes region.
That cold front will then usher in a very brief round of rain during the day Saturday to much of the Northeast and northern Mid-Atlantic region.