The deluge of rain and thunderstorms will continue from the southeast through much of the northeast from now through this weekend. In some cases, it will persist into early-next week as well. It’s all thanks to a Bermuda High off the coast that’s been fueling a deep tropical flow of moisture from the Caribbean Sea. This tropical flow will contain precipitable water values of over two inches across much of the East Coast, indicating an extremely moist atmosphere that can produce heavy rains.
On Thursday, another washout of a day may be possible for parts of the Mid-Atlantic, especially near the Mason-Dixon Line. Rain will sneak into southern New England and the Lower-Hudson Valley in the morning before high pressure pushes that moisture to the south. To the north, it will be a dry day. More scattered thunderstorms will pop in the afternoon from the central Gulf Coast through the Ohio River. There will also be scattered storms in Florida up through the Mid-Atlantic, especially in the afternoon. Between at least Wednesday and Thursday, there is a higher-than-normal risk across much of the Mid-Atlantic. These persistent rounds of rain are further indicative of a rather wet 2018 spring.
On Friday, a broad area of lower pressure will be moving northward from the northeastern Gulf Coast through the northeast into Friday night. This will enhance rainfall rates as it carries more moisture air in from the tropics. A washout of a day will be likely — again — across much of the Mid-Atlantic, and flash flooding will remain a threat. The greatest risk for flooding will be near the Mason-Dixon Line, where rainfall rates may exceed 0.5 inches per hour. Rain will work into southern New York and New England by the late-afternoon. Farther south, numerous scattered showers and storms will be around across most areas east of the Mississippi River and south of the Ohio River. A few showers will be possible, however, back into eastern Ohio and western Pennsylvania. Heavier rain will then move into southern New York and much of New England Friday night.
On Saturday, there won’t be any areas of steady rains across the eastern third of the US. Instead, there will be many showers and thunderstorms affecting most of the region. Heavier rain is possible from the Outer Banks through the eastern Florida coast, which is where the highest atmospheric moisture will be located.
The weather will be quite similar on Sunday with scattered showers and storms. A cold front is approaching from the north and west, which will bring in a more focused line of thunderstorms to the Ohio River Valley. That front will then clear out the moisture and usher in a period of nicer weather for the start of next week to the Northeast while scattered storms persist much of next week across the Southeast and Mid-Atlantic. We’re not expecting any widespread rain events or any washouts for the Southeast and Florida next week as relatively lower moisture values return.
Rainfall totals will remain heavy across the East with a widespread two to three inches of rain forecast through Monday. Localized areas in the Mid-Atlantic will likely exceed six inches of rain.