A drought continues to affect much of the Southeast U.S. following a relatively dry fall and winter so far, but another round of heavy rain will help alleviate those drought conditions this weekend as inches of rain come down. A developing surface low pressure will be the main instigator for this organized rain event as warm, moist air flows north from the Gulf of Mexico.
This Friday, showers and a few thunderstorms will develop and from into a line in a west to east orientation, spanning from the ArkLaTex through the Carolinas. That line of moderate to heavy rain will gradually move northward into the evening toward the Tennessee Valley before it turns into a widespread rain overnight. Meanwhile to the south, a new area of rain will begin to develop in south Texas by the evening. This area of rain will be the main culprit for the heavy rain tonight, which may lead to flooding in some areas, especially southeastern Texas and the Mid-Mississippi Valley.
So overnight Friday, rain will be widespread, affecting much of the Tennessee and Ohio River Valleys from that first batch. Then the second area of rain associated with the surface low to the south will lead to rain with pockets of heavy rain from eastern Texas and into portions of Arkansas, Louisiana, Mississippi, and Alabama. Some of these heavier areas of rain may contain embedded thunderstorms with gusty winds up to 50 mph.
Then on Saturday, the rain will continue to become heavier and more widespread. Showers will even spread as far north as the Mid-Atlantic and southern New England by the end of the day Saturday. The main activity, however, will be focused in the South with rain forecast from eastern Texas through portions of the Gulf Coast states, the eastern Carolinas, and into the Ohio and Tennessee Valleys. There is the marginal risk for flooding due to the risk for rainfall rates to exceed two inches per hour at times from the southern Appalachian Mountains through southeastern Texas, including Houston.
As we get into Saturday night, the rain will clear out of the South-Central Plains while continuing across the Southeast and up the East Coast. A widespread rain is forecast from southern New England through the Northeast coast into the Mid-Atlantic, western Carolinas, Ohio and Tennessee Valley, and to the mid-Gulf Coast. The most moisture will be found in the Gulf Coast states, so that is where there’s the best chance for those heavy rainfall rates and for localized flooding.
On Sunday, the rain will continue across portions of the East while this same storm brings snow to portions of the Great Lakes and into northern New England. The rain across the South won’t be in the form of a widespread, steady rain but instead there will be scattered showers and thunderstorms mainly east of the Mississippi River. Several lines of thunderstorms may even develop by the evening hours as some sunshine allows for daytime heating and instability. A few showers are still expected in the Ohio and Tennessee Valleys, but most of that activity should clear out by the afternoon while much of the Mid-Atlantic and southern New England experience a washout of a day.
The weather will remain pretty much the same Sunday night with rain affecting much of the U.S. East Coast and into the Southeast. There is even the concern for localized flooding as the rain continues in southern New England and on Long Island. These areas may exceed over two inches of rainfall with this rain event, which will end for them early-Monday morning.
Speaking of Monday, the rain will clear out of the Northeast and Mid-Atlantic as a Canadian high pressure surpasses the moisture to the south. Remember, high pressure indicates sinking air, so that makes it real difficult for clouds and precipitation to develop in those conditions. In the Southeast, rain and thunderstorms will continue across the Carolinas into Georgia and the Florida Panhandle. The rain will be more scattered and spotty in nature from Louisiana through Alabama.
Portions of the middle and end of next week will remain wet for much of the South as a constant flow of moisture off from the Gulf of Mexico continues. We’ll of course have details on this continuing rain event as we get closer to this time period.
Again, there is the concern for flooding and heavy rain with this event. Our rainfall forecast indicates where the heaviest rain will fall with a widespread two to three inches of rainfall expected. Even three to five inches is anticipated in the southern Appalachians. Also in the New York City area into southern New England, which our graphic does not show, a widespread one to two inches is expected through Monday.