Several waves of low pressure over the southern Plains will trigger rounds of heavy showers and thunderstorms to parts of the Deep South and the Ohio and Tennessee River Valleys through midweek. Not only will heavy rain be a concern, which may trigger localized flash flooding, but there will also be some severe weather in the form of isolated severe storms.
A delaying mesoscale convective system (MCS) will bring a round of heavy, strong to severe storms to the Red River Valley and ArkLaTex region Monday morning. Some gusty winds will be present, but the main issue will be the blinding rain during the morning commute. There will also be a few scattered showers and storms present across the central Plains behind that MCS and Ohio River Valley during the morning hours. Now into the afternoon, that MCS should dissipate for the most part. That will allow for the development of numerous, hit or miss thunderstorms across the central and southern Plains. Given the unstable environment, spotty showers will be possible across the Upper Midwest and Great Lakes, while storms become more widespread across the Ohio and Tennessee River Valleys. Several large clusters of storms are also forecast to form, and these clusters will be the ones to watch for severe weather thanks to 30-50 knots of wind shear present under the trough of low pressure. Damaging winds, large hail, and an isolated tornado are all possible.
Overnight Monday, one wave of low pressure will takeover and strengthen as it tracks from the ArkLaTex to the Ohio River Valley. This will add as a focal point for an enhancement in the rain and thunderstorms. Therefore, heavy rain and flooding may be a concern in this part of the country and into the Tennessee River Valley. Elsewhere, much of the convection should diminish, besides the lingering spotty storms across the southern Plains and Midwest.
A secondary wave of low pressure will bring a cold front through central Texas and eastern New Mexico Monday night. Ahead of that front will be a line of scattered showers and thunderstorms, some of which may be severe. That front will attempt to reach the Gulf Coast, likely washing out in the process.
On Tuesday, the remnants of the showers and thunderstorms from Monday night will affect southeastern Texas into much of Louisiana — especially away from the coast — mainly during the morning hours. As the front pushes through midday and high pressure comes in from the north, the southern Plains and ArkLaTex will dry out, while organized showers and storms track into the Southeast Tuesday afternoon into Tuesday night.
To the north, showers and embedded thunderstorms will remain in the forecast across parts of the Ohio and Tennessee River Valleys. By this point in time, the low pressure will begin to track into the eastern Great Lakes region, so that will bring showers into the interior Northeast.
This low pressure will be one of the features that will allow for tropical moisture to stream in from the south, thus allowing for another period of heavy, flooding rains to parts of the East Coast much of this week. Meanwhile across the central US, it will be mainly dry but cool.
Through Tuesday, rainfall will generally range between 0.5 and 1.5 inches, but some locales may exceed the 3 inch mark in Oklahoma and the western Ohio River Valley.