...There is a slight risk of severe thunderstorms over parts of the
Western Gulf Coast...
...Heavy rain possible over parts of the Lower Mississippi Valley/Western Gulf Coast...
A slow moving upper-level low over Western Texas will move to the Lower Mississippi Valley by Wednesday evening. The system will produce showers and thunderstorms over parts of the Southern Plains/Lower Mississippi Valley that will shift eastward by Wednesday.
Meanwhile, a front over the Great Lakes and the Northeast will move
southward to the Mid-Atlantic/Ohio Valley by Wednesday evening. Showers and thunderstorms will develop along the front over the Great Lakes and over the elevated areas of the Central Appalachians on Tuesday. The showers and thunderstorms will move southward to the Ohio Valley/Mid-Atlantic by Wednesday.
Rain will develop over parts of the Northeast on Tuesday, ending by Wednesday afternoon.
Another front over the Northern High Plains to the Great Basin will move eastward to the Upper Mississippi Valley while extending westward across the Northern High Plains into the Great Basin by Wednesday evening. Showers and thunderstorms will develop along and ahead of the boundary over the Northern Plains that will move eastward to parts of the Upper Mississippi Valley by Wednesday morning.
Similarly, another upper-level low will move onshore over the Pacific
Northwest Tuesday evening into Wednesday. The system will produce rain over parts of the Pacific Northwest late Tuesday night that will expand into parts of the Northern Rockies on Wednesday.
Late night rain and late afternoon/evening showers/thunderstorms will develop over parts of the Northern High Plains on Wednesday.