A big split in the weather pattern will drive the story over the next week. Early-season heat will continue across parts of the Southwest, Plains, and Mississippi Valley, with some areas running more like late spring than late March. At the same time, a strong cold front will sweep across the northern half of the country, bringing rounds of rain, some mountain and northern-tier snow, a chance for strong thunderstorms, and a sharp return to cooler air for the East. By early next week, warmth expands again from the West into the Plains, while increasing Pacific moisture may begin pushing back into the Southwest.