ABC News(NEW YORK) — Lake Effect snow has ended in the Northeast and temperatures are actually set to trend milder across the eastern U.S. over the next few days.Attention turns immediately to a complex system developing in the western U.S. and part of this system will track across the country this week and set off yet another widespread heavy rain event in the South.On Sunday morning, there are some snow showers from Idaho to California with areas of limited visibility and slippery travel. As this storm system starts sliding south today, both precipitation and winds will increase from California to Wyoming.Winds in the San Francisco Bay area could reach 45 mph today which could cause some downed trees and power lines Sunday.In Southern California, there is also a small chance of thunderstorms with hail Sunday evening in the lower elevations and winds in the hillsides and mountains of Southern California could gusts up to 45 mph. Light snow will be possible on parts of I-5 through Grapevine and locally up to 6 inches of snow will be possible in southern California.Locally, up to 14 inches of snow will be possible in parts of Wyoming through Sunday and early Monday and travel on I-80 through southern Wyoming could be affected.On Monday, a part of this system will move eastward and begin a multi-day heavy rain event for parts of the southern U.S. The first batch of rain will move into parts of the Ohio and Tennessee Valley on Monday with the heaviest rain from Kentucky to northern Alabama. There could also be some strong thunderstorms over this area on Monday night with some gusty winds possible.On Tuesday, another impulse will sneak in and could cause another round of heavy rains to spread from Texas to Georgia with strong thunderstorms possible again.Widespread heavy rainfall could bring some flash flooding in the region too and some severe weather will be possible across parts of Texas with damaging winds, large hail and brief tornadoes possible.On Wednesday, another round of widespread showers and thunderstorms will move into the Deep South and bring additional chances for flash flooding.There is increasing confidence that the highest rainfall totals this week will be over portions of Mississippi, Alabama and northern Georgia. Portions of Mississippi and Alabama have seen more than a foot above their average year to date rainfall. If the heaviest rain tracks close to some of this region – flash flooding and river flooding could quickly become a concern in the region this week. Copyright © 2020, ABC Audio. All rights reserved.