(NEW YORK) -- Two storm systems are set to merge in the West on Wednesday and bring heavy snow and wind to the Rockies and rain to the Southwest.
Winter weather alerts have been issued for six states from Washington to Colorado for snow and high winds.
The northern storm system is already moving through the Pacific Northwest on Wednesday morning with rain in Seattle and Portland, and heavy snow in the Cascades.
At the same time, a developing southwest flow will ride along the jet stream, bringing rounds of moisture to the Southwest.
By Thursday morning, the two systems will begin to merge and the rain will continue in the Southwest -- with snow for the mountains.
Locally, up to 1 inch of rain is expected in the desert, and up to a foot of snow is possible all along the Rockies.
Heavy rain and flooding
With warm weather comes rain for much of the Mid-South and into the Appalachians.
A flood watch has been issued for four states -- Ohio, Kentucky, West Virginia and Virginia -- from Wednesday evening through Friday evening.
Rain is already falling in the Tennessee and Mississippi River valleys, and it will continue through most of the day.
By Thursday, a new storm system will move into the Ohio Valley and Appalachians with more rounds of rain, which could be heavy at times.
A cold front will move through the same area on Thursday night into Friday morning, bringing more heavy rain to an already saturated ground, making flooding likely.
The heaviest rainfall amounts will be from Tennessee into southern Pennsylvania, where up to 2 to 4 inches could fall.
Copyright © 2018, ABC Radio. All rights reserved.