Alerts cover the entire Eastern Seaboard on Thursday as heavy rain gets ready to soak the region for the next two days.
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Two storms continue to move east Thursday as they merge together over the East Coast.
The western storm brought wind gusts up to 97 mph in the Rockies and up to 15 inches of snow in Idaho on Wednesday. Colorado also saw up to 8 inches of snow, shutting down parts of I-70 west of Denver.
As the storms move east and merge together, flood watches have been issued for the entire East Coast from Florida to Maine. There are 17 states under flood watches on Thursday.
The southern storm is developing in the Gulf Coast on Thursday morning and spreading heavy rain into Georgia and Florida.
By Thursday afternoon and evening, the southern storm will move north and east bringing severe storms to most of Florida and coastal North and South Carolina. Damaging winds, hail and even a few tornadoes are possible in the regions.
Heavy rain will also spread into the Tennessee Valley and eastern Ohio Valley. The worst flooding Thursday will be in Florida and the Carolinas.
Some rain will begin in the mid-Atlantic and parts of the Northeast, but it will not be too heavy Thursday.
By Thursday night into Friday, heavy rain will move into the Northeast with flooding possible in major cities like Washington, D.C., Philadelphia, New York City and Boston.
A huge area along the East Coast will see up to 3 inches of rain, with even more possible locally in Florida.