I don't have much to add in regards to the severe weather Thursday. The limiting factor of the severe weather will be the low-level moisture, while there may be enough for large hail and downburst winds, it may limit the tornado development.
The coastal storm will stick around for several days. The operational models seem to be handling the storm poorly by spreading the rain out over a large area. Thinking right now is the rain makes it up to Harrisburg to southern Connecticut.
Heavy rains associated with the upper-level low will hit the Carolinas into Virginia. Some areas could get over a foot of rain by Monday!
The heavy rains are still coming and someone is going to have up to a foot of rain and flooding.
Major problems the end of the week and weekend as another round of flooding rains occur and Joaquin could impact the mid-Atlantic.
The Northeast will be the center for flooding rains through the weekend. Joaquin could bring troubles late in the weekend.
A stormy week for the Eastern part of the country. Heavy rains will be the main issue.
Stormy along the East coast this weekend and perhaps in the Gulf of Mexico late in the weekend and early next week.