Fig. 1: GFS 4-day rainfall forecast for the remains of Ira passing through the East U.S. this week.
Fig. 2-5: GFS 24-hour rainfall forecasts for the remains of Ida for Monday/Tuesday (top) and Wednesday/Thursday (bottom).
Discussion: Although Ida is weakening moving north and later northeastward an immense rain storm will emerge along the path of this storm this week due to lingering tropical characteristics into tomorrow and merging with a frontal system mid-to-late week (Fig. 1).
Ida will weaken to a tropical storm today moving into southwest Mississippi and a depression by tomorrow morning in northeast Mississippi. Most of today’s rain is east of the inland-traveling tropical storm. Featured is squalls that can produce 5-10 in. of rain, attendant flash flooding and severe weather including tornado risk (Fig. 2).
On Tuesday Ida becomes extra-tropical but still able to produce severe weather including tornado risk in the eastern Tennessee Valley and developing heavy rains in West Virginia (Fig. 3).
A cold front will merge with the remains of Ida midweek. The result is an increasing veil of heavy rain from the Mid-Atlantic region including Washington, Baltimore and Philadelphia to New York City which causes more flash flooding (Fig. 4).
The remains of Ida are offshore by Thursday but still able to bring heavy rains to southeast New England (Fig. 5).