About that southward-moving tropical system...

TD Arlene moved south in the open Gulf. That's pretty rare.

Tropical Storm Arlene made a full loop and significant southward movement in the open Gulf of Mexico - an incredibly rare behavior in the historical record.

Only two storms on record have ever made significant southward movement in the Gulf of Mexico:

Fern (1971), which made a southward turn post-landfall in Louisiana and moved westward before making a …