I knew that Stacy Stewart wrote the latest discussion without looking at the signature. Very detailed.
Here's a part of the discussion...relevant to the movement Frank is tracking.

...THE INITIAL MOTION ESTIMATE IS 265/5. 12Z AND 18Z UPPER-AIR DATA
INDICATE THE SUBTROPICAL RIDGE TO THE NORTH OF KATRINA HAS CHANGED
LITTLE WHILE AN INVERTED MID- TO UPPER-LEVEL TROUGH HAS DEVELOPED
NORTHWARD FROM THE CARIBBEAN SEA TO KATRINA. THE TROUGH IS EXPECTED
TO INDUCE A SLIGHT SOUTH OF DUE WEST MOTION FOR THE NEXT 12 HOURS
OR SO.