Shear really isn't a consideration this early in "the game", so to speak, because the primary mechanism for upward vertical motion, and resultant surface pressure falls/low development is divergent jet forcing. Been peeking at the RUC analysis fields and they've been showing some pretty sick H25 divergence and H70 omega (upward vertical motion) fields since early this morning offshore the breadth of the Florida east coast. Looks like some sort of low level vort south of GBI and west of Andros.

The evolution of the developing cutoff low on watervapor imagery is quite dramatic, with a nice "doughnut hole" developing over Tampa Bay. By tonight, the water vapor presentation will be striking - likely resembling one of those wrapped up occluded winter surface lows you see south of the Aleutians.

Over the next day or so, there should be some pretty big rainfall totals along the Florida east coast, and especially over south Florida.