From the latest TWO (5:30 pm ET issuance):

SATELLITE IMAGES AND SURFACE OBSERVATIONS INDICATE THAT A LOW
PRESSURE SYSTEM NEAR JAMAICA HAS BECOME BETTER DEFINED TODAY.
SHOWER AND THUNDERSTORM ACTIVITY HAS ALSO INCREASED AND BECOME
BETTER ORGANIZED... AND UPPER-LEVEL WINDS HAVE ALSO IMPROVED
SIGNIFICANTLY. ENVIRONMENTAL CONDITIONS ARE GRADUALLY BECOME MORE
CONDUCIVE FOR A TROPICAL DEPRESSION TO POSSIBLY FORM LATER TONIGHT
OR ON SATURDAY. THIS SYSTEM IS FORECAST TO MOVE SLOWLY WEST OR
WEST-NORTHWESTWARD... AND INTERESTS IN JAMAICA... CUBA... AND THE
NORTH-CENTRAL AND NORTHWESTERN CARIBBEAN SEA SHOULD CLOSELY MONITOR
THE PROGRESS OF THIS DEVELOPING SYSTEM. AN AIR FORCE RESERVE UNIT
RECONNAISSANCE AIRCRAFT IS TENTATIVELY SCHEDULED TO INVESTIGATE THE
SYSTEM TOMORROW... IF NECESSARY.