11.   A weak low pressure trough extends from near Guadeloupe and Martinique this morning north-northeast across the Atlantic to a very weak low pressure circulation over the central Atlantic.

12.   A weakening upper level low pressure trough moved west across Puerto Rico during the night accompanied by scattered showers.

13.   A short wave low pressure trough will move rapidly southward from the coasts of New Jersey and Delaware today and will reach Puerto Rico on Friday.

14.   A weak low pressure trough is moving westward today across Puerto Rico.

15.   An upper-level low pressure trough passed to the south of Puerto Rico and the Virgin Islands Wednesday morning.

16.   An increase in cloudiness and shower activity can be attributed to this low pressure trough as it spreads westward to the Virgin Islands and eastern Puerto Rico tonight.

17.   An upper level low pressure trough remains in about the same location between Puerto Rico and the Virgin Islands as it has since Thursday.

18.   An upper level low pressure trough that was located across Puerto Rico and the Virgin Islands yesterday has weakened and moved east of the area.

19.   An old frontal boundary which is the remains of a cold front is drifting southward through the Atlantic and is aided by an upper level low pressure trough.

20.   An upper level low pressure trough is now stationary across Puerto Rico but is in the process of weakening.