11.   John Weems, the shuttle launch weather officer, said that a weak tropical system is directing rain and gusty conditions toward Florida.

12.   Many of the long-term predictions are based on research by William Gray, a Colorado State University forecaster who tracks tropical systems and the forces that create them.

13.   On Sunday, the rain from Gabrielle will push into the Atlantic Ocean as jet stream winds carry the tropical system out to sea.

14.   On Wednesday, the marginal tropical system will move eastward across the Gulf of Mexico toward Florida.

15.   Paradoxically, the tropical low-pressure system formed in a region of high barometric pressure.

16.   Satellite images of precipitation over the Rockies and great swirling tropical systems over the Gulf and Caribbean are irresistible.

17.   Sinking air behind the tropical system will sponsor plenty of sunshine from Boston to Washington.

18.   Sometimes, a stalled tropical system can be its own enemy, promoting upwelling cool water that causes the storm to weaken.

19.   Such inflated rainfalls along the Gulf Coast in September can only occur when tropical systems are involved.

20.   Subsiding currents of air behind the tropical system will squelch clouds across the southern Plains and Texas.