11. Isolated thundershowers will develop in the afternoon, as a trough of low pressure presses east through the region. 12. In early September, a trough of low pressure moved south into the Gulf of Mexico, and became stationary. 13. Around 1830 trough of low pressure . 14. This precipitation was associated with an unstable local aimass aided by the proximity of a trough of low pressure . 15. The disturbance was part of a broad trough of low pressure settling over the west coast of North America. 16. A trough of low pressure digging into the West Coast brought unsettled weather to a chunk of the West. 17. Farther west, scattered showers and thunderstorms will speckle the southern Rockies as a trough of low pressure drifts overhead. 18. The precursor trough of low pressure produced torrential rainfall across Florida, peaking at 17.5 inches ( 440 mm ). 19. As the disturbances pressed inland Sunday night, they started to carve out a trough of low pressure over the Rockies. 20. The depression then eventually opened up into a trough of low pressure by 00 : 00 UTC on September 1.
