major trough

major trough

[′mā·jər ′trȯf]
(meteorology)
A long-wave trough in the large-scale pressure pattern of the upper troposphere.
References in periodicals archive ?
There was no high pressure advance, while yet another secondary trough built behind, another frontal collapse, while in the upper air west of Namibia a major trough formed, evolving into a clearly marked cut-off vortex.
Further support looms at the next major trough on daily charts at the Feb.
We just dug around where the major trough was and we got a split in the pipe.
Although I am quite a good sailor, I remember one fierce crossing where we hit a major trough in the middle of the night, like the Poseidon Adventure.
Our average daily good (not denied, cancelled or withdrawn) loan locks hit a major trough in the third week of October as consumers held back in response to the rise in mortgage rates that began in late September.
This weakening enabled a major trough to form and intensify up to the upper troposphere, 200hPa level and, by model prognostics, shape into a neat cut-off vortex pattern.
A major trough passed quickly south of the Cape, only to be succeeded even quicker by another system, while a northwesterly drift persisted aloft, as witnessed by several successive morning's turbulent altocumulus sheets.
With a major trough and its cold front moving south of the Cape, being driven by an anticyclone well to the south, our dry air patterns remain into next week, by which time low-level moisture extends into our skies; but this is absorbed by the dry upper air, though.
Friday sees this vortex weakens to be absorbed by a major trough moving in from mid-Atlantic reaching the Cape by Saturday, moving on by Sunday.
Its activity is limited as it is pushed across the land-mass by a ridge so giving way to a major trough and vortex core presently further south over the Atlantic.
Currently, the South Atlantic features a major trough above the surface from the 60[degrees]S vortex (surface) to the 35[degrees]S latitudes.
The persistent and intense anticyclone on the southwestern Atlantic generates two major troughs, Saturday and Tuesday but both follow the same dissipating example, leaving all but the extreme southwest within a northerly orientated flow for the new week.