Polar trough

{
  "id": "MLC-T-MET-008032",
  "term": "Polar trough",
  "field": "Meteorology and atmospheric science",
  "definition": "A trough in the circumpolar westerlies of large enough amplitude to extend into the tropics in the upper air, a term used in tropical meteorology. At ground level it appears instead as a trough within the tropical easterly flow, while at moderate heights the winds near it are westerly.",
  "see_also": [
    "meridional front"
  ],
  "url": "https://mlchart.com/terminology/meteorology/polar-trough/"
}