Khaberni - Low pressure systems in Jordan usually start with the onset of the rainy season, but their timing varies from year to year. In some years, the first systems form at the end of September/October, while in other years they start in early November, and in other years the first one arrives in December, with some years seeing their arrival delayed until February as occurred last season.
Climatic factors affecting the arrival of low pressure systems to Jordan, and the weather specialists at Arabs Weather have stated that several weather factors influence the extent to which low pressure systems reach Jordan, the most important of which are:
1- Location of the jet stream:
The jet stream is a fast-moving path of winds in the upper layers of the atmosphere, which directly controls the path of low pressure systems.
2- Arctic Oscillation (AO):
Arctic Oscillation or Arctic fluctuation is an index to measure the intensity of low pressure systems over the Arctic. When the indices are in positive values, it means the intensification of low pressures above the Arctic and the stabilization of the polar vortex. However, when the indices collapse and are in negative values, it means the formation of a high-pressure system over the Arctic and the collapse of what is called the polar dome.
3- North Atlantic Oscillation (NAO):
The NAO index measures the differences in atmospheric pressure between Iceland and the Azores. Negative values help push low pressures towards the Mediterranean and the Middle East, while positive values tend to push them northward.
4- Location of the Siberian high pressure:
The winter Siberian high represents an area of extremely cold high pressure. If this high extends westward, it can block low pressures and prevent them from reaching our region.
