Upper tropospheric cyclonic vortex

A weak inverted wave in the easterlies is generally found beneath it, and it may also be associated with broad areas of high-level clouds.

Symbiotic relationships can exist between tropical cyclones and the upper level lows in their wake, with the two systems occasionally leading to their mutual strengthening.

When they move over land during the warm season, an increase in monsoon rains occurs Using charts of mean 200-hectopascal circulation for July through August (located 9,200 metres (30,200 ft) above sea level) to locate the circumpolar troughs and ridges, trough lines extend over the eastern and central North Pacific and over the North Atlantic.

[4] In the Northern Hemisphere, the tropical upper tropospheric trough (TUTT) normally occurs between May and November, with peak activity between July and September.

James Sadler suggested a revised model for the TUTT during the early part of the typhoon season in the western Pacific.

Both Sadler and Lance Bosart have shown that the tropical upper tropospheric trough cyclonic cells are caused by the mid-latitude disturbance riding around the western side of the tropical upper tropospheric trough when the subtropical ridge to its south is quite weak.

Toby Carlson evaluated data over the eastern Caribbean sea for October 1965 and pinpointed the presence of an upper tropospheric cold-core cyclone.

Cumulonimbus clouds and rainfall occur in the southeast quadrant, approximately 5° latitude (or 555 kilometres (300 nmi)) from the upper cyclone center.

The area of heavy rain is generally located in the northeast quadrant approximately 5° of latitude (or 555 kilometres (300 nmi)) from the eye.

[13] Across the north Indian Ocean, the formation of this type of vortex leads to the onset of monsoon rains during the wet season.