Tropical cyclone Jason was the first tropical cyclone to affect the Eastern region during the 1986/87 season. It developed into a tropical low at about 0000 UTC 6 February within a cloud mass over northern Cape York Peninsula and the northeastern Gulf of Carpentaria.
The tropical low then moved west-southwest across the Gulf of Carpentaria and deepened gradually, even though the upper air structure was not favorable for cyclogenesis. When midway across the Gulf near 12.6°S, 139°E, the system reached cyclonic intensity, with a central pressure of 985 hPa, at 0600 UTC 7 February. The system continued to move west southwest and deepened a further 10 hPa before turning west northwest around 1200 UTC 8 February when near 13.4°S, 137.4°E. Up to this time the track was similar to Irma , some three weeks earlier. As the cyclone approached the coast the first of two loops commenced at 1800 UTC 8 February, taking about 12 hours to complete. The coastal crossing occurred about 0000 UTC 9 February near Caledon Bay. As Jason weakened over land on the 10th it looped a second time.
Ex-tropical cyclone Jason then drifted slowly southward and moved over water again by 0000 UTC 11 February. It had moved into an area where the upper air structure favored development and it reached cyclonic intensity a second time at about 0300 UTC 11 February near 13.9°S, 136.3°E with a central pressure of 990 hPa. From this point its track was first east across Groote Eylandt, then southeast.
Jason continued to intensify and became a severe tropical cyclone about 1800 UTC 12 February with a central pressure of 970 hPa near 15.1°S, 139.6"E. At about 0000 UTC 13 February Jason made its final turn from southeast to southwest and three hours later made landfall some 40 kilometres northeast of Burketown with a central pressure of 975 hPa.
The maximum intensity was reached at about 1800 UTC 12 February with a central pressure of 970 hPa which was maintained until 0000 UTC 13 February. The highest reported wind speed was 158 km/h at Burketown at 0520 UTC 13 February. The lowest recorded pressure was 981 hPa at Mornington Island at 0030 UTC 13 February. The highest reported storm surge was 2 metres at 0500 UTC 13 February at Karumba but it is estimated that the surge reached3.5 metres along the uninhabited coast west of Karumba. The residents of Karumba were evacuated as Jason approached the coast.
Jason destroyed most buildings in the Northern Territory community of Baniyalla. Some damage was also reported from Burketown and Gapuwiyak. There were no deaths or serious injuries.