Hurricane Pali

The first tropical cyclone of the 2016 Pacific hurricane season, Pali originated as an area of low pressure within a persistent trough, near the equator on January 6, 2016.

The next day, Pali reached its peak intensity as a Category 2 hurricane, with 1-minute maximum sustained winds of 100 mph (155 km/h)[nb 1] and a minimum central pressure of 978 mbar (hPa; 28.88 inHg).

This made Pali the second-lowest latitude tropical cyclone on record in the Western Hemisphere at the time, which was extremely unusual, given the unfavorable conditions that are usually in place around the equator.

Pali had severe impacts in Kiribati, grounding a cargo ship and killing four people, in addition to causing major coastal flooding, although the total amount of damage was not specified in the island nation's report to the World Meteorological Organisation (WMO).

[2][3][4] As currently defined, the Pacific hurricane season lasts from May 15 to November 30, the period in which tropical cyclones are most likely to develop across the basin.

Tropical Depression Nine-C quickly dissipated by the start of 2016, leaving behind a large area of moisture across the equatorial Pacific.

The low and the trough drifted northward, as the subtropical ridge spanning the region was significantly weakened by a passing extratropical storm in the North Pacific.

[1][15] Pali continued intensifying through the first half of January 8 and nearly reached Category 1 hurricane strength, with maximum 1-minute sustained winds reaching 70 mph (110 km/h), but easterly vertical wind shear caused by the ridge aloft increased and disrupted its center, causing the storm to start weakening and curve northwestward.

[1] Steady weakening continued through January 9, as Pali's deep convection was displaced to the west of its low-level circulation center and intermittently pulsed, later leading to a sharp decrease in the storm's intensity.

The lack of persistent deep convection resulted in Pali being a weaker system, but this permitted the storm to be more resistant to the easterly wind shear, causing its forward motion to decrease significantly.

[1] The ridge of high pressure weakened and retreated southward on January 10, which caused the vertical wind shear to gradually diminish.

[1][16] During the next few days, Pali rapidly weakened while turning back towards the south-southwest, due to steady increases in southerly vertical wind shear and the loss of Coriolis force.

The track of Hurricane Pali (in red), compared to those of the other tropical cyclones in the NOAA's database, dating from 1842 to 2015
Map plotting the storm's track and intensity, according to the Saffir–Simpson scale
Map key
Tropical depression (≤38 mph, ≤62 km/h)
Tropical storm (39–73 mph, 63–118 km/h)
Category 1 (74–95 mph, 119–153 km/h)
Category 2 (96–110 mph, 154–177 km/h)
Category 3 (111–129 mph, 178–208 km/h)
Category 4 (130–156 mph, 209–251 km/h)
Category 5 (≥157 mph, ≥252 km/h)
Unknown
Storm type
triangle Extratropical cyclone , remnant low, tropical disturbance, or monsoon depression