southern pacific Severe Tropical Cyclone Amos

[Somerset Squall]

A new tropical cyclone, named Amos, has formed a few hundred miles west of Samoa and about the same distance northeast of Fiji. Winds are at 35kts. The cyclone has some deep, centralised convection and improving banding features. Amos is forecast to strengthen steadily over the coming days over warm water and low shear. In a few days, increasing shear and cooler along track sea temperatures will serve to weaken Amos. JTWC expect a peak of 60kts before this occurs.

Amos is currently heading westwards on the north side of a weakening ridge to the south. A sharp turn back eastwards is expected as the southern ridge continues to weaken and a stronger ridge to the north begins to dominate. Once more, a meandering track, a common thing this year.

 

Edited April 22, 2016 by Somerset Squall

[Somerset Squall]

Amos has strengthened more than originally anticipated. Winds are at 75kts, and the system is developing an eye, embedded in the central dense overcast. Further strengthening is expected as Amos moves east-southeast towards Samoa, with winds of 100kts+ now expected as shear is low, waters warm and outflow very good. Rapid intensification is possible.

[Chris W]

Fiji Met forecast track showing destructive to very destructive winds crossing Samoa's western Savai'i island (including some popular tourist areas) at Category 4 before grazing the south coast of the eastern Upolu island away from the capital Apia, with widespread gales across both islands. 

http://www.met.gov.fj/aifs_prods/65661.html

Savai'i is thankfully less populated than Upolu.  They remember Cyclone Evan well there and are better prepared this time, but this is looking more significant today.

[Somerset Squall]

Indeed Chris. Amos has accelerated eastwards at a faster pace than forecast, meaning it probably will not turn south in time to prevent a severe impact. Winds are up to 90kts according to JTWC, with no further strengthening forecast. A storm of this strength is more than capable of causing damage and flooding however.

 

[Chris W]

Thankfully not such a severe impact on Samoa as feared as one stage, as Amos remained Category 3 and stayed further north than expected (it had been forecast to directly cross Apia).  Something of a relief, definitely.

[Somerset Squall]

Amos died a death shortly after clearing Samoa, as strong shear tore it apart, which was not expected to happen. Regeneration is not expected.