Severe Tropical Cyclone Atu

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[Somerset Squall]

The depression has been upgraded to Tropical Cyclone Atu this morning, continuing the active South Pacific season, with intensity rising to 55kts. The system has rapidly developed a central dense overcast feature and an eye appears to be forming. Atu is currently moving through Port Vila, causing damaging winds and heavy rain here. As a subtropical ridge forms to the east, Atu should be steered southwards away from Port Vila. The cyclone should remain to the east of New Caledonia but could bring some adverse weather here too. With low shear, warm sea temps and good upper level outflow, Atu should continue to intensify before becoming extratropical north of New Zealand over colder water.

[Somerset Squall]

Eye now evident on satellite imagery:

[Somerset Squall]

Atu has stengthened rapidly overnight, becoming a Severe Tropical Cyclone with an intensity of 90kts. Atu's eye has contracted and become better defined. Low shear, warm sea temperatures and good outflow should allow further strengthening over the next couple of days, and I believe Atu could become a cat 4 on the SS scale before extratropical transition begins over colder water. Atu is likely to become a very potent extatropical storm northeast of New Zealand in about 72-96hrs time.

[Cookie]

impressive looking system, thanks for the updates mate

[Somerset Squall]

Atu maintains a very small eye and has continued to intensify. Intensity has risen rapidly to 110kts, a high end cat 3 on the SS scale. Cat 4 looking very likely now.

[Somerset Squall]

Atu developed a pinhole eye last night and attained an intensity of 115kts, making the cyclone a cat 4 on the SS scale. Atu then underwent an eyewall replacement cycle, typical of intense systems. The cycle is now complete, but has weakened Atu to 100kts. Atu is still in a low shear environment and waters remain warm so the cyclone should re-intensify at least modestly through today and tomorrow before the southerly track puts Atu over waters below 26C.

[Somerset Squall]

Atu has acclerated southeastwwards out of the tropics and is well on the way to completing extratropical transition. Atu is still expected to become an intense extratropical cyclone east of New Zealand.