Diverging Cyclone Threats: Maila Lingers, Vaianu Targets New Zealand

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Written by Aaron Studwell, Ph.D., Energy Meteorologist & Analyst, for IIR New Intelligence

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Summary

Tropical cyclones Maila and Vaianu present distinct but impactful risks across the South Pacific. Maila's slow movement raises prolonged flooding threats near Papua New Guinea, while Vaianu's transition toward New Zealand expands wind and rainfall impacts across critical infrastructure zones.

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Maila - Powerful but Uncertain, A Slow-Moving Risk Engine

Tropical Cyclone Maila (30P) remains a high-end threat in the Solomon Sea, though its structure is beginning to show signs of atmospheric stress. Current intensity is estimated to be near 105-115 knots (120-125 miles per hour (mph)) with a cloud-filled eye and increasing asymmetry. Dry air and easterly shear are impinging on convection on its eastern side. Despite that degradation, the broader environment remains supportive, with very warm sea surface temperatures near 29-30°C and favorable winds aloft.

The primary concern in the near term is Maila's slow forward motion. The system has been quasi-stationary at times, drifting west at only 2-3 knots. While this leads to regional ocean cooling from rainfall and ocean churning, intensification is forecast over the next 24 hours. This same slow forward motion also increases the risk of prolonged rainfall and coastal impacts across portions of Papua New Guinea and the surrounding maritime region.

Forecast guidance indicates a transition toward a more defined west-northwest to southwest track over the next 24-72 hours as the subtropical ridge builds eastward. This is forecast to accelerate Maila toward Cape York, Queensland, though track confidence remains low due to significant model divergence. Intensity guidance is more consistent, with steady weakening expected as upwelling, increasing mid-level shear, and eventual dry air entrainment take hold.

From an energy and infrastructure perspective, the Port Moresby region, particularly the ExxonMobil PNG LNG facilities, sits within the broader envelope of risk. Further east, the Puma Energy PNG Limited, Alotau Refined Products Storage Terminal will experience a close call as Malia skirts past the Milne Bay region. Even without direct landfall, the combination of persistent rainfall bands and coastal storm surge could lead to localized flooding, access disruptions, and operational slowdowns. Subscribers to Industrial Info's Global Market Intelligence (GMI) Oil & Gas Plant Database can click here and here to see the related plant profiles.

Given the slow evolution of the system, impacts may be drawn out rather than acute, increasing cumulative stress on logistics and infrastructure.

Vaianu - Transitioning South, Eyes on New Zealand

Tropical Cyclone Vaianu (31P) presents a more straightforward but still impactful scenario. Maximum sustained winds are estimated to be near 75 knots (85 mph). The system is beginning to encounter a more hostile environment with strong vertical wind shear and dry air intrusion Satellite presentation reflects this, with convection displaced and the low-level center partially exposed.

Vaianu is tracking south-southeastward along the western side of the Pacific subtropical ridge; the cyclone is forecast to continue on a southerly path over the next 36 hours. Unlike Maila, track confidence here is high--strong model agreement showing a continued push toward New Zealand's North Island. As the system progresses, it will cross into cooler waters and begin subtropical transition, with winds gradually weakening into the 40- to 50-knot range.

Unfortunately, weakening does not equate to reduced impact. As Vaianu expands and transitions, its wind field is expected to significantly expand, broadening the geographic footprint of impacts. The system is forecast to make landfall over New Zealand's North Island over the upcoming weekend. It will likely transition into a subtropical cyclone, embedded within a larger-scale trough and jet structure.

The Auckland, New Zealand, metro area is effectively in the crosshairs of this evolution. While peak winds may be lower than tropical thresholds at landfall, the combination of strong gradient winds, heavy rainfall and coastal surge introduces meaningful risk. Urban flooding, transportation disruptions, and power outages are possible, particularly given the expanded wind radii and rain shield.



Industrial Info's PECWeb platform indicates there are 36 onshore oil and natural gas-related plants in the possible storm path. These include a few refined product import terminals, while the others are generally infrastructure. Off the eastern coast of the North Island of New Zealand, there are four oil and natural gas production platforms and a floating production, storage and offloading vessel.

Key Takeaways

• Maila remains intense but structurally stressed, with slow motion increasing prolonged rainfall and flooding risk.
• Port Moresby and nearby LNG/refined product infrastructure face disruption risk despite no direct landfall.
• Forecast uncertainty for Maila's track remains high, though weakening is likely longer term.
• Vaianu is weakening but expanding, with high-confidence track toward New Zealand's North Island.
• Auckland metro area faces elevated risk of flooding, wind damage, and power disruptions.
• Broad infrastructure exposure exists across northern New Zealand, including terminals and offshore production assets.

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About IIR News Intelligence
IIR News Intelligence is a trusted source of news for the industrial process and energy markets, powered by Industrial Info Resources' Global Market Intelligence (GMI).

About Industrial Info Resources
Industrial Info Resources (IIR) is the leading provider of industrial market intelligence. Since 1983, IIR has provided comprehensive research, news and analysis on the industrial process, manufacturing and energy related industries. IIR's Global Market Intelligence (GMI) helps companies identify and pursue trends across multiple markets with access to real, qualified and validated plant and project opportunities. Across the world, IIR is tracking over 250,000 current and future projects worth $30.2 trillion (USD).