Sim timeDay 0 · 00:00

Classification—

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Central pressure—

Storm surge—

2032 °C

26.5 °C genesis threshold Forecast cone Ensemble

Inspector Hover over the basin Read sea-surface temperature, shear, steering flow and wind at any point.

Click open water to seed a tropical disturbance · Space pauses

Cyclone Lab

A tropical disturbance feeds on warm ocean water, spins up under the Coriolis force, and is steered across the basin by the large-scale flow. Shear, land and cold water tear it apart.

Playback speed 6 h / s

Environment drag while it runs

Warm pool (SST anomaly) +0.0 °C Vertical wind shear 5 m/s Latitude of basin (south edge) 8°N Steering wind (trade easterlies) 6 m/s Recurvature latitude (trough) 28°N

Saffir–Simpson scale

TDTS12345

Click on the ocean to seed a disturbance.

Max wind—

Pressure—

Eye wall radius—

Gale radius (34 kt)—

Motion—

Peak surge—

Environment at the storm

Structure cross-section through the centre

Life cycle history and ensemble forecast

What you are seeing

Fuel. Intensity chases a thermodynamic ceiling that grows with sea-surface temperature above ≈ 26.5 °C. The storm churns up cold water and leaves a cold wake that starves slow movers.
Spin. Near the equator the Coriolis parameter vanishes, so disturbances cannot organise below ≈ 5° latitude.
Shear tilts the vortex, exposes the low-level centre and ventilates the warm core with dry air.
Steering. The storm is carried by the deep-layer mean flow plus beta drift toward the north-west. Past the trough latitude the westerlies recurve it north-east.
Surge is driven by onshore wind squared, the low-pressure dome and the size of the wind field; the right-front quadrant is the worst.

Simplified model: Holland-type wind profile, Atkinson–Holliday wind–pressure relation, relaxation intensity dynamics, 20-member perturbed ensemble. Storm clouds are drawn 1.6× larger than scale so the eye stays visible.