Buffeting the island chain of Vanuatu, Donna has resulted in severe damage throughout the northern provinces, though the exact extent is unknown in the absence of good communication.

On 1 May, the day after the official end of the South Pacific cyclone season, the Joint Typhoon Warning Center (JTWC) began monitoring an area of disturbed weather about 1,455 km (905 mi) west-northwest of Nadi.

Though it possessed an oblong area of low pressure partially exposed to the northeast of deep shower and thunderstorm activity, the system was embedded within an environment of moderate wind shear, good upper-level outflow, and warm ocean temperatures.

[3] The storm tracked slowly eastward through the northern islands of Vanuatu but consolidated rapidly as upper-level winds became light, prompting the FMS to upgrade the disturbance to Tropical Depression 21F at 18:00 UTC on 2 May.

[8] The JTWC, meanwhile, upped the cyclone to the equivalent of a Category 1 hurricane on the Saffir–Simpson scale, citing consolidation of deep convection near the centre and satellite intensity estimates around 120 km/h (75 mph).

[12][13] Shortly thereafter, the effects of increased northeasterly upper-level flow became more prevalent as the storm's cloud pattern changed to a central cold cover and then devolved into patchy areas of moderate convection.

[20] With a solid ring of deep convection surrounding a well-defined 55 km (35 mi) eye,[21] the FMS upgraded Donna to a Category 5 cyclone at 00:00 UTC on 8 May, estimating that the storm possessed 10-minute sustained winds of 205 km/h (125 mph).