FORECAST DISCUSSION

MONDAY 27th APRIL 2026 – A.M SHIFT  

TODAY:

The easterlies remain persistent over the forecast zone, accumulating lower cloud content over the easternmost shores of the main islands. Data from the sounding profile of the atmosphere indicates elevated precipitable water & convective potential energy, which induce the development of convective clouds over interior areas, resulting in brief, isolated showers and possible thunderstorms. The inclusion of solar radiation in the early hours has initiated such development; therefore, anticipate such conditions for today and expect them to ease towards the evening.

TUESDAY THROUGH SUNDAY:

Global weather models suggest that the trade-wind weather regime will persist across Samoa throughout this outlook period. A high-pressure system is expected to dominate the mid-levels, maintaining an easterly steering flow. The lack of a significant upper-level forcing mechanism suggests that cloud development will be largely diurnally driven during this outlook period. This synoptic pattern may induce a relatively dry airmass and subsidence aloft over the region, which may inhibit significant convective storm development and growth. NWP indicated a surface trough to migrate near the forecast zone later in the week which may induce rainfall activities, however, high uncertainty for the meantime.

MARINE OUTLOOK:

The latest marine observations from Aunu’u and King Poloa wave buoys indicate that wave heights continue to fluctuate below the advisory threshold of 2.5 metres. The wave watch models suggest that wave activities will persist well below the advisory threshold for the rest of this outlook period.

ADVISORIES/WARNINGS:

NONE

Weather Duty Team:

AN, FU. Namulau'ulu & A. Uili