FORECAST DISCUSSION

THURSDAY 16th APRIL 2026 – A.M SHIFT

REST OF TODAY:

The moist easterly wind flow remains prominent in the lower atmosphere – driven by a strengthening high pressure system. However, a weak trough of low pressure lies further east from our shores – aligning with the latest satellite images. Sounding profile of the atmosphere indicates instability over the area, coupling with PWAT of 49.43mm – also indicating moisture content more focused to the south with fragments being advected over the group. Withal, the predominant easterlies remain over the area, whereas the onset of showery activities may be limited only to solar radiation on setting localised convections due to surface heating and orographically enhanced showers for the group.

FRIDAY THROUGH WEDNESDAY:

Global weather models suggest that gentle to moderate easterly trade winds will dominate the surface through at least Friday. A high-pressure system currently centred east of Australia is expected to move eastward, pushing the South Pacific Convergence Zone (SPCZ) near south of Samoa during the weekend, and is likely to bring showery conditions over the group – although activities may be limited due to a weaker system approaching. A high-pressure ridge may linger over the region during this period, providing light, variable steering flow, suggesting a lack of vertical disruption to convective development. In addition, southwesterly to westerly winds aloft are forecast to dominate the uppers through at least Sunday, before an upper high moves over the region. These synoptic weather patterns may inhibit significant widespread convection over Samoa, although moderate to heavy falls are still likely in parts of the group.

MARINE OUTLOOK:

The latest marine observations from Aunu’u and King Poloa wave buoys as well as altimeter data indicate that wave heights have fluctuated below 2 metres over the past 12 hours. These wave activities are forecast to persist throughout this outlook period, posing no significant wave-related hazards to the islands’ marine waters.

ADVISORIES/WARNINGS:

NONE

Weather Duty Team:

MJS, Albert Niko, Fuimaono Uili Namulauulu, Lemauga Christopher Baker.