SYNOPTIC DISCUSSION

MONDAY 06thAPRIL 2026 PM SHIFT

TONIGH INTO TOMORROW:

As of now, the easterly wind flow remains prevalent over the vicinity of Samoa, since a ridge of high pressure extending from the south, located east of New Zealand. Which withholds the newly upgraded Tropical Cyclone CATEGORY 3 Vaianu stationed to the northwest of Fiji, while forecasted to move southeastward. Yet, it poses no imminent threat to the Samoan Islands.

The sounding profile for the area of concern, it indicated low-level moisture content, weak deepening wind vertical structure, weak low-to-mid level wind shear and instability. As a result, it generate diurnal variation weather patterns. Furthermore, no upper level system for longevity but strong southwesterly aloft which sheared developed observed convective clouds. For that reason, the satellite data collectively observed afternoon showers mainly windward locations and interior areas. For tomorrow, expect a decreased cloud coverage in the early hours of the morning, then in time, expect afternoon showers due to intense surface heating. Lastly, due to the Tropical Cyclone Vaianu movement tracking to the southeast, this swerve the mean wind flow to be northeast.

WEDNESDAY THROUGH SUNDAY:

The model consensus, general agreed that the previously named ridge of high pressure system extending from the east of New Zealand will be the dominant weather feature. This system, will maintain the course of the Tropical Cyclone Category 3 Vaianu, with the forecast track predicted to shift southeastward, with a low chance of impact over Samoa. On that note, this means the trade wind regime is most likely to persist over the forecast area, with the mean wind flow veer from northeast to north on Wednesday and then northwesterly on Thursday through Friday as the previously stated ridge of high pressure extends across the country. Then on Saturday into Sunday, it will descend to the south, which the wind become easterlies. Throughout the outlook period, there’s probable chance of no upper level forcing, so expect diurnal weather patterns.

MARINE OUTLOOK:

The latest marine observations from King Poloa, Aunu’u wave buoys, and altimeter data indicate that wave and swell heights fluctuate around 2 metres. Global wave models suggest that wave activity fluctuate below 2.5 metres over Samoa’s marine waters until Saturday into Sunday where there’s a low chance of significant wave height that may enter Samoa’s southern marine waters.

ADVISORIES/WARNINGS:

NONE

Weather Duty Team:

A. Liu, A. Niko, A. Uili, & F.U. Namulau’ulu.