SYNOPTIC DISCUSSION

TUESDAY 07th APRIL 2026 PM SHIFT

TONIGHT INTO TOMORROW:

The satellite data collectively indicated developed cloud formation mainly over highlands and the southern portion of both Samoan Islands in the afternoon. Such weather phenomena is largely driven by diurnal atmospheric conditions since the easterlies remains prevalent over the area of responsibility. On that note, the sounding profile clearly indicated low-level moisture content, weak deepening wind structure, weak steering wind flow and instability. Thus, promote vertical cloud formation, yet it was restricted by the southerly aloft that generated a weak upper convergence zone and strong wind shear environment. As a result, it formed short-lived towering cumulus and cumulonimbus mainly across windward locations. Then eventually eased and dissipated through early evening. Principally, the prevailing mean wind flow is forecasted to veer and become northeasterlies later tonight into tomorrow with the diurnal weather patterns is very likely over the area, and some showers along the wind flow. 

THURSDAY THROUGH MONDAY:

The numerical weather predictions, generally agreed with a moderate-to-high chance of minimal rainfall activities throughout the outlook period. So, a ridge of high pressure system extends over Samoa from the south, bringing fine weather with showers mainly over highlands. Yet, this system descends to the south on Friday as the Tropical Cyclone Category 3 continues to track southeastward with a no chance of impacting the Samoa islands. Thus, this again re-introduced the trade wind regime or easterlies with showers along the mean wind flow on Saturday through Monday in the new week. Model indicated as well the movement of an upper-level trough near the island chain over the weekend, this situation likely to trigger some rainfall activities.

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 will 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:

LMSA, P. Huch &A. Uili.