FORECAST DISCUSSION

MONDAY 04th MAY 2026 AM SHIFT  

TODAY INTO TONIGHT:

Early this morning, various satellite channels signified developing isolated convective clouds across the vicinity, as the moist northeasterlies now prevails. Meanwhile a convergence zone or SPCZ currently lies to the south of Samoa responsibly influencing Samoa’s weather while steadily moving near the forecast region. Cooperatively the sounding profile and total precipitable water animation still revealed abundant moisture content. What’s more, present weak mid dry slot, weak low-level wind shear, and moderate instability. In addition, regardless of an observed upper level strong wind shear over the area of concern, there’s a upper level diffluence that generates divergence aloft, in which supports vertical cloud growth, which provided showers and a few thunderstorms. The model consensus, suggested that this system is likely to move closely near the area later tonight, maintaining unstable weather conditions.

TUESDAY THROUGH SUNDAY:

The numerical weather guidance, generally exhibit that the convergence zone or South Pacific Convergence Zone (SPCZ) may slightly locate near south of the country, that would prolong showery and thundery activities at least Wednesday. Furthermore, in this time frame the previously stated upper level diffluence, may continue to enhanced the surface system. Since the intensified high pressure located to the northeast of New Zealand steered eastward, causing the system to descend to the southeast on Thursday. Then the mean wind flow veered to the east-to-southeast, which would reinforce the trade wind regime with passing showers and diurnal weather patterns in the later part of the outlook period.

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. Global wave models suggest that a southerly combined wind waves and swells may approach the group and likely affect the southern marine waters from Wednesday through Saturday. These wave activities has a low potential that could impact Samoa’s marine areas during this period.

ADVISORIES/WARNINGS:

NONE

Weather Duty Team:

A. Liu, A. Sofeni, C. Baker & N. Tutasi.