SYNOPTIC DISCUSSION
WEDNESDAY 04th MARCH 2026 AM SHIFT

TODAY:

Stable weather conditions have been observed across Samoa as the easterly wind flow continues to prevail over the country. Dry and suppressed convective activities are seen over the region as per satellite data, where no thunderstorm developed within the vicinity over the past 12 hours. The easterlies continue to persist at the upper levels with a strong wind shear environment. The high-pressure systems still located further southeast of Samoa, which responsible for directing light easterly wind flow, with few fair weather cumulus across the group while major convective activities associated with the SPCZ remains positioned further south.The weak relative vorticity at 850mb over the group contributes in convective inhibition, these atmospheric conditions may continue to withhold thunderstorm development, apart from few congestus clouds possible over highland areas as a result of localized effects. Therefore, expect generally fine weather with few showers in some areas today.

THURSDAY THROUGH MONDAY:

Global weather models suggest that the easterly trade winds will dominate the forecast area by Wednesday, as the aforementioned high-pressure ridge shifts southward. This synoptic pattern is expected to maintain the SPCZ positioned further south of Samoa throughout this outlook period. As a result, trade-wind showers, coupled with possible localized afternoon convection will be the primary rainfall mechanism. Otherwise, predominantly fine weather conditions are anticipated during this period. A weak upper-level trough may linger over the group by mid-week and may induce some atmospheric instability; however, lack of low-level moisture and surface uplift would result in minimal rainfall activity across the group. Additionally, a surface trough is forecast to move over the island group on Friday, likely resulting in a slight increase in showery conditions. The easterly trade wind regime should dominate the remaining days of the outlook period.

MARINE OUTLOOK:

The marine observational data, generally indicated wave and swell heights fluctuates below 2.5 metes, posing no threat to our coastal and marine waters today into today. Furthermore, this observed wave trend could likely to persist through next 4 days with the low-probability in the outlook period.

ADVISORIES/WARNINGS:
NONE

Weather Duty Team:
A. Niko, A. Sofeni, P. Huch & C. Baker.