SYNOPTIC DISCUSSION
WEDNESDAY 11th MARCH 2026 AM SHIFT
TODAY:
The weather map analyses show that the trough of low pressure located west of Samoa coincides well with the latest observational data, revealing convective activity to the west associated with the system. Meanwhile, much moisture and unstable conditions over Samoa, due to the dominance of the moist northeasterly wind flow, continue to persist across the group. The satellite data indicates developing convective storms to the north and west of Samoa, moving over the area and bringing cloudy conditions, periods of heavy falls with gusty winds in some areas of the group. Additionally, deepening northeasterlies refine that moisture advection over the region, which is reflected on MIMIC Total Precipitable Water (TPW) imagery. A strong southwesterly wind aloft persists, steering upper clouds and moisture over the islands. However, no significant uplift over the forecast area may result in easing weather through the evening.
WEDNESDAY THROUGH MONDAY:
Global weather models suggest that the easterly trade winds will dominate the forecast area through at least Saturday. Model consensus hints that the SPCZ may fluctuate further south of the group in a suppressed and disorganized formation throughout this outlook period. Speed convergences along the easterly trade winds are expected to induce showery conditions with gusty periods this week, although predominantly fine weather is expected across most areas. In addition, a weak short-wave trough is forecast to move across the group on Saturday, but unfavorable environmental conditions may suppress the system. The lack of a significant upper-level forcing throughout this outlook period suggests that cloud development will be largely diurnally driven over the forecast area.
MARINE OUTLOOK:
The latest marine observations from Aunu’u, King Poloa wave buoys and altimeter data indicate that the wave and swell heights fluctuate below 2 meters, suggesting no imminent threat across Samoa’s marine waters. Global wave models suggest that wave activities will persist below the advisory threshold of 2.5 metres throughout this outlook period.
ADVISORIES/WARNINGS:
VALID: HEAVY RAIN ADVISORY
Weather Duty Team:
A. Niko, LI. Tuatipi, P. Huch & C. Baker.