SYNOPTIC DISCUSSION
SATURDAY 07th MARCH 2026 AM SHIFT
TODAY:
A trough of low-pressure has moved south of Samoa, allowing the moist northerly wind flow to dominate and keeping unstable atmospheric conditions across the group. Satellite imageries this morning show a developing line of convective activity just north that are gradually moving towards the group. The morning ascent from Pago (12z) indicates an unstable atmosphere with a precipitable water value reaching 57.29mm which is also well reflected in MIMIC Total Precipitable Water (TPW) imagery. Relative vorticity field at 850mb reveals a strong vorticity environment positioned just south of the group with a weak deep-layer wind shear over the region. For today, convective storms moving from the north are expected to bring scattered showers with heavy downpours in some areas and thunderstorms. Gusty winds are also expected during periods of heavy rain across the group.
SUNDAY THROUGH FRIDAY:
Global weather models suggest that the aforementioned low-pressure trough will continue to move southward, with moist northwesterly winds dominating the group through at least Sunday. Model consensus hint that the SPCZ may fluctuate over the forecast area in a disorganized formation. In addition, another short-wave trough is forecast to move across the group on Monday bringing showery conditions with the potential for brief moderate to heavy falls. From Tuesday, speed convergences along the Easterly trade winds are expected to induce showery conditions in the upcoming week, with surface winds potentially exceeding 25 knots at times.
MARINE OUTLOOK:
The latest marine observations from Aunu’u, King Poloa wave buoys and altimeter data indicate that the wave and swell heights fluctuate at 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:
Kalapani, Sofeni, Baker & Maualaivao.