SYNOPTIC DISCUSSION
FRIDAY 06th MARCH 2026 PM SHIFT

TONIGHT & TOMORROW:

Light and variable winds were observed across the islands with thundery activities which occurred late morning through the afternoon as a result of a surface to mid level trough stationed over the group. CIMMS observations indicated the presence of favorable mechanisms for cloud development with a weak signature. GOES-18  satellite animation depicted lightning activities associated with the aforementioned synoptic setting. Togitogiga AWS registered the peak value for 5 mins rainfall observations when convective cells were observed at the mountainous regions of Upolu. Weak sheared environment is being marked over our AOR with sufficient moisture hinted through the vertical profile of the atmosphere. The surface rain-maker system is predicted to descend southward whilst the mid-trough stations over the island chain tomorrow afternoon. The conditions of the atmosphere remains conditionally unstable and maintains the vulnerability of the area of forecast to heavy falls and gusty winds even though there is a weak divergence anticipated aloft.

SUNDAY THROUGH THURSDAY:

A surface to mid-level trough is forecasted to relocate northward of the islands by Sunday reducing the trend for rainfall accumulation for the start of this outlook period. The axis of the SPCZ will continue to fluctuate further west of the SWP region with trade wind regime anticipated for the new week. A ridge of high pressure will enter the upper atmosphere and dominate during Monday through Tuesday. An upper trough is forecasted to relocate over the zone in the last days of the upcoming week. A surge along the Easterly trend is expected to generate periods of rain during mid-week elevating the chance of 25-35 knots particularly for the low to mid-level atmosphere. Therefore, expect brief showers with gusty Easterlies for Tuesday through Thursday.

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:
Gafa, Kalolo, Huch & Uili.