SYNOPTIC DISCUSSION
SUNDAY 30th NOVEMBER 2025 PM SHIFT

TONIGHT INTO TOMORROW:

Unsettled weather conditions continue to prevail over Samoa, due to the presence of a trough of low pressure system in the vicinity. The satellite imagery confirms that the persistence of this system is associated with thunderstorms and lightning, although most activity is concentrated offshore. The Pago Pago sounding profile also illustrates a significantly moist atmospheric vertical profile, with a PWAT value exceeding 60 mm, which aligns with the broad moisture content depicted in the MIMIC TPW animation loop. The dominance of upper divergence in the area of responsibility corresponds to the extensive cloud cover observed in most locations. Consequently, periods of rain with heavy downpours and occasional thunderstorms are expected tonight.

For tomorrow, the majority of global weather models predict that erratic weather conditions will persist across our area of responsibility. This is attributed to the embedded trough of low pressure, which is expected to remain in the vicinity. There is a possibility of enhanced convective activities as the downstream northwesterly flow aloft of the upper trough approaches the western side of the group. Therefore, the previously issued warnings and advisories will remain in effect for all land areas of Samoa.

TUESDAY THROUGHSATURDAY:

Global weather models suggesting that a weak low circulation may likely to develop closer to the area of responsibility from the west by Tuesday into early . This may advance the likelihood windy conditions with precipitation wise likely to be reduced. The eastward movement of the upper trough located to the western side from the forecast region with the axis is forecast to linger over the islands on late Tuesday may likely catalyzed the aforementioned circulation. Meanwhile, easing conditions may persist on the mid-week with the reduction in rainfall accumulation within the 24hr period and may likely towards the conclusion of the outlook period. Periods of passing showers may likely to landfall as the southeasterly trades on Friday towards the latter day of this outlook period. Southeasterly into southwesterly aloft will likely to dominate the upper atmosphere by Thursday into the conclusion of the forecast period which corresponds to the slight mostly fine anticipated conditions.

MARINE OUTLOOK:
High northerly swells are forecast to impact all the marine waters of Samoa from tomorrow into Tuesday. Moderate to rough seas may likely to be observed across all the marine waters of the group due to the anticipated conditions – Thus, the Marine Advisory remains valid for all the country’s marine waters.

ADVISORIES/WARNINGS:
VALID: HEAVY RAIN WARNING

VALID: FLOOD ADVISORY

VALID: MARINE ADVISORY -  ALL OF SAMOA

Weather Duty Team:
Gospel N, Albert N, Punipuao H & Aquinas U