SYNOPTIC DISCUSSION
THURSDAY 25thDECEMBER 2025 AMSHIFT

TODAY INTO TONIGHT:

The satellite images, showcase the SPCZ remains to the south with the embedded trough of low pressure that composed of rainfall and thunderstorms. Even, though the most areas of the country experienced slight fair weather, but the vertical profile of the atmosphere confirms that it is considered conditionally unstable. Further, early hours of this morning that a short-lived convective clouds formed within the vicinity that generate periods of brief heavy falls and a few thunderstorms. So, atmospherically for today, there’s available low-level moisture advection, with weak low-to-mid level winds and sufficient instability plus the intense daytime heating. Hence, there’s a likelihood of brief heavy downpours and a few thunderstorms mainly over elevated and windward location this afternoon.

For tonight, expect diurnal weather patterns that may extend through tonight. Thus, the highlighted advisories remains enforced for all of Samoa.

FRIDAY THROUGH WEDNESDAY:

Generally model consensus, suggested that the SPCZ may slowly move near the island chain on Friday with the low chance that could landfall over the vicinity on Saturday. The model’s perspective, evince that the potentiality for severity and longevity is low. Concurrently, there’s a likelihood of proper weak low-level weak circulation formed over the area of forecast, this would shift the SPCZ to the north of Samoa on Monday through the later part of the outlook period. But, in the upper atmosphere, an upper trough of low pressure is forecasted to progress eastward and it composed of a upper diffluence on Friday that with a low probability that it may hover over the region until Monday. So, the likely expected weather scenario, it requires thorough evaluation and advise any major changes.

MARINE OUTLOOK:

The latest marine observations continue to show that wave and swell heights remain below the advisory threshold of 2.5 meters. Global wave models suggest that these wave conditions will persist below the advisory threshold during this forecast period.

ADVISORIES/WARNINGS:
VALID: HEAVY RAIN ADVISORY

VALID: FLOOD ADVISORY

Weather Duty Team:
A. Liu, A. Niko, L. C. Baker, & F. U. Namulau’ulu.