SYNOPTIC DISCUSSION

MONDAY 30^th JUNE 2025 PM SHIFT

TONIGHT INTO TOMORROW:

As of now, the prevailing southeasterly wind flow remains prevalent over the area of responsibility. What’s more, the Samoa’s fine weather conditions with brief afternoon showers mainly over highlands and windward locations. On that note, radiosonde profile indicate low-level moisture content with instability which coincide with the integrated water vapor animation. Even so, the upper-level dry airmass and the strong wind shear hinders the vertical cloud formation. Hence, the satelite data indicate flares of cirrus indicating overshooting cloud tops.

Tomorrow, a high-pressure system locate over west of New Zealand, slowly progressing eastward, this predicted weather conditions will increased the dominated wind flow. Also, directing low-level cool and dry air flow over Samoa. Anticipate, southerly aloft in the upper atmosphere to persists along with strong wind shear. Therefore, anticipate fine weather apart brief showers. 

WEDNESDAY THROUGH SUNDAY:

The model consensus evince, that the previously named high-pressure system will steadily progressed eastward and likely relocate south of Tonga but still east of New Zealand. At this point, there is a possibility the prevailing southeasterly wind flow may reach wind strength of 20 knots or more on Wednesday into Saturday but mostly concentrated to the southern district of the Samoan Island group. Then, eventually decreased on Sunday and the later part of the outlook period. Simultaneously, the upper atmosphere compose of weak southerly winds signifying a weak wind shear follow by a weak upper trough on Saturday into Sunday. It is highly advisable to monitor any major changes and report accordingly.

MARINE OUTLOOK:

Wave height observations recorded across Samoa’s marine waters this morning have decreased below 2.5 metres. The wave models, suggest another high-pressure system is predicted to direct fresh-to-strong southeasterly wind flow that would generate rough seas, elevated swells and waves which is highly expected  to exceed 2.5 metres or more on Wednesday through Saturday. For that reason, a Advisory level is likely to issued in the next 24 hours for all open and marine waters of Samoa.

ADVISORIES/WARNINGS:

NONE

Weather On-Duty Team:

A. Liu, L. I. Tuatipi, F. U. Namulau’ulu & N. Tutasi.