SYNOPTIC DISCUSSION
SUNDAY 22ndMARCH 2026 AM SHIFT
TODAY INTO TONIGHT:
Generally, the elongated SPCZ still lingers to west near Solomon Is extending to the southeast, which is the south of the Tonga islands. Since, the trade wind regime remain persisted and predominate over the area of responsibility, with partly cloudy within the vicinity. Notably, through the levels, as observed by the sounding profile showcase continued available moisture content near the surface, deepening wind alignment, mid level dry airmass, and instability. What’s more, specifically in the upper atmosphere where the upper level low linger just the north, with weak wind shear environment. Further, anticipate sea breeze convergence due to the diurnal atmospheric cycle and orographic precipitation at windward locations, which may trigger afternoon convections that could generate both showery and thundery activities regardless of the sunniness. In time, there’s greater chance that the easterlies to dominate through tonight.
MONDAY THROUGH SATURDAY:
According to the current model consensus, that the mean wind flow gradually steered northeast on Monday, with a slight increase of moisture signature that could provide shallow showery and a few thundery activities. Then on Tuesday, the predicted prevailing wind flow slowly veered to the east while becoming weakening in wind strength through Wednesday. This forecasted synoptic setup, suggested the eastward propagation of a developed ridging to the east of New Zealand. Eventually, on Thursday it becomes light and variable, signaling a weak convergence zone or the SPCZ that may shifted near the area of forecast on Friday through Saturday.
MARINE OUTLOOK:
The latest observed marine data continues to reveal that wave and swell heights across Samoa’s marine waters are still below the 2.5 metres threshold value, which poses no threat. Wave models suggest this trend is expected to persist throughout the forecast period.
ADVISORIES/WARNINGS:
NONE
Weather Duty Team:
A. Liu, A. Sofeni, C. Baker, & A. Uili.