FORECAST DISCUSSION

MONDAY 19th NOVEMBER 2018 (PM SHIFT)

TONIGHT:

A weak trough of low pressure remainswithin the vicinity of Samoa associating with a cloud band over the forecast zone on the latest satellite imageries. Sounding reveals a slightly unstable atmosphere with deep Westerlies in mid-upper levels. Light Northerly winds variable at times recorded across the Islands from the sites. An upper divergence concentrated Eastward of the group. The trough is predicted to remain on its weakening trend within the nowcast period. Expect cloudy periods with isolated brief showers. Possible thunderstorms on shoreline, mainly Eastern side of Upolu Island.

TUESDAY TOWARDS SUNDAY:

The sub tropical ridge will push the trough further north of the islands and will set these systems to remain there for a period of time. Although, numerical predictions states the systems to migrate northwards, moisture content associating with it will still linger, thus expect showers to occur from time to time. An improvement is expected on Wednesday as the sub-tropical ridge gain dominance. Isolated showers may or may not occur depending on the velocity and the differentiation of wind velocity that will somewhat materialize a speed convergence near our vicinity. By early Saturday, a convergence zone together with a trough will descend over the islands from the northeast, and models predicts isolated showers to likely occur in that time of the outlook period.

MARINE OBSERVATION & OUTLOOK:

Latest data from the Aunu’u Wave Buoy show wave heights ranging from 1-2 metres in height. Therefore our advisory remains inactive as because of observations not exceeding our advisory threshold, models states an outlook prediction of swell and wave activity to remain below the advisory threshold for the rest of the outlook period.

ADVISORIES & WARNINGS:

NONE

FORECASTER:

E.Toluono