FORECAST DISCUSSION

TUESDAY 23rd JULY 2019 (AM SHIFT)

TODAY:

A trough of low pressure lies within the vicinity of Samoa, associated with cloud and showers and embedded thunderstorms. Cloud coverage has increased overnight with showers observed mainly Southern side. An intense high pressure to the Southwest may push the trough Northward within the nowcast period, though its associated activities will remain over the forecast zone. Therefore, expect isolated showers. Thunderstorms are likely along the south of the forecast zone and over highlands in the afternoon with moderate fall potential.

WEDNESDAY TOWARDS MONDAY:

The convergence south of the trough descends over the group by Wednesday with a wind change to the northeast once again with an upsurge in rainfall until Thursday and Friday. The easterly winds are likely to increase above 20 knots between Thursday and Saturday. The ridge will again dominate by the weekend bringing mostly fine weather from the trade winds. However, showers can be expected along the eastern shores with the potential for moderate afternoon falls on highlands from daytime heating. For early next week, the light to moderate easterly flow dominates.

MARINE OBSERVATION & OUTLOOK:

Observational data reveals waves height below advisory thresholds. Expect an increase in wave activity for the south and east coast for Thursday toward Saturday. JMA model does not highlight this strengthening of the winds to be significant but the UKMO ensembles indicate a high probability for winds exceeding 20 knots within the forecast zone during the same period.

ADVISORIES & WARNINGS:

NIL

FORECASTER:

TOLUONO