Heavy rain and flash flooding with gale force winds are forecast over southern Tonga for the next 24 hours Tonga Met warned at 1pm Monday, July 1.
Forecaster Pesa at Fua'amotu weather centre, said that the heavy rain and flash flooding is expected with the conversion of a cold dry NW airflow meeting a warm moist airflow also from the NW.
Rainfall predictions from the models forecast on the website windy.com show a cloud cover of 98% over the capital at times, with exceptionally high rainfall forecast.
Tonga Met’s 1:00pm weather bulletin stated that an active trough of low pressure lies slow moving over Vava'u, Ha'apai, Tongatapu and 'Eua. Associated clouds with occasional rain and gale force winds will continue to affect the group today and tomorrow.
The forecast to midnight tomorrow for Vava'u, Ha'apai, Tongatapu and 'Eua is Fresh to strong East to Northeast winds, rising up to gale force winds at times.
Mostly cloudy and overcast with periods of occasional rain, heavy at times with possible isolated thunderstorms. Possible flash flood in low lying areas due to heavy rain.
The gale warning remains in force for land and Marine areas. The outlook for Wednesday is East to Northeast winds 25-30 knots, rising up to 35-40 knots at times.
Rough to very rough seas (3 to 4 Meters). A heavy damaging Easterly swell (up to 4 Meters).