A gale warning remains in force for all land and coastal areas of Tonga as meteorologists warn of strengthening winds, heavy rain and possible thunderstorms over Monday and Tuesday, 15-16 June.
A high-pressure system located far south of Tonga continues to generate cool, fresh to strong south-easterly winds across the country, while a low-pressure system to the north-west is expected to move slowly south-eastwards towards Tonga. As the weather system approaches, easterly winds are forecast to intensify, bringing deteriorating conditions across the island group.
The Tonga Meteorological Service forecasts strong to damaging gale-force winds at times across Tonga through Monday night, with cloudy conditions and possible occasional showers forecast nationwide.
Tongatapu and 'Eua
Forecasters warned that conditions are expected to worsen on Tuesday, particularly in Tongatapu and 'Eua, where fresh to strong east to north-easterly winds could gust to destructive storm-force levels. Cloudy skies, periods of rain that may become heavy later in the day, and possible thunderstorms are also forecast for Tongatapu and 'Eua.
Vava'u and Ha'apai
Vava'u and Ha'apai are expected to experience fresh to strong north-easterly winds with damaging gale-force gusts, while the Niuas can expect strong winds and heavy rain with possible thunderstorms.
The severe weather outlook follows an unusually cold start to the week, with temperatures in Nuku'alofa forecast to reach a maximum of 24 degrees Celsius on Monday and fall to 21C overnight.
Marine conditions are also expected to remain hazardous, with gale warnings in force for all coastal waters of Tonga, including Tele-ki-Tonga and Tele-ki-Tokelau waters where a previous strong wind warning has been upgraded.
A high surf warning, extreme high tide warning and small craft advisory remain in effect nationwide.
Tonga Met forecast east to south-easterly winds of 20 to 30 knots across coastal waters on Monday, with gusts of up to 40 knots and rough to very rough seas reaching between three and four metres.
Conditions are forecast to deteriorate further on Tuesday around Tongatapu, 'Eua, Tele-ki-Tonga and Tele-ki-Tokelau, where winds could strengthen to 35 knots with gusts of up to 50 knots. Seas in those areas are expected to build to between four and six metres.
Authorities are urging mariners and coastal communities to exercise extreme caution, particularly as extreme high tides and hazardous surf continue to affect shorelines around Tonga.
The mean sea level pressure recorded at Fua'amotu Airport at 6am today was 1020.4 millibars, with relative humidity at sixty nine percent.
