Covering period of Thursday 18 – Monday 22 May – MetService is forecasting a stormy end to the week for parts of the country, due to a deep low and its associated front approaching from the Tasman Sea. The front moves over first, today, bringing heavy rain and possible thunderstorms. Aotearoa New Zealand then has a slight reprieve before the low moves across the central North Island with pace, bringing strong winds and showers on the weekend.
Meanwhile, a front tied to the low brings a period of heavy rain and northeast gales to northern Aotearoa New Zealand from Thursday afternoon through to Friday afternoon. Several Severe Weather Watches and some Warnings have been issued by MetService. Thunderstorms and localised downpours are also possible, which could cause localised flooding.
Little explains, “The front that moves across the North Island from Thursday afternoon isn’t expected to stall, unlike recent heavy rainfall events, and will move quickly southeastwards to lie to the east of the country by Friday afternoon. However, surface flooding and slips are still possible even during this shorter rainfall event, as some areas may receive heavy rain due to the tropical moisture and thunderstorms involved.”
The low-pressure system is expected to track across the central North Island on Saturday, bringing another round of rain or showers to most regions, along with a period of westerly gales and large wave conditions to northern regions.
Little comments, “A period of westerly gales will also affect northern parts of the country on Saturday as the low moves eastwards across the central North Island. The gusty westerly winds and already sodden soil, means people are advised to be prepared for power outages due to falling trees disrupting power lines.”
He continues, “Rain or showers are forecast for most places on Saturday, with the west of the North Island and Tasman region likely to be the wettest places. ”
Once the low moves to the east of Aotearoa New Zealand a cooler, unsettled west to southwest flow becomes established. Frequent showers are likely in the west of both islands through until at least early next week, with showers for eastern areas from time-to-time.
For media enquiries or to arrange an interview with one of our meteorologists please call 04 4700 848 or email metcomms@metservice.com
Understanding MetService Severe Weather Warning System
Severe Thunderstorm Warnings (Localised Red Warning) – take cover now:
This warning is a red warning for a localised area.
When extremely severe weather is occurring or will do within the hour.
Severe thunderstorms have the ability to have significant impacts for an area indicated in the warning.
In the event of a Severe Thunderstorm Red Warning: Act now!
Red Warnings are about taking immediate action:
When extremely severe weather is imminent or is occurring
Issued when an event is expected to be among the worst that we get – it will have significant impact and it is possible that a lot of people will be affected
In the event of a Red Warning: Act now!
Orange Warnings are about taking action:
When severe weather is imminent or is occurring
Typically issued 1 – 3 days in advance of potential severe weather
In the event of an Orange Warning: Take action.
Thunderstorm Watch means thunderstorms are possible, be alert and consider action
Show the area that thunderstorms are most likely to occur during the validity period.
Although thunderstorms are often localised, the whole area is on watch as it is difficult to know exactly where the severe thunderstorm will occur within the mapped area.
During a thunderstorm Watch: Stay alert and take action if necessary.
Watches are about being alert:
When severe weather is possible, but not sufficiently imminent or certain for a warning to be issued
Typically issued 1 – 3 days in advance of potential severe weather.
During a Watch: Stay alert
Outlooks are about looking ahead:
To provide advanced information on possible future Watches and/or Warnings
Issued routinely once or twice a day
Recommendation: Plan
