MetService is forecasting a series of fronts which will make their way over the country this week, bringing strong northwesterly winds and periods of rain, particularly for the South Island. On Thursday, a cold southwesterly flow takes over, and while it brings some clearer skies over the South Island, it also leads to lower temperatures.
This evening, a cold front reaches the South Island, preceded by strengthening northwesterly winds and accompanied by periods of heavy rain in the west. Strong Wind Watches have been issued for the Southland and Otago Regions, as well as the Canterbury High Country. Heavy Rain Watches are also in place for Fiordland and the ranges of the Westland District. These Severe Weather Watches are in place through the night into the early hours of Tuesday morning.
A Strong Wind Watch has also been issued for Wellington and Wairarapa from Carterton southwards, as the front moves onto the lower North Island overnight.
MetService Meteorologist Juliane Bergdolt elaborates, “As the cold front moves northwards early tomorrow morning, northwesterly winds strengthen over the lower North Island. Winds may approach severe gale at times within the Watch area, particularly about the hills, before weakening rapidly and moving eastwards off the country Tuesday night.”
Overnight from Tuesday into Wednesday a low-pressure system passes just to the south of the South Island, bringing another cold front onto the lower South Island.
Bergdolt details, “We see a repeating pattern on Wednesday as another front moves northwards up the country, reaching Christchurch around midday. Much like Monday’s front, it is preceded by strengthening northwesterlies and potentially heavy rain. Severe Weather Watches may be issued for similar regions as earlier in the week in the coming days. However, this front is followed by strong and cold southwesterly winds, bringing a distinct dip in the temperatures just ahead of the long weekend.”
Looking ahead the Easter forecast still has some uncertainties, with a low-pressure system to the northeast of the North Island that may have a part to play. However, the driest weather will be in the South Island, with Central Otago, inland Canterbury, and the West Coast most likely to see the sun. However, there will be a chill in the air so wrap up warm for any early morning Easter egg hunts.
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.
