There are several Severe Weather Watches and Warnings associated with the front today. Wind and rain Watches are active for much of the lower and central North Island. Orange Heavy Rain Warnings are in place for the Tararua Range and Mount Taranaki. A Severe Thunderstorm Watch has also been issued for The Marlborough Sounds, western and southern areas of the North Island up to Waikato. As the front progresses northwards there is a chance of a Severe Thunderstorm Warning, a localised Red Warning, being issued in these areas. There is also a risk of Thunderstorms outside the watch area in Auckland, Bay of Plenty and Taupo from this afternoon.
MetService Meteorologist Juliane Bergdolt advises: “The thunderstorms carry the risk of heavy rain and localised downpours, with rainfall rates of 25 – 40 mm/h possible within the watch area. Surface and flash flooding is a risk with these amounts of rain in such a short timeframe. Strong winds with possibly damaging gusts between 90 – 100 km/h can also be expected in the vicinity of a thunderstorm.“
For the South Island, most Warnings and Watches associated with this front have now been lifted. Over the course of this morning, thunderstorms were observed about the Southern Alps and the Marlborough Sounds. Rainfall accumulations reached 67 mm in Milford Sound and up to 86 mm in western parts of the Marlborough Sounds. Gale force northwesterly winds were recorded about the Canterbury High Country with gusts up to 140 km/h in exposed places.
The strong northwesterly winds will generate heavy swells along the western coast on Tuesday morning. Swells of 4 to 6 metres are possible around the West Coast, Kapiti, and Taranaki coastlines.
Behind the front the wind changes to a strong, and cold, southwesterly, strongest about coastal Southland, Clutha and Dunedin where a Severe Wind Watch has been issued for Tuesday until 2pm. Temperatures are set to drop with an influx of cold air from the south. A Road Snowfall Warning has been issued for Crown Range Road, where snow flurries are possible overnight, but are unlikely to settle. In the lower South Island, daytime temperatures are expected to stay in the low teens on Tuesday, with Invercargill’s maximum at 11°C. “The combination of cool temperatures and strong winds can also lead to wind chill, making the perceived temperature even lower.” says Bergdolt.
On Wednesday the weather starts to settle with a ridge of high pressure moving in over the country, leading to the return of calmer weather for the second half of the week.
Please keep up to date with the most current information from MetService at www.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
