Thunder & lightning very very frightening
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Posted December 09, 2019
Media Release: MetService
New Zealand weather forecasters have been very busy so far this summer. MetService meteorologist Andy Best comments, “The weather pattern over Aotearoa has been more spring-like than summery, as weather systems continued to bombard our shores, bringing gale to severe gale northwesterlies, torrential rain and severe thunderstorms.”
“A ridge of high pressure north of the North Island remained in place since the start of last week. This so-called “blocking ridge” slowed systems down as they moved onto the country, allowing large accumulations of rain and preventing many of the fronts from moving up the North Island.”
Last Tuesday and Wednesday, the fronts which moved over New Zealand resulted in Strong Wind Warnings and Watches being issued, extending from inland Canterbury northwards across much of the lower North Island, and gusts well over 100km/h were recorded in the Capital on Tuesday. Over the South Island, these fronts delivered heavy rain, accompanied by thunderstorms about and west of The Divide with a number of weather stations in the Alps recording 250 to 400mm in a 24hr period.
Severe Thunderstorm Warnings were issued on Saturday focusing on developments near Hokitika, as well as for an area just north of Warkworth. In the 24 hours leading up to 7am Sunday morning, 109,000 lightning strikes were recorded over New Zealand and our surrounding waters, with 18,000 specifically over the land. Previously our records had only seen 44,000 strikes over both land and sea. Thunderstorms can bring localized flooding and downpours which have caused disruptions to travel.The good news is that during Monday we see a change to the weather pattern as a cold front moving up the country sees the rain over the South Island easing to showers, with the showers slowly becoming few and far between.
As the cold front moves northeast across the North Island, the frontal rain eases to a mix of fine weather and isolated showers during Monday morning, although there is a chance of afternoon showers and thunderstorms popping up over inland areas. Tuesday looks like a mainly fine day, as a ridge moves over central and northern parts of the country.
A ridge of high pressure behind the front brings a couple of calm wind days to start the week, but the weather retains a very spring-like flavour.
On Wednesday a front affects the far south, and there’s a low-pressure centre near East Cape too. Those features bring rain to those areas, but elsewhere is mainly fine.
Thursday looks to be mainly sunny, with afternoon showers for inland parts of both islands, while Friday sees a front move up the South Island bringing more rain to the West Coast.
This kind of changeable pattern is more spring-like than summery, but although the weather is changeable this week, thankfully less severe weather is expected. All indications are that impacts will be nothing like what was seen last week.