As predicted yesterday Zelia is rapidly weakening before making landfall in New Zealand, however the ex-tropical cyclone is still packing a punch.
The air pressure is plummeting in the Far North as Zelia races towards the upper North Island.
In the past hour the outer-bands have pushed into the Far North with the “compact” storm centred about 300kms to the north west and closing in fast.
Gale force winds have also arrived at Cape Reinga, with gusts to almost 90km/h.
WeatherWatch.co.nz head weather analyst Philip Duncan says the air pressure gradient between the cyclone and land was quite significant earlier this morning. “The air pressure was around 1000hPa at Cape Reinga and just 980hPa a couple hundred kilometres to the north. To put that into perspective in a normal storm we would see that pressure difference stretched out across the entire length of the country, not the length of just one region”.
Mr Duncan says just like the lines on a topographical map the air pressure lines (isobars) are tightly packed around the centre of this low. A steep drop in air pressure means severe winds.
However Zelia’s air pressure is “filling in”, with the barometer rising sharply inside the depression quickly.
Current air pressure is estimated at 990hPa with winds averaging around 90km/h and gusting to an estimated 120km/h. If Zelia was still a cyclone she would have a Category 1 status.
WeatherWatch.co.nz predicts heavy rain will spread down Northland this morning with winds becoming very strong by late morning or early afternoon as the centre of the low moves by.
Latest Satellite Map – Zelia is the small blob of white cloud just north of NZ / Weatherzone
“Tropical Cyclones are very different to other lows that we get in New Zealand. With other lows the strong winds are usually created in a squash zone between a deep low and a large high. With a tropical cyclone the severe winds are only near the very centre so we can have destructive winds for a hundreds kilometres or so from the centre but then a few hundred kilometres away it’s mostly calm”.
Zelia is merging with the remnants of Vania and another low in the south that contributed to the flooding in Victoria, prompting MetService to issue numerous severe weather warnings yesterday.
MetService still has well over a dozen severe weather warnings in place, which were issued at 9:10am.
Meanwhile very humid conditions left by ex-tropical cyclone Vania made for an uncomfortable sleeping night for many. In Auckland humidity reached 100% with foggy conditions reported across the region.
Auckland currently has 98% humidity.
The Stats as of 9am: Joint Typhoon Warning Centre & MetService
Earlier story (7:15am)
WeatherWatch.co.nz last night predicted Zelia was going to make landfall much further north and this morning that prediction remains mostly in place as Tropical Cyclone Zelia races towards the upper North Island at 55km/h.
WeatherWatch.co.nz says the centre of this tropical cyclone is now likely to track directly towards Northland and it will move across or very near the upper North Island.
“Due to the unique shape of Northland the centre of Zelia may pass to the west, the east or make a direct hit, but either way conditions will be rough across northern New Zealand for a time” says Mr Duncan.
“This means a period of severe gales may hit parts of Northland, Coromandel Peninsula and Eastern Waikato today”.
As of 8:30am MetService still did not have any severe weather warnings for those regions however they do have a Severe Weather Watch which indicates warnings may still be issued. MetService don’t usually issue severe weather warnings between midnight and early morning and more may be issued shortly should conditions warrant it.
“This storm is going to be short and sharp for the upper North Island with conditions quickly returning to normal by tomorrow morning or even tonight in the far north”.
Mr Duncan says people in northern, western and central regions should be aware of all current warnings
on 17/01/2011 9:03pm
No sign of any rain north of Kaitaia yet.1008 pressure with 25 kph nor ‘ easters. Dont tell me this ones going to slip down the east and miss us,surely we’ll get some rain out of it .
on 17/01/2011 8:59pm
Sounds as though Thames/Coromandel will get off pretty lightly … yes??? Hope so – we have a creek bisecting our property here in Thames … with a 3-story-high waterfall at the back of the section! 🙂 Any prediction on what we MAY we expect?
on 17/01/2011 10:43pm
Hi there Jane,
At this stage we expect gale force winds for a time right down the western side of the Coromandel/Kaimai ranges. You could get some heavy rain for a while too, but the worst will be south of you.
on 17/01/2011 8:43pm
What is napier going to be like tonight? I have a flight in to there around 8.30pm and dont fancy a bumpy ride or diverted plane!
on 17/01/2011 10:42pm
Hopefully conditions wont be severe enough to cause any divertions. Expect a few bumps though!
on 17/01/2011 8:18pm
As at 9.18am, Whangarei air pressure has dropped to 993hpa!