Severe Cyclone Gita to track over southern Tonga, later Norfolk Island & NZ area (+8 Maps)


Severe Tropical Cyclone Gita is a Category 3 storm as it starts to curve towards southern Tonga today and Monday. The powerful storm is likely to become a Category 4 cyclone as it turns and tracks westwards over the next 24 to 48 hours.

WeatherWatch.co.nz says Gita will affect southern Tonga later on Monday/early Tuesday and could directly swipe the capital Nukuʻalofa with damaging winds, storm surge and flooding. The one positive is that it will be moving quickly and may only be severe for around 12 hours as it passes over.

However it's possible the storm may make a direct hit on the capital and is a very serious situation. Yesterday Gita was a weaker storm and badly damaged Samoa.

If the cyclone just tracks a little further south it could significantly reduce damage in Tonga but powerful cyclones are so intense they often 'wobble'. By that we mean while the models pick a fairly clear path the storm moves like a spinning top on a table and can zig zag a little as it tracks along, this can mean anyone in the path could be saved at the last minute if it jogs away, or as we saw two years ago with Cyclone Winston a last minute wobble saw the Cat 5 storm directly hit Fiji's main island when modelling didn't initially forecast that. Tonga should be on high alert until the storm passes on Tuesday morning.

So what happens after Tonga?

It's helpful to see most computer modelling now agreeing on the most likely path which will see it track westwards south of Fiji on Wednesday and Thursday. This was similar to much of the reliable long range models and ensembles we were looking at last week too. WeatherWatch.co.nz says the central air pressure is forecast to drop considerably with ECMWF (a trusted European model) saying it will fall to 930hPa (Hectopascals) which is incredibly deep and indicates the storm will continue strengthening for the next four or five days. The cyclone looks likely to peak in strength around mid to late this coming week.

By Friday night it's likely Severe Cyclone Gita will run into less favourable conditions and very slowly start to weaken, a process which can take several days to happen. It should also start to drift more south west by then, taking it closer to New Zealand and the Tasman Sea.

Norfolk Island, part of Australia just to the north west of New Zealand could also be in the firing line for a direct or very near hit by the end of this coming week. The island is home to around 2000 people.

WILL GITA HIT NEW ZEALAND?
For a week now numerous reliable computer models and ensembles have been picking New Zealand to be in the path of the remnants of this storm. In saying this, there is still a long way to go before being able to lock in how strong Gita may be when it reaches New Zealand and what specific path it will take.

WeatherWatch.co.nz says it's looking increasingly likely that New Zealand will be directly affected by Gita however modelling doesn't agree on the timing of the low arriving nor does it agree on intensity - ie, will it be severe. Based on all the computer modelling in the public domain plus private data from various agencies it looks as though Sunday or Monday (one week from now) will most likely see the low coming in to New Zealand from the north west but being a week out this is still not a done deal and locked in - it could still change. Whether or not it will be a storm or just a low is still something we cannot lock in - therefore we cannot get much more detailed. 

We still hope to be more specific on Monday or Tuesday about future tracking into the New Zealand area. Tropical storms do behave differently to other lows and tend to have a bit of a mind of their own. While computer modelling can be incredibly accurate in this day and age it's important to note that they do get things wrong, especially when talking about a specific area of severe weather over a week away. However the power and size of this low means it is certainly one to monitor in the week ahead.

COULD IT STILL MISS NEW ZEALAND?
Yes - although so far the evidence isn't suggesting this. We also can't lock in if it will bring severe weather to New Zealand or just a period of more normal rain and wind. Keep up to date with the latest news at WeatherWatch.co.nz and in the coming days we expect MetService to also start providing their thoughts on likely tracking and regions possibly impacted. For now, the focus should remain on Tonga which is next in line and directly in the path of this severe tropical cyclone.


CYCLONE HIGHLIGHTS AS OF 11AM SUNDAY

**Information specifically made for WeatherWatch.co.nz by qualified meteorologists at The Weather Company**

  • Tropical Cyclone Gita is located near Niue (16.9S, 168.6W) with maximum sustained (1-minute) wind speed 140km/h (75 kts) with gusts to 170km/h (90 kts) - this has already turned out to be stronger than yesterday's forecast.
  • The forecast track is turning clockwise and will direct westward this coming week.
  • Gita will develop to 180km/h (100 kts) around Tuesday morning as it passes through Tonga and will likely be Category 4 (out of 5).
  • Models suggests that Gita will track further southward towards New Zealand and it may make landfall there around the next weekend.


- Past, current and future tracking of Cyclone Gita via the Joint Typhoon Warning Center (JTWC) (US Government)

Future tracking via the Fiji Met Service


- Current satellite, position and 'cone of uncertainty' showing most likely future track courtesy of our partners at The Weather Company/IBM


- Himawari satellite

- Himawari visible satellite

- Colourised satellite map via NOAA (US Government)

- WeatherWatch.co.nz - now with daily news and forecast updates on Severe Cyclone Gita


Comments

Gita

Hi guys Hat tip for the very good commentary on this one. The models do seem locked in to a hit on the North Island but at what strength is really the question. I do recall some years ago a cyclone which reacted in a similar way passed through Cook Strait. This could do the same. Keep up the good work it will be interesting Cheers Dave