Tropical Cyclone Harold

[Cyclone Tracy]

The tropical low also known as invest 90P has rapidly developed in the Australian area of responsibility in the last 12 hours and has been upgraded and named by the BoM to be TC Harold.

[Chris W]

Well-expected by the models, but I’ll second that it’s development has been early. Now to see where it heads, currently potentially looking to slide southeast but that’s from modelling that doesn’t even think it should be a TC right now.

[Cyclone Tracy]

EC's latest 18Z run producing a high end cat 4 devastating hit on Vanuatu's Port Vila late Monday into Tuesday.

[TonyT]

Danger, Will Robinson! Remember that model initialisation is running on significantly reduced data inputs at present. All model output will see fluctuations in accuracy as a result, and I would hazard a guess that tropical cyclone positions and intensities would be the most likely to be affected. More and larger grains of salt needed at this time!

[Cyclone Tracy]

Yes, agree. The early intensification of Harold not picked by any of the main global models is a good example of the guidance forecasts struggling with missing data. The satellite estimates are now locked on though, so it might improve a little. Another interesting point with large chunks of data missing is they may not accurately estimate the strength of the subtropical ridge. He could go towards Fiji or NZ....the old fashioned manual plotting off satellite imagery might be important for Harold.

[Cyclone Tracy]

Harold looks a lot more organised this morning on sunrise. 60 Knots, 985 hPa and upgraded to cat 2 by Fiji Met.

[Chris W]

Clear eyewall forming there, as you say very compactly organised too and headed for at least cat 3. Those thunderstorms being drawn in aren’t exactly small themselves, amazing image.

[Cyclone Tracy]

11am NZT IR showing inner eyewall lightning strikes, cloud tops between -90c to -100c and the core is warming. Harold is currently attempting to become an annular severe tropical cyclone.

[Cyclone Tracy]

The deadly pinhole eye is appearing, now down to 958 hPa and 100 knots on the satellite estimateing method of advanced dvorak technique. Harold is now as RI bombing tropical cyclone , strong Cat 3 and fast heading towards Cat 4 status.

[Awhituobs]

well that escalated quickly

[ben g]

Absolutely no mention of Harold on any of the local Vanuatu news websites that I've seen. All just covid -19. Hope it doesn't catch them off guard with everything else going on..

[Chris W]

The deadly pinhole eye is appearing, now down to 958 hPa and 100 knots on the satellite estimateing method of advanced dvorak technique. Harold is now as RI bombing tropical cyclone , strong Cat 3 and fast heading towards Cat 4 status.

Best image I can find so far from today here that shows the eye:
https://www.hurricanezone.net/tcgraphic ... 1585975443

Himawari:
Visible https://www.nrlmry.navy.mil/tcdat/tc20/ ... LATEST.jpg
IR https://www.nrlmry.navy.mil/tcdat/tc20/ ... LATEST.jpg

JTWC has sustained winds of 120kts and gusting 145kts by 36 hours, maxing out at cat 4 before it heads southeast and encounters strong wind shear in about 3 days’ time.

[Cyclone Tracy]

High frequency barrage of inner eyewall lightning. Harold is erupting.

ADT method showing 949 hPa and 110 Knots. Now unofficially cat 4.

[Cyclone Tracy]

941 hPa and 115 knots (1 min ave) at 6am NZT. Officially a high end cat 4.

[Awhituobs]

is a very small/compact TC though

[Cyclone Tracy]

Most models on the 12z run have Harold losing the SE steering and forward momentum over the next 24 hours which is not good news for parts of Vanuatu. Beyond that, southern areas of Fiji need to keep a very close eye on Harold as the subtropical ridge looks like it is stronger than models had previously thought.

[Chris W]

Metservice projecting that Harold will intensify to category 5. The numbers yesterday were close but this system has gone beyond expectations every day, so it's not surprising really. Thoughts with those in Vanuatu ahead of this. Got to add severe to this thread title for sure.

[Cyclone Tracy]

Pretty much stationary during today as a cat 4. An eyewall replacement cycle looks to have occurred in the last 24 hours going by the microwave imagery. Another round of inner eyewall lightning has kicked off in the last hour, so Harold might be attempting a shot at becoming a major league cyclone later tonight.

[Nev]

Harold was upgraded to Cat 5 by Fiji Met around 1:30am this morning, with max 10-minute winds up to 110 knots (205 km/h) and a central pressure of 930 hPa.

This is also the first South Pacific Cat 5 TC since Gita in February 2018, and the strongest TC to hit Vanuatu since Pam completely devastated the archipelago in March 2015.

[Awhituobs]

well defined eye now
and its moving east faster..straight for one of the northern islands ..disaster

[Chris W]

That’s just a serious storm, symmetrical around the core with a potent leading area of convection as well. Sheltering may be tough with physical distancing rules, but hopefully any aid will not be slowed getting there. Of course you hope for it not to be as bad as feared but it looks like a heavy hit.

[Cyclone Tracy]

A complete top shelf annular cyclone and a donut of destruction. Vanuatu's largest Island Espiritu Santo is about to come under the 'stadium effect' as the sun rises.

[Cyclone Tracy]

Harold's inner eyewall on the SW side is now generating lightning again as he brushes the island's coast. He continues to mature on approach to the Island.....

[Cyclone Tracy]

On the latest 18Z run from EC & GFS, the cyclone's core is incorrectly positioned between 70 km & 75km at 2pm NZT. EC doesn't even have the eye passing over any part of the Espiritu Santo Island on the 18Z run (it already has). For severe weather, the almost real time inaccuracy of most global models since the downgrade of airline flights is truly remarkable.

[Awhituobs]

especially for areas of the globe where ground based weather ballons are not able to be beefed up (which they are doing in europe now)