Any Cyclones that were still "tropical" ever reached NZ?

[igaquo1]

I've been tracking the progress of Hurricane Ike. I noticed the last forecast to be issued by the US National Hurricane Centre for this storm said that it start becoming extra-tropical at 40.4 degrees north.

So this made me wonder, have any Tropical Cyclones ever reached NZ still with tropical characteristics? Such as having a warm core of convection and thunderstorms and having no fronts. I don't recall one in the past 25 years.

Cyclone Bola and Giselle were both extra-tropical.

Is it theoretically possible that we could get one? Or are the seas too cool to the north of the NI?

Jeremy

[Manukau heads obs]

a very fast moving one might just still have those characteristics by the time it reached North Cape...
I think the TC in the late 50's, 958 hpa, at cape reinga, cant remeber the name off hand, would be the best candidate...

[Nev]

Hi igaquo1, No, there is no evidence that a tropical cyclone has ever reached NZ waters intact. And yes, sea-temps around here are generally too cool to sustain it, plus it will encounter strong vertical wind shear (e.g. high-level jet streams) that will destroy the mechanism that maintains it, and so it undergoes transition into an ex-tropical cyclone. Cyclones like Bola and Giselle can however retain the clockwise circulation and the very moist air it contains when they reform into a cold-core, mid-latitude cyclone.

[Nev]

I think the TC in the late 50's, 958 hpa, at cape reinga, cant remeber the name off hand, would be the best candidate...

That would be Cyclone Ida with a recorded 963 hPa at Cape Reinga on March 15, 1959.

[Manukau heads obs]

Ida, thats the one...it was moving at 30 knots I think!

[Nev]

Actually 35 knots just N of NZ before it's centre suddenly veered SW into the Tasman Sea.

[Myself]

I think the sub tropical jet may well shear it to death, so you would need that to be well south. Whilst it does dip quite a long way down at times....not generally for prolonged periods.

[Willoughby]

The Gulf Stream helps the hurricanes immensely there get to high latitudes in the North Atlantic with water above 26C. Here in the SW Pacific we really don't have any supporting currents of tropical origin - nearest one is the East Australian Current, which in itself is too small to have much effect this side of the Tasman.

Of course we have the 'disadvantage' of having the moderating Antarctica continent and southern oceans to keep warm waters at bay here in the mid-latitudes.

[NZstorm]

Regarding T. cyclones in the late 1950's, the technology didn't really exist to get a proper analysis of them. There was no satellite imagery for starters.

[Manukau heads obs]

yes, true....I remember my dad telling me of forecasts back then like, winds incresing to hurricane force in the next 24 hours.....but nothing happened....must have been hard to know where the center was (its hard enough with a sat image once its gone extra tropical anyway), just relying on ship /airliner reports....

[Nev]

Yes, for that reason, 1933 may still hold the record for the most Atlantic hurricanes in one season.

Re the SW Pacific sub-tropical jet-stream, I seem to recall that some TCs have survived intact at much lower latitudes well to the E of NZ (perhaps because the sub-tropical jet-stream dips more or is weaker there). Maybe if NZ was say about 1,000kms further E, the chances of a fast-moving, intact TC making landfall would greatly increase?

[Manukau heads obs]

yes, I remember seeing some in the late 80's or was it early 90's that still look very much intact about the latitude of the Kermadec islands, but further east...and , yes, the ITCZ dips south more as you go east....