A MetService spokesman said tornadoes were fluky and rare in New Zealand, and were impossible to accurately predict.
Eh? On what scale?
They were a combination of factors driven by unstable weather conditions, with cold unstable air hitting warm air, and were more likely to emerge during thunderstorms.
This particular thunderstorm/MCS was no where near the cold air but rather downstream of the sub-tropical moisture. On a synoptic scale they're right.. but not even close on a meso scale.. which is what i'm gathering they're suggesting from this statement. The low-level shear that wasn't mentioned was the killer blow this time yesterday.
Attached is the 3am IR satellite, 900mb wind vectors for 3am Wednesday and wind field over inland Hawke's Bay (GDAS analysis)
Looks like a third run of this type of system is due this Sunday / Monday again too.. someone will have to start a new thread!
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Yes Foggy, next system over Northern NZ due Monday will be interesting. With 500mb temps progged to be around -20C with this system, instability looks like it should be good. GFS is currently suggesting CAPE around 800. I think May/June period is going to be big for NZ weather.
heardf from a neighbour that we had a close ligthning strike this mornnig that put the power out brefly....my weather station is somehow affected (web site not updating)...will know more when we back home from the bay of islands (where it is sunny!) this afternoon
yes,I agree, next 2 months should see some big weather systems, due to warm tasman and fading (?) la nina
Rain with a few heavy showers just clearing here now, feels very cool this morn 15C.
Warmer moist air returns Sunday to set up that next incoming Low, some interesting weather on the cards early next week
Another 13mm this morning, on top of the 2mm yesterday and 56mm Tuesday! The ground here is soaked - any further rain now will just create puddles and run-off.
Will be interesting to see how much we get out of the Sun/Mon rain, the low at this stage looks to be around 1000hPa as it crosses the NI with substantial rain across much of the island. Sadly the term holidays end on Sunday
Then more unsettled weather with another low possibly crossing the lower SI, looking like it could be about 980hPa.
Brian, didn't you only just lose power from a lightning strike in your area not too long ago?!
Kelburn reported (will be able to confirm by tomorrow) 94.4mm to 9am today after prolonged moderate rain overnight. So April is an even more extreme example than March was of a month with a high rainfall total (about 211mm, more than double average) on relatively few days.
Kkapiti Coast had some shops and houses damaged by the 29th's rain, city mainly a lot of Fire Service calls, slips and some house/shop flooding after last night's effort.
Just in response to the comments about tornado prediction etc. You will notice on page 4 of this thread where Tokww posted the text of my Severe Thunderstorm Watch issued late Tuesday morning and again about mid afternoon, it actually stated...
...There is also a low risk of isolated tornadoes, especially near the front in eastern Bay of Plenty and northern Gisborne on Wednseday morning.
So there are some methods to narrow down where they might occur.
well it damn baketed down between 9:30 and 9:50am here. Walking to uni i got saturated by a car driving through flooding on symonds st and my unbrella got turned insideout 4 times due to the wind. Was a horrible walk to uni!! dont think there has been any significant rain since.
the sounding is nice today, but i think the cold front is pushing any heating we may have gotten today away to the north of the country, where it will probably produce substantial thunder
Sure is looking like a very unsettled and very wet start to May upon us...Metservice thinks rain may become heavy in Northland and just onto the top half of Auckland on this Sun/Mon - and then if we get the depression that some models are predicting late week (strong pressure gradient, rainy unstable W/SW)...wow!
Lots of pretty low-topped Cb's scattered around the region. Got drenched in the cold rain on the bike into town . Temp dropped to 13.4C earlier after the cell passed.
Yes, looks like next low will be a north of Auckland event. The GFS plots the instability over Auckland city but I doubt this. I suspect we will get some cold easterly rain here and the interesting weather (milder conditions with thunderstorms) will be over the top half of Northland. But we can only watch with interest.
. Temp dropped to 13.4C earlier after the cell passed.