Lightning in the Tasman area

[Vertigo]

Im just curious of your collective thoughts as to why is it that the east coast of Aus tends to generate a hell of a lot of lightning activity? It seems to occur as convection over Brisbane to Sydney, and off into the sea further south along polar fronts. I know the SST's are fairly high near the coast, but would this affect storms forming over the deserts? Can someone explain the conditions over that area, and why its so good for Cb formation? Or is it such a great location that even the TCu's produce good lightning? If so, why?

Also, in regards to the polar fronts, why is it that the similar fronts dont produce similar levels of lightning 15o of longitude nearer to us? Tasmania/NSW gets the good stuff

[Manukau heads obs]

i think its:
warm sea temperatures
and different airmasses coliding...continental semi tropical and maritime semi tropical (i.e higher dew points and lower temperature than over the land)
and
the fact you get a venturi effect offering downwind of the east ausralian divide (strong upper level westerlies, and a strong surge up the eastern australian coastline of cooler air too (one the system deepens ) (same thing happens with storm enhancement east of Gisborne)

[Willoughby]

Well put Brian.

Also to add, diurnal convection over the sea at night will usually keep these storms firing and peaking just as the sun returns. Quite an impressive squall line there right now! It will most likely die within the next couple of hours.

[Vertigo]

so really they are just extremely lucky to get the tropical N-NNW from SE asia, combined with a dry desert like landmass supportive of nighttime cooling? does this promote development as far south as tasmania, or out in the southern tasman?

[spwill]

I recall living in Sydney seeing lightning out of just about any Cb cloud where as over Ak Cb clouds dont like producing lightning , Sydney having better surface conditions for convection resulting in more cloud hieght I guess.

[NZstorm]

You get airmass modification over continents, the mid level lapse rates steepen during the warm season due to warming in the lower layers. Add some moisture to this and you end up with big CAPE numbers. The more CAPE, the more pronounced the lightning activity.

[Vertigo]

the last lightning active front we just had lost all activity just as it hit nz, right on cue. its a recurring pattern it seems! why is this?

[Manukau heads obs]

sea surface temperature in the Tasman sea is still 19oC
but soil temperature over the land is now only 15oC
so that is one consideration
also though alot of the action moved SSE over the western waikato, northern taranaki, rotating around the low

[spwill]

the last lightning active front we just had lost all activity just as it hit nz, right on cue. its a recurring pattern it seems! why is this?

Must be moving away from the better upper air and or surface air conditions often moving into Ridging here.

[jrj]

Consider it done....

[Manukau heads obs]

hey , cool, a tornado was produced on that front last night...met service did have a severe thunderstorm watch out for the BOP, and a chance of tornadoes
I am not suprised they got one in that area when you look at the sat image animation, as it looks like a small low developed as it moved across the rotorua area...
ps, this should really be in the other thread about the NI weather event though....

[NZ Thunderstorm Soc]

http://www.hbtoday.co.nz/localnews/stor ... ubsection=

This posting is in the wrong topic. Should be posted in the Lows and cool change, Apr 26 - May 4 topic topic

JohnGaul
NZTS

[Vertigo]

weeeoow, lots of activity sparking up in the tasman today!

lightning.jpg

didnt know any other place for this