Possible Storms, September 3-4, North Island

[Tornado Tim]

Looks like the north Island will be on the receiving end of some fronts passing in from the Tasman on Monday.

Lightning Activity on the fronts looks be isolated due to unfavourable forcing and as a result a lower Buoyancy.

The following troughs posses a little higher risk of lightning due to colder temperatures aloft and the associated showers that could develop on it. The main jet should be located just of the NE of the NI and the weaker upper level flows associated with the jet are forecasted to cross with the upper trough. Its a question if those upper level winds will help the trough with the convection it should have.

Seems like a low to mod risk of a shower turning out a bit of lightning for Northern sections of the NI.

[Manukau heads obs]

certainly has got windy here from the NE

[spwill]

Satellite shows only a small area of Cb in the cold trough currently, see how that develops as it moves toward us tomorrow.
Looks like another low risk on Tuesday as another trough sweeps the country.

[David]

Whangerei reporting 31 mm rain in the past hour!

This Bay of Islands station reported 69 mm between 7am and 9am
http://www.wunderground.com/weatherstat ... =IBAYOFIS5

[NZstorm]

Very heavy burst here atm. Front is living up to expectations as wet one!

[Manukau heads obs]

teeming down here too
approaching 20mm here now

[spwill]

Torrential rain here just now, must be the Frontal line.

[Tornado Tim]

Signal on the Auckland Radar is getting quite badly attenuated atm.....

[David]

Radar showing some real heavy rain heading this way, already up to 22 mm

[David]

Max rain hit 132 mm/hr here - lots of surface water!

[Manukau heads obs]

31mm here now...looking forward to the sunshine to follow!

[Manukau heads obs]

wind change to the SW here
so must have been a small low that passed over

[NZstorm]

The shortwave coming into the west of the North Island tomorrow pm should produce atleast a little lightning. Its a decent looking system and the 500mb temps certainly look cold. The big limiting factor is the poor moisture.

6pm Tuesday 500mb chart on the gfs.

[Thunder]

I'm sorta hoping we get something here but we'll see, look forward to what happens up north.

[NZstorm]

I'm sorta hoping we get something here but we'll see, look forward to what happens up north.

Looks like a set up for Canterbury as well Aaron. The trough comes across Canterbury like an express train this afternoon being driven by the subantartic jet.

300mb wind chart.