NZstorm wrote:Yes, but i think there is one factor far more important than timing(time of day). And that is time of year. Really need the insolation to get thermals rising and get decent sea breeze activity. Labour weekend onward as you will be aware. But late summer(Feb/Mar) tend to be dud months for thunder in the east of the South Island because the upper air tends to be a lot warmer by then. As I have suggested in an earlier post, cold upper air is the usual form of instability in the east of the South Island rather than humid conditions on the surface, which can be the cause of instability from Waikato northward.
Yes well Steven.
I was refering to the first sentence of my statement.
For this time of year, timing is a major factor.
As we become warmer and the colder southerlies develop there is an excellent chance of thunderstorm development especially here in Canterbury, as long as the skies are clear.
The timing factor may become lesser in the warmer summer months but then now with the cooler summers we are getting, there is a lesser chance of thunderstorm development because there is is not that stimulation, mainly because of increase cloud cover, and to the fact that cold fronts from the south have to go over in the afternoon to actually produce a thunderstorm. It dosen't happen in the air behind it because the wind has gone around the the south.
Thre Prognosis for a good thunderstorm in Canterbury is that is has to be of these factors.
1: A good NE onshore sea-breeze, ENE the better
2: Lots of sunshine prior to the front arriving
3: Low barometer = 1000hPa, or lower the better
4: ENE "Hanging in there" until taken over by the southerly
5: The actual front/convergence line moving across about 3pm ish? this depending on the how active the front is
Cheers
JohnGaul
NZTS
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