In my opinion i think tomorrow is a very decent set up maybe even severe thunderstorms in an area between just south of Ashburton up to about Rolleston.
Severe i mean as in 20+mm hail i think the 5-15mm hail MS have is still abit low especially for this area, storms tomorrow will be slow moving due to the lighter variable winds and coastal E-NE winds look very likly especially about the coast.
With that slow nature in cell development generally the ice particles can stay up longer in the cloud therefore larger hail, thats my theory anyway.
I know its only still reasonably early in the season but i would be almost tempted to have a high risk in this area i mentioned above, and a moderate risk over the remainder of Canterbury.
We have seen simular set ups like this before and going by this ( sometimes in severe thunderstorm occasions ) the strongest storms are in this area, I think September 4th was simular but definatly January 18th 2009 comes to mind.
Time will tell, i will be out able to chase from 2pm onwards im getting away early from work bugger it

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