The conditions that produced widespread thunderstorms, hail and downpours in the upper North Island on Tuesday have slightly changed for Wednesday, with an easterly flow dominating.
On Tuesday light winds/sea breezes from opposing directions (a westerly from the Tasman Sea and an easterly from the Pacific side) met over land creating huge cloud build ups well before the middle of the day had arrived.
This time today and the easterly breeze is dominating, pushing shower activity westwards to the Tasman Sea and creating less opportunities for major cloud build ups, especially in coastal places like Auckland City centre.
However, this may change into the afternoon as daytime heating continues. Waikato and inland Northland have higher chances for downpours today.
As of 11am eastern Coromandel Peninsula, Western Bay of Plenty and northern Northland had some showers and downpours.
Like guessing which kernel of corn will pop first into popcorn in the microwave it's hard guessing which clouds today will build up and 'pop' into thunderstorms or major downpours.
The stronger the breeze the less likely there is of cloud build ups, which is why the inland areas have a slightly higher risk today as coastal areas are a bit windier due to the easterly air flow.
The risk for downpours increases this afternoon and early evening then fades again overnight.
Highest risk areas today for thunder – or big downpours – looks to be Northland, rural Auckland and Waikato.
The risk returns again tomorrow in the North Island but fades by Friday.