This convection produces pretty unsettled weather and the rain becomes more localised, which means smaller areas can be hit harder and faster.
The snowy conditions in Te Pohue proved difficult for drivers with police responding to a one-vehicle crash at about 4.43pm.
The vehicle had gone off the road at the top of the hill past Te Pohue but there were no injuries reported.
However, this icy blast was not expected to last with temperatures forecast to rise back into the high teens today with a northwesterly flow.
Mr Mercer said there should be a high of 17C for Hastings and Napier today with the temperatures rising again towards the end of the week.
"Napier and Hastings will reach the low 20s from Wednesday with the northwesterlies bringing the warmer weather."
The north-westerly flow meant winds came from over the mountains rather than from the southern ocean, which had delivered this "cold air mouth" felt yesterday.
It was expected to be a fine spring day today before the showers returned tomorrow evening.
"The showers should clear on Thursday but they will come back again on Friday and continue going into the weekend."
Mr Mercer said this unsettled weather was very typical of Spring.