Mr Adams said the sunny spells from yesterday would fade, as cloud increases throughout the day and winds change to a southerly.
"The rain will come through the hills first and as the southerly approaches on Friday rain will spread to most of Hawke's Bay."
He said there was also convection about today but unlike earlier this week it is more to the west of the country.
The convection on Sunday and Monday sat over the entire North Island and was the reason behind the chaos in Waipukurau, when they were hit with a rare burst of thunder, lightning, hail and torrential rain.
"This time Hawke's Bay are out of the main risk area and are nationally excluded. You may get the odd shower but are not likely to see any thunderstorms."
The temperatures are equally as unsettled as the weather with the high tomorrow just 16 degrees compared to 23 degrees on Saturday and 18 degrees on Sunday.
"It is a bit up and down, but the temperature drops on Friday with the southerly and on Sunday as the front moves in."
For farmers like Te Mata Park Trust Board chairman Bruno Chambers this spring weather had been extremely pleasant and he said it could not have been kinder.
The combination of rain and heat meant the growth of feed during lambing had been "fantastic".
"The only problem we have now is that there is not enough animals to eat all the grass. We have had great grass growth, as good as we would ever get."
He said the absence of the westerly winds had been a bonus, as the grass was not getting dried out.
"With the Autumn drought we were handed a tough winter so this has been great for us and sets us up as we head in to summer."