By Thursday night, the forecast had already prompted a decision to transfer the show's shearing competition, featuring the first match of a Wales development team.
The Shears, likely to attract 60-100 shearers, will now be held at Tauwharetoi Station. in Ruakituri Valley, Rd, off Tiniroto Rd.
Shearing convener and award-winning farmer Bart Hadfield, of Ruakituri, said that using the weather-watching systems he monitors for use in running the farm, he believed there would be significant rain.
His committee agreed it wanted to avoid the risk of having to cancel at the last minute on Saturday, when competitors would have already been on the road, some from as far away as 350-400kms.
In 2010, the show was washed out by heavy rain which made the showgrounds almost inaccessible, but the shearing was then also able to still be held, in another woolshed.
Show event manager Laura Hooper said that apart from some sign of rain in the morning, the first day on Friday, including equestrian events, a rodeo, sheep dog trials, a speedshear and a fundraising concert supporting Australian bush fire recovery to be completed without problems.
MetService was forecasting at least 10mm of rain for Wairoa on Saturday, and there were similar expectations for the site of the January 6-7 Tangoio forest fires, where crews have continued working to ensure all hot-spots are extinguished.
Principal rural fire officer Trevor Mitchell, who had until the fall of more than 25mm on Monday and Tuesday, been planning for crews of 25-30 people working on the site for four to five weeks, said crews, now down to 12-13 people would have the weekend off.
Hawke's Bay Civil Defence Emergency management reported "The fire is 100% controlled - woohoo!", and the firefighting had been handed back to forestry company Forest Management New Zealand, but warned it didn't mean the fire was "completely extinguished."