A tropical cyclone from the Coral Sea in the next 10 days looks increasingly likely, Weatherwatch meteorologist Phillip Duncan says.
It makes forecasters optimistic about rain for the northern half of the North Island.
The Coral Sea is the usual hatching ground for tropical cyclones that peel away and down through the South Pacific.
The country has had some rain in the southern North Islan with 50mm to 170mm being reported.
However, most of the country north of Taupo remains in drought.
Niwa analysis shows parts of Hawke’s Bay, north Waikato, Manawatu, Northland and Coromandel with soil moisture deficits of 110-130mm, similar in many cases to the same time last year but significantly drier than the historical average.
Average deficits for this time of year are 50-70mm.
“This storm system to our northwest later next week may link to a more usual low pressure system coming through in the Tasman Sea. This gives a chance for wet weather to move into drought zones 10 days from now.”
For the past four months NZ has been blighted by high pressure systems that have effectively blocked moist Southern Ocean systems penetrating much beyond Canterbury or have caused wet weather to go east or west of the country.
“It may sound a bit harsh but a good cyclone now, even if it brings a bit of property damage with it, is what we need to really deliver some serious rain to these regions that need it so much.”
The risk of heading into winter with inadequate moisture levels remains a real risk.
Duncan said farmers can take heart from the patchy rain in many areas and shorter days reducing the amount of evaporation.
“And the soil temperatures are still very good so any rainfall will get very good growth results and the shorter days should not be too much of a concern with that in mind.”
