KEY POINTS:
A number of rain bearing fronts have started to appear around New Zealand giving some farmers comfort at a particularly dry time of year. Officially we are in a neutral period - in other words no La Nina (wetter) and no El Nino (drier).
El Nino and La Nina are worked out by sea temperatures and this year, while we're in a neutral period, the atmosphere above doesn't seem to quite agree. Lately La Nina-type weather has been developing with lows and rain bearing fronts popping up all over the place.
The biggest difference between this Summer and last is the fact that the highs aren't holding firm over New Zealand. Literally last summer we had a high covering most of New Zealand for most of the Summer months - that stopped rain getting into the usual places and led to unusual droughts in regions like Southland and Waikato.
This year the biggest difference would be that the highs are moving offshore quickly and allowing lows to move in and deposit rain mostly along the west coast with a few sprinkles making it to the east. At least one or two lows a week seem to have been impacting our country lately.
I spoke to James Renwick, Climate Scientist at NIWA in Wellington and he said that we're going in to a more disturbed phase at the moment. By that he means we're not getting big clean highs holding firm over the country and instead little lows and fronts are appearing all around and over New Zealand.
"We're not in La Nina as such but unusual stuff has been happening in the tropics...the atmosphere thinks there's a La Nina happening". He predicts that it'll possibly just fizzle out and drier weather could return to most places.
He says there's a chance a weak La Nina could develop and that would favour average and maybe a little more than average rain in northern centres like Whangarei, Auckland and Tauranga.
James Renwick says soil moisture levels are lowest in places like Hawkes Bay and Gisborne where they're already lower than at this time last year. Other regions are still drier than they should be but a little wetter than this time last year.
With perhaps a slight leaning towards La Nina the possibility for sub-tropical depressions moving down is definitely higher. This is something I talked about a few weeks ago and with very warm waters in the Coral Sea this Summer we might see a few big lows drift down.
With this more 'disturbed' weather pattern cloudier conditions are likely in a number of places but it's certainly not cold. Temperatures are comfortable and I still think Christmas Day will be a warm or hot one no matter where you are in New Zealand.
A developing low early next week may also see a little bit of rain moving in to our driest regions, such as the east coast. But rainfall estimations by the Weather Watch Centre aren't high - predicting just a 40 per cent to 60 per cent chance of anything precipitation.
With a low moving in from the west that usually means just a few sprinkles on the roof for those in the east. What the east coast desperately needs is a low to form to the east of New Zealand - but that's not in the picture at this stage.
What are conditions like where you are? Post a comment below and let us know what it's like where you live.
Philip Duncan
Photo / Doug Sherring
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