The large high that brought us not only our big snow storm last week but temperatures over 20 degrees this week, is finally starting to move out into the Pacific Ocean.
The centre of the high – which yesterday crossed Auckland and Northland bringing plenty of anti-cyclonic gloom, is today mostly to the east of Northland – although a smaller, secondary bubble of high air pressure exists just to the west of Auckland.
By tomorrow the high will continue to slowly trek eastwards slowly lowering the air pressure over the country. So what does that mean? Well the lower the air pressure the more unstable the weather can be – ie, lows can move in, strong winds and heavier rain are more likely.
But nothing stormy is in the forecast for the next few days – apart from the possibility of some heavy rain in northern New Zealand. This is due to a small area of low pressure that has hounded Queensland all week with heavy bands of rain and showers. It isn’t a large low but the rain within it is sub-tropical, slow moving and heavy. There may be pockets of heavy rain later this weekend in the Far North – and we’ll keep you posted.
Meanwhile in the South Island the early spring westerlies continue with another surge of wind pushing back in again later today and during Friday. While it’s unexpected to be too blustery in most main centres the wind flow could again see some localised areas hitting the 20 degree mark (or higher) in eastern areas – but it all depends on the exact wind direction, speed and timing. It’s these three factors which can often make calling Christchurch’s high so tricky. In some cases places like Darfield can be 22 degrees while Christchurch is on 14… due to the warm winds not hitting the city, either due to lack of strength or just slightly the wrong wind direction. The nor’west arch – a band of cloud that appears during a nor’wester – can also block the sun and hold back the temperatures until it passes.
The warm South Island winds will come and go over the next few days at least.
Who has what today?
on 25/08/2011 3:07am
What are the odds of another such high moving in from the west and giving a repeat of the last few weeks? I see some mention of snow risk remaining for the rest of winter. Or are there low odds of a cycle repeating and we’re moving on to spring?
on 25/08/2011 3:16am
The chances of a repeat of last week would be unlikely but certainly we have high risk for another snow event within the first two months of spring. There are some big highs rolling in – the next week looks set to move on to NZ in around 9 days time but the angle of it doesn’t support a snow storm at this stage – but we’ll be closely monitoring – and will alert our readers here at WeatherWatch.co.nz the second we get a significant hint of another snow storm.
on 24/08/2011 8:47pm
According to the Metservice 3 day rain forcast (http://www.metservice.com/national/maps-rain-radar/rain-radar-forecasts/rain-forecast-3-day not sure if you will allow this link – I know how you guys are in competition!), the rain just misses us here in Northland and only scrapes Cape Reinga. How accurate is that forecast?
on 24/08/2011 9:03pm
Hi Mark, we don’t use any of their data for predicting so have no idea how accurate their rainfall maps are – we use the rainfall prediction maps provided by http://www.WeatherMap.co.nz and have found them very accurate this year. Yep there’s definitely the chance it may be further to the east but the risk is there for it to settle over some parts of Northland so we’ll keep a close on it.