This Week's Weather Forecasting 13th - 17th August 2012

[JennyLeez]

In Brief From the Metservice

Tuesday
North Island, occasional showers, mainly in the west. South Island, rain, with high country snow, from Canterbury to Southland gradually clearing, cloudy periods elsewhere, with a few showers north of the Glaciers.

Wednesday
North Island, showers, mainly in the north and west. South Island, mostly cloudy, showers from Nelson to Westland turning to rain later.

Thursday
North Island, a few showers, clearing in the east and south. South Island, rain in the west spreading to the fiords, and easing to showers further north, increasing fine spells elsewhere.

Friday
North Island, a few showers in the north and west, mainly fine elsewhere. South Island, rain or showers in the west clearing, mainly fine elsewhere.

Chatham Islands
Rain, becoming lighter and less persistent on Wednesday and strong or gale easterlies abating. Outbreaks of rain on Thursday.

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[Derek]

Going by Ogimet charts, it does look like showers are going to be around in places for much of the week, but there’s likely to be nicer weather about too depending whereabouts in the country you are.

My pick is that by Tuesday we should see rain clearing from the east coasts of both the north & south islands – it’ll hang around longer in the south though (may take till the end of the day down there). Meanwhile, in the north island, the north and west are likely to get showery weather right through to Thursday.

For a lot of places, Tuesday could end up being quite a nice day.

Thursday I think could be the best day of the week, light wind if any, and fine in most places with just a chance of showers or light rain on the west coasts and in the far north.

On Friday, we see a high sitting to the north of the country and a new low sitting in the south Tasman – that’s going to bring more rain and the west coasts of both islands will see it first with north westerly winds.

That high could well end up blocking the incoming low, have to wait and see how things develop through the week.

Here's a couple of Ogimet charts, the first is midday for Tuesday and second is for Thursday - on these the coloured overlay shows a 6 hr accumulated rainfall expectation and cloud cover is grey. 

[OhauitiWeather]

Updated 8:40am --- They have been relentless for the past month - and this coming weekend will be no different as yet another large Tasman Sea low takes aim for New Zealand bringing more flooding and slip risks.

Since mid July the nation has seen a significant step up in heavy rain makers completely fixing any areas that were not too long ago getting low on water, like North Otago and South Canterbury. 

Heavy rain - which continues to fall today across many eastern regions - has caused dozens of highway closures, detours and partial closures mainly in eastern facing regions.

WeatherWatch.co.nz - which predicted in March that NZ had a high chance of snow storms and southerlies for the first half of winter, then predicted in July a much warmer and wetter period for early August says it's still hopeful for a drier end to this month with increased westerlies...but it may not be dry for everyone.

"With westerlies we tend to see eastern areas dry out and warm up while western areas, particularly in the South Island, may see more cloud and wet days" says head weather analyst Philip Duncan.

"Temperatures are also more likely to return to average for many areas with less of a sub-tropical element to the equation".

Mr Duncan made the call at the end of July that the worst of winter was already behind us, despite being in the coldest part of the year.  Writing in his weekly WeatherWatch.co.nz column on Saturday mornings Philip said the wetter, warmer, July pattern would last until mid-August".

The incoming low for this weekend may be the last of the big lows with some models showing more spring-like westerlies following after, however WeatherWatch.co.nz says it's still too early to confirm with the weather currently so unsettled around the country.

The rest of August

Today WeatherWatch.co.nz says the rest of August will be generally mild with average rainfall.  The weather news authority has also eased it's General NZ snow risk (for snow to sea level) to moderate for the next two months.  "This time last year we still had a high risk for snow to sea level and on this Monday a year ago we had snow falling in Christchurch, Wellington and Auckland.  This year we're in a much warmer pattern".

The easing of the risk means, generally speaking, conditions should stay mild or around average.  It doesn't rule out the risks of further severe frosts, southerlies and snow storms - but the moderate rating used exclusively by WeatherWatch.co.nz does signal that prolonged nationwide cold spells are looking less likely.

*Updated Story *

Another low this coming weekend

And more warm, wet, weather is the on the way. 

WeatherWatch.co.nz forecasters predict another low will again drive bitterly cold, wet and windy weather to eastern Australia while at the same time pulling down warm, sub-tropical conditions over northern New Zealand along with a moderate risk of more rain warnings for New Zealand.

During this past weekend Aucklanders woke to 15 degrees on Sunday morning while on the other side of the Tasman residents west of Sydney had snow with strong, cold, southerlies.

The timing of this next low remains messy - but our feeling is that it will move in across the weekend, starting as early as Friday night for some and as late as Sunday for others.  We'll continue to monitor very closely and should be able to nail down details tomorrow.


- WeatherWatch.co.nz
http://www.weatherwatch.co.nz/content/yet-another-large-tasman-sea-low-coming-winter-winds-down

[OhauitiWeather]

In Wednesday's weather video Philip Duncan and nzherald.co.nz team up to bring you the latest on the current rain and showers around NZ today and what the rest of this week and weekend looks like.

We also look at the next big low rolling in around Sunday and Monday - two sets of good news here - 1) it's likely to be short lived.  2) It may well herald a westerly change in our weather pattern which should see drier, sunnier, weather to saturated areas in the east.  Still early days - but Phil takes a look at early next week and explains.

Link to Video:



-Weatherwatch.co.nz
http://www.weatherwatch.co.nz/content/video-yes-more-rain-coming-then-a-change

[OhauitiWeather]

Another low pressure system is set to move into and deepen in the Tasman Sea this weekend however thankfully unlike the last few depressions that have come over New Zealand this one will be shorter lived.

WeatherWatch.co.nz forecasters are keeping an eye on the incoming system, Weather Analyst Aaron Wilkinson says “This incoming low is set to move into the Tasman this weekend then move across the country on Monday before moving offshore out to the east on Tuesday and Wednesday, the low isn't being held up by a blocking high like the last few systems and is instead this time being nudged out of the way by an anticyclone coming in behind it”.

Some rain is set to affect the west of the North Island on Saturday while sunnier weather lies out east, during Sunday wet weather becomes a little more widespread however the east coast of the North Island and Southland may remain dry. On Monday and Tuesday the flow changes to the southwest bringing showery conditions to the country.

Mr Wilkinson goes on to say, “The heaviest falls are looking to be from Taranaki down through to the top of the South Island and about Buller on the West Coast during Sunday, sodden parts of Canterbury and Otago will escape the heavy rain this time round although there will be some wet weather in the form of showers early next week in the east of the South Island”.

WeatherWatch.co.nz
http://www.weatherwatch.co.nz/content/incoming-low-pressure-system-%E2%80%93-time-shorter-lived