Charts looking fairly decent this time around,fairly confident of snow below 100m in a few areas of Canterbury if the charts keep going the way they are.
Sounds like a similar set-up to the event in March which brought the violent southerly squall to Wellington and Marlborough, but pre-frontal land heating shouldn't be a factor this time of year.
I think the change will hit just after 11am places north from mid Canterbury i mean, so there will be some brief heating beforehand but not much.
With it being early September i wouldnt expect any actual thunderstorms for Canterbury, but the typical thundery type showers a few claps here and there in the heavier shower cells.
With this convection possibly brings the risk of brief snowflakes to quite low levels at times, but this southerly is quite fast moving with some omph!! in it so i expect there will be more than just brief showers.
The southern annular mode (Sam), which measures the strength of the vortex, has been at record highs in the past month, meaning the polar air has been locked around Antarctica.
However, computer models show Sam is expected to weaken over the next few weeks and return to negative values for the first time since April, allowing polar outbreaks to head north towards New Zealand, Australia, South Africa and South America.
MetService spokesman Bob McDavitt said it was too early to say which countries would get the freezing southerlies. However, the computer predictions meant the South Island was at risk.
This is laughable. Anyone who looks at southern hemispheric weather patterns knows this isn't true. I invite anyone here to look at the weather in Victoria during the month of August, to see they have recorded exceptional snowfalls on all their skifields. You can't get that unless polar air has advected north.
Climate is what you expect. Weather is what you get.
Its been more to do with the Altitude of the those Australian ski fields as to why they've recorded such exceptional snowfalls and less to do with any Antarctic polar air mass,this past winter and even i see today there has seen quite a number of depressions that have developed over the lower half of Australia that have moved east bring those snowfalls
Yes and parts of australia have also had good rains too so thats got to help as its been the dry winters they have been getting that have starved them of snow.
Back to todays weather and its a frosty start here with -1C, had no weather at all last night/arvo so it just sliped on out to sea as todays front might do too.
melja wrote:Yes and parts of australia have also had good rains too so thats got to help as its been the dry winters they have been getting that have starved them of snow.
Back to todays weather and its a frosty start here with -1C, had no weather at all last night/arvo so it just sliped on out to sea as todays front might do too.
Oh dear melja, you got a frost there,ive got a 7C NW this morning.
The southern annular mode (Sam), which measures the strength of the vortex, has been at record highs in the past month, meaning the polar air has been locked around Antarctica.
However, computer models show Sam is expected to weaken over the next few weeks and return to negative values for the first time since April, allowing polar outbreaks to head north towards New Zealand, Australia, South Africa and South America.
MetService spokesman Bob McDavitt said it was too early to say which countries would get the freezing southerlies. However, the computer predictions meant the South Island was at risk.
This is laughable. Anyone who looks at southern hemispheric weather patterns knows this isn't true. I invite anyone here to look at the weather in Victoria during the month of August, to see they have recorded exceptional snowfalls on all their skifields. You can't get that unless polar air has advected north.
Much of the snow arrived in August , May to July had just about no snow for those Aussie fields. Only in the last few weeks have we been seeing the deep southerlies on the weather charts for our region. Dunedin and Invercargill have had a lack of the usual sleet and snow events over winter.
the lows themselves even when cutoff cause enough divergence for snow,anyway even us havent had the usual SW winds (which I dont miss) though today and tomorrow be an exception.
About 8pm last night I went out to get some firewood from the garage, we had a brief heavy shower and I saw one flash of lightning out over the back of Sugarloaf.
Blue skies here in Waddington. However, in the last 15 mins or so the wind has picked up and some very high, thin, cloud has formed... keeping eyes peeled...
Read that article. Its a beat up. The reason for our lack of southerlies is the 3 month long preference for blocking highs in our corner of the world. If you follow southern hemispheric maps, as I do, there have been plenty of strong SW flows on the other side of this block, and over other ocean areas. So to suggest that 'polar air has been locked up' is nonsense.
Falls Creek, Hotham, Mt Buller for sure are up around 1700-1800m but the are also about the same latitude as Auckland....and snowfalls were down around 900-1000m during their storms. These snowfalls were classic cold advection falls, with deep lows well SSW of Tasmania and cold cyclonic vorticity on the W NW and N quadrants. To try to suggest that polar air wasn't involved is wrong. Go to BoM and look back at the maps.
News Flash: The South Island is at risk every spring from polar outbreaks.
Climate is what you expect. Weather is what you get.
