Icy blasts make for impressive facts and figures

Well another cold blast for the country as we wind down the final week to the shortest day of the year. Here are a few stats from Tuesday's Antarctic blast...

- Blizzards in Dunedin and Gore
- Wind chills of -7 in Invercargill and Dunedin at dawn
- Wind chill of -8 in Queenstown at sunrise
- Wind chill of -5 in Wellington early afternoon
- Staggering wind chill of -20 on the ranges in northern Southland
- Snow flurries to about 100m in Hutt Valley
- Sleet in Palmerston North
- Snow closed State Highway 2 over the Rimutaka Ranges yesterday afternoon.

Some pretty impressive facts and figures and as we expected earlier in the week it was the cold air that was the main feature. Although in Dunedin I'm sure you'd argue it was the snow. It's been a funny old winter so far... this is the 3rd significant blast from the south but the first to really impact a populated place. For those who love snow it's simply been unlucky - especially those in Christchurch hanging out for a snow day. For farmers and everyone else who could do without it the wind direction has been your blessing in invisible disguise.

The 3 past polar blasts all had large highs to the west (out in the Tasman). This helped fire up the southerlies across the country but also meant the snow was short lived and didn't 'hang around'. The high just expands eastwards and shunts the polar air out over the Pacific. So the air slides up the South Island's east coast, hits Wellington and the lower North Island then moves out to the east. For a real snow maker a low is needed off the Kaikoura coast churning up cold south easterlies right into the South Island's east coast while the northern side of the low feeds down moist, warmer, air. It's a recipe for a decent snow storm but so far we haven't seen that set up.

There's something else that we've lacked so far this winter, in my view anyway. And that's southerly lows coming up from the southern Tasman Sea firing thunderstorms and hail storms and squalls along the western coastline from Greymouth to Auckland and Northland. Taranaki's had a few thunderstorms but so far nothing significant. Some will be very thankful of that following the damage from previous years thunderstorms....I, on the other hand, love them. And I think I can say that... it was a squall or small tornado that blew my huge gum tree over on to my newly built fence early last year. (that I built by the way) (oh with the help of my father). Despite the pain of building it all over again and losing a number of nice plants...and the aerial on my roof....I wanted to experience it all over again. In the words of Hank Hill from King of the Hill..."the boy ain't right".

But this Sunday is the shortest day (and Monday is pretty much the same too) so some see this Sunday as the official start of Winter. Not me, I called winter starting back in May this year...hey it was cold enough. Certainly in America and Canada summer officially kicks off on June 21st.

As for our southerly friend (or enemy) well he's gonna stick around for a few more days yet. In fact, possibly strengthening again this weekend in some places. For those who don't like this extra cold air there is good news - north easterlies are back in the forecast for midway through next week. For those who hate the rain... make the most of the next few days as most places, apart from a few showers here and there, should be mostly dry.

Watch out for black ice this morning if you're heading out... temperatures in Central Plateau and Central Otago are tipped to drop well into the negatives...possibly -7 or -8.

Top: Otago and Southland bore the brunt of the Antarctic blast, recording wind chills which almost reached -10. Photo / Otago Daily Times