Cold southerly outbreak

tich · Unread post by **tich** » Wed 21/07/2004 22:38

Looks like a southerly blast sweeping up over NZ tomorrow. Typical stuff predicted for the country with this change - a period of rain/showers, with snow to about 300 metres in the South Island and 600-700 metres for the North Island. MetService has this outbreak coming quickly, but not lasting for long - easing on Friday. However, after what's been happening in the North Island lately, complications could easily set in, ie a trough forming on the cold front as it crosses the North Island and prolonging and/or intensifying the cold southerly outbreak. Let's see what happens.

NZstorm · Unread post by **NZstorm** » Thu 22/07/2004 07:24

This morning, looks like snow down to about 600m with the front.
Desert Road will close tonight.

tich · Unread post by **tich** » Thu 22/07/2004 09:09

The southerly blast has certainly hit Chch this morning - about 3-4C, raining, and with a gusty southerly. AA Report mentions high country roads being affected by snow - The highway near Tekapo closed, and chains needed on Porter's and Arthur's passes.

Michael · Unread post by **Michael** » Thu 22/07/2004 11:13

Cold and wet here today occasional showers Light Westerlies but winds should be SW and galeforce soon

Thunder · Unread post by **Thunder** » Thu 22/07/2004 13:21

Big black cloud about to hit, hail just beggining to fall, increasing in intensity as I type! Not very big though (hail that is). Surely some snow on B'sP from this! Getting heavier, and hail slightly bigger to! Hail covering the ground! will melt away soon, heavier hail now!!!!\:D/

A bit of fun!

Biggest hails official size, 5mm!! I've now seen it!! LoL And I didn't bring my camera today, grrrr.

tich · Unread post by **tich** » Thu 22/07/2004 13:58

However, after what's been happening in the North Island lately, complications could easily set in, ie a trough forming on the cold front as it crosses the North Island and prolonging and/or intensifying the cold southerly outbreak. Let's see what happens.

Now looks like a trough is forming on the cold front about to sweep over the North Island, so things should be a bit more complicated than simply a cold showery southerly change - rain is forecast for the east of the North Island tonight, with snow to 500-700 metres.

We've already had snow to low levels (Darfield) on the Canterbury Plains this morning according to XTRA news, and hail showers are continuing in Chch. (see daily obs thread) About 7C in northern South Island centres on Noon obs, but only 3C in Kaikoura, so must be snow to low levels there.

Thunder · Unread post by **Thunder** » Thu 22/07/2004 14:27

Hi Ben

Regarding the snow thing and where I've seen it in the past from the other thread in the daily obs forum. Below is a map of lyttleton, the black line I've added indicates what I tend to think of the port hills. The blue box shows the area where I've seen snow in the past from Chch through a gap in the port hills, it's a hill somewhere there on the other side of lyttleton (Diamond harbour side).

Other map is another view of Chch I drew showing how I've seen the snow at times from Chch. And 03 storm chaser looks to of seen today. And no it didn't take long, just a bit of time to kill. Some small hail returning as I type. Town Cryer added for fun and car falling off summit Rd for lack of another hill which i didn't have time to draw.

Editied:

Just been reading your other post Ben and understand what you mean about the port hills being mainly the Northern facing side. I would probably agree with you there. So..... through that gap in the port hills we'll call that Bank's Peninsula we can see with snow.

NZstorm · Unread post by **NZstorm** » Thu 22/07/2004 20:24

I see Met Service are predicting upto 20cm on Desert Road overnight.
And with the fine weather coming for the weekend, the Ski field operators will be in the clover.

Isolated thunderstorms with hail overnight in the west of the NI, judging by NZPP sounding and satellite imagery.

Michael · Unread post by **Michael** » Thu 22/07/2004 20:28

Boring rain going here tonight

tich · Unread post by **tich** » Thu 22/07/2004 20:47

Down to about 2C in Chch now - skies have generally cleared, but if there are any more showers still due, they could easily fall as snow now that it's so cold. My father told me on the phone that there was snow down to about 350-400 metres around Akaroa, but he said he didn't notice any hail at his place. (western side of Akaroa harbour)

I wonder if the Port Hills are in some kind of 'snowshadow', often sheltered from the south by Banks Peninsula's hills, especially Mt Herbert. This may explain why there are some wet and very cold outbreaks (like today) in which there's no snow visible on them, yet there are low level falls elsewhere in Canterbury, ie on the plains and Banks Peninsula.

tich · Unread post by **tich** » Thu 22/07/2004 20:53

So..... through that gap in the port hills we'll call that Bank's Peninsula we can see with snow.

I've just had another look at your map Aaron. Actually the bit of Banks peninsula I could see this morning (cloud has again obscured it) would be part of 703 metre high Mt Evans, the easternmost high hill on the southside of Lyttleton Harbour.

Thunder · Unread post by **Thunder** » Thu 22/07/2004 21:17

Cheers Ben, I think I know were your talking about. But yeah, that little hill in my picture is one that seems to pick up snow in winter.

Interesting you say about the rain shadow thing, I went to Bob Cowders house (one of the founding members of the NZTS, I guess that's right John?), you meet him that night of that CW meeting at John's house. Actually you most likely new him before me! Anyway, he's got this picture he took on top of the Port Hills showing the Canterbury Plains. When you look at it you relise there's this massive semi circle in the picture streaching right across the plains with an area of no snow, it shows how B'sP rain shadow affects / effects (I forget which one) the Canterbury Plains and Chch. A great looking shot!

May lightning go near you this evening in Auckland!

tich · Unread post by **tich** » Thu 22/07/2004 22:09

The cold air must be moving onto the North Island this evening - 9PM obs show temps down to single figures from Auckland southwards, and just above 0C in Waiouru. Should already be snowing on the central plateau, though AA Road Report doesn't yet warn of snow problems on Desert Road and other highways. At least MetService has given advance warning of a major snowfall event in the central North Island, unlike the previous 2 such events this winter. Hopefully no-one should be caught out and stranded by snow on the roads this time.

Still some clouds about in Chch, though no precipitation for some time.

Manukau heads obs · Fri 23/07/2004 08:00

hi
only 4.5oC here this morning with a SSE wind...thats about as cold as we get with the wind blowing!
(and its 4.8oC in central auckland)
could almost be snow on the highest ranges in the area (as there is showers around)

anyway, was talking to my father in law in turangi
2m of snow on the central NI skifields now!
all raods are closed in the area at the moment
snow right down on the foot hills

TonyT · Unread post by **TonyT** » Fri 23/07/2004 08:27

Icy here this morning - overnight frost despite some light SW breeze has frozen water on the paths, roads, etc from last evening's showers. Very slippery, but should melt soon as the sun is working on it!

tich · Unread post by **tich** » Fri 23/07/2004 08:52

We had another burst of showers overnight in Chch; I thought I heard hail again and quite possibility snow could've fallen as well, but not settled. There's a slight dusting on the Port Hills this morning, down to a quite low level. Clear skies now.

Thunder · Unread post by **Thunder** » Fri 23/07/2004 09:53

3rd frost we've had this year and I suspect we'll get our 4th tomorrow. Icy roads out there, the wheels spun a few times at one or two places. My Dad just put new tyres on the car yesterday!

Got some snow on the part of the Port Hills near me. Last year this is about the same amount that fell on it when all you other guys across the other side of town got all that snow! Pics Below.

Andy · Unread post by **Andy** » Fri 23/07/2004 09:57

Frost number 89

Yep another good frost last night, -7.2 degrees.

Cloud has creeped in from the east now, so not very warm..

ATM -3.2 degrees

Gary Roberts · Unread post by **Gary Roberts** » Fri 23/07/2004 11:23

Andy wrote:Frost number 89

Yep another good frost last night, -7.2 degrees.

Cloud has creeped in from the east now, so not very warm..

ATM -3.2 degrees

Another magnificent day here, Andy. We only got down to -6.4 at 08:34 this morning. A wee bit chillier down in Alex! No cloud here yet, and hopefully it'll stay that way. It's around 2.6Â° here right now, and the sunshine is very nice, so not too bad at all.

tich · Unread post by **tich** » Fri 23/07/2004 17:09

Seems like the eastern North Island ranges/high country is getting the worst of this snowy blast, rather than the central plateau, which got it last night. The NOAA satellite this morning has a front moving up over the BOP, but doesn't look like anything more than light rainfalls there. But the eastern BOP ranges (eg the Ureweras) should be getting more, including snow, to add to the problems of residents in remote places like Ruatahuna. The 9.52AM satellite shows blue (which I guess means a decent blanket of snow) on the Kaimanawa foothills southeast of Taupo (which was only about 2-3C this morning) - no wonder the Napier-Taupo highway has been closed.

03Stormchaser · Unread post by **03Stormchaser** » Fri 23/07/2004 18:40

When aaron says frost 3, the sea is his back door! Its more around 15-20 frosts for the most of CHCH!! Todays was the worst with alot of black ice on the roads, I had a near miss on the way to work, lucky no one else was coming the other way!!

NZstorm · Unread post by **NZstorm** » Fri 23/07/2004 19:28

That snow looks more like frost.

According to TV1 the temp at Jade Stadium tomorrow night will be 1C.

tich · Unread post by **tich** » Fri 23/07/2004 22:07

That snow looks more like frost.

It certainly looks more like a frost than snow, being such a light cover, but as it's lying above a defined altitude on the photo, instead of being confined the shaded spots, it must be snow. BTW I saw on TV1 Sports News that grounds workers had to 'clear ice' off Jade Stadium in preparation for tomorrow night's game (may the ABs triumph again!) - could some hail, sleet, or even a little snow have settled there overnight. There was nothing lying around my place (near Botanic Gardens) this morning.

Looks like the snowy conditions in the eastern high country of the North Island may finally be easing. I'd say that these heavy snowfalls could also be affecting the higher ranges of the eastern BOP - I wonder if the melting might affect the levels of rivers flowing into the flood ravaged areas?

Thunder · Unread post by **Thunder** » Fri 23/07/2004 23:33

That thought sprung to mind as soon as I also saw it Steven W. But it seems to be a very light fall of snow, more than likely will be gone by tomorrow.

Yes your right 03stormchaser, only 3 frosts out by the beach. Inland certainly gets alot more than I do. I know what you mean about the black ice! it was in quite a few places. The News reported accidents attributed to the black ice.

Manukau heads obs · Sat 24/07/2004 07:20

coldest morning of the winter so far in the auckland area
-2 in waiuku
3 here
only 3.3 in central auckland!