Wintry weekend looming

Chris Raine · Unread post by **Chris Raine** » Sun 05/10/2003 09:50

Invercargill Sunday morning . Interesting night from my last report. Had a squally period just after midnight with light snow showers with winds gusting to 35 kts. Wind died but at about 0500 in came the snow and a freshening SW. Temp fell to 0.8 degrees. Got about 1 cm snow out of that shower. Now at 0900 obs Temp 3.5 degrees, light snow showers out of shallow Cb's.RH = 78 %. Slow improvemnt now ,but feels real cold out in the wind.

Yes Aaron I am the same Chris. Just been busy in my real job recently. Will try to keep everyone updated as the deep south sees the first arrivals of the fronts from the South Tasman.

Cheers

Andy · Unread post by **Andy** » Sun 05/10/2003 09:59

Wide spread snow has fallen in Central Otago this morning and over night.

Heard on the radio that Kingston has 10cm, and Ettrick has arounf 10cm.

Eastern Southland and South Otago have simlar amounts.

Alexandra had around 1cm this morning after an over night frost, but the suns out now, so it's melting fast.

Temp 2.0
Pressure 1005mb

tich · Unread post by **tich** » Sun 05/10/2003 10:08

Fine this morning in Chch, though I could see wintry looking shower cloud to the northeast earlier - the 9AM radar shows shower activity in North Canterbury. (Cheviot area)

tich · Unread post by **tich** » Sun 05/10/2003 11:44

Seems like the wintry blast is far from over this morning. According to webcams (see http://www.piperpat.co.nz/nz/webcams.html) St Arnaud, Nelson Lakes, is blanketed in snow, while Wellington has been wet with only 5C. (snow on Rimutaka Road?) Sunny this morning in Chch, but clouds have started building up, and a cold southwetserly has freshened up again.

jeffsweather · Unread post by **jeffsweather** » Sun 05/10/2003 13:04

Looks like snow flurries on this image from http://www.cityofdunedin.com/weather/today_window.htm
+2.2C

South westerly gusting to 45km/h with patchy clouds and 9C in Hillmorton.

Thunder · Unread post by **Thunder** » Sun 05/10/2003 14:04

Wow! snow in Dunedin!

The biggest pic there of some Cu gave me a little hail shower. Other pics are of what is floating round here today. The lower right hand carner one is a pic of a Cb offshor but it's hard to make out, there's a few offshore with what looks like hail falling from their bases.

Sunny here at present but the SW is fresh and cold!

Cheers
Aaron Wilkinson

Michael · Unread post by **Michael** » Sun 05/10/2003 15:05

Cold here too with the SWer at Gale force and some showers-Good for giving headaches!

NZstorm · Unread post by **NZstorm** » Sun 05/10/2003 15:43

The observed thickness at Invercargill midnight last night was 5185

I like the pics Aaron, but they show quite stable conditions. November to January is the likely time for t/cu cb in Canterbury

tich · Unread post by **tich** » Sun 05/10/2003 16:13

I've just been out to Sumner and walked up Scarborough hill, which has excellent views to the north. While it was fine over the Chch area, North Canterbury has been a different story - lots of squally hail type shower cloud. I watched a particularly intense looking squall move from about the Waimakiriri Gorge (about 1.45PM) to Motunau beach area (about 3PM). I didn't notice any thunder and lightning, but almost certainly there would've been hail, and quite probably snow to low levels. (North Canterbury/Oxford foothills already have a good fresh looking coating, probably down to 600 metres or even lower) Shower/hail activity could also be affecting outer Banks Peninsula. Mt Herbert has a patchy snow cover on its summit, but it looks like remnants from last weekend's storm.

This wintry southwesterly has not eased, despite a rising barometer. The wind has become strong and gusty in Chch this afternoon. Clouds are moving across the city as I write, but no shower activity visible at present.

TonyT · Unread post by **TonyT** » Sun 05/10/2003 16:27

A very thin veil of snow to about 100m on the North Canty hills overnight, which promptly melted by mid morning. As Ben says a few showers knocking around this afternoon, we had the lightest fall of snow flakes and snow pellets here at one point, light enough to go out in and enjoy without feeling at all wet! But other than that the showers are very isolated as the clouds are so small. Windy though, 25-30knots, but easing a fraction now.

I dont think any of the clouds were big enough to produce serious squalls, thunder, or large hail, but the little veils of precip as they floated, err zoomed, past were very pretty. Winds should drop later tonight and with the dewpoints below zero a severe frost is on the cards for Monday morning, we are picking -3 to -4 on the Plains, perhaps -2 in the city. Also likely to be significant frosts in Marlborough, Nelson and perhaps the Bay of Plenty. The NI east coast may escape with the winds possibly dying away there too late to get far below zero (but if not, watch out for frozen chardonnay).

At one point this afternoon Chch airport was giving temps of +9 and dewpoints of -6, which I think translates into RH values in the 20%s! So you can see why the showers are so small.

Here's hoping nobody hasd planted their tomatoes out yet...

Thunder · Unread post by **Thunder** » Sun 05/10/2003 16:32

I hope some lows come by Steven during November, despite it ment to be La nina, Lets hope lots of thunderstorms then....hehe.

Hi Ben

I think I know the cloud / squall line your talking about. The photo in the bottom right hand corner I think is the front of it (the front of a Cb). Other photos are of Cb's offshore and on the outer edges of Banks Peninsula(above Scarborough), like you say Ben hail most likley will be affecting these areas. I also thought "I wounder if there's any thunder and lightning?", I'm not sure. Steven, I remember you saying that the Cb's would be at 6000m for Dunedin / Invercargill going by the midday soundings, would it be the same for Chch?

Here's the pics.

Cheers
Aaron Wilkinson

P.S Big dark cloud outside at the moment (underside of Cb), may get a
hail shower. Radar should be interesting.

tich · Unread post by **tich** » Sun 05/10/2003 17:10

A very thin veil of snow to about 100m on the North Canty hills overnight, which promptly melted by mid morning.

100 metres? Is that a typo, or did the snow really get that low. I suspect the latter, as the snow level on Mt Grey was (I guess - not easy to see actual level from such a distance) about 600 metres or lower early this afternoon.

P.S Big dark cloud outside at the moment (underside of Cb), may get a hail shower. Radar should be interesting.

I could see that from central Chch - perhaps I should've stayed in Sumner to get a better view. Though I probably wouldn't been directly under it - towering cbs are usually further away than you think. (I think Aaron will confirm how close it was) The 4PM radar shows more coastal Canterbury activity than the 1PM radar. The are more orange 'blobs' moving up from the south - maybe one of these could affect Chch (as I write, I can glimpse cloud building far to the southwest, though it'll probably affect only the Banks Peninsula)

TonyT · Unread post by **TonyT** » Sun 05/10/2003 17:32

About 100m I reckon, the hills west of Amberley had that hazy green look to them first thing this morning which says light snow mixed in with the grass, but it had all greened up like it usually is by mid morning, leaving the snow which fell Friday night to about 500m on the higher hills like Mt Grey.

NZstorm · Unread post by **NZstorm** » Sun 05/10/2003 19:01

Aaron, again nice photos. These clouds are interesting because of the advanced state of glaciation and obviously wintry precipitation under them.
Tops could be as high as 5000m but more likely 4000m. Not the type of cloud that would produce thunder. These clouds are actually quite weak.

For thunder, I look at the sounding for chance of cb tops to 7000m or more(no chance of that today). I also look for the possibility of strong convection ( positive CAPE). Not likely today.

But there will be a good storm in Canterbury soon, possibly before the end of October. But as I suggested, November to January is the best time.

NZ Thunderstorm Soc · Sun 05/10/2003 19:28

Yes ,well um............

Lots of glaciated Cbs around today especially over and around the back of BP. I considered them to be too advanced, lacking 'pregnancy potential' resulting in dead Cb forms so didn't persue any further interest in them. Obviously the sun not strong enough to penetrate the cold southerly flow that is over us at the moment, rendering an onshore flow to render resistence to the southerly.
Some snow flurries were noted in Oxford so that could of resulted in the low snow lavels that TonyT noted around Amberley>

JohnGaul
NZTS

tich · Unread post by **tich** » Sun 05/10/2003 22:38

The skies are now clear in Chch and the wind is dying away - frosty tomorrow morning. Could be record frosts in many parts of the country overnight - unfortunately for crop growers.

This has certainly been a wintry outbreak this weekend, severe even for a month where icy blasts are still not uncommon. I wouldn't be surprised Dunedin's (Airport I presume) 3C maximum is a record low for October. TV1 weather even mentioned brief snow flurries in Kelburn just before noon. Napier and Mahia got down to about 6C this afternoon - quite probably snow on the Napier-Taupo Highway and other hill country in the area. There could even have been snow on some higher ranges to the north of the central high country, as Taupo has been showery at times today with single-figure temperatures. (Desert Road is now closed)

Thunder · Unread post by **Thunder** » Sun 05/10/2003 22:50

Your right Ben, when I went outside I relised that the anvil of that Cb was over me and the darkish part was beyond Scarlborough on the outer part of BP, so yeah....they can look closer than they really are.

I turned on the radio and no static, your definately right Steven / John, no thunder potential with these clouds, mayby as they travel further NE out to sea off the east coast of the N Island?

I took a quite a few more pics and there was a bit of mammantis type cloud about on the underside of one or two of the Cb's anvils, it didn't show up aswell in the photos I took but you can still notice it ok.

There you go, anvils, Cu clouds, mammantis on undersides of anvils, also a pic showing how darkish looking it got out to sea. I might post a bigger pic of one of the mammantis type ones as it gives a slightly different perspective when you see it larger.

Gona be cold tonight!

Cheers
Aaron Wilkinson

Dean. · Unread post by **Dean.** » Mon 06/10/2003 19:08

I have spent the last 4 days in Queenstown and the storm largely went around the town,we had a few snow flurries on Sunday.
Ashburton had a snow shower yesterday.
Typical southwester,Southland and Coastal Otago copping the worst.
Cheers.

NZstorm · Unread post by **NZstorm** » Mon 06/10/2003 20:33

Yes, Queenstown is quite sheltered on a southwester. You need to good front to get snow that far inland on a southwest flow.

tich · Unread post by **tich** » Mon 06/10/2003 22:16

Ashburton had a snow shower yesterday.

Do you know when this snow shower occurred Deano? Chch stayed fine all Sunday, despite wintry clouds on the horizon.

Your right Ben, when I went outside I relised that the anvil of that Cb was over me and the darkish part was beyond Scarlborough on the outer part of BP, so yeah....they can look closer than they really are.

I heard that there was considerable hail in some places around Akaroa Harbour (Wainui, Robinsons Bay), on Sunday afternoon from that cb - but no mention of low-level snow over there.