Polar outbreak June 19th to 21st

[David]

Models are playing around again with a polar scenario around 20th June and beyond... some insane 850mb temps showing up (-10 in parts of the South Island)

gfs.stormcast.bsch.init-2013061400z.fcst-201306200900z.t850.nz.null.png

Map from here http://nz.bsch.com.au/stormcast.html

[Bradley]

Yeah David all the models are onto it and have been consistent the last number of runs, it has it arriving Wednesday night/Thursday morning. Will wait until Monday though before I start talking about it too much on here!!

[NZstorm]

The very cold air is coming mid week but the 12Z European pushes the system through much faster than the gfs.

[CHCH Weather Chaser]

Yes GFS this morning is insane. Showing about 50mm for this event but for the polar air next week 120mm with thickness around 525. It will change obviously, imagine if it didn't, we could have snow up to the windows

[Richard]

Yes GFS this morning is insane. Showing about 50mm for this event but for the polar air next week 120mm with thickness around 525. It will change obviously, imagine if it didn't, we could have snow up to the windows

Your right,if it stays on track it could be one very nasty snow fall

[TonyT]

Yes GFS this morning is insane. Showing about 50mm for this event but for the polar air next week 120mm with thickness around 525. It will change obviously, imagine if it didn't, we could have snow up to the windows

In 1918, shortly after the Coleridge power station opened, there was a very heavy snowfall which covered the Canterbury Plains and foothills. The power went off, and the mayor of Christchurch offered a reward (10 guineas I think) to whoever could get to the power station to confirm they were alright. Two blokes skied from Upper Riccarton to Coleridge in roughly a straight line (ie over the top of the fences). I would imagine (although we have no way of knowing) that the weather situation which brought that event would have been similar to the one predicted for this week.

[Storm Struck]

Does anyone have maps they can dig up of the 1992 event? I think ive asked this before but I just want to see if this low is similar because I seem to remember it was a two part system.

[Bradley]

Try this site storm struck, it has archived weather data/maps that go way back for all over the world: http://nomad3.ncep.noaa.gov/cgi-bin/pdi ... e=map&dir=

[Orion]

Does anyone have maps they can dig up of the 1992 event? I think ive asked this before but I just want to see if this low is similar because I seem to remember it was a two part system.

To which 1992 event do you refer? the snowfall early in July (eight to ten inches here) where everyone rushed about taking "snow photos" or the August snowfall, thigh-deep and overwhelming?
I recall that winter was particularly dull and dreary through July and August, quite apart from the snows.

[Storm Struck]

Does anyone have maps they can dig up of the 1992 event? I think ive asked this before but I just want to see if this low is similar because I seem to remember it was a two part system.

To which 1992 event do you refer? the snowfall early in July (eight to ten inches here) where everyone rushed about taking "snow photos" or the August snowfall, thigh-deep and overwhelming?
I recall that winter was particularly dull and dreary through July and August, quite apart from the snows.

That's what it was two different events , yeah I mean the second bigger one Christchuch had over 35cm.

[Richard]

Does anyone have maps they can dig up of the 1992 event? I think ive asked this before but I just want to see if this low is similar because I seem to remember it was a two part system.

To which 1992 event do you refer? the snowfall early in July (eight to ten inches here) where everyone rushed about taking "snow photos" or the August snowfall, thigh-deep and overwhelming?
I recall that winter was particularly dull and dreary through July and August, quite apart from the snows.

That July one was more a North Canterbury event where the farm i was working on got 75 -80cm,i cant remember all the particular details but i'm sure that on was a area of slow moving low pressure over the top of the South Island.

[Orion]

Somewhere I have the Press with the weather-map for that August snowfall: I recall for sure there was a depression just off the Canterbury coast; there were quite strong southerly or SE winds blowing very fine snow into deep drifts here. Extraordinary event; unforgettable.
The "depression off the Canterbury coast" scenario has brought us other good snowfalls as well, just can't recall the dates though.

[CWUweather]

Looking nasty for the South Island East coast wednesday afternoon through to thursday afternoon. Seriously, if the models stay the same we are looking at 20cm plus in chch

[matttbs]

Metservice have just updated their Canterbury forecast for wed/Thur - snow to low levels. I think we are looking at a significant weather event

[CHCH Weather Chaser]

Yes GFS this morning is insane. Showing about 50mm for this event but for the polar air next week 120mm with thickness around 525. It will change obviously, imagine if it didn't, we could have snow up to the windows

In 1918, shortly after the Coleridge power station opened, there was a very heavy snowfall which covered the Canterbury Plains and foothills. The power went off, and the mayor of Christchurch offered a reward (10 guineas I think) to whoever could get to the power station to confirm they were alright. Two blokes skied from Upper Riccarton to Coleridge in roughly a straight line (ie over the top of the fences). I would imagine (although we have no way of knowing) that the weather situation which brought that event would have been similar to the one predicted for this week.

Wow imagine that! Ofcourse the GFS will downplay whats its showing at the moment as we get closer to the time surely...its just a question of whether it downplays it heaps or just a little to still be very significant.

Few spots of rain every so often today. Nothing really wetting the ground though. If the model runs hold true for this over the next 24 hours, even although its about 4-5 days out it may warrant some early warnings to the media so people can stock up? It does look a very serious situation at the moment.

[Bradley]

2C max on Friday now the metservice is forecasting for Darfield. not a huge anount of moisture but some extremely chilly temps, especially with the wind factored in. i wonder when the Metservice will issue a warning on this, in the past they have been quite cautious with these kind of systems...

[Richard]

2C max on Friday now the metservice is forecasting for Darfield. not a huge anount of moisture but some extremely chilly temps, especially with the wind factored in. i wonder when the Metservice will issue a warning on this, in the past they have been quite cautious with these kind of systems...

Should be issued in the severe weather outlook due any minute i would think.

[CHCH Weather Chaser]

Yes mention of heavy snow in the outlook now.

[CHCH Weather Chaser]

Latest gfs run just through has significantly dropped moisture for the polar blast next week but still some moisture there and thickness down to 512!

[CWUweather]

Latest gfs run just through has significantly dropped moisture for the polar blast next week but still some moisture there and thickness down to 512!

Yip lets hope it pick up again with the next run. what time will that be? anyone know? but yes thickness 512, lowest i have seen it. Bitterly cold too

[matttbs]

Correct me if im wrong but after this intense polar outbreak there seems to be another lining itself up for a direct hit a couple days after? Thickness around the 520 mark

[CWUweather]

Yes, looking like a repeat of August 2011 or even 1992. Still a while out but seems to be holding well. Moisture back off a little on the last run but still going for a decent amount on the South Islands east coast. We will know more by Monday or Tuesday but will be interesting to see what the next run says in about 1 hour when it comes through!

[CWUweather]

HOLY MOTHER OF GOD! Moisture has picked up hugely bloody hell!!!!!!! although thickness back up at bout 525mb still, look narly!

[tich]

Does anyone have maps they can dig up of the 1992 event? I think ive asked this before but I just want to see if this low is similar because I seem to remember it was a two part system.

Yes, got them on an old Met Society newsletter. (in notable weather events written by Trevor McGavin) Latest ECMWF for Thursday looks strikingly like the August 1992 event. Other models may be less extreme, but still a significant polar blast for both islands.

[Richard]

Looking at the BOM maps for Antarctic for Wednesday the polar airmass comes right from the Ross Sea area and a ridge sinks south,the perfect combo.