NZ Weather Forum

harveyt86 wrote:Hi all, long time lurker first time poster. I'm a real amatuer but to my untrained eyes looking at the models it seems like the wind is coming from a little too far east now during the heaviest precip? Either way it looks like being an interesting few days ahead!

Yea i see that harvey, but by that stage the coldest air is already here surrounding NZ so it shouldnt matter.

Metservice have forecast snow for timers and ashVegas thurs/fri and lots of it by the looks of it, 30+cm

Latest GFS very consistant with moisture showing 90mm for CHCH but the thing that has changed is the thickness had dropped down to 520 on the back end for around 15mm of it. So at this stage looks like rain with heavy falls through to late Thursday then snow looking more likely at sea level overnight Thursday throughout Friday.

12Z gfs has a secondary upper trough over the South Island Friday. Last couple of model runs have had it out to the west of the South Island but latest run has it over the SI. Something to keep an eye on in the gfs as this would generate snow showers to sea level.

GFS model for midnight Friday.

NZstorm wrote:12Z gfs has a secondary upper trough over the South Island Friday. Last couple of model runs have had it out to the west of the South Island but latest run has it over the SI. Something to keep an eye on in the gfs as this would generate snow showers to sea level.

GFS model for midnight Friday.

yaaaay back on track it seems thurs night/ into fri!!

Wow, metservice going for 9C for Christchurch Thursday now, seems like it could be about 3-4C too warm!!!

The moisture coming from this developing storm is getting more and more moisture in it, Latest GFS has it now well truely affecting Wellington too. Just wondering from what you pro weather forecasters can see is this gonna turn into low level snow for us like 100 or 200 metres?? Or is it going to end up being heavy sleet and rain for 24 hours??

Yeah I think 9deg is a little optimistic by M/S

This is turning more and more like a June 06' event, very little snow for anything at sea level in Canterbury but a massive amount for anything inland and at elevation...

Bradley wrote:Wow, metservice going for 9C for Christchurch Thursday now, seems like it could be about 3-4C too warm!!!

How the heck is it gonna be 9 degrees when the isobar lines come directly from the antarctic?? I think the metservice have got it wrong, or the computers generating the models are just plan confused and havnt factored in the freezing cold southerly currently on its way. Its abit like the 2006 storm, warm front comes across Tasman sea and collides with freezing southerly which caused mass snow dump in Canterbury. Maybe the MS are finding this hard to forecast?

Its also getting more and more easterly in the wind as the predictions progess too. I find it really hard to see sea level snow in that scenario, just not believing it is going to be anything other than a large and annoying amount of rain for most of us - yet. Happy to be wrong!

Razor wrote:Its also getting more and more easterly in the wind as the predictions progess too. I find it really hard to see sea level snow in that scenario, just not believing it is going to be anything other than a large and annoying amount of rain for most of us - yet. Happy to be wrong!

Just got Phil duncans report, hes still saying snow to sea level possible even tho it maybe brief to sea level for Wellington. I think i will go with Phils forecast. MS seem to playing it safe

Avalanche wrote:

Razor wrote:Its also getting more and more easterly in the wind as the predictions progess too. I find it really hard to see sea level snow in that scenario, just not believing it is going to be anything other than a large and annoying amount of rain for most of us - yet. Happy to be wrong!

Just got Phil duncans report, hes still saying snow to sea level possible even tho it maybe brief to sea level for Wellington. I think i will go with Phils forecast. MS seem to playing it safe

Charming - if it happens. Already a very drab damp month here (last sunny day was the 7th with a shortish topup on the 10th). The only upside is that following the southerly there may be a fine period like the aftermath of the August 2011 event.

Dan Corbett on TV1 breakfast mentioned about the marine layer..i.e the southerly needs to overcome that
(i.e the 12C sea surface temperature to the SE of the South Island is warming the air above it)

Bradley wrote:Wow, metservice going for 9C for Christchurch Thursday now, seems like it could be about 3-4C too warm!!!

9C is the high for today, with tomorrow's high being 7C.
'NiwaWeather' currently going for a high of 8C today and 5C tomorrow.

I see the 500 drops down to 520 for some of the precip again now. This really has been a very confusing week of runs, I am still no clearer on what may or may not take place!

weatherwatch still predicting snow to sea level for christchurch tonight, but metservice just has rain and wintry showers

Dan Corbett on radio saying no significant snow risk for chch city. Sounds like metservice styled on 200-300m levels

The current situation is so marginal, with such a big lump of moisture to play with, the models really do need to get the temps bang on or the snow level will change significantly. While all the data I can lay my hands on still says sea level will be in the melt zone, it will only take a 1-1.5deg temp change at 850 and it will be all on for sea level snow. In Christchurch the margins for error on this are very very fine, and the consequences in terms of the outcome just huge. Places like Darfield, Hanmer, Oxford, Cheviot are all really in the gun though, and I hope everyone there stays safe.

It's gone very quiet here since people now think this is a non Chch event

Looking great on the radar from the south and it getting colder here in Dunners

I was just thinking that too.

TonyT wrote:In Christchurch the margins for error on this are very very fine, and the consequences in terms of the outcome just huge. Places like Darfield, Hanmer, Oxford, Cheviot are all really in the gun though, and I hope everyone there stays safe.

Hi Tony What are your thoughts on places like Southbridge & Leeston? We have been known to get snow when the city doesn't and then we have nothing when the city does! I use the Metservice forecast for Rakaia as it's the only one kinda close and that is saying snow to sea level Friday at the moment?

I truly dont know! This is totally a double or nothing wait and see situation.

Southbridge.. that isnt to far away from rolleston is it?? new model run GFS is through, suggests snow from about 10 or 11pm tomorrow night into fri.

Just saw an article segment on 3 news mentioning a particular Facebook page and the author, not sure what to make of it