Possible Polar Blast coming this weekend 4th to 7th May

[Avalanche]

I have noticed the last few GFS runs showing a decent Antarctic storm possibly forming this weekend Saturday 4th May.
Still early days of course. Some good moisture forming off the developing low to the south too. Looks to be a east coast snow event if it takes place. Early start to winter me thinks time to load the wood box.

[CWUweather]

Tobe honest, i think its to early for any decent snow event. Yes certainly going to be cold, some showers/periods of rain but nothing to amazing. Although, i would love to be wrong!

EDIT: Yes GFS are going to town with the moisture levels on the latest update, strong southerlies too, although, till to warm i think for any decent winter storm

[CHCH Weather Chaser]

There were a couple of runs that had thickness around 522 earlier in the week but latest for Canterbury is more around 534. Hint at a brief period of heavy rain. GFS putting out a quick 50mm for Christchurch currently but no consistancy with that at all at present.

I think there is certainly potential for ski fields to see some of the white stuff. Lets hope it delivers for them. The set up of the high however reminds me of the last couple of snow storms where you have a long narrow high in the Tasman. Hopefully some more of these set ups right in the middle of winter

[Storm Struck]

It will be a good set up for the typical autumnal thunderstorms with hail along the windchange, they can be quite nasty but awesome to be in .
Its always safer to say snow to 300-400m at this stage as its still reasonably early in the season, but anything can happen these days the seasons are all out of wack now .

[NZstorm]

Its still early days to be sure but 300m looks a likely snow level for east Otago. Perhaps 600m for lower North Island and 1000m for central NI. Looks Sunday/Monday time frame.

[NZstorm]

The UKMET, ECMWF and GFS vary a bit. But it does look like the cold air will pass through in the Sunday/Monday time frame.
The ECMWF points to heavy inland snow for the South Island.

[Avalanche]

It probably wont occur but just imagine if that low thats dropping to the east happened to clash with the southerly coming up. Just a thought!!

[CWUweather]

It probably wont occur but just imagine if that low thats dropping to the east happened to clash with the southerly coming up. Just a thought!!

To put it mildly that would change things significantly. If that happens it would be a similar setup to August 2011 hahah

[CWUweather]

Accuweather predictin 50mm of rain on sunday night for chch of this system. My question is, it's meant to be 1 degree that night, so why not hail or snow? at least wintry

[NZ Thunderstorm Soc]

Accuweather predictin 50mm of rain on sunday night for chch of this system. My question is, it's meant to be 1 degree that night, so why not hail or snow? at least wintry

..............or a surprise thunderstorm?

[Avalanche]

It probably wont occur but just imagine if that low thats dropping to the east happened to clash with the southerly coming up. Just a thought!!

To put it mildly that would change things significantly. If that happens it would be a similar setup to August 2011 hahah

Significant thats for sure, the low barometric pressure sure drops quick as it sinks south. Shame its not closer would be pretty exciting for a change. The drought been a bit boring. I think its looking more an awesome snow storm out to sea lol. Are well Winters just beginning who know what might happen.

[Storm Struck]

I can see what you mean if that low to the east of the North Island gets abit closer it could get sucked in by the land and form its own SE flow over the eastern North Island, and then from then on it would be a question of how far south it would drift into Sunday ohh that would be juicy.

But anyway the frontal system and asociated troughs will have enough punch for us to have some exciting weather anyway, some of the showers on Sunday will be deep CB convection too so there could be brief snow flakes atleast down to 200m at times as we have seen happen in the past.
Snow to sea level in May isnt unusual but it is a rare occurance, it has happened a few times from memory but just breifly, im not saying it will this weekend but you can never rule it out.

[CWUweather]

I can see what you mean if that low to the east of the North Island gets abit closer it could get sucked in by the land and form its own SE flow over the eastern North Island, and then from then on it would be a question of how far south it would drift into Sunday ohh that would be juicy.

But anyway the frontal system and asociated troughs will have enough punch for us to have some exciting weather anyway, some of the showers on Sunday will be deep CB convection too so there could be brief snow flakes atleast down to 200m at times as we have seen happen in the past.
Snow to sea level in May isnt unusual but it is a rare occurance, it has happened a few times from memory but just breifly, im not saying it will this weekend but you can never rule it out.

Couldn't agree more. Will be bloody cold, sleety showers maybe, odd snow flurry maybe even lower than 200m overnight saturday and early sunday morning. showers will most likely continue throught the early part of the week. First decent cold blast this year if all goes to plan haha

[CWUweather]

I actually think the the low coming down the north could actually come closer than you think, it is still a while off and you never know what will happen. It doesn't take much of a direction change and it could get interesting haha. but we will have to wait and see. Also the low is very deep, just east of about wellington at 6am sunday. 972hpa. SHIITT

[Avalanche]

Yea ive noticed this morning that its now even closer that low its almost slingshoting itself around the the southerly coming up. I noticed the isobars getting pretty tight too so maybe a blocking high in the east could have it moving back towards the east coast. Will be interesting to see what the latest GFS says from now on to whether it gets worse or eases up.

[CHCH Weather Chaser]

Metservice in their Canterbury Plains update for Saturday going for Rain with Heavy Falls and snow to 400m. As you say Avalanche - will have to see what the next run or two suggest.

[Storm Struck]

The latest runs through are showing this system as being very nasty now, rainfall totals up for the east coast and severe gale force southerlies as the low deepens to 972hpa off the coast.
This could be recipe enough for a snow to sea level event at some point more into Sunday i would say, because thats really cold air being dragged up and some decent falls in there.
I dont know why MS forecast that for Saturday because its not kicking in until early Sunday morning now around 1-3am, so that kinda questions whether there will be thunderstorms on the change or not now.
But anyway its the first run thats showed it being like this, and it can change but when it shows up like that closer to the date you can be fairly confident thats what is set to happen.

[CHCH Weather Chaser]

I dont know why MS forecast that for Saturday because its not kicking in until early Sunday morning now around 1-3am, so that kinda questions whether there will be thunderstorms on the change or not now.

Metservice are saying for Sunday. They have a high of 20 here on Saturday. They are going for rain developing Sunday...

But yes it is looking a little more nasty - all dependant on how those 2 systems merge. GFS putting out around 30-35mm at the moment. We shall see what tonights run says.

[CWUweather]

The latest runs through are showing this system as being very nasty now, rainfall totals up for the east coast and severe gale force southerlies as the low deepens to 972hpa off the coast.
This could be recipe enough for a snow to sea level event at some point more into Sunday i would say, because thats really cold air being dragged up and some decent falls in there.
I dont know why MS forecast that for Saturday because its not kicking in until early Sunday morning now around 1-3am, so that kinda questions whether there will be thunderstorms on the change or not now.
But anyway its the first run thats showed it being like this, and it can change but when it shows up like that closer to the date you can be fairly confident thats what is set to happen.

Well that escalated quickly!

[CWUweather]

This is just looking more and more likely to happen by the hour. Looking colder, wetter and judt downright ugly! going to be a very interesting sunday!

[Storm Struck]

Looking at the metrogram runs its still looking abit too warm i think for anything to sea level, but as i say i think we will see the freezing level drop to about 200m at times in denser CB clouds and over in the evening on Sunday.
THK is running through about 536 and the 850mb is at lowest -4C , so probly more 300-400m.
What will be interesting will be the activity we get with it in the form of heafty showers running in off the ocean which is still quite warm as ive mentioned, could be some good heavy hail showers with thunder and lightning at times.
The wind will also be something to watch, time will tell in the next few model runs.

[tich]

Snow to sea level in May isnt unusual but it is a rare occurance, it has happened a few times from memory but just breifly, im not saying it will this weekend but you can never rule it out.

Very rare in (at least early) May in Chch, but probably more likely in the far south. Alot depends on whether the flow is southerly or southwesterly.

[melja]

And im sure it will be SW, 90% of the time it is in these events.

[Storm Struck]

We really are just going to have to wait and see as the models are shifting all the time, its now a Sunday/Monday event instead of coming in as a strong frontal system its being slowed up and turned into a deepening low.
But the low centre is positioned to move up the west coast directing a very strong Southerly flow over the east coast, i guess we will know by Saturday to be sure.

[CWUweather]

I dont know how accurate the MS 3 day maps are but they are forecasting this to be very nast for the S. Island east coast