Thunderstorms/hail eastern South Island 19th Nov!!

[Storm Struck]

I thought seeing as tomorrow is looking like the best set up this season that it warrented a new topic, its fairly good from what I can see on the models will go for a high risk at this stage myself low risk of a severe cell.
The models suggest the area of potential convergence will be about the coastline but it may even stretch inland onto the plains, an initial early morning SW could see a few heavy showers but the second wave later on 3pm onwards will have the best chances.
Given the upper jet is running in at 40-45kts over Canterbury and cold upper air of -30C hail could be 20-25mm in a stronger organised cell pushing the severe category.
-4c LIs 500-600 cape and tot,s up past 50, its looking fairly juicy and is my day off so I can chase .

[mikestormchaser]

There seems to be an upper level westerly witch bithers me? Not sure if that would be a killer but the winds dont seem strong at the surface so if a NE sea breeze can get going as Nzstorm has mentioned then things should look good.

[03Stormchaser]

Yeah does look pretty decent. I may be stuck at home early on, finally getting fiber in my house (ordered it Oct 19th!) I'm going insane with out it lol

BTW good to see BSCH back up and running.

[NZstorm]

There seems to be an upper level westerly witch bithers me? Not sure if that would be a killer but the winds dont seem strong at the surface so if a NE sea breeze can get going as Nzstorm has mentioned then things should look good.

Looking like a strong enough westerly to keep out the E breeze unfortunately.

So it will be a southerly buster into a westerly type thunderstorm set up. There will be thunder but its the easterly that typically creates the better storms.

[mikestormchaser]

There seems to be an upper level westerly witch bithers me? Not sure if that would be a killer but the winds dont seem strong at the surface so if a NE sea breeze can get going as Nzstorm has mentioned then things should look good.

Looking like a strong enough westerly to keep out the E breeze unfortunately.

So it will be a southerly buster into a westerly type thunderstorm set up. There will be thunder but its the easterly that typically creates the better storms.

Yes I did think a W would bother me, but in saying that it could go the way for the better. Always hopeful anyways.

[NZstorm]

Another possible negative is the mid level moisture clouding skies up. May not be so bad tomorrow but the GFS is showing plenty of moisture aloft.

[Storm Struck]

That westerly is there this morning but not as strong as last night thankfully, so it would be ideal if a coastal wind snuck in before the change.
But even so there will still be storms on the change, the cape values are the highest ive seen so far this season 600-700.
Ashburton to Banks Penninsula even Christchurch is my pick of area for the more punchier storm activity.

[Razor]

Forget any action in Chch today, strong westerly quarter winds persistent, anything blowing well out to sea

[mikestormchaser]

Forget any action in Chch today, strong westerly quarter winds persistent, anything blowing well out to sea

The westerly is certainly a trouble maker today I thought it would be a bother yesterday knowing it was present today but there is still a chance of a nice gust fronty storm witch may clip the city later but very coastal. Definitely not a high risk today. I think Metservice are on the money with moderate.

[spwill]

The big instability numbers showing in the GFS will be based around a dewpoint of 6 or 7C for coastal Canterbury, currently a dry air westerly there, Hilmorton showing 20C with a dewpoint 0.8C
I reckon there is a good chance of the flow going onshore ahead of the Southerly today as there looks to be good heating taking place.

[melja]

Im with Razor, W, Nw been building all morning. Ne may well come in but after the change.

[Razor]

Yup I've been on the Port Hills all day and it's even stronger westerly than my last post now. Weak shower activity blowing out over the back of Banks Peninsula, it's a fizzer I reckon

[Storm Struck]

Yup I've been on the Port Hills all day and it's even stronger westerly than my last post now. Weak shower activity blowing out over the back of Banks Peninsula, it's a fizzer I reckon

Most of the best action wont be until later yet after 4pm, some scattered CU going up around the plains now too not just coastal and westerly dropping back.
Its not out of the question there will be storms just how coastal and will a sneaky NE get in there somewhere.

[melja]

Dont think a Ne is going to sneak in anywere, howling Nw north of the waimak and now thick high cloud in the last 20min so there goes the heating.

[petem8nz]

Dont think a Ne is going to sneak in anywere, howling Nw north of the waimak and now thick high cloud in the last 20min so there goes the heating.

Have look at the port hills mate!

[Orion]

Some rain in Ashburton at the moment, some of the drops sounded large and as if falling from a great height.

[RichyDunedin]

Decent thunderstorm north of Dunedin. Just returned from Te Anau and there were a few big storms building on the way to the coast. Between Dunedin and Oamaru I've seen a few coastal storms on the radar.

[Orion]

More large raindrops, with hailstones this time.

[tich]

Something over Lake Ellesmere right now. (red on radar)

[melja]

Dont think a Ne is going to sneak in anywere, howling Nw north of the waimak and now thick high cloud in the last 20min so there goes the heating.

Have look at the port hills mate!

Not sure anything i can see over there will be of any help in having thunderstorms over this way, there long gone and being taken offshore by the strong NW.

[dogmelon]

Its doing that river of showers/storms from ashburton to banks peninsula thing again.

[03Stormchaser]

Just seen a photo of hail stones in Oamaru of about 20-25mm

[Nev]

Issued about 30 minutes ago…

MetService - Severe Thunderstorm Watch

Valid to: 7:30pm Wednesday 19 Nov 2014
Issued at: 3:46pm Wednesday 19 Nov 2014

MetService - Severe T-storm Watch Chart - Nov 19, 3.4pm.png

SEVERE THUNDERSTORM WATCH

Issued by MetService at 03:46 pm Wednesday 19 November 2014
Valid until 07:30 pm Wednesday 19 November 2014
This watch affects people in the following weather forecast districts:
Christchurch
Canterbury Plains

A line of active thunderstorms extends from the Rakaia River to Banks Peninsula. These storms are bringing hail of 15-20mm, and intense rainfall.

There is a risk that one or two of these storms may produce hail of around 25mm diameter, and possibly large accumulations of smaller hail.

Also, hourly rainfall rates could locally exceed 25mm.

Issued by: Mads Naeraa

This watch will be updated by: 07:30 pm Wednesday 19 November 2014

[Orion]

Some nasty-looking cloud to my north-east at present.

[NZ Thunderstorm Soc]

Interesting development to the south observed from here this afternoon.
Persistent West to NW here.
Now a gust-front looks as though it is going to come through.
Lots of sfericals coming through earlier.