29/01/2016 11:53 AM AEDT | Updated 15/07/2016 12:51 PM AEST

Storm Nation: Why The Weather Has Gone Mad Pretty Much Everywhere

Dramatic storms have swept into Sydney on Friday afternoon, with lightning striking Sydney Tower and heavy rain recorded in many suburbs. A second front of storms is also roaring into Canberra, while Brisbane and Melbourne may see more storms later Friday afternoon.

There are some creative adjectives in official Bureau of Meteorology forecasts this Friday. Words like "severe" and "gusty" precede the word "storms" for a whole range of locations. It's going to be wild out there, people. The weather itself is being very creative at the moment.

"We have very consistent language as to whether we point out that storms are likely to be 'severe' or not," Bureau of Meteorology Climatologist Agata Imielska told The Huffington Post Australia.

"If we see certain indicators, we do distinguish between just a 'thunderstorm' and a 'severe' storm in our forecasts."

We'd thought maybe that the Bureau says "severe" just to protect its bureaucratic backside from a backlash if there's a wild piece of weather like December's Kurnell storm in Sydney.

But that's not the case at all. Severe really does mean severe. And today, it's severe all round. As this Friday rolls on into the afternoon, our eastern capitals are experiencing all sorts of meteorological mayhem.

Finally!! I got one! #sydneystorm #westfield #lightning #thunderstorm #storms

A photo posted by Mike Morrow (@mikejmorrow) on

Severe storms with the possibility of hail and even tornadoes are forecast for those cities and many nearby towns. These are just the latest storms in what has been a pretty wet summer in many parts.

The worst of the weather will be later this afternoon as the atmosphere heats up. Having said that, Canberra is already getting a dose.

This was at 10:30 am on Friday

Here's the weird thing. This was supposed to be a dry summer for the southern and eastern half of Australia. El Niño summers typically are. In fact El Niño often causes droughts.

What's an El Niño, again? Long story short, it's a warming of tropical waters off northern Australia which has all sorts of consequences -- chief among them, dry summers in eastern Australia. But this summer, there's been no shortage of wet, wild weather in areas where you'd ordinarily expect 35-degree dry days.

Why? We put that to Imielska, who told us that it was not quite as simple as El Niño = dry Aussie summer.

"El Niño does generally result in dry conditions, but mainly in winter and spring. In summer the relationship becomes pretty variable. The onset of the Australian monsoon is a moisture source that weather systems can tap into," Imielska said.

"Sea temperatures off the east coast and west coast are warmer than normal, so they're supplying a lot of moisture."

If weather jargon bores you, imagine a dry packet cake mix that someone mixed with a chocolate pudding mix. That's not very technical but it gives you half an idea what's going on.

Today's weather map illustrates a typical day this summer pretty well. Quick weather lesson: Know that air circulates clockwise around a low pressure system. So you've got that big dirty low between Melbourne and Adelaide bringing nasty weather from down south. And as the air circulates around it, it's dragging down tropical air and moisture.

This means :(

The bottom line? Today will deliver more of the BBQ-busting wet and stormy weather most Australians have already seen plenty of this summer. And the weekend's not looking a whole lot better for the eastern capitals.

Now for some statistical fun. Normally when you throw around rain statistics, you talk about the amount that has actually fallen. But there's another measure which reveals much. It's mean rain days, or in other words, the days on which 1mm or more of rain falls in any given month.

  • Canberra normally has 5.6 rain days in January. Today is its ninth.
  • Sydney normally has 8.7 rain days in January. Today will likely be the 12th.
  • Melbourne normally has 5.6 rain days in Janaury. Today is its eighth.

That's an indication of the type of bummer summer we're having. It's been consistently wet and stormy, and today could be one of the worst days. Be careful out there, and don't so anything silly in a storm like walking near drains or playing cricket with a metal bat on top of a hill.

Oh, and if you're in Perth, enjoy that. You'll be dry today, as you usually are in January, and none of this applies to you. Carry on.