Weather question
 

OK, so it's hot in the UK now (so I gather). Like it's been hot in Lisbon for the last, I dunno, month. Yesterday it was cooler (27C), bit cloudy, bit breezy (some serious gusts), a few big thundery spots of rain. Last night it was still 27-28, quite high humidity, and then at 7.20pm the precipitation started.

HAILSTONES! Frikkin rocks, I'd say some up to 12mm or more! Bouncing and twanging off my car roof - I've yet to check it for dents but I have my suspicions.

After 3-4 minutes it changed to a typical summer downpour.

How the hail do we get ice out of the sky like that in Lisbon in July?

no idea but its gonna rain here over the weekend :D

ohh did I mention Im going to Rhodes tonight ;) :D

Global Warming....it's the ice caps falling from the sky :D

27C, pah, that's not hot. Should be 36-37 today here in Blighty :D

meh....37 is like a winters day where I'll be in 3 months...for the next 7 years!...Bugger! I burn easily

http://www.bbc.co.uk/weather/5day.shtml?world=0248

Today? We've had it for the last two weeks :razz:

I'd take a stab at it being the height at which thunderstorm clouds go to. ie - pretty high up and its much colder up there. :)

Spot on! Thunder clouds are caused by the heated air rising very quickly. It carries an enormous amount of water at that temeprature, as vapour.

Friction in the clouds between particles seperates charges, and the result is a thunderstorm.

The height to which the clouds rise is enormous, causing the water vapour to condense, then freeze into hailstones.

Alcazar

Thanks :)

Been very hot here for 2 weeks too ;)

Tis the same here, we get hail storms of biblical proportion in summer, hail damage is covered in our car insurance as hail damage is so common here, fortunately Mercedes pay to have the clouds seeded to prevent mahoosive hail forming, a few years ago my mates STi7 was wrecked by hail damage and had nearly every panel replaced. There is a technical reason why hail forms but I can't rememebr it, something todo with it starting to form then getting caught in up drafts that send it up to colder parts of the sky then falling getting caught in the updraft again, every time it gets recircled it gets bigger and bigger until it is to big for the up draft to contain anymore then it all comes plummeting down like a shower of golf balls.

Sorry for not being to technical but hopefully you get the idea :D

But if hot air rises why's it so damn hot down here and so cold up there?

I have some friends in Bahrain. They think it feesl warmer here. Over there everything is air conditioned (houses, hotels, cars, businesses). Best pack your woolly jumpers I'd say.

Air is (mostly) transparent, so the sun's rays, both lighting and heating, pass THROUGH it. Touch your window glass? Is it as hot as, say, your brick wall? Nope.

When they reach the ground, etc, the rays come into contact with solid, opaque objects, and, being unable to pass through them, raise their temperature. Even the sun's LIGHT is changed into heat.

It's contact with, or nearness to, this heated surface that heats the air.

As warmed air rises, it loses the heat, passing it to cooler air descending. Only when the earth's temperature is very high can it rise fast enough, and carrying enough water, to cause a thunderstorm.

Mostly, the warmer air rises, and cooler air rushes in to take it's place: a breeze. This phenomenon is most obvious at the seaside, since the sea takes MUCH longer to warm up than the land, hence cooler onshore breezes.

The reasons that the sea takes longer to heat up depends on the movement of the water, heting it to a much greater depth than the land, the specific heat capacity of water, (quite high), and the fact that even quite mucky water is still fairly transparent to light and heat.

Alcazar;)

What a load of bullsh!t ;)

:D

Alcazar

Nimbus clouds are amazing.

Mick

lucky bugger!!!! I went there in 2003.... i'm off to Kefalonia in 13 days !:luxhello:

Wurzel is quite right about the up draughts. That's how the hail stones grow and grow.

As to the temperature have you noticed the temperature indicated on the tv screen on passenger flights. At cruising altitude, which is typically the height of the top of serious thunder clouds - the anvil shaped ones- the outside temperature is typically -60 C. That is seriously cold.

Here's a diagram from BBC weather that shows what happens.

http://www.bbc.co.uk/weather/weather...mes/hail.shtml

You mean it really is the clouds crashing together then :D

You can count yourself lucky they weren't this big!

http://www.chaseday.com/hailstones.htm

http://www.theweatherprediction.com/severe/gianthail/