Summer 2017 - General Discussion

hatrickpatrick

Seems that the root of the upcoming change in Weather is that the Jet Stream is about to take a southward plunge. I have very little knowledge of how the jet stream works (as in, what factors determine where it will be positioned at a given time) but to those who do, what conditions have to be in place to cause it to push northward and therefore allow high pressure to build from the south?

Gaoth Laidir

Casement 25 degrees at 11 am.

Gonzo

23C here with a real feel of 26C.

Feels just like a morning in Malaga, very impressive warm wind and heat outside for morning!

I wish this would last all the way to September without any interruption. Looking at the temps for next week is a real shocker and a reality check to where we live.

Elmer Blooker

just a bog standard summer's day here 21.2c which is not much above average.

Gonzo

24C here now and 25C at Phoenix Park, 11am.

ronnie3585

Was out walking in shorts and an t-shirt last night at 10pm, it was so bright and pleasant - if only it were like this all the time!

ninebeanrows

Upto 25 in the Park, looks like we could reach 30, always cooler near coast with sea breeze but EIDW could get 28 at 5pm

John.Icy

Yeah not great here in Dublin 9 yet. Continuing to clear up by the minute however so it should get going eventually, delayed start.

pedigree 6

Road temperature is 42c on Clonmel Bypass.

https://www.tiitraffic.ie/weather/

Haven't been following the weather reports the last few days as have been very busy. But the road temperatures must have been fairly high.

I see here in wexford my own local road that the tar was melting and some chunks of the top layer were coming up from sticking to the wheels of traffic.
You wouldn't think the fine weather would be destroying roads.:rolleyes:

spoonerhead

Temperature is flying up since the clouds cleared about an hour ago, not far from the Phoenix park

Elmer Blooker

John.Icy wrote: »

Yeah not great here in Dublin 9 yet. Continuing to clear up by the minute however so it should get going eventually, delayed start.

Yes, its getting going now up to 23.2c from 21.2c in about 20 minutes since I last posted!

sryanbruen

hatrickpatrick wrote: »

Seems that the root of the upcoming change in Weather is that the Jet Stream is about to take a southward plunge. I have very little knowledge of how the jet stream works (as in, what factors determine where it will be positioned at a given time) but to those who do, what conditions have to be in place to cause it to push northward and therefore allow high pressure to build from the south?

You have to know what the Jet Stream is first of all. The Jet Stream is a ribbon of air high up in the atmosphere that brings all the low pressure systems across Ireland. It's typical of the Jet Stream to go straight through Ireland which would bring very unsettled weather. However, the temperatures are very changeable with this kind of setup and there is no guarantee what sort of temperatures you can see. When the Jet Stream is on a northerly track so up to Iceland or Scotland, it gives away to high pressure building up from the south and with this, temperatures are above average because winds are coming from a southwesterly, southerly or southeasterly direction. As a result of course, the source of air is coming from southern Europe which can be very warm. December 2015 had winds coming from a straight southerly which meant for its extraordinarily warm nature. When the Jet Stream is on a southerly track, it means that high pressure either builds over us or to the north. This in turn leads to northerlies or easterlies. For northerlies, high pressure has to be over Greenland and Iceland with low pressure to the east of the UK or over Scandinavia. For easterlies, high pressure has to be up to the north of Ireland or over Scotland. May 2017 just gone was a very easterly month for example. If this is the case, the temperatures will normally be on the cool or cold side. The odd one out to this however is when the winds are coming from the east in Summer, especially so in July, August and September. May and June less so. Winds are coming off a cold continent in Winter thus why easterlies are cold then but in Summer, winds are coming off a warm continent thus why easterlies are warm or even hot then. When there is a large contrast between the temperatures in the Atlantic Ocean or North America aka the warm air and cold air fighting against each other, the Jet Stream tends to get powered up. Winter 2013/14 was a very cold Winter in the eastern seaboard of the USA. This deep cold air did not mix well with the mild air trying to push up from the south of the USA at the same time thus why the Jet Stream became more powerful. As a result, our Winter 2013/14 was exceptionally stormy thanks to this. A southerly tracking Jet Stream, like in much of 2010, Summer 2012 and March 2013, is more frequently to happen if the Jet Stream is not that powerful.

With all that considered, I think it's time to truly answer your question on what causes the Jet Stream to be in the position it does be in like on a northerly track this past week. Well first thing is the Season you are in. You might be like, how does Season affect the Jet Stream as you have seen plenty of different "seasons" in Ireland as in March 2013 be Winter or December 2015 be Summer :pac:. Well in Winter, the Jet Stream tends to be more powerful as a result of a large temperature gradient/contrast between Arctic and tropical air masses. This goes back to on why I think we're getting stormier winters because of Global Warming. The warming adds energy to the Jet Stream - and creating an even larger contrast between the air masses. In the Summer, the Jet Stream tends to be weaker as a result of a much less extreme contrast between air masses. The Jet Stream is said to follow the sun as it moves north with warm air and south with cold air. A powerful Jet Stream has the frequency to change position more so than a weak Jet Stream - thus why you can see these big swings in Winter from like daytime temperatures of 13-15c one day then 4-6c the next day.

Another thing is the Coriolis Effect - basically Earth spinning on its axis if you don't know what it is. The Jet Streams flows east all the time. In other words, you won't see the Jet Stream flowing towards the west of Ireland from the east. However, whilst the Jet Stream flows east all the time, it often meanders across the atmosphere. These meanders flow slower than the rest of the air. They are called Rossby Waves. They move slower as a result of the Coriolis Effect and turn west in respect to the flow that they are embedded in.

There is no specific factor on why the Jet Stream can change position but there are plenty of signs showing that a more powerful Jet Stream has the ability to change position a lot. It all depends on how tight the gradient between the air masses are, the Season and the Coriolis Effect.

EDIT: Btw, it's not impossible to have powerful Jet Streams outside of Winter just that it's much more difficult to do so as the Arctic or cold air masses are less intense to contrast with the tropical air masses.

DOCARCH

27c at Phoenix Park at 1200.

Can't tell you what temp it is in Dublin 16 due to the fact that I am in Lanzarote....where it is not as warm as the Phoenix Park!

Xenji

Only 18.3C in Castlebar, very overcast with humidity just over 90%.

Supercell

Bit of a sea breeze here pegging back temperatures at 24, very humid, feels a lot hotter.

JCX BXC

DOCARCH wrote: »

27c at Phoenix Park at 1200.

Can't tell you what temp it is in Dublin 16 due to the fact that I am in Lanzarote....where it is not as warm as the Phoenix Park!

Ditto, although I'll be able to pull my up weather station history when I go back.

Elmer Blooker

DOCARCH wrote: »

27c at Phoenix Park at 1200.

Its just been announced on RTE radio 1 that it is 27.7c at the Phoenix Park!
I'm only 23.9c, the difference as few miles can and proximity to the sea can make.

Rebelbrowser

DOCARCH wrote: »

27c at Phoenix Park at 1200.!

I reckon it should go north of 30c so. Peak heat on days like this seems to be 5pm so a long way to go.

spoonerhead

I'm just a bit south of the Phoneix park in D12, it's ridiculously warm and it's only 1pm

cherryghost

Lads I'm sweating. This isn't normal from these parts.

pad199207

Ridiculously warm here now, ya wouldn't get this in Spain!

Gonzo

getting close to 28C here now, real feel of 30C and UV Index of 5.

making this day the warmest day I have experienced here since at least 2006.

I was in Spain during the heatwave of 2013.

I reckon today will easily be the warmest day of 2017 and highly unlikely to be matched or beaten. If it does this will be a golden summer.

Gonzo

Phoenix Park confirmed 28C @ 1pm.

ninebeanrows

28C at Phoenix Park

27C at Casement

A slightly less warm 25C at Dublin Airport with a 12 knot SE breeze

Murrisk

Phoenix Park 28 at 13:00. New high temp. It's been fun watching that stat change all week!

RobertKK

My weather station went to 24.9C at 10.25am.
Then fell.
Currently 23.6C but humidity is rising.

Gonzo

I wonder will the high heat hold on till 6pm this evening, when will the cooler air filter through here.

The east and south-east could still have a pleasantly warm 19-22C tomorrow.

back to the mid teens for next week.

mickmackey1

I'm not jealous of the Europeans with their mid-30s, anything over 26 is distictly uncomfortable.

Murrisk

Murrisk wrote: »

Phoenix Park 28 at 13:00. New high temp. It's been fun watching that stat change all week!

And only 55% humidity. I was preparing for a close day but it's not so my head feels OK currently!

Gonzo

28C will probably be the high of the day, the extreme high temps seem to be confined now to the east coast, temps up to 12C cooler in the western third of the country already. Cooler air should be filtering through here over next few hours.