Model Output Discussion

[reef]

The GFS 18z is one to forget for those who like above average conditions in summer. I suspect after this week that the strong northerly shown would feel rather cool:

http://www.wetterzentrale.de/pics/Rtavn1561.png

Of course being July its never going to be cold, but there are 850hPa temperatures of around 0C involved so its certainly a potent airflow for the time of year. GFS has maxima of 14-15C north of the Midlands for the day after, but this is more likely to be high teens. Still a good 12C lower than today though!

Its quite a way out mind you, but theres pretty good ensemble agreement:

http://www.wetterzentrale.de/pics/MT8_Manchester_ens.png

FI then has low pressure systems slowly moving in before further northerly bursts after in a repeat pattern. Quite a change of setup, it will be interesting to see if it plays out (though probably rather unpopular if it does!)

[mushymanrob]

looks like the breakdown will could be disapointing if its storms you like quite remarkable really.

[GRHinPorts]

The 00Z GFS is suggesting an Azores High trying to ridge in from the SW from T120 but never quite succeeding in coming across the UK with low pressure centred over Scandanavia.

Would I be correct in suggesting this would bring a spell of anti-cyclonic gloom (he says hopefully as preparing to go out and work in another scorching day in the hot sun) but not much rain?

[Frosty.]

I have to smile at autumnal Frosty?

autumnal and one THINKS, I would have thought, of shortening days, leaves changing colour, temps, for here, around 15C at best in October afternoons.

yes you are correct in a flow from a cooler direction and rather unsettled at least for a few days.

As to when we get another longish dry spell I suspect it will be before 'some considerable time', perhaps as early as mid July leading towards the end?

perhaps that could be classed as 'some considerable time'?

I admit that it was OTT for me to say autumnal but next week is looking even more unsettled than it did on yesterday's charts. The GFS 00z is indicating a strengthening Northerly airflow with showers and longer spells of rain, it does then show a marked improvement for the following week but that is deep FI and therefore very suspect at this stage.

[conor123]

It does seem this breakdown won't be as bad as initially anticipated as on each run the temperatures for this weekend have been increased.

E.g 26/7c is still likely in the South East now on Saturday with temperatures in the low twentys elsewhere generally and still 24/25c across much of the South on Sunday which is hardly on the cold side.

[mushymanrob]

fi starts quite early imho, witrh no one really declaring exactly what will happen, great uncertainty although the general theme is for pressure to drop over scandinavia, high to our west with a mid atlantic ridge, leaving us in a spell of cool fresh northerlies.

on the plus side (as has been mentioned) it doesnt look particually wet.

roll on the next heatwave, im loving this!

[Glacier Point]

fi starts quite early imho, witrh no one really declaring exactly what will happen, great uncertainty although the general theme is for pressure to drop over scandinavia, high to our west with a mid atlantic ridge, leaving us in a spell of cool fresh northerlies.

on the plus side (as has been mentioned) it doesnt look particually wet.

roll on the next heatwave, im loving this!

Quite agree Rob, models seem not to have much a grip on a coherent signal beyond the beginning of next week which sees that ridge in the Atlantic work its way gradually eastwards and pressure to remain low over Scandinavia c/o an upper trough / cut off low.

Total angular momentum is still -1 SD below normal although much of this comes from the southern hemisphere - in the northern hemishphere montain torques look to be the best guide suggesting a weakly negative mean zonal wind state:

http://www.cdc.noaa.gov/map/images/reanaly...m.sig.90day.gif

http://www.cdc.noaa.gov/map/images/reanaly...ltaum.90day.gif

Tropical convection is somewhat sporadic although perhaps some signs of the west Pacific starting to spark into life around the dateline (see previous posts for significance of this).

http://www.bom.gov.au/bmrc/clfor/cfstaff/m...m/OLR/m.3d.html

Convection is also building across the Indian Ocean and the MJO may well develop amplitude into phase 2 fairly shortly.

Surface winds and sea surface temperatures look ripe for convective activity to spread eastwards if and when this activity develops.

http://cimss.ssec.wisc.edu/tropic/real-tim...s/wavetrkP.html

Meantime, in the tropical Atlantic the surface wind flow continues to suggest an absence of strog sub-tropical ridge (Azores High):

http://cimss.ssec.wisc.edu/tropic/real-tim...s/wavetrkA.html

Put all these incohrent and weak signals together and you don't get much for days 8-14 apart from perhaps a persistence of weak ridge over the UK or just to the west, perhaps becoming more located over the UK over time and strenghtening as the upper low over Scandinavia steadily fills.

The real interest at the moment is when tropical convection is going to kick off in the Indian Ocean and Pacific - a watching game - although given some releatively benign summer-time conditions next week, not too bad coming on the back of what we are experiencing now.

Edited July 2, 2009 by Glacier Point

[William of Walworth]

"Incoherent and weak signals" seems exactly right .... very hard to predict how long the cool down will last. Certainly some scope for hope that more HP influenced conditions will return, moving in from the SW later on. FI for sure but certainly not a prospect to be dismissed at all, at least for the South.

And as rob says, not an extremely wet looking breakdown either.

Edited July 2, 2009 by William of Walworth

[SMU]

http://www.wetterzentrale.de/pics/Rtavn3842.png

Summers over folks- Nights are closing in- Hot spell ends tomorrow - High lattitude blocking set to continue & is that the first -10 850 I see developing right at the top of the screen...

S

Edited July 2, 2009 by Steve Murr

[geoffw]

gp what are the chances of a very hot spell come the end of july?kkkkkkkkkkkkkkkkk

[chionomaniac]

http://www.wetterzentrale.de/pics/Rtavn3842.png

Summers over folks- Nights are closing in- Hot spell ends tomorrow - High lattitude blocking set to continue & is that the first -10 850 I see developing right at the top of the screen...

S

I am sure it will have gone by winter!

That is as funny as a winter is over post on 2nd Jan!

[Bottesford]

http://www.wetterzentrale.de/pics/Rtavn3842.png

Summers over folks- Nights are closing in- Hot spell ends tomorrow - High lattitude blocking set to continue & is that the first -10 850 I see developing right at the top of the screen...

S

is all I can think when I saw that!

Thankfully summer is not over which is good since it hasn't been going that long yet!

[Eugene]

Good to see steve murr back, i think he was just having a bit of fun, he shouldn't be taken too literally saying summers over, he's right though the synoptics aren't conducive to summer heat with winter like high lattitude blocking continuing, i actually feel this hot spell was a fluke, we were extremely lucky we didn't have LP stuck over us, the HP cell to our north just extended its influence over us but it could of easily been different, next week is looking much cooler with 850`s upto 15C cooler in england.

[Alex95]

I really hope we don't get locked into a bad pattern as happened last August after the late July hot spell

On the bright side, there were plenty of northerlies in 1995 (June in particular, but also at the very end of August) so hot weather could easily return later, but it will probably be the end of July if it does.

[Noctilucid]

Good to see steve murr back, i think he was just having a bit of fun, he shouldn't be taken too literally saying summers over, he's right though the synoptics aren't conducive to summer heat with winter like high lattitude blocking continuing, i actually feel this hot spell was a fluke, we were extremely lucky we didn't have LP stuck over us, the HP cell to our north just extended its influence over us but it could of easily been different, next week is looking much cooler with 850`s upto 15C cooler in england.

I wouldn't say that this hot spell was a fluke, the likes of Glacier Point and Chionomaniac (and others!) were prediciting some serious heat weeks ago when everyone else was in despair and there was no sign of anything on the major models, all in all the long range forecasting bunch did a fantastic job.

The signs leading to a hot spell were picked up long before it happened, so it was hardly a fluke that popped up out of nowhere.

Edited July 2, 2009 by jshaw

[johnholmes]

about as much of a fluke as next winter is going to be like 1963-not

as has been pointed out several on this site had predicted this dry and for most pretty warm even hot spell up to a couple maybe even 3 weeks ahead.

it really is best, for newcomers, to read the posts from the more rational people on the model thread and elsewhere on this site-you will soon get to know those that are more reliable-trust me!

[mushymanrob]

, i actually feel this hot spell was a fluke,

you crack me up....

[hotsummer]

Will we see any further warm spells though.......that will be in some minds! This could be it and I believe this is it. I don't think we will get another spell lasting this long again this summer. Even we may have well experienced out highest summer temperatures.

Now I dread the jet coming down and the rest of summer becoming wetter and cooler with conditions turning average at best. This current spell of weather is awesome and I'd love to see a fast reload but this is the UK and I'm aware that these conditions aren't regular for our Island.

DATA question!! Does anyone know of a summer where we had more than 1 spell of above average warmth and sun lasting 5 consecutive days or more?

[Methuselah]

Tbh, I can't see any reason to suppose that that's it for summer this year. Just something more average for a while.

[Eugene]

Fairwell Mr 564 dam line we might not see you again midlands northwards for a long time :lol: ... maybe only briefly in the far south like on GFS 12Z with cool northerlies then the atlantic jet getting going :lol:

http://www.wetterzentrale.de/pics/Rtavn063.png

http://www.wetterzentrale.de/pics/Rtavn123.png

This week is abit like getting a PS3 for your birthday only for it to be so cruelly snatched away from you after less than a week

[Costa Del Fal]

I cant see why people are thinking summer is over because this spell of hot weather is nearly over. This is classic british weather and how can you write off summer when there is another 2 months to go! It does look like some Average weather coming up with Sunshine and showers but temperatures fairly pleasant. I do feel things will improve again probably from Mid July onwards.

[Jezzer]

DATA question!! Does anyone know of a summer where we had more than 1 spell of above average warmth and sun lasting 5 consecutive days or more?

Didn't we have plenty of similar spells throughout the summer of 2003?

[hotsummer]

Didn't we have plenty of similar spells throughout the summer of 2003?

Wasn't it more of just one long spell.....? I don't know, I wasn't here for the full summer. Kind of WHY I asked the question...!

[Jezzer]

Wasn't it more of just one long spell.....? I don't know, I wasn't here for the full summer. Kind of WHY I asked the question...!

Could have a point there :lol:

ahh memories, now that was a cracking summer, one of the greats! :lol:

[hotsummer]

Could have a point there :lol:

ahh memories, now that was a cracking summer, one of the greats! :lol:

Wish we would have a 1976 summer. I wasn't around in those days! Would love to see that in this country!