Model Output Discussion 12z 10/05/13

[Summer Sun]

Hope that is the case Gavin and that the ECM are over exaggerating things at the moment.

Apparently the ao/nao are predicted to go a bit negative. My perception of that would be some cold overnights with some frosts hence a bit of high lattitude blocking and possible northerlies.

How unsettled it will be is open to question I feel currently.

 

Yes the NAO is currently looking like it will go negative

 

[Tamara]

If we look at todays NH ECM output as an example, then we can see that todays chart shows moreorless the start of the 'draining' process of the polar vortex out of Canada and Greenland as it breaks up as a result of the Final Warming of the stratosphere with energy about to eject SE towards the Uk to bring this weeks unsettled, cool and showery weather.

 

Then if we take a look at Day 10 we can see how the vortex over the pole is starting to head towards summer type conditions, although not quite there yet: i.e noticeably less organised with smaller residual pockets of vorticity remaining. Such as one which, if we take the ECM at face value, is ejecting SE and arriving to the NW of the UK. Much the sort of thing that bluearmy hints at in his post.

 

 

So, we could argue that this might be heading towards the last phases of energy remaining to disrupt across the atlantic and we wait to see how the pattern evolves from the heights that have built to the north in response to the final warming. Will we see background factors then becoming more conduisive for mid latitude high pressure linking into Scandinavia pehaps by months end as the present vortex break up signal eventually completes itself and fades?

 

There have been hints of this from GEFS long term ensembles - its a case of waiting to see if this next signal is picked up across the models in the post 15 day period as that timeperiod becomes more reliable. But this is some way off and for sure, at least until after then, it looks to stay unsettled and cool for the time of year

[snowking]

Stronger hints beginning to develop in the GFS now for a more settled spell towards the end of this month:

 

 

It will be some days yet before we can get a decent comparison from the ECM EPS suite, but the timing fits in perfectly with expectation at present.

 

The MJO just beginning to show hints of an eventual phase 1 progression (both the GFS and GEM moving towards this area):

 

 

The 500mb anomaly projection for phase 1 in May ties in nicely with a potential Azores HP influencing the UK:

 

 

If we roll this forward into June:

 

 

So my thoughts for later in the month and into the start of June remain the same - settled weather taking over, and it could end up being one of the best periods of the summer

 

SK

[Purga]

Apologies to John if you feel I misrepresented you, I guess 'cool & wet' could sound a bit stronger than 'cool & showery' but let's hopefully not fall out over it. I always compliment you on your excellent anaylsis and knowledge and value your posts immensely.

I won't respond to other posts which make personal digs as I believe this is a forum where we can all discuss a fascinating subject and a pleasant hobby for most of us. Sometimes we may disagree on interpretation of what the models show and we can all be guilty of being biased by our own preferences at times but it makes for good debate and is a great way to learn by being engaged.

Anyway, enough of that, I will stick by what I have been seeing and if one refers to my previous posts will see as 'Cool and wet (showery) looks more likely than warm and dry'. Bit in brackets added!

Having said that, I think next week (especially towards the weekend) could throw up some very interesting weather with low pressure developing to the east and SE over a very warm and humid continent and a relatively cool airmass over the UK. A small shift west and we could be looking at some potetially torrential downpours more so in the east / se.

 

GFS 06z FI does go with the cool regime in line with the cpc upper air anomaly charts

 

[Guest pjl20101]

Totally believe you snow king and trust your judgement. That is how I see things currently and am going to disregard the newspaper hype for next month as its not very helpful currently and going Ott with wet predictions currently.

[Frosty.]

Charts still look terrible. 

 

The Gfs 06z shows a recovery/salvage operation in FI with high pressure ganging up to the south and southwest and across northeast europe, there are signs that the cool trough conditions will eventually crash and burn but will go down kicking and screaming. The next five days look cool and very showery with thunder and hail, there is also a spell of torrential rain on tuesday to keep an eye on, the track is further south on the 6z but it then curves back across scotland to give them a soaking, apart from the persistent rain spreading east today and on tuesday, it's a sunshine and heavy showers outlook until next weekend, there is a chance that next weekend will see the risk of widespread showers wane with longer sunny periods and just a scattering of showers with temperatures recovering to just above average in the south next weekend, FI then shows the azores anticyclone ridging towards the uk and I have high hopes that by the end of may or just before, our weather pattern will be looking a lot more summery.

[Frosty.]

Continuing signs of improvement  towards may 26th on the latest met office update which would suggest more settled and relatively warmer conditions by then which ties in with the very latest Gefs 06z mean, our patience will ultimately be rewarded, longer range prospects for June are also improving with warm and drier weather on the way. hopefully this means we will see a lot more of the Azores high than last summer.

Edited May 12, 2013 by Frosty039

[mushymanrob]

Stronger hints beginning to develop in the GFS now for a more settled spell towards the end of this month:

 

 

It will be some days yet before we can get a decent comparison from the ECM EPS suite, but the timing fits in perfectly with expectation at present.

 

The MJO just beginning to show hints of an eventual phase 1 progression (both the GFS and GEM moving towards this area):

 

 

The 500mb anomaly projection for phase 1 in May ties in nicely with a potential Azores HP influencing the UK:

 

 

If we roll this forward into June:

 

 

So my thoughts for later in the month and into the start of June remain the same - settled weather taking over, and it could end up being one of the best periods of the summer

 

SK

 

but with respect, theres along way to go before the mjo reaches phase 1, and it might not do so.

[legritter]

I would realy love to see a good warm spell it would certainly do me good and millions of others .but looking at all the available data at our disposal Changeable wet and on the cool side sums it up for quite a while but a few signs that pressure could rise to our south later in the month .its quite possible that the Azores high could kick in or it may just stay asleep untill this december ,just in time to spoil the party .i have noticed around the internet chat rooms that there are no big longrange forecasts well not many but who knows whats past that horizon but im pretty sure what ever it is will be noteworthy .untill something changes big aloft and that could be happening right now i personally think sand bags at the ready ,here we go again but it could all change into a flaming June ,BBQS out but nobody can afford the food ,catch you all up after tonights runs cheers 

[Milhouse]

A spell of fine weather showing up on the GFS 12z next weekend with temperatures recovering and pressure rising.

 

[Purga]

A spell of fine weather showing up on the GFS 12z next weekend with temperatures recovering and pressure rising.

 

In the meantime some wintry preciptaion on the north

 

Later extending as far south as N ireland & N Wales

 

In the sunshine it will feel quite warm as is usual at this time of year so an interesting contrast.

[Milhouse]

A spell of fine weather showing up on the GFS 12z next weekend with temperatures recovering and pressure rising.

 

The key things is where does that low pressure go thats to the north of the UK. It tracks northwards according to the GFS 12z allowing high pressure to build from the south.

 

[Frosty.]

A much better Gfs 12z in FI with the azores high ridging northeast and high pressure then building strongly over the uk with increasingly warm weather during late may, actually next weekend also brings a window of fine weather with weak atlantic ridging bringing mostly dry and fairly sunny weather with temperatures close to average but late may looks great.

[nitro_deluxe]

Also nice to see a potential heat spike heading N out from France..

[Frosty.]

Also nice to see a potential heat spike heading N out from France..

Yes the gfs 12z is full of potential for a late may warm spell which would last into june, this run reflects the trend to a settled outlook on the Gefs mean which has been showing for many days now.

[Milhouse]

UKMO showing a rather deep area of low pressure over Germany which could be close enough to prove troublesome. Temperatures gradually on the up despite the northerly. Warm air coming around the top of the low should ensure its not that chilly, except for eastern coastal areas.

[049balt]

http://wxmaps.org/pix/prec4.html

 

Very positive.

[Frosty.]

The UKMO 12z shows a ridge trying to push in from the west next friday which indicates the showers would be less widespread and heavy on friday with more in the way of sunshine and with light winds it would feel pleasant and if that low to the southeast ends up any further east then we should have a fair weekend as the gfs 12z shows. Wednesday and thursday look great for thunderstorms breaking out widely.

Edited May 12, 2013 by Frosty039

[Milhouse]

GEFS mean at T=240 supporting an Azores ridge.

 

[Frosty.]

The latest GEFS 12z mean is looking even better this evening from T+240 hours onwards, it shows high pressure taking over, initially via the azores high/ridge and then due to a large blocking scandi high, temperatures also rise during this period into the low 70's F and perhaps heading towards 24c 75f during the last week of may into early june.

[Milhouse]

Ensemble mean trending above average later on.

 

http://www.wetterzentrale.de/pics/MT8_London_ens.png?6767676767

 

I suspect the number of rain spikes round about the 19th indicates that low pressure for next weekend has to be watched closely as its position has yet to be nailed down.

Edited May 12, 2013 by Milhouse

[Guest pjl20101]

I am wondering with what Gavin partridge our friend has thought about this week? As I've not visited gavsweathervids.com recently.

[Summer Sun]

A lot of positives to take tonight for another warm up as we move into the final 10 days or so of the month the most important thing tonight is we have ensemble support

 

 

Now over the coming days there could well be some runs which are not so good but thats the way it is sometimes the best thing to look for is trends and the trend of late has been a warming trend so far that is holding firm all we need now is ECM to jump on board

 

[Frosty.]

A lot of positives to take tonight for another warm up as we move into the final 10 days or so of the month the most important thing tonight is we have ensemble support

 

 

Now over the coming days there could well be some runs which are not so good but thats the way it is sometimes the best thing to look for is trends and the trend of late has been a warming trend so far that is holding firm all we need now is ECM to jump on board

 

Yeah Gavin it's got good support now, I don't know why anyone would want cool unsettled weather to go on and on, it's time for sustained warmth and sunshine and we don't have long to wait, the timing actually looks perfect with the fine spell beginning just before official summer starts.

[Summer Sun]

Yeah Gavin it's got good support now, I don't know why anyone would want cool unsettled weather to go on and on, it's time for sustained warmth and sunshine and we don't have long to wait, the timing actually looks perfect with the fine spell beginning just before official summer starts.

 

And don't forget another BH weekend from the 25th to 27th inclusive 2 settled warm ones in the space of 3 and a half weeks is very rare for this country

 

Edited May 12, 2013 by Gavin.