Model Output Discussion 31/03/14 onwards.

[knocker]

The 12z GFS run has convective cloud cover from the south west to Lincoln and into Scotland on Wednesday and Thursday. East of that line quite respectable temps. But it's a long way hence.

[bluearmy]

the entire ncep suite continues to prog showers this evening across england. its done so all week and there still looks to be nothing doing. very odd. i can accept an isolated shower bereaking out but it seems to have picked up some instability for this evening at the beginning of this week and hasnt dropped it at all.

[IDO]

The GFS op and Control in FI have been trending in the last few runs for the trough, in some form or other to stick around for longer. The latest op keeps it till the end of May, with plenty of rainfall potential and uninspiring temps. Even GEM, that has always been the most optimistic is now by D10 still holding the UK under an upper trough:

 

 

The ECM mean for the 0z indicates temps below average:  

 

Early days to worry about that.

 

The wettest days for the south next week appear to be Monday evening-Thursday morning (GFS) as a warm front tracks north, followed by a cold front moving from the SW to the NE. Temps above average prior to the cold front clearing NE on Wednesday bringing in a cooler flow and temps moving back to average or just below. GEM have now downgraded their uppers and are closer to the GFS op than they have been previous runs. UKMO slightly more progressive with the cooler uppers this evening.

 

The convective potential has been downgraded due to the models making less of any plume of warmer uppers, so Monday afternoon & evening now the only real high risk day on the GFS op.

Edited May 16, 2014 by i'm dreaming of...

[shaky]

Hmmm!!interesting ecm this evening!!things stay further west especially for Monday and Tuesday and the humid air never really leaves and it actually makes a comeback again at 168 hours!!

[Milhouse]

Perhaps a greater chance for something drier and still warm

 

[Scorcher]

 

 

The wettest days for the south next week appear to be Monday evening-Thursday morning (GFS) as a warm front tracks north, followed by a cold front moving from the SW to the NE. Temps above average prior to the cold front clearing NE on Wednesday bringing in a cooler flow and temps moving back to average or just below. GEM have now downgraded their uppers and are closer to the GFS op than they have been previous runs. UKMO slightly more progressive with the cooler uppers this evening.

 

The convective potential has been downgraded due to the models making less of any plume of warmer uppers, so Monday afternoon & evening now the only real high risk day on the GFS op.

 

There seems to be a lot of emphasis in this post on the supposed cooler than average temperatures after midweek- but what about before? The latest GFS op looks warm until Wednesday at least with temperatures above average for many on Wednesday too. The ECM 12Z is warmer than this with plenty of warm uppers well into FI.

Edited May 16, 2014 by Scorcher

[Summer Sun]

A very interesting ECM indeed

 

A very warm start to next week as we all know by now then by Thursday the 850's look slightly lower for the south but how much that will affect the temps I don't know, still very warm for the north

 

 

The working week ends with temps probably slightly lower for all but still pleasant

 

 

But just for time for yet another BH weekend the 850's start to rise turning things very warm once more

 

 

Wet at times yes but also some drier day which would feel very warm especially in sunny periods

Edited May 16, 2014 by Summer Sun

[Milhouse]

The ECM definitely provides food for thought this evening with a much drier last few frames to what its been showing for the past few days. Low pressure moves off to the south west allowing us to just about tap into some of the heat on the continent.

[ANYWEATHER]

The ECM definitely provides food for thought this evening with a much drier last few frames to what its been showing for the past few days. Low pressure moves off to the south west allowing us to just about tap into some of the heat on the continent.

Im afraid the likely progression is "eventually" an eastward push from the Atlantic, a normal meteorological occurrence...

[A.J]

hmm, the ECM after the short term just doesn't make sense to me and looks implausible going from T120 - T144.....we go from going from a slack pressure regime with slack south easterly flow with shallow low pressure to the south and south west over Biscay and a trough to the west of Scotland, to an organized LP centred off Cornwall with a central pressure of 988mb....that's an impressive pressure 'bomb' of 20mb in 24 hours.....doesn't seem likely to me

 

 

 

[IDO]

There seems to be a lot of emphasis in this post on the supposed cooler than average temperatures after midweek- but what about before? The latest GFS op looks warm until Wednesday at least with temperatures above average for many on Wednesday too. The ECM 12Z is warmer than this with plenty of warm uppers well into FI.

 

 

It is being forecast by the models that the Conus will become flatter around the 8-14 day period. This in theory should de-amplify the Atlantic ridge and push the UK trough east. Leading to a slack Atlantic flow from around D8.

 

GFS and GEM suggest the jet will be south of the UK as it follows the trough digging SE-E, hence lower uppers. What the ECM 12z does, contrary to recent inter runs is to break off the upper low; GFS and GEM only cut off the low transiently before restoring the flow. This allows the jet to travel north of the UK and a surface ridge builds between the jet and the upper low.

 

ECM D10:   GEM: 

 

This appears to be an outlier solution (again) from ECM. Has little support from this morning's mean:

 

 

One GEFS at D10 has this solution. The main cluster follows the op and control.

[ANYWEATHER]

At day6 both models  agree that's the ecm and gfs  will bring the Atlantic in....

[Frosty.]

Tonight's Ecm 12z op run is even better than last night, it shows a prolonged summery spell with no end in sight to it either, indeed, towards the end of the run the weather hots up even more, it stays either warm or very warm (locally hot) and becomes increasingly humid next week with a continental SE'ly flow encouraging thundery showers and outbreaks of heavy rain to break out and also spreading up from france as we lose our current anticyclone by the start of next week and replace it with a trough to the southwest which looks like taking control of our weather but although the run shows shallow troughs drifting around the uk at times, high pressure cells also have a significant impact with a lot of dry and sunny weather too, a very slack, slow moving weather pattern which looks like charts we would love to see during the height of summer..Enjoy it Guys..BBQ weather this weekend

[summer blizzard]

Humid and potentially thundery.

 

Western Scotland though looks spot on for sustained warmth and sun.

[A.J]

a couple of posts pruned....model discussion please folks 

[knocker]

Tonight's Ecm 12z op run is even better than last night, it shows a prolonged summery spell with no end in sight to it either, indeed, towards the end of the run the weather hots up even more, it stays either warm or very warm (locally hot) and becomes increasingly humid next week with a continental SE'ly flow encouraging thundery showers and outbreaks of heavy rain to break out and also spreading up from france as we lose our current anticyclone by the start of next week and replace it with a trough to the southwest which looks like taking control of our weather but although the run shows shallow troughs drifting around the uk at times, high pressure cells also have a significant impact with a lot of dry and sunny weather too, a very slack, slow moving weather pattern which looks like charts we would love to see during the height of summer..Enjoy it Guys..BBQ weather this weekend

 

Not sure I understand that and where you are getting your ECM humidity predictions from? Just an observation.

Edited May 16, 2014 by knocker

[IDO]

JMA Summer Forecast recently updated.

 

June:  Looking like the best month according to JMA.

 

July:  Cool and unsettled.

 

August:  Cool and unsettled again.

 

The last week of May JMA anomaly: 

 

In line with tonight's NOAA:    Heights rising from the NE as the lower heights sink and the trough flattens.

 

The ECM upper temp mean for the 12z run:   OP run: 

 

The op about 4c higher upper temps than the mean.

 

Both the GEFS and ECM mean building heights over the UK in the last few days of May:

 

 

 

Ties in nicely with the JMA June anomaly...

[bluearmy]

The period post latter part of next week completely uncertain. the trend i have picked up over the past few runs is for the upper low to become cut off the the sw. whether that becomes the direction of travel over the w/end remains to be seen.

[Captain Shortwave]

Again the question is are the ensembles too far east again?

That euro/Scandinavia ridge is holding firm even to day 10. I would be surprised if we didn't get another surge of very air hitting the uk.

The end of July 2013 comes to mind. Similar pattern with low heights west/south west of the uk and a strong ridge to the east. It took over 10 days to fully breakdown and return us to Atlantic westerlies with the hottest day since 2006 being recorded during that spell. Something similar could happen here as even the mean shows this long wave pattern near enough stuck in place for several days.

ECM on its own and consistent with its evolution of the cut off low. Similar to the GEM and it's sharper and more west based solution for this weekend into next week. It was an outlier, but it was very close to the mark.

Edited May 16, 2014 by Captain shortwave

[Man With Beard]

Back from holiday, and I see the models are no nearer sorting next week out that when I left!

 

Really shows that you can't just say "T96 is reliable, T192 is unreliable" - it doesn't work like that, 8 days ago some of us were confident about 23C being reached this weekend (and we were shot down by a few) - but it was a simple forecast, a key trigger low in the Atlantic was consistently forecast by ECM at T96/T120, which naturally led to a build of High Pressure over the UK at T144-T192, I decided ECM was likely to be right if consistent over 4/5 runs so I made the forecast.

 

This week, the models have been trying to forecast a breakaway low heading almost North to South, against the normal East/West flow of our weather, with a steep temperature gradient directly to the east/west. The positioning of these lows is very difficult to pin down until even T72, and if the dividing line between cold/warm is anywhere over the UK, the forecast goes down even to T24, I think. So in complete contrast to last week, when I felt I could forecast at T192, I don't even think I can forecast beyond T48 at the moment. The only thing I think is certain is rain - a few places are going to get very very wet sometime next week, as the strong temperature gradient will encourage an active front. SW seems favoured for this, but I wouldn't rule anywhere out. Warmth wise, eastern side looks favoured but all uncertain, 50% chance of 25C being reached I'd say, 25% chance of 27C, even. 

[knocker]

You can see where the ECM is going with the upper air evolution.

 

[shaky]

18z gfs similar to the ecm with a slight pressure build from the south east again from mid week!!interesting!!and it remains warm all week!!

[Captain Shortwave]

Hmm next weekend is worth keeping an eye on. I think there is potential for something even warmer than what we are currently experiencing. That ridge to the east does show signs of trying to assert itself more by next weekend. We could get a very warm or even hot southerly going if the ridge is close enough and the flow aligns nicely.

Edited May 16, 2014 by Captain shortwave

[knocker]

What revelations await today I wonder. I was wondering about the August bank holiday and then I thought, get a grip knocker. Anyway sticking to the immediate future which surprisingly is still not been unanimously resolved as can be seen. I’ve posted some fax charts but for a brief description will stick with the GFS.

 

Tomorrow all is well with a  front over central Ireland stretching to Stornoway accompanied by rain.

 

Then things begin to differ. The low is just off the west Wales coast 999mb with general rain over Ireland, Wales, west Midlands, north of England, south west Scotland and parts of the west country.

 

Tuesday sees the low in mid Wales 1003mb with much the same rain set up as Monday although now all of the west country is involved and the rain in Wales could be quite heavy.

 

Wednesday a subtle change with the low centred northern France and a trough covering the UK with a rain belt running west/east across N. Ireland and N. England.

 

By Thursday this edged north to central Scotland.

 

Temps are a bit immaterial but Sunday very warm and after that generally not bad and still pretty warm in the east.

 

Next weekend? A low to the SW with an easterly flow over the UK.

 

 

[Captain Shortwave]

Again a large variety in surface conditions next week. ECM showing a classic plume scenario on Thursday with 850s of 20c getting into the Low Countries with the 12c isotherm clipping the east coast of the uk. Couple that with low heights pushing north/north west this could very well go bang.

All the models differ in surface conditions by this point so little confidence but it is interesting to see it crop up.

Beyond this and well into FI fun the ECM builds a strong scandi high bringing a warm weekend, perhaps very warm in the south east. Also notice the thundery low developing over Western France. Could go bang again.

Edit - wow that day 10 chart. Victory for the euro/scandi block. If that chart verified then we would be looking at the first heat wave of the year. That output is definitely a banker.

Apologies for the lack of charts as I'm posting on an iPad and have no idea how to post charts on this.

Edited May 17, 2014 by Captain shortwave