Model Output Discussion 31/03/14 onwards.

[Captain Shortwave]

Look where the jet is...straight through the UK. The higher pressure to the N and E is merely serving to ensure the Azores high can't pull NE across the UK for any great length of time- especially so with its attempted retrogression and tilt towards Greenland. Any firing up of the jet and the Azores high would be blasted even further away. Like you say, the best hope from there would be an LP stall but even that would be a stop gap situation until the troughing won out.

 

There is potential situation whereby the Azores and Scandi high link......however the jet would need to veer well N for this to happen and it requires the jet to ease of sufficiently for the link to occur. You also need to see a +ve NAO pattern emerge with a sharp fall in heights across Greenland.

Yep we need something to change upstream really to give the Azores high a real push. The GFS ens show pretty much the picture with energy in the Atlantic squeezing between the two high pressure cells and maintaining low heights over central/southern Europe.

One thing I will say is how close the pattern is to what the CFS and other long range models have been saying for a while. Persistent higher than normal heights to the north east with cooler and wetter conditions for southern Europe. You just wish they could do better with the winter weather patterns 

Edited May 24, 2014 by Captain shortwave

[phil nw.]

Most important thing there....drop in heights around Greenland....

Signs of that too on both Naef's and ECM mean ht anomalies certainly although no agreement on where to place them.

http://modeles.meteociel.fr/modeles/gens/naefs/run/naefs-0-0-240.png?0

http://www.meteociel.fr/modeles/ecmwf/runs/2014052400/EDM101-216.GIF?24-12

 

an overall trend though for falling +ve anomalies to our north by day 10 compared to the current pattern.

[damianslaw]

An unsettled outlook for the foreseeable future, with the Jetstream anchored over the country thanks to strong heights to our north and east, consequently the azores high will be forced to stay in resident to the SW. The outcome slow moving trough action giving rise to heavy downpours/showers and longer outbreaks of rain. SE parts will always stay the warmest and on occasion some of the rain may turn thundery. NW parts may well see the best conditions over the coming days with less in the way of heavy precipitation, but it hardly looks a sunshine calm scene. Rather disappointing in the main with temperatures average at best.

 

It is the kind of set up prone to sudden developments, it looks increasingly likely that Monday will be a very wet day in the SE portion of the country thanks to a developing system moving up from France. The BBC have only just mentioned this suggested turn having been calling for a sunny dry day on Monday, all in all this bank holiday looks like being preety disappointing. We did very well with easter mind and may day Monday was a good one as well.

Edited May 24, 2014 by damianslaw

[knocker]

And then.............but considering the uncertainties surrounding the 500mb anomalies for shorter time spans very low confidence in this although the ECM has been pushing for a flattening of the flow for a while. And the jet isn't a done deal.

Edited May 24, 2014 by knocker

[Milhouse]

Next weekend shaping up quite nice on the GFS 12z. Increasingly dry and warm with scattered showers for the south west.

 

 

 

 

[Captain Shortwave]

Out of the two I certainly prefer the UKMO solution

That ridge should hold and start to develop a more typical Euro/Scandi ridge, though there would be question marks about how close low heights in the Atlantic would get further on from this.

Not too keen on the GFS's northeasterly, that is a cloudfest waiting to happen. On the other hand the GFS is chucking out different solutions at day 6 with every run so confidence is very low

Edited May 24, 2014 by Captain shortwave

[Summer Sun]

Next weekend shaping up quite nice on the GFS 12z. Increasingly dry and warm with scattered showers for the south west.

 

 

 

 

 

UKMO doesn't look too bad either certainly on Friday with a ridge of high pressure building

 

[Milhouse]

And much better from the GFS 12z in the low res part as well. Demonstrates the uncertainties as we enter summer proper. The heat builds in FI

 

[draztik]

Wondered why the GEM wasn't being touched upon, then I checked it out!

T192 &t222

Yikes!

[Winter Cold]

Which model is showing the best thundery potential tonight? I guess GEM is just full on low pesssure and frontal rain..

Edited May 24, 2014 by phil nw.
Removed off topic chat-please keep to model discussion only in this thread.

[ANYWEATHER]

The rain for Monday looks like pushing across southern parts of the Uk ,during Monday morning according to the nmm-6 High resolution model....

[Captain Shortwave]

I think even the weather forecasts are heading towards at least half a wet day in the south on Monday now, if not more.

Further ahead....

 

I need to order a canoe I think

I will ignore the ECM/GEM and rock back and forth in my chair holding a tub of straws with the letters G, F and S written on them

Edited May 24, 2014 by Captain shortwave

[ANYWEATHER]

I think even the weather forecasts are heading towards at least half a wet day in the south on Monday now, if not more.

Further ahead....

 

I need to order a canoe I think

I will ignore the ECM/GEM and rock back and forth in my chair holding a tub of straws with the letters G, F and S written on them

Although the 06z gfs run showed low pressure in its whole run...

[knocker]

Having kicked the 00z ECM ops into touch somebody kicked it back again. Still sticking to a trough from the cold air in the east on the 500mb anomaly giving a cyclonic surface analysis for the UK as the Azores high retreats, This wasn't supported by the ens on the last run and I'll be surprised if it is this time. Markedly different to the GFS.

Edited May 24, 2014 by knocker

[ANYWEATHER]

Its always good to look at both sides of the coin from gfs 06z and 12z, very big difference between both runs.....

[ANYWEATHER]

Gfs and Ecm Differ greatly at the ten day range......

[summer blizzard]

Well done to the GFS18z, seems to have hit the nail and got backing from both GEM and the Euro.

 

[phil nw.]

The 6-10 day and 8-14 day noaa output are painting the same picture you are visuaalising phil, my only concern is LP over eastern europe maybe coming to our shores with very much a mid atlantic ridge. However we will just have to wait and see if it comes to fruition or not.

Yes a tenuous ridging of the AH next week-end still modeled on the 12z ens ht forecasts.

We can compare the NOAA and ECM means here

 

still some uncertainty on this though.Some op runs still favour a trough coming across from the west.

 

Some weakening of the jet running across the south next week end is apparent from the Gfs mean though so a window for the ridging to occur.

 

notice though a little residual energy still pushing against that ridge and i think this is where the uncertainty lies in how this plays out.The ECM op has the jet pushing through.

[knocker]

The EPS  has the jet further north that more meets the scenario of low pressure maybe developing to the north whilst the HP still retreats. The Eps is more in line with ops run this time around but this still a somewhat fluid anomaly position I feel.

 

[johnholmes]

Yes a tenuous ridging of the AH next week-end still modeled on the 12z ens ht forecasts.

We can compare the NOAA and ECM means here

http:////f1.nwstatic.co.uk/forum/public/style_images/tctc91_simplify/attachicon.gif814day.03.gifhttp:////f1.nwstatic.co.uk/forum/public/style_images/tctc91_simplify/attachicon.gifecm500.192.png

 

still some uncertainty on this though.Some op runs still favour a trough coming across from the west.

 

 

The NOAA output does seem to be tending more towards a more settled idea over the last 2-3 days and with continuity into the 8-14 period beginning to show?

[knocker]

Well the ECM for the same period?

Edited May 24, 2014 by knocker

[phil nw.]

The NOAA output does seem to be tending more towards a more settled idea over the last 2-3 days and with continuity into the 8-14 period beginning to show?

They do John but the ECM op runs continue to show an Atlantic cut off trough across the north next week end.

Naefs and ECM Ht anomalies are not showing a strong enough signal for a robust high building right across so i reckon the jury is out on this.

Edited May 24, 2014 by phil nw.

[Costa Del Fal]

Excellent GFS 12z and 18z for here in Cornwall next week. High pressure building in and warm, sunny blue skies again! Quite a change since when I last looked at the charts yesterday I'm sure?

 

But then other models arent looking so great so lots of changes to come. Both extremes on offer tonight.

Edited May 24, 2014 by Blizzards

[knocker]

Morning all just getting out the crystal ball for next weekend. The latest GFS is not going for a build up of heights from the Azores  high.

 

The anomaly chart for Sunday and Monday has a weakening ridge running SW/NE over the UK but the dominate feature is a cold pool stretching from N. Canada to Iceland and Scotland pushing the weakening ridge SE.

 

Surface features.

 

Saturday has the UK sitting in a col between HP to the SW/NE and LP to the NW/SE.

 

Sunday pretty similar but by 00z the low to the NW is far more influential with frontal troughs over Stornoway with the UK in a SW airstream as the AZ high nips back SW.

 

By Tuesday the low pressure to north has taken over giving a wet day over most of the UK and the HP now back in mid Atlantic.

 

This isn’t all bad news. Temperature wise Friday (maybe mid 70s), Sat. and Sunday looking quite warm.

 

Oh and the jet on Sunday is running SW/NE from the Caribbean to the west of Scotland.

Edited May 25, 2014 by knocker

[Captain Shortwave]

Very little consistency from the models with each other and themselves, the GEM/ECMs limpet UK trough is gone and replaced with different solutions.

ECM

Another cut off low pushing into Southern Europe, more easterly winds later on with temperatures close to average if a little higher but the risk of heavy and thundery rain in the south.

 

GEM

Stronger Azores ridge, eventually breaks later on to bring low pressure to the west of Scotland, average conditions if rather wet, especially in the north west of the UK.

 

UKMO

Looks like it's trying to make the Scandi high hold on in position. Looks like it would be another solution where low pressure heads south of the UK.

 

GFS

Azores high moves in and aligns the jet SW/NE. This flattens the Scandi high and brings a return to pretty traditional conditions for the time of year with a generally westerly flow (some warm weather mixed with cooler PM interludes).

 

Completely different solutions from all the output this morning. Makes forecasting beyond mid-week hard, let alone much further out.