Model Output Discussion 12z 20/04/13

[SnowObsessor90]

I have to say I do like how the pattern eventually evolves later on in this particular GFS run with high pressure to our east starting to exert more of an influence, the ECM has also toyed with this idea over recent runs so certainly something to watch out for that is for sure.

Edited May 7, 2013 by SnowObsessor90

[bluearmy]

The models are still coming to terms with next weeks troughing. we are far from establishing where the worst of the weather is likey to be and the trend is still west of the uk for the lowest heights

[Frosty.]

There are some positives to take from the GEFS 12Z mean with high pressure developing to the northeast in FI and shunting the trough out to the west, it also warms up later in FI so hopefully there is light at the end of the tunnel with a prolonged warm spell perhaps evolving later in may. In the meantime, the 12z mean again shows a slight pressure rise for the south spreading east with pressure of 1015-1020 mb, however, most of the uk will be on the wrong side of the polar front jet and look like having a prolonged cool and unsettled spell, next week looks particularly cyclonic with heavy slow moving showers with thunder but also sunny spells and temps in the low to possibly mid teens celsius but dropping like a stone when a shower moves across. Overnight it looks rather chilly next week with the lighter winds where skies clear with a touch of grass frost in prone areas.

[Guest pjl20101]

Retweeted a tweet by matt Hugo and he said because the MJO would be according to the ec 32 and the cfs vs 2 be entering phase 3 and 4 for mid may that it wouldn't bode well for settled conditions. Can sadly believe that I'm afraid.

[Frosty.]

Retweeted a tweet by matt Hugo and he said because the MJO would be according to the ec 32 and the cfs vs 2 be entering phase 3 and 4 for mid may that it wouldn't bode well for settled conditions. Can sadly believe that I'm afraid.

it could be worse though, sunshine and showers is much more interesting than dry and rather cloudy, great potential for storm fans in the next few weeks, especially next week.

[Milhouse]

Well thats a shame, but its only May and an unsettled spell during the middle of the month does not have a bearing on how the Summer will pan out. I guess we will have to just endure it and look for a return to the warmth for the final week (hopefully 2) of the month. On the plus point it looks like all parts should see some decent rain which has to occur at some point to avoid the countryside wilting and looking arid. Plus this is a different unsettled pattern to the one of last May. The jet stream is still fairly sluggish and there is not an endless train of low pressures heading up from the south west like last year.

Edited May 7, 2013 by Milhouse

[Summer Sun]

it could be worse though, sunshine and showers is much more interesting than dry and rather cloudy, great potential for storm fans in the next few weeks, especially next week.

 

After last years dismal weather sunshine and showers will suite many rain is badly needed in many areas now one positive thing is the low pressure conveyor belt of 2012 isn't re appearing so far

 

ECM shows an unsettled weekend with sunshine and showers the best we can hope for this coming weekend with low pressure set to dominate

 

[Milhouse]

Disappointing ECM so far to T+144, but the plus point is all areas will see some rain to green things up. Hoping to see winds turn more southwesterly and eventually southerly like the 0z showed to raise the temperatures.

Edited May 7, 2013 by Milhouse

[Milhouse]

A southwesterly of sorts develops at T+168 but with coolish upper temperatures. Light winds though so it would feel fairly pleasant but it would be the recipe for some slow moving heavy downpours. High pressure building over Europe which is nice to see.

 

[Frosty.]

Well tonight's Ecm 12z op run has slammed that window of opportunity shut for a fine spell in the south this coming weekend but the gefs 12z mean and gfs 12z op run still offers slight hopes with the window left ajar for now. For most of the uk it looks like a prolonged unsettled and rather cool spell is almost upon us but it's not doom and gloom, there will still be some pleasantly warm sunshine between the sudden downpours.

[Summer Sun]

Some quite warm uppers get dragged up into the SE at t192

 

Warmer for most at t216 as a south easterly flow sets up

 

Edited May 7, 2013 by Gavin.

[Milhouse]

Some quite warm uppers get dragged up into the SE at t192

And that should continue for the remainder of the run. I cant see those warm uppers being cut off.

[ANYWEATHER]

And that should continue for the remainder of the run. I cant see those warm uppers being cut off.

At such a long way off ,you can almost write that off!!  

[tinybill]

http://www.meteociel.fr/modeles/gfse_cartes.php?mode=2&ech=204

 

looking deep into fantasy world  i just hopeing this summer not going like last year summer  !!!!

[ANYWEATHER]

Unsettled in the 10 day range although gfs and ecm differ with the relation to how the lows develop. Ecm keeps the northern blocking ,less so the gfs, although gfs was very similar about 24hrs ago....  

[Gibby]

Good evening. Here is the report on the 12 noon outputs from GFS, UKMO, GEM, NAVGEM and ECM for tonight Tuesday May 7th 2013.

All models show Low pressure deepening to the SW of the UK and moving NNE towards Northern Ireland over the next 24 hours. A front will move NE across all areas apart from the far North of Scotland over the period. A band of heavy rain will sweep NE overnight reaching Eastern areas tomorrow, weakening as it does. Clearer, showery weather will follow with a strong and blustery SW wind. On Thursday the Low deepens further near Ireland and a secondary feature runs East over England and Wales with gales and heavy rain or showers the order of the day. Through the latter stages of the week and weekend all models show the low finally move away to the NE but leaving behind a brisk and cool WNW flow with showers and sunny intervals for most.

GFS shows a very disturbed spell of weather next week as a Low pressure complex slips South over the UK to dominate the whole week's weather with showers or longer spells of rain throughout with hail and thunder locally as well as some short drier spells with a little sunshine. As we move deep into FI Low pressure does retract towards a position NW of the UK with occasional rain bearing troughs blowing through with rain mixed in with rather longer drier ad brighter conditions by the end of the run when it becomes warm and humid in the South and East.

The GFS Ensembles show a tight cluster of members throughout the run tonight with all of them showing rather cool conditions with frequent and heavy showers the general theme. There seems little to choose between North to South with regard to precipitation with all areas at risk from some heavy rain at times.

The Jet Stream tonight shows the flow moving NE towards the UK. In the following week the flow trends North over the Western Atlantic then South to the West of the UK to set up a Southerly position across Southern Europe.

UKMO tonight shows a showery WNW flow over the weekend with some sunny spells in many places between the showers. It will feel rather cool in the blustery breeze. Through the beginning of next week the weather remains very showery as reinforcements in the shape of Low pressure from the NW arrives on Monday keeping the heavy shower risk going and maintaining unspectacular temperatures.

GEM tonight shows a deep UK trough setting up next week with plentiful rain and heavy showers likely for all in temperatures close to normal at best and sometimes somewhat below.

NAVGEM shows very little change from the other output except that it holds up the second Low pressure sinking down from the North a little longer consequently reducing the shower risk in the South on Sunday and Monday of next week.

ECM shows a very showery picture tonight with Low pressure moving SE towards Western Britain early next week replacing the showery WNW flow this weekend. Spells of rain interspersed with heavy showers in rather cool conditions look likely for the early and middle portions of next week and as the Low slips further South ending near the SW approaches it sets up a potentially very wet spell late next week with humid and moist air to the East engaging with the unstable air aloft.

In Summary it's the same story as this morning's output with little optimism towards warm and sunny weather from any model tonight as the deep trough anchors near the UK. This means that all areas are at risk of heavy showers and thunderstorms. There will be some dry and bright spells too and given it is now May any sunshine will feel very warm. However, this will help fuel the atmosphere further, especially if as ECM suggests some warm and humid air mixes with our cold pool aloft endorsing the risk of copious rainfall in places later, most likely in the South.

[Milhouse]

At such a long way off ,you can almost write that off!!  

But you can still say on May 7th that we may be looking at another Summer like 2007  (see your earlier post).

 

The ECM 0z mean was hinting at a more continental influence to end the run with uppers rising so the ECM 12z op is not an outlier

[Gael_Force]

Retweeted a tweet by matt Hugo and he said because the MJO would be according to the ec 32 and the cfs vs 2 be entering phase 3 and 4 for mid may that it wouldn't bode well for settled conditions. Can sadly believe that I'm afraid.

 

I was not aware that the EC 32 or the CFS v2 forecast the MJO phases - have you a link to where this was said?

[ANYWEATHER]

But you can still say on May 7th that we may be looking at another Summer like 2007  (see your earlier post).

 

The ECM 0z mean was hinting at a more continental influence to end the run with uppers rising so the ECM 12z op is not an outlier

Yes, but looking at the extended outlook, I see almost a repeat performance synoptically from the models,[looking at trends etc] per usual recent summers as to if it happens,Who knows! but  short to medium term little point in looking for finer detail, as the devil in the detail will change. The ten day outlook looks unsettled from all models though!!  

[Frosty.]

The Ecm 12z finds a way of drawing very warm and humid continental air northwestwards across the uk in FI, it would be really nice following the cool cyclonic pattern to swap it for a very warm and humid spell with sunshine and more thundery showers.

 

These charts are very nice, what a lovely plume of warmth that is

[Guest pjl20101]

Gael_Force I don't think I have a link, but you can look at his tweets on his page and that should help you.

[legritter]

Evening ,atleast we have some very interesting weather coming up for our little island .like previouse years Here we go again comes to mind .ECM seems keen on UK having low pressure near or on us and GFS similar but with a promise of some warmth later in outlook .having spent last end of may june and early july in canada i missed a lot of our action ,but it did make news on the canadian weather shows so perhaps this year i can witness it first hand .so lets enjoy what we have and hope something warm and lasting but not boring arrives .

[Evening thunder]

Hmm, clever selection of eye-catching charts, Frosty039. Nothing exceptional there. Temperatures of between 6-10C at 850 hPa aren't especially high, despite what the colour shadings might fool some into thinking. Doesn't look particularly warm at the surface either, considering the synoptics preceding the period in question.

 

I've omitted the "shock" smiley from the quote above.

 

Not exceptional for May but I reckon a few sheltered western or north-western parts could get 23-24C if that were to occur (unlikely of course), after all they did today and uppers on those charts are a couple degrees higher. Wouldn't be as widespread warmth though with cloud/rain/showers etc in places of course but can think of much worse.

 

Must admit those charts do tend to over-do the warm shadings I agree but I've seen Frosty09 use them quite a bit recently not just for warm weather so I don't think  he cherry picked them just to make it look warmer.

[samadamsuk]

Hey all .. so yes the worry is, atleast for some, that we get stuck with troughs that pile up against the continent until most of the summer is out. However - even this pattern, if it has been repeating for 5 years, should evolve at some point. From mid range into FI, and we see the trough retrogress slightly, atleast putting us on the southerly flank of an atlantic low - so unsettled, then possibly warm, possibly very wet, and too far out to really be promising, but there none the less. 

 

Cheers, Sam

[Polar Maritime]

Not exceptional for May but I reckon a few sheltered western or north-western parts could get 23-24C if that were to occur (unlikely of course), after all they did today and uppers on those charts are a couple degrees higher. Wouldn't be as widespread warmth though with cloud/rain/showers etc in places of course but can think of much worse.

 

Must admit those charts do tend to over-do the warm shadings I agree but I've seen Frosty09 use them quite a bit recently not just for warm weather so I don't think  he cherry picked them just to make it look warmer.

 

Yes I agree, A little unfair to state he cherry picked them, Karl is only one of a few with unbiased veiws regarding the models on this forum.

 

One of the best posters on here.

Edited May 7, 2013 by Polar Maritime