Model Output Discussion - Spring 5th March Onwards 6z--->

[ANYWEATHER]

Evening Folks. Settled weather for another week, then the models ,ecm and gfs  show much more unsettled conditions.....Devil in the details apply

[Milhouse]

The ECM 12z has high pressure slipping back south again throughout next week which should help to cut off the cool easterly that many are going to experience this weekend. Its the longevity of high pressure thats up for question though with the ECM prolonging it until the end of the week, whereas the GFS has a more unsettled look at T+168 but still warm.

[johnholmes]

And to keep the 'cold' kettle going see the NOAA output below>

Somewhat different to the charts of 2 days ago and just maybe the synoptic models had something.

http://www.cpc.noaa.gov/products/predictions/610day/500mb.php

As I keep saying, interesting chart watching and comparisons as we count down to what is now 216h.

 

http://www.cpc.noaa.gov/products/predictions/610day/500mb.php

 

And hardly anyone around to watch this really interesting model see saw-sad I think, when it has the potential to be as dramatic, cold wise, as anything that created so many pages of hype in the winter.

Edited April 17, 2015 by johnholmes

[Polar Maritime]

Could not agree more there John, Very interesting synoptic's indeed.

[knocker]

And looking at the GFS and ECM anomalies for last night.

 

The breakdown starting post T168 with the blocking HP Canada/ Greenland, LP N. England and the LPoff of N. Norway with the trough orientated SW of the UK. At this time the flow is  more W/SW with around average temps but by day ten the trough is more N/S over the UK with a ridge mid Atlantic veering the upper flow NW and colder than average temps. Although I'm not looking at anything too alarming.

Charts courtesy weatherbell

 

Just to add I agree entirely with your post above John.

Edited April 18, 2015 by knocker

[johnholmes]

Well both GFS and ECMWF show something not too different from the 240h chart of a couple of days ago, so maybe not a direct northerly blast but a colder shot being shown by both around 192h. This now being supported by the NOAA 6-10 last evening. If this turns out close to the mark it will be, I think, the 2nd time since last autumn that one of the synoptic models has led the way to a marked pattern change. Highly unusual that. Of course it may not happen but it is now about a 40% compared to less than 10% 48 hours ago.

[knocker]

And as far as I can see this cooler spell may be but a transient interlude as the ext. period has the Azores HP reasserting itself. Best not to get ahead of ourselves though.

[Polar Maritime]

ECMWF shows a Northerly flow after flopping the idea last night. Yes agree there Knock, Where this will lead to is still unknown as you say. Will it be a pattern change, Or just a blip... A very interesting period for model watching. Hats off to the GFS 

 

 

Edited April 18, 2015 by Polar Maritime

[Gibby]

HERE IS MY LATEST ANALYSIS USING DATA SUPPLIED BY THE NWP OUTPUT COVERING 5 OF THE WORLDS MOST POWERFUL WEATHER COMPUTERS ISSUED AT 08:00 ON SATURDAY APRIL 18TH 2015.

 

THE CURRENT GENERAL SITUATION High pressure will lie across Northern Britain with a strong and cold Easterly flow across the extreme South.

 

http://www.wetterzentrale.de/pics/Rtavn001.gif 

 

MODELS-2 WEEK HEADLINE A lot of dry, settled and occasionally warm weather across the UK at first before becoming much more unsettled with rain and showers at times later.

 

THE GFS JET STREAM ENSEMBLE FORECAST The main Northern arm of the Jet Stream remains well North of the UK over the coming week before weakening and being replaced by a stronger Southern arm, the West to East axis of which will be moving North over the UK in week 2 strengthening as it does so.

 

http://www.netweather.tv/index.cgi?action=jetstream 

 

GFS OPERATIONAL The GFS Operational this morning shows High pressure in control of the UK weather for the next week or so before declining towards next weekend as pressure falls from the West leading the UK into a more unsettled and eventually mobile Atlantic airstream with Low pressure to the North pushing troughs East across all areas at times delivering rain and showers and average temperatures. 

 

http://www.wetterzentrale.de/pics/Rtavn1441.gif

 

http://www.wetterzentrale.de/pics/Rtavn3841.gif 

 

THE GFS CONTROL The GFS Control Run also shows a slow transition to more unsettled weather after the next week with more emphasis on colder and stronger North winds for a time with showers or rain with the unsettled and often rather chilly weather for all areas under predominantly NW winds continuing then until the end of the run.

 

THE GFS CLUSTERS The GFS clusters show a predominance of Low pressure in control of the weather over the UK in two weeks with just a 10% group indicating High pressure near or over the UK. The rest show winds largely from between West and North with varying degrees of unsettled weatehr and from some members rather cold Northerly winds.

 

http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=euro&MODELL=gefs&MODELLTYP=2&BASE=-&VAR=cpre&HH=372&ZOOM=0&ARCHIV=0&RES=0&WMO=&PERIOD=

 

UKMO UKMO shows High pressure gradually dissolving away to leave a slack pressure gradient across the UK later next week. It will stay largely dry through the period with some sunshine and the fresh and chilly wind across the South of the UK is shown to gradually die away.

 

http://www.wetterzentrale.de/pics/Rukm1441.gif 

 

THE FAX CHARTS The Fax Charts continue to show High pressure in control over the UK all the way out to 120hrs positioned in a far from ideal place though up to the North and NW. A resultant cold and chilly feed from the North Sea will continue to mask otherwise warm and sunny weather with chilly breezes from the North or NE with more cloud cover at times especially across the South and East.

 

http://www.weathercharts.org/ukmomslp.htm#t120.

 

GEM GEM today shows High pressure too across the UK next week with fine and settled weather for all. It then shows a steady transition to cloudy and windier weather with falling pressure and rain at times under Westerly winds towards the start of the second week, this affecting all areas.

 

http://www.wetterzentrale.de/pics/Rgem2401.gif 

 

NAVGEM NAVGEM too feeds Low pressure slowly in from the West next weekend with rain spreaading slowly East across the UK with temperatures close to average levels for late April.

 

http://www.wetterzentrale.de/pics/Rnvg1681.gif.

 

ECM ECM today continues to predict a change in the weather in a week's time as it too develops Low pressure around or near the UK with cyclonic winds delivering rain or showers at times in sometimes strong and blustery winds.

 

http://www.wetterzentrale.de/pics/Recm2401.gif

 

ECM 10 DAY MEAN(12z) The ECM 10 Day Mean Chart  from last night maintains the cyclonic feel with a likelihood of Low pressure to the North of the UK with a cyclonic Westerly flow likely in 10 days with rain at times.

 

http://www.wetterzentrale.de/pics/Reem2401.gif 

 

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The trends this morning remain focused towards a much more unsettled spell developing from later next week with Low pressure much more influential for all.

 

31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKM & ECM The current verification statistics for the past 31 days shows ECM leading the way at 3 days with 97.6 pts followed by UKM at 97.0 pts and GFS at 96.3. At 5 days ECM  continues to lead the field at 89.0 pts over UKMO at 89.0 pts and GFS at 86.9. At 8 days ECM remains the leader with 65.4 pts over GFS's 59.6 pts. Then at Day 10 ECM retains superiority at 46.1 pts over GFS at 43.6. 

 

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day3_PMSL_MSL_G2NHX.png 

 

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day5_PMSL_MSL_G2NHX.png

 

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day8_PMSL_MSL_G2NHX.png

 

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day10_PMSL_MSL_G2NHX.prig

 

 

MY THOUGHTS The models remain focused on fine weather across the UK for another week with High pressure close to the North, strong early in the week but declining later on allowing the chilly NE or East feed across the South to eventually die out and make things feel rather warmer than currently here. Cold air will be bottled well North of the UK early in the week but as High pressure declines and builds over Greenland some of this cold air will be pushed South into the Atlantic ot even towards the North of the UK. As this then engages with the more seasonal air across the UK and Europe developing cyclogenesis will occur with the parent Low from this predicted to lie somewhere either just to the West, over or just to the North of the UK. This will bring much windier and changeable conditions across the UK, probably over next weekend and then lasting through week 2 as the pattern sets into a more traditional High to the South and Low to the North pattern with rain or showers at times in blustery Westerly winds. Positioning of individual Low pressure features could alter of course over model outputs in the coming days which could bear influence of extent and depth of the change expected but with a couple of days now of models highlighting this change it has a fairly good chance of verifying. So in a nutshell if you can get out of the cold wind across the South and the cloudy and showery blip for some Eastern parts tomorrow let's enjoy what remains of the fine and dry weather in the coming week because it maybe that next week this time things will look far more disturbed across the UK.

 

Next update from 08:00 Sunday April 19th 2015

[Gibby]

ECMWF shows a Northerly flow after flopping the idea last night. Yes agree there Knock, Where this will lead to is still unknown as you say. Will it be a pattern change, Or just a blip... A very interesting period for model watching. Hats off to the GFS 

 

 

 

 

I will remind readers that GFS has not led in any verification Stats since I started putting them within my reports three months ago so any credit towards them over ECM is ill founded I'm afraid.

Edited April 18, 2015 by Polar Maritime
To separate post from quote. .

[Polar Maritime]

Maybe not Gibby, But for this change now showing across the Models to a cooler more unsettled spell towards Months end, The GFS was the first to pick the signals up. Granted it has been dropped and picked back up many times. So for that alone my hat is raised.

Edited April 18, 2015 by Polar Maritime

[Peejayem]

Maybe not Gibby, But for this change now showing across the Models to a cooler more unsettled spell towards Months end, The GFS was the first to pick the signals up. Granted it has been dropped and picked back up many times. So for that alone my hat is raised.

 

It has four runs a day and forecasts out to T384.....would be fairly useless if it wasn't the first to pick the signals up?

[Captain Shortwave]

Slightly off the topic of the week 2 trends, here is another one of those cold pools which decides to just plague our weather.

Note the shortwave over Scandinavia

Now lets follow its progress of irritation (it brings low cloud and drizzle in from the east).

Monday

Over the UK

Tuesday

West of Scotland

 

Wednesday

Eastern Scotland

 

Thursday

Eastern England

 

Friday

Over South east England, now as a distinct area of low pressure. 

 

Not only does this bring cloudier conditions for many, but also facilitates a quicker breakdown than was currently predicted a day or so back.

 

This cold pool's journey does not mean fun for the UK unfortunately.

 

Moving on......

Edited April 18, 2015 by Captain shortwave

[Polar Maritime]

It has four runs a day and forecasts out to T384.....would be fairly useless if it wasn't the first to pick the signals up?

 

Take a read of Johns excellent post, As this is not normally the case.

 

J/H

 

Well both GFS and ECMWF show something not too different from the 240h chart of a couple of days ago, so maybe not a direct northerly blast but a colder shot being shown by both around 192h. This now being supported by the NOAA 6-10 last evening. If this turns out close to the mark it will be, I think, the 2nd time since last autumn that one of the synoptic models has led the way to a marked pattern change. Highly unusual that. Of course it may not happen but it is now about a 40% compared to less than 10% 48 hours ago.

Edited April 18, 2015 by Polar Maritime

[Frosty.]

I think support is growing for a colder/unsettled shot from the nw/n beyond T+168 hours, as shown on the Ecm 00z. Looking at the week ahead, it will be largely settled with the best of the sunshine and highest temperatures in the west but we should all see sunshine at times and feeling pleasantly warm in the sun but where skies clear at night, a touch of frost is likely.

Edited April 18, 2015 by Frosty.

[johnholmes]

 

I will remind readers that GFS has not led in any verification Stats since I started putting them within my reports three months ago so any credit towards them over ECM is ill founded I'm afraid.

 

 

It has had one previous success, not good on memory but if I could find time it would show in the huge data files I keep for every day for the 500mb anomaly charts. Somewhere in this past winter GFS did beat these charts, and other models, in predicting a marked change in upper air pattern. So whilst I agree with your comments in the main Gibby there are exceptions, this MIGHT be another one along with ECMWF synoptic outputs. We have to wait 8-9 days to see if they each had the 240h prediction 2 days ago correct.

[knocker]

If it's of any interest the ECM parallel and ops run for 12Z yesterday

 

ops

 

At T192 the 500mb anomaly has a small low Biscay with ridge Germany curving over the UK and with a depression mid Atlantic. This evolves by T240 to LP just north of Scotland with trough SWS over Ireland and SW flow of the UK as the HP is nudged SE. And a ridge mid Atlantic.

 

Par.

 

At T192 small low SE France and ridge over UK  By T240 low just SW of Cornwall and lows lining up eastern seaboard to Greenland ready to sweep SE.

Edited April 18, 2015 by knocker

[Eugene]

ECMWF shows a Northerly flow after flopping the idea last night. Yes agree there Knock, Where this will lead to is still unknown as you say. Will it be a pattern change, Or just a blip... A very interesting period for model watching. Hats off to the GFS 

 

 

 

 

Hopefully a pattern change, we really need the rain now especially the southeast, followed by a dry cold northerly which wouldn't be too bad.

[Frosty.]

The Gfs 6z shows a good week coming up with high pressure in control, temperatures slowly recover, becoming pleasantly warm, especially during the second half of next week, the weather turns more unsettled by Friday but temperatures stay respectable in the south of the UK, rather cooler further north. The further outlook shows changeable weather with some dry, warm and sunny weather but with showers and longer spells of rain too, especially in the north, coolest in the north with the south having temps around average but sometimes warmer.

Edited April 18, 2015 by Frosty.

[Frosty.]

The GEFS 06z mean shows a trend to more generally unsettled weather from the end of next week onwards but at no stage indicates anything particularly cold. The second half of next week will bring above average temperatures and good sunny spells but from Friday it turns more unsettled, once the unsettled spell kicks in, temps are likely to slip back to nearer average but it would still be pleasantly warm in the dry and fine intervals between bouts of wet and windy weather, the south is likely to have the best of the fine weather and temperatures within the generally unsettled pattern which is normal.

Edited April 18, 2015 by Frosty.

[Frosty.]

The Gfs 12z is a colder run through week 2 compared to 6z with mainly NWly winds (Pm airmass) and some wintry ppn, at least for northern hills and a higher risk of night frosts. In the meantime, although tomorrow will be much cooler and cloudier in the east with scattered showers, the trend next week is for warmer and sunnier conditions, especially the 2nd half of next week which shows a spell of very pleasant weather before a gradual change to unsettled conditions, lol it's so quiet in here I'm probably just talking to myself...

Edited April 18, 2015 by Frosty.

[Winter Cold]

Evening all

 

Well the 24th now counting down like clockwork in the models, its good to see the interesting charts making their way forward. Looks like we'll get some weather by the end of next week:

 

ECM, GFS and now UKMO also in range:

 

     

 

 

The unsettled theme is then maintained on both the ECM and GFS right to the end of their respective runs:

 

                                       

 

Also they both show a strong PM blast towards the 28th so feeling chilly in the NW winds and showers if it verifies:

 

                    

Edited April 18, 2015 by Winter Cold

[Frank Trough]

Could not agree more there John, Very interesting synoptic's indeed.

 

the reason there is less interest is because it potentially delivers weather which doesn't benefit anybody. Like it or not, that's a fact.  Cold and wet? no thanks.

 

I think the outlook looks fairly horrifying - setting up for a very cold, wet (relatively - it won't actually be "cold" IMBY) spell which could extend and deliver the usual appalling May. Nothing to cheer.

 

The only twinkle of light i can think of is that if it was January it wouldn't verify because a shortwave would appear at t+84 which scuppers the whole thing. Any "cold" is still in FI for the south so it will change but to be honest i'm resigned to an extended unsettled and poor spell, however long it lasts.

 

It actually reminds me a bit of the end of march 2012 where high pressure retrogressed and then basically destroyed the rest of the summer.

[damianslaw]

In the near term, after a temporary cooler cloudier damp blip tomorrow, its more of the same, with plenty of dry sunny pleasantly mild weather for all early next week, the SE and E will also loose the current chilly NE breeze. Nothing overly warm but decent all the same.

 

All models agree on a change come mid week - classic retrogression of the high out towards Greenland pulling down a much cooler feed from the NW with associated low pressure/trough features which will bring a significant change compared to what much of April has delivered, but nothing out of the ordinary, these kind of synoptical evolutions favour April/May much more than any other time of year.

 

So make the most of early next week after what will have been a fairly lengthy spell of benign very dry quiet weather, this time next week likely to be chilly windy and wet...

[Frank Trough]

In the near term, after a temporary cooler cloudier damp blip tomorrow, its more of the same, with plenty of dry sunny pleasantly mild weather for all early next week, the SE and E will also loose the current chilly NE breeze. Nothing overly warm but decent all the same.

 

All models agree on a change come mid week - classic retrogression of the high out towards Greenland pulling down a much cooler feed from the NW with associated low pressure/trough features which will bring a significant change compared to what much of April has delivered, but nothing out of the ordinary, these kind of synoptical evolutions favour April/May much more than any other time of year.

 

So make the most of early next week after what will have been a fairly lengthy spell of benign very dry quiet weather, this time next week likely to be chilly windy and wet...

 

...in the north, possibly in the south. The METO still the the Atlantic trough playing a bigger part.