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

[Frosty.]

The Gfs 6z ends on a high note, it would be nice to think we could look forward to an increasingly warm and settled spell from mid may wouldn't it? In the meantime, the BH weekend indicates a warmer feel than currently, low to mid 60's F with sunny spells / showers, the warmer air pushing up from the south behind a band of heavy rain sweeping north across the UK on Saturday night / sunday followed by sunshine and thundery showers. Through next week it could become more settled for a short time but generally it still looks unsettled with sunshine and showers and a risk of heavy / thundery rain but at least temperatures recover from the end of this week onwards and rather warm at times through the outlook.

Edited April 28, 2015 by Frosty.

[johnholmes]

It is of course crucial just where the uuper trough and upper ridge settle down. As the pattern shown by frosty above suggests it 'could' be a more settled and warmer outlook by the dates given on those charts. However, I would be careful at the moment as none of the anomaly charts shows the ridge as close as that. All 3 (the ones I use) show the UK more under the influence of the trough rather than the ridge. Although perhaps the far SE might be more favoured by about 10 days from now. Further ahead with just the NOAA 8-14 for me to use, other than taking a look at other output that goes that far out, and the main idea is perhaps for a more W'ly type of pattern with any ridging or +ve heights too far away to be of much use even in the far SE?

link below

http://www.cpc.noaa.gov/products/predictions/814day/500mb.php

As some of us are prone to write, more outputs needed to be more sure of the 14+ day period.

[mushymanrob]

Now! We all know weather pattern matching doesn't work!!!

 

doesnt it?... it can do but of course isnt a hard fast rule... (the point being that writing off 'pattern matching' is as inaccurate as pattern matching itself... sometimes patterns do follow similar routes, but not always by far.)

however...

historically there does appear to be a correlation between dry/wet. long periods of mainly dry weather do seem to change by giving way to a lengthy wetter period. id suggest a lengthy wetter period is more likely to follow a lengthy dry one, then a period of 'less dry' weather.  so im not so much saying spring 07/08 were warm and dry therefore summer 15 will be wet, as much as 'after a lengthy dry spell its likely to be followed by a lengthy wet one'. this would apply to any time of the year of course.

the anomaly charts are now suggesting a southwesterly upper flow, so maybe the outlook isnt going to be as dry as the period we have just enjoyed.

 

edit... by 'wetter weather' i mean reasonably wetter then the seasonal norm, not just an end to dry.

Edited April 28, 2015 by mushymanrob

[Summer Sun]

ECM anomaly charts showing a drier settled spell developing from around May 11th, temps back down to around average after a warm wet start

 

 

Charts WSI euro weather

Edited April 28, 2015 by Summer Sun

[knocker]

It is of course crucial just where the uuper trough and upper ridge settle down. As the pattern shown by frosty above suggests it 'could' be a more settled and warmer outlook by the dates given on those charts. However, I would be careful at the moment as none of the anomaly charts shows the ridge as close as that. All 3 (the ones I use) show the UK more under the influence of the trough rather than the ridge. Although perhaps the far SE might be more favoured by about 10 days from now. Further ahead with just the NOAA 8-14 for me to use, other than taking a look at other output that goes that far out, and the main idea is perhaps for a more W'ly type of pattern with any ridging or +ve heights too far away to be of much use even in the far SE?

link below

http://www.cpc.noaa.gov/products/predictions/814day/500mb.php

As some of us are prone to write, more outputs needed to be more sure of the 14+ day period.

 

Wouldn't disagree John but just to say the EC32 is certainly looking at no influence from the trough around that date and the ext 00z ECM anomaly (perhaps not surprisingly) supports this but I agree a few more runs under the belt needed to firm up on this evolution but I'm hopeful.

[Frosty.]

The GEFS 6z mean suggests there is good support for warmer weather, at least for the south in the extended outlook period (T+240 range) I still think we will see a change from the current chilly below average temperatures to pleasantly warm conditions through the BH weekend despite being unsettled, there should be sunny spells too. A band of rain is expected to push north with warmer air following in behind with sunshine and heavy showers from the south, chance of temps into the high teens celsius sun / mon.

[Frosty.]

The Gfs 12z shows very warm weather in the south later next week and mid may looks more settled and generally warmer with high pressure building in...Looking good.

[Frosty.]

Taking a closer look at the BH weekend on the Gfs 12z, Saturday starts fine and cold with a widespread frost away from the south but after a sunny start, clouds thicken and SEly winds strengthen and persistent rain spreads north and east, however, it stays fine for a while further east and north, winds increase to Gale force in the northwest of the UK. The rain clears north on Saturday night with Sunday looking brighter with sunny spells but heavy and thundery showers developing, becoming pleasantly warm in the south and east. BH Monday looks a drier day for the south and east with fewer showers and longer sunny spells with temps around 60F, most of the unsettled weather across the northwest. Another few unsettled days with cooler Atlantic air but later next week becomes drier, brighter and warmer in the south, staying cooler and unsettled in the north, then signs of high pressure becoming more dominant through mid may.

[Milhouse]

Forget cold being seasonal for this time of year, the outlook for the BH weekend looks more like the time of year. Its been quite a dry spring so a more changeable period wont do us any harm. Bands of rain passing through but some decent drier slots too and in the sunny periods it should raise temperatures into the mid teens. And beyond the weekend signs still there for pressure to rise from the SE. A bit of an improvement over some runs of late.

[Summer Sun]

Pressure rising slowly from the south towards the end of next week on tonights ECM something GFS has hinted at on and off for a few days now

 

 

Still only hints at this stage and with the low still near by it could quite easily turn unsettled with the high not making in-rodes

[damianslaw]

Reliable timeframe - generally unsettled with cool conditions in the north prevailing, nearer average temps in the south over the weekend but a wet start, rain edging northwards and becoming slow moving, could be a very disappointing bank holiday weekend for the northern half of the country.

 

Next week - a slow stubborn trough anchoring itself over the country, there are hints of pressure rises to the SE longer term as the trough dissipates to the NE, but far too long away to call with any certainty just how things will develop.

[Milhouse]

The ECM mean points towards an increasingly warm and changeable week next week with the best of the warm and dry conditions across the SE.

 

[knocker]

The GFS this morning is still looking at an area of rain running NE Saturday evening/Sunday morning. After that it's best left for another day.

[Frosty.]

The Gfs 00z shows a delay to the weekend rain with Saturday largely fine with sunny spells after a frosty start, rain and stronger winds then sweep up across the UK sat night / sun morning, some of it heavy but then becoming brighter and showery with a risk of thunder, turning pleasantly warm in the south during Sunday, BH Monday looks unsettled but with sunny spells and pleasantly warm, around 16/18c.

Next week looks unsettled but at least temperatures become higher, at least across southern UK, no polar chill next week, more of a tropical maritime influence. High pressure builds in just before mid may and works hard to bring a more settled spell to many areas.

Edited April 29, 2015 by Frosty.

[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 WEDNESDAY APRIL 29TH 2015.

 

THE CURRENT GENERAL SITUATION A cold front will clear SE England this afternoon with a Low pressure area over Scotland drifting East into the North Sea tomorrow.

 

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

 

MODELS-2 WEEK HEADLINE Unsettled  and changeable with bright spells and showers or rain, heavy and wintry on hills in the North at first. Becoming less cold and possibly drier later especially towards the South and East.

 

THE GFS JET STREAM ENSEMBLE FORECAST The Jet Stream is focused to blow on a much more Southerly track especially over the Atlantic and while well South of Britain too for a time it shows signs of moving North across Britain later as pressure rises over Europe.

 

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

 

GFS OPERATIONAL The GFS Operational this morning shows a very changeable period over the coming two weeks. The cold feeling weather at present will move away North behind a front moving North across the weekend and then the UK settles into a changeable pattern with all areas seeing at least a little rain at times under various mostly shallow Low pressure areas crossing the UK. The focus of most of it moving towards the North and West nearest to lowest pressure at times with some longer drier spells become established especially in Week 2 across more Southern and Eastern areas closest to higher pressure as it moves in at times.

 

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

 

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

 

THE GFS CONTROL The GFS Control run is very different in general terms as it makes much more of an unsettled first week with rain and strong winds at times as a deep Low positions just North of the UK while week 2 shows High pressure establishing across the UK with fine and dry weather for many. While it will feel cool in Week 1 under wind and rain Week 2 should be warmer with more in the way of sunshine.

 

THE GFS CLUSTERS The GFS Clusters today show a lot of High pressure influence across the UK in two weeks time but the positioning of such being very unclear with the main focus of it being across the UK in the shape of a ridge from the SW, West or NE.

 

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 this morning shows the main message of the weather becoming rather warmer next week under a SW flow. Low pressure to the NW will ensure some rain falls at times for many with the North and West seeing the most but the South and East not entirely immune too.

 

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

 

THE FAX CHARTS The Fax Charts show a battleground scenario developing from the start of the weekend as a cool ridge establishing from the North over the coming days only slowly gives ground to milder SW winds behind a series of occluded fronts edging very slowly North across the UK over the holiday weekend.

 

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

 

GEM GEM this morning shows quite changeable conditions across the UK over the coming 10 days. After a chilly start to the period Low pressure troughs and Low pressure itself moves North across the UK and introduces milder air which then persists through next week fuelled by a deep Low in the Atlantic for a time with Southerly winds.

 

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

 

NAVGEM NAVGEM shows troughs to the SW moving slowly North at the weekend though it is shown to need several attempts before succeeding towards the end of the weekend leaving next week with rain at times associated with Low pressure drifting North to the West and slowly introducing less cold air on a SW flow to England and Wales at least later.

 

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

 

ECM ECM this morning also shows unsettled weather through next week as Low pressure remains influential to the West of the UK. It should slowly become less cool especially in the South and there are signs of High pressure building across the UK towards the end of the run pushing the unsettled weather away to the NW by next weekend.

 

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

 

ECM 10 DAY MEAN(12z) The ECM 10 Day Mean Chart  from last night shows the Jet Stream likely to be back to the NW of the UK allowing higher pressure to the SE to restrict more unsettled weather towards the North and West of the UK with slow improvements to the South and East with generally less cool weather.

 

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

 

NOTABLE TREND CHANGES FROM PREVIOUS RUNS There is very little trend shown this morning between output with all models showing their own interpretation of fairly benign synoptics towards the end of the period.

 

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 97.4 pts followed by UKM at 96.8 pts and GFS at 96.1. At 5 days ECM  leads UKMO with 88.4 over UKMO's 88.0 pts with GFS at 85.4. At 8 days ECM remains the leader with 61.6 pts over GFS's 58.9 pts. Then at Day 10 ECM retains superiority at 45.1 pts over GFS at 43.5. 

 

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 In the longer term this morning there appears to be no clear signals with a variety of options and synoptics on offer across the UK in the 10-14 days time block. In the short term although rather clearer signals are shown the devil will be in the detail and timing as the current cool and showery theme gives way to a ridge from the North on Friday. At the same time Low pressure down to the SW will be attemping to push occluded troughs North across the UK and introduce milder SW winds behind. It's progress looks slow and erratic and it may be early next week before the front reaches Northern Scotland. By that time the milder SW winds will have reached most other areas but with Low pressure likely to lie either to the West or NW further rain and showers at times look likely though SE areas may become rather drier late next week as pressure rises over Europe, a part of the theme that shapes the latter frames of the output runs this morning. The one common theme looks to be the rise of pressure across the UK most pronounced within the GFS Control run while the operational and clusters show improvements more marginal and then GEM and ECM showing their own versions of this theme at Day 10. So with no definitive clear decision of where High pressure will likely lie it makes it hard to pin down any detail on what type of better weather such a High might bring and where. However there is plenty of time for the models to sort that dilemma out and in the meantime we'll concentrate on the changeable pattern of the next week where most places will see some rain at times and things should slowly warm up too but it might take some while for warmer air to reach the far North and NE. 

 

Next update from 08:00 Thursday April 30th 2015

[Summer Sun]

Hints again from ECM that towards the end of next week things could settle down with only the extreme north west potentially prone to some rain / showers

 

 

Day 10 ens from ECM supporting a rise in pressure

 

Edited April 29, 2015 by Summer Sun

[knocker]

The anomalies this morning would seem to indicate that the pattern change around the 9th is still on course although some  discrepancies remain at day ten.

The ECM is more emphatic at moving the Atlantic trough west and building the ridge over the the UK whereas the GFS is going for a more general build up of heights. Having said that in the ext period both consolidate the ridging over the UK so things looking quite good.

Charts courtesy weatherbell

Edited April 29, 2015 by knocker

[Frosty.]

The Gfs 6z shows a risk of heavy showers and thunderstorms developing tomorrow, especially across England and pleasant sunny spells in between.

[Frosty.]

Looking closer at the BH weekend on the Gfs 06z op run. Saturday starts clear and frosty, coldest further north but Saturday looks a fine day with plenty of sunshine although probably becoming hazy during the day as high cloud increases ahead of the rain later, rain, some of it heavy and strengthening winds push north and east to all areas on Sat night / sun morning, Scotland looks cold and wet on Sunday but warmer air spreading north across England and Wales with sunny spells before heavy and thundery showers develop. BH Monday looks largely fine with pleasantly warm sunny spells across the southern half of the UK. Looking further ahead, some unsettled / settled spells and temperatures look better with some very warm days towards mid may.

[mushymanrob]

noaa looking decent ...

looking like a mean upper trough to our west will retrogress and pressure rises to our near continent when comparing both charts

 

a warm enough, unsettled but not overly wet away from the northwest in a southwesterly upper flow.

pretty decent weather

[Frosty.]

At last, the first mention from the met office that towards the middle of the month there is a chance of somewhat drier and warmer conditions developing at times, especially across the southeast. The Gfs in particular has been showing this for a few days now and it's good to see the experts mention it for the first time.

[Milhouse]

The GEFS 6z mean shows a strong chance of high pressure to be over or near the UK at day 10.

 

[East_England_Stormchaser91]

At last, summery charts showing their hand and the jet ever more likely to be on it's way to where it should be.

Always a good sign when the blues on the 500hpa charts are becoming locked in over Greenland and the pole and oranges and reds appearing to the south

[knocker]

At last, the first mention from the met office that towards the middle of the month there is a chance of somewhat drier and warmer conditions developing at times, especially across the southeast. The Gfs in particular has been showing this for a few days now and it's good to see the experts mention it for the first time.

 

The EC32 has been pushing this for a while.

[Captain Shortwave]

The UKMO turning things drier and warmer as we head into next week.

The eastern half of the UK could eek out a decent if brief southerly from this. Trouble is the uncertainty on the placement and orientation of the trough.

 

The GFS keeps things pretty unsettled with the trough closer to the UK. Though the south east does potentially catch some thundery rain from the continent.

The GFS in particular does't seem to be sure how the Atlantic profile will sit considering it has had Atlantic heights over the past few runs, ditched this time.

Typically low resolution produces potential 30C charts

Edited April 29, 2015 by Captain shortwave