Model Output discussion 1st September 00z------->

[I remember Atlantic 252]

The Gfs 6z shows a blocked pattern with high pressure becoming centred to the NE or N of the uk dominating low res, with no atlantic threat but low pressure to the south occasionally edging north creating stronger Ely winds across the south for a time but generally lighter further north. In the meantime, this weekend looks fine with a ridge of high pressure but next week becomes more unsettled from the northwest with showers and longer spells of rain but the longer term signal is for increasingly settled conditions to become established through late sept / early oct with pleasantly warm sunshine but with chilly nights and a risk of mist and fog.

 

Hopefully Frosty a repeat of 2011, where we had a warm end to Sept/ start of 0ct, not a fan of heat but ideal in late Sept when it's too late to feel 'too' hot

[Frosty.]

Hopefully Frosty a repeat of 2011, where we had a warm end to Sept/ start of 0ct, not a fan of heat but ideal in late Sept when it's too late to feel 'too' hot

Yes I agree and looking at the latest GEFS 6z mean, its looking very blocked /  pleasant during late sept / early october...nationwide.

Edited September 19, 2015 by Frosty.

[Zenarcher]

Plan to try and do this daily and compare the GFS, ECM, UKMO, JMA, ICON, GEM, NAVGEM, NASA, CMA, FIM and the CFS all up to 240 hours along with the ECM and GFS ensembles. For each day whatever model has the most support will be shown for that time.

 

24 Hours Sunday (ECM)

 

High pressure sits over the UK while a low pressure system to the West of Iceland begins to push away the high pressure.

 

48 Hours Monday (NAVGEM)

 

High pressure moves away from the UK while the low over Iceland begins to weaken.

 

72 Hours Tuesday (JMA)

 

The low pressure from Iceland now sits over the UK.

 

96 Hours Wednesday (GFS)

 

Low pressure still sits over the UK while another low forms to the West of Iceland.

 

120 Hours Thursday (ECM)

 

The low off from Iceland begins to move down to the North West of Scotland as it slowly weakens.

 

144 Hours Friday (ECM)

 

Low pressure sits over the Northern half of the UK while high pressure starts moving in from the South West.

 

168 Hours Saturday (FIM)

 

A large low pressure system forms to the South East of Greenland while high pressure moves in from the South East and covers most of the UK.

 

192 Hours Sunday (ECM)

 

The high pressure over the UK gains more strength as does the low out near Greenland.

 

216 Hours Monday (CFS)

 

The trend at this range shows high pressure sticking to the North East.

 

240 Hours Tuesday (CFS)

 

The high pressure trend to the North East continues and has good support at the moment.

[Frosty.]

The Gfs 12z shows a change to unsettled weather for most of next week with lows sliding southeast across the uk but from the end of next week pressure rises across the uk and next weekend becomes fine and pleasantly warm for many areas, especially the south and east. Looking further ahead, high pressure becomes dominant to the E / NE of the BI with a good deal of pleasantly warm and sunny weather but with chilly nights and a risk of overnight mist and fog where skies clear and winds fall light but there could be too much breeze at times for that to become a major problem, low res is blocked and anticyclonic but subtle shifts in the high's position mean some days are warmer and sunnier than others but overall for those who prefer quiet autumnal weather, this run should, for the most part, satisfy.

Edited September 19, 2015 by Frosty.

[Newberryone]

Hopefully Frosty a repeat of 2011, where we had a warm end to Sept/ start of 0ct, not a fan of heat but ideal in late Sept when it's too late to feel 'too' hot

 

Yes I agree and looking at the latest GEFS 6z mean, its looking very blocked /  pleasant during late sept / early october...nationwide.

Guys, be ultra careful with regards to what you wish for. We don't want this autumn to be too reminiscent of 2011, for what I remember turned out to be a cold lovers nightmare as we were constantly plagued by the wretched Azores high throughout the season resulting in temps being well above average. Christmas Day alone being a typical example. 

[Frosty.]

Guys, be ultra careful with regards to what you wish for.

It's not really a case of what we wish for, it's just what the models are showing but having said that, I'm sure many on here won't mind a decent spell of quiet and pleasantly warm weather during late Sept / early October. I don't think it will have any bearing on what follows this winter.

[ANYWEATHER]

The tropical storms or ex tropical storms are really making a mockery of computer model output, as always! Just look at the ten day ops from ecm and gfs, that will give you some idea of what I'm talking about. Tomorrow's models will show something different at this time frame.

[bluearmy]

Just to note that the gem view of day 10 has support from the ECM spread at that timeframe.

[knocker]

Although tonight's anomalies disagree on the configuration of the HP at day ten the ecm does adjust it's position in the ext period so HP remains the dominate theme.

http://www.tropicaltidbits.com/

 

[Scorcher]

The GFS 18z run gives us a brief burst of summer at the end of September. It would be a little flashback to late September/early October 2011!

 

27Sep.png 28Sep.png 29Sep.png 30Sep.png 1Oct.png

 

Yes it's come more into line with the ECM with the high pressure more favourably placed for higher temperatures- a very promising development but it is still in FI. Support appears to be growing though. Nights would not be particularly cool with that setup either and temperatures considerably above average by day.

[knocker]

The GEFS (P) 18z anomaly is still looking good to go with some quite warm weather possible.

Charts courtesy weatherbell

 

[Polar Maritime]

This mornings GFS towards the end of the Month shows the Low move in off the Atlantic, Effecting the North with the South remaining more settled, It will be interesting as to where the actual track of the Low will end up over the coming days of modelling. Certainly some scope for more settled conditions after the Low has moved through with these synoptic's especially so for the South, But looks to be short lived as another Low waits to swing in over the UK from the West.. All to be resolved.  

Edited September 20, 2015 by Polar Maritime

[Scorcher]

 

Another excellent run this morning in the latter stages from the ECM op. The high pressure build is now coming into the reliable timeframe as well. Could be some very high temperatures for the time of year if this latest run comes off.

Edited September 20, 2015 by Scorcher

[Scorcher]

 

UKMO now also showing the pressure build for next weekend- could be great timing yet again if the Euros are correct with the high moving in on Saturday.

[knocker]

Nobody seems to have posted the NOAA take recently. I know you are keeping a beady eye John. They do appear to be supporting the build up of HP, okay not extensive ridging, and the relegation of the dreaded trough, As always the key will be in the detail

Edited September 20, 2015 by knocker

[mushymanrob]

Nobody seems to have posted the NOAA take recently. I know you are keeping a beady eye John. They do appear to be supporting the build up of HP, okay not extensive ridging, and the relegation of the dreaded trough, As always the key will be in the detail

 

tbh theyve changed abit, so lack consistency but broadly suggest a swing towards high pressure domination?

that supports the current ops rather nice pressure build to our south, which if became reality would produce some very nice dry warm conditions but without so much horrid dew.

[johnholmes]

Nobody seems to have posted the NOAA take recently. I know you are keeping a beady eye John. They do appear to be supporting the build up of HP, okay not extensive ridging, and the relegation of the dreaded trough, As always the key will be in the detail

Indeed I am, the ECMWF-GFS version is less consistent than NOAA. As you post its versions do suggest that the upper trough may have less influence for a time. No sign of major heat, major surface lows or any early northerly so far. The unknown will continue to be if any tropical storm features get into the Atlantic. If they do then all models can be forgotten until that system has been and gone so to speak.

below is the link to the NOAA prediction centre. It is usually fairly accurate on the position and movement of any centres.

http://www.nhc.noaa.gov/graphics_at5.shtml?5-daynl#contents

Edited September 20, 2015 by johnholmes

[Captain Shortwave]

Day 6 charts

 

GFS

 

UKMO

 

ECM

 

GEM

 

All models show high pressure trying to build north eastwards from the Azores. At this time frame there are varying degrees of success, the Euros look pretty bullish about getting the high in around the UK locale. The GFS has this a little further south and the GEM is further south still and in fact keeps things unsettled in the north with only the south benefiting somewhat. That said the models overall favour another fine and pleasant weekend. Beyond this we see a tropical system west of the Azores trying to interact with a deepening Atlantic trough seen below.

There is pretty good agreement on that system being there, so it could come into play over the next few days model output wise. Certainly potential for some very warm conditions to develop if the high places itself in a favourable location.

ECM looks decent

 

GFS ens look good too

 

We will have to wait and see, but this set up seems to hold more promise with a bit more solid support compared to the weekend we are experiencing now which always looked like a two day wonder.

[Gibby]

HERE IS MY LATEST ANALYSIS USING DATA SUPPLIED BY

THE NWP OUTPUT COVERING 5 OF THE WORLDS MOST

POWERFUL WEATHER COMPUTERS ISSUED AT 09:00 ON

SUNDAY SEP 20TH 2015

THE CURRENT GENERAL SITUATION.  A ridge of High pressure will move away SE away from the UK later today as a Low pressure trough moves East across the UK later tonight and tomorrow followed by a showery Westerly flow.

GFS Current Time

MODELS-2 WEEK HEADLINE  Becoming less unsettled next week with longer drier spells with most rainfall likely in the form of scattered showers.

THE GFS JET STREAM FORECAST  The GFS Jet Stream Forecast shows the flow troughing back down over the UK over the next day or so where it blows in a trough like fashion around the UK for much of the working week. It then migrates back to a more Northerly latitude across Northern Britain where it remains quite strong for a while blowing West to East before becoming much more broken and ill defined later in the second week.

GFS Jet Stream Forecast 

GFS OPERATIONAL The GFS Operational Run today shows Low pressure in control over the working days of this week as one centre drifts SE down the North Sea over the early days of the week and then another crosses East to the North of Scotland soon after midweek with rain and showers for all of the UK at times. By next weekend a SE/NW split in the weather develops as High pressure over Europe spreads dry and mild conditions across the South and East while the North and West continue to see some rain at times. This pattern sticks around for a while before High pressure moves East over Europe and more unsettled weather arrives from the SW later with more unsettled conditions for all to end the period.

GFS +144hrs

GFS +384hrs

THE GFS CONTROL  The theme of the GFS Control Run this morning is very similar to the operational through much of the period though the methodology of returning unsettled weather across the UK in Week 2 is via an ex tropical storm which could bring some temporarily heavy rainfall across the South as it moves it's way East across England and Wales towards the end of the period.

THE GFS CLUSTERS(14 Days) The GFS Clusters this morning still show a lot of variation between members on the conditions likely to lie across the UK in 14 days time with the confusion remaining on how and what influence High pressure from the Azores affects the UK at that time with a slight bias towards drier conditions towards the South and East while more unsettled conditions are more likely towards the North.

GFS 15 Day Clusters

UKMO UKMO today shows Low pressure slipping SE across the UK at the start of this week and then a re-run as a new Low passes east to the North of Scotland with a week of rain and showers at times with a drier period over Wednesday. Then a NW/SE split develops in time for next weekend with the South and East becoming dry and fine under a ridge while the North and NW see cloudier and breezier conditions under SW winds and some rain at times. 

UKMO +144hrs

THE FAX CHARTS  The Fax Charts this morning show a changeable week with rain at times as Low pressure and troughs continue to move east across the UK from the West right up to next weekend.

UKMO Fax Charts +120hrs

GEM  GEM too shows an unsettled week under West or NW winds with rain and showers at times before a more SE/NW split develops next weekend as pressure rises over Europe and sets up a SW flow across the UK with rain at times restricted mostly to the North and West for a time before moving SE to other areas late in the period.

GEM +240hrs

NAVGEM NAVGEM follows a similar track with unsettled and changeable conditions for all this side of next weekend under west or NW winds and rather cool feeling too at times. Then over next weekend a NW/SE split develops on this run too with a dry and warmer phase next weekend over the South and East before the more unsettled conditions further to the NW spread back east across the UK under a trough a week or so from now.

 

NAVGEM +168hrs

ECM ECM this morning is looking good with the same theme of changeable conditions this week giving way to an improvement first in the South extending to all but Northern Scotland later in the period with fine and quiet Autumnal weather with fine and potentially warm days mixed with cool and foggy nights. Only the far North of Scotland look like seeing any rain by the runs end as High pressure at day 10 extends from Germany across all of England and Wales. 

 

ECM +240hrs

ECM 10 DAY MEAN  The ECM 10 Day Mean Chart  from last night too shows High pressure well in control of the weather across much of the South and SE  with any rain bearing fronts restricted to the far North and NW.

 

ECM 10 DAY MEAN CHART

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The models have firmed up somewhat towards a NW/SE split likely to develop in the weather following another changeable and often cool week for many.

31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKMO & ECM

The Verification Statistics of GFS, UKMO and ECM show at 24 hours ECM ties with UKMO at 99.4 pts each with GFS coming in third at 99.2 pts.  At 3 days ECM leads at 96.6 pts with UKMO  at 96.4 pts while GFS lags behind at 95.6 pts. At 5 days ECM ties with UKMO at 86.5 pts  each then GFS at 84.0 pts. Then at 8 Days ECM still leads at 58.0 pts over GFS's 50.7 pts. Finally at Day 10 ECM leads GFS at 37.0 pts to 33.4 pts from GFS.

 1 DAY VERIFICATION STATS 

3 DAY VERIFICATION STATS 

 5 DAY VERIFICATION STATS

8 DAY VERIFICATION STATS

10 DAY VERIFICATION STATS
 

 MY THOUGHTS   With this weekend's ridge slipping away SE from the UK over the next 24 hours we are looking at another period of West or NW winds delivering cloud and rain or showers to much of the UK again this week. It will often feel cool in the blustery West winds but in between the rain there will be a fair amount of dry weather too especially in the South on Wednesday. Then things start to look more straightforward from the start of next week as it's looking more and more likely that we will be looking at a NW/SE split in the weather for a while at least with High pressure building close to SE Britain and warding off any influence from the Atlantic towards the far North and NW. It's then a matter of how long this pattern remains before the Atlantic forces back and this remains unclear this morning with some output indicating that some progress towards this outcome will occur quite quickly while others keep any inroads on a much slower timescale. ECM offers the best scenario again this morning and this is backed up quite nicely with it's recent ensemble data with High pressure becoming a dominant player in the UK weather for quite a while, extending fine and settled weather to all but Northern Scotland for some considerable while. While there is growing confidence towards a quiet spell of weather for much of the UK from next weekend with warm and sunny days in the South mist and fog will be an issue by night and morning as well as chilly nights and the North may take a long while to join in these conditions if at all. We also have to be mindful of a lot of tropical air and depressions floating about in the Western Atlantic at times and the movement and track of these as they enter the Jet stream could have ramifications on the synoptic patterns over NW Europe so while in themselves they don't look like affecting the UK much if at all going by this morning's output they could change a pattern quite quickly if they don't behave as predicted and we will have to watch for that at least. Nevertheless, having said that there is nothing alarmist in weather terms over the UK in the next few weeks with just some rain at times this week and the possibility of a lot of benign and anticyclonic style Autumn weather for many next week, at least for a while. 

WORST CHART OF THE DAY 00z RUN

GFS CONTROL RUN +324HRS

The accolade for the worst chart of the day goes to the GFS Control Run at T+324hrs this morning as it highlights what can happen to ex tropical storms as they engage the Atlantic Jet stream as on this example it brings the remains of it across the heart of England and Wales in the following 24 hours with extra heavy rainfall and wind as a result of the warm moist air contained within it.

BEST CHART OF THE DAY  00z RUN

ECM +216HRS

For the best chart I have gone for the Day 9 chart from ECM which shows a large and blocking anticyclone across and just to the east of the UK bringing warm (for the time of year) air across most of the UK with very pleasant weather by day but mist and fog by night. these blocking Highs can be slow to give way so let's hope ECM can continue this theme as we draw nearer the time.

Next update from 09:00 Monday Sep 21st 2015 

 

http://www.norton-radstockweather.co.uk/Model-Analysis(2859336).htm

Edited September 20, 2015 by Polar Maritime
Copied over with Windows 10 in warp speed time, With little time..

[Captain Shortwave]

ECM ens

 

GEM ens

 

Good support for the GFS ens from the ECM suite, the GEM ens like the operational are less keen.

[MR EXTREMES]

ECM ens

GEM ens

Good support for the GFS ens from the ECM suite, the GEM ens like the operational are less keen.

It must be noted that heights don't look like being a sustained feature for the UK more of a fleeting visit.

Few days of warmth then the alantic fronts slowly eroding away and western side tend to keep more cloud with some unsettled weather.

And more especially nw Scotland being more unsettled as has been seen for most of the summer.

Southeast always best with heights close by

Edited September 20, 2015 by emotional rollercoaster

[Scorcher]

It must be noted that heights don't look like being a sustained feature for the UK more of a fleeting visit.

Few days of warmth then the alantic fronts slowly eroding away and western side tend to keep more cloud with some unsettled weather.

 

The building of the high appears to be different to previous spells though, it moves up more from the south as opposed to the west as we've seen most of this summer/early autumn. Certainly if the ECM is correct this morning it could be sustained for a fair period with lows finally going well to the north of the UK. The end of the run produces an incredible chart for the time of year- it's still a very long way off but this would probably rival 2011:

 

 

[Polar Maritime]

The GFS 6z continues to show a NW/SE split towards Months end, With Lows skirting the N/W while the South stays settled with a warm S/SE flow. Into the start of the new Month, And another Low out in the Atlantic try's to move in from the S/W but shows to loose the battle with the block holding on strong to our N/E.

As John mentioned early'er and has been the case over the past few weeks, Due to Tropical Storm features resolving expect further differing evolutions to come over the next day or so re detail on Low pressure tracks over the UK.

Edited September 20, 2015 by Polar Maritime

[knocker]

No TCs in the Atlantic >35 kts since Grace on 9/7. This is the first time this has happened from 9/8-9/19 since 1966

 

Just saying

[snowy weather]

No TCs in the Atlantic >35 kts since Grace on 9/7. This is the first time this has happened from 9/8-9/19 since 1966

 

Just saying

What is TC?