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

[johnholmes]

Interesting differences today in the anomaly suggestions for the 6-10 day outlook from yesterday, today from NOAA also similar. That is the worst of any cold looks to finish in the 5-9 day time scale. Not so on the EC-GFS version, although they are not consistent in this or with each other. Overall they show the colder north of west flow at 500mb continues with a fairly marked trough over and just east of the UK.

I wonder which suite will be nearer the mark come the first 2-3 days in May?

The cold pattern change about to start was predicted by the synoptic models first, that is before the anomaly charts which is quite unusual. So interesting model watching for a week or so to come.

[summer blizzard]

Let it pour..

 

[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 25TH 2015.

 

THE CURRENT GENERAL SITUATION A trough of Low pressure will move South across the UK slowly today and tomorrow followed by a cold and unstable NNW flow

 

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

 

MODELS-2 WEEK HEADLINE Becoming unsettled  and changeable with bright spells and showers, heavy and wintry on hills in the North for a time. Local night frosts still possible.

 

THE GFS JET STREAM ENSEMBLE FORECAST TheSouthern arm of the Jet is strongest at the moment lying near Spain . This extends North to lie across Southern parts of the UK for much of the period undulating North and South at times in association with a Low pressure trough near the UK.

 

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

 

GFS OPERATIONAL The GFS Operational this morning shows Low pressure and cool conditions affecting the UK weather for much of the coming week as a Northerly flow establishes tomorrow. then through the week this slowly backs Westerly and a ridge follows across the UK by next weekend. Through week 2 changeable weather returns with rain and showers borne off the Atlantic maintaining the cool theme with rain or showers at times.

 

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

 

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

 

THE GFS CONTROL The GFS Control run follows a similar pattern to the operational today though it does build High pressure strongly across the UK at the very end of the run with rain and showers dying out then to be replaced by dry and more settled conditions.

 

THE GFS CLUSTERS The GFS clusters today show no clear message this morning with a mix of options offered to lie across the UK in two weeks time, ranging from westerly winds and rain at times from off the Atlantic to dry and fine weather under a ridge over the South or to the West of the UK.

 

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 a showery cool West or NW flow early this week followed by an active depression moving East across the UK Wednesday with rain for all followed by a more showery and still cool NW flow late in the week as the Low slowly moves away East over Europe.

 

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

 

THE FAX CHARTS The theme of the Fax charts this morning is to weaken the Northerly feed of cold air quite quickly in the first half of next week with an active Low pregrammed to move in from the West or SW on Wednesday

 

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

 

GEM GEM this morning shows quite a changeable pattern through the next 10 days as the cold NW flow early in the week is replaced by Low pressure around midweek with rain for all and a ridge at the weekend with a dry and fine interlude for most. the pattern still looks changeable and unsettled with further rain towards the West and SW at the end of the period.

 

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

 

NAVGEM NAVGEM shows changeable and showery conditions for the most part but with a more sustained period of rain midweek as a Low moves East. Then a large Low pressure over the Eastern Atlantic drives cloud and rain North and East across the UK at the end of the period.

 

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

 

ECM ECM this morning shows an unstable outlook with Low pressure never far from the British Isles over the next 10 days. Showers or rain at times remains the focus of the model with all areas at risk with temperatures no better than average and often rather cool.

 

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

 

ECM 10 DAY MEAN(12z) The ECM 10 Day Mean Chart  from last night shows a Low pressure belt lying across the Atlantic and the UK maintaining the risk of showers or rain at times 10 days from now.

 

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

 

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The trends this morning show a common theme of Low pressure driven weather with centres close to or over the UK.

 

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 97.3 pts followed by UKM at 96.8 pts and GFS at 96.1. At 5 days ECM  ties at 88.4 pts over UKMO also at 88.4 pts and GFS at 86.0. At 8 days ECM remains the leader with 62.4 pts over GFS's 58.4 pts. Then at Day 10 ECM retains superiority at 47.0 pts over GFS at 42.0. 

 

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 High pressure dominated weather of late has gone for the time being and in it's place we look like moving into an unstable flow with rain or showers and some very cool weather for a time especially across the North early next week when some snow showers are possible on the hills and some unwanted night frosts too more widely. Then as we look to the latter end of the week there is strong support for a new Low to move East across the UK giving all areas a period of more prolonged rain together with strong winds and followed by more cool and showery weather late in the week. By next weekend there is some support from some models that pressure may recover for a time with a dry and brighter interlude across the UK as ridge looks as though it may cross the UK from the West but then in the longer outlook models it looks like any rise in pressure will be shortlived as further Low pressure moves into the UK from the West or SW with further rain and showers at times to end the forecast period. While temperatures never look like being particularly warm with a lot of cool air aloft dictating the changeable nature of the weather sunshine between the showers will feel pleasant enough and coupled with the occasional rainfall will aid the growing process. So in a nutshell a changeable spell of weather to come over the two weeks for all areas with some rain and showers and temperatures near or a little below normal but still with the unwelcome risk of occasional night frosts where skies clear and winds fall light. 

 

Next update from 08:00 Sunday April 26th 2015

[johnholmes]

re my past 1136 last night

This morning and ECMWF is more like NOAA 6-10 again but with some fairly small differences. GFS has changed yet again, this time with a fairly marked vortex NE of the UK.

I would bet on the NOAA 6-10 being nearer the mark=a more W'ly flow

 

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

This would still leave the UK in a relatively cold 500mb flow

[Milhouse]

A glance at this mornings ECM 0z mean shows a move away from the very unseasonable cold that we were predicted to get. A northerly flow doesnt really have time to establish at the end of the week before the next low moves in off the Atlantic ushering up slightly milder air.

 

 

The ECM op indicates we could get a brief spell of settled and cool weather at the weekend, but not overly cold due to the very cold uppers not managing to make their way south. Night frosts could still occur though.

 

[knocker]

John to my untutored eye this mornings GEFS looks  very similar to the NOAA 6-10. Obviously the direction of the surface flow over the UK will be governed by the position of the low to the east.

Chart weatherbell

 

EDIT

I see the ECM has the trough slightly more NE and subsequently the Atlantic trough pushed a tad east as well.

Edited April 25, 2015 by knocker

[Iceaxecrampon]

This looks great, becoming very warm through early may on the Gfs 6z, I'm looking forward to hot summer plumes and Azores high's.

 

 

...I hope you are right as the CH has just gone to ON

 

 

 

 

I stopped posting as winter was meant to be over.

 

This is of course not uncommon but definitely unwelcome for wildlife and nature.

 

Ian

[Frosty.]

The Gfs 00z shows almost a repeat of the unseasonably cool weather next week during week 2 as well...ie. very unsettled and rather cold with sunshine and showers, wintry on hills and not just on hills and occasional bouts of persistent rain and strong winds, however, it's not cool or cold all the time with the south having low teens celsius a few times in the week ahead and next weekend becomes warmer with temps into the 60's F so it would feel pleasant, especially in the strong sunshine.

[Frosty.]

Something to look forward to hopefully, the Gfs 12z shows warm weather returning from the south later in low res with temperatures into the 70's F. One of the things I like looking out for from late spring and throughout the summer is the 564 dam line and I'm hoping we will see plenty of it close to the UK in the next 4-5 months.

Edited April 25, 2015 by Frosty.

[damianslaw]

Very quiet in here, despite much more variety in the charts compared to recent weeks - probably a sign no-one likes what is on offer... but we have done very well these past 3 weeks.. I said its a preety tall order for synoptics as we have seen much of this month sustaining themselves beyond 3 weeks.

 

What are the charts showing - a very different picture, sustained cool weather especially in the north, showery airstream, but some decent sunny conditions especially in the south. Notable cold nights in the north, plenty of frost about.

 

Uncertainty regarding bank holiday weekend, but at this range, in a word it doesn't look particularly warm, indeed could be a real chilly one.

[Milhouse]

Regarding the Bank Holiday Weekend. Winds look light on the latest GFS 12z so temperatures in the low teens would feel pleasant in the strong early May sunshine. The very cold uppers being held at bay to the north. Its an improvement on last nights GFS 12z thats for sure which had a northerly gale and rain off the north sea.

 

[summer blizzard]

GFS the outlier with its warmth, Euro and JMA in particular are bad to day 10.

 

[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 SUNDAY APRIL 26TH 2015.

 

THE CURRENT GENERAL SITUATION A cold and unstable NW flow will move down across remaining Southern areas of Britain and continue for the next 24-48hrs.

 

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 for a time. Local night frosts still possible.

 

THE GFS JET STREAM ENSEMBLE FORECAST The Jet Stream is engaging a flow further South than currently generally to a point South of the UK where it remains for much of the next two weeks undulating North and South slightly as troughs affect the UK at times.

 

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

 

GFS OPERATIONAL The GFS Operational this morning shows Low pressure and cool uppers affecting the UK this week. the cold north flow to begin with backs towards the West early in the week with showers at times. Conditions then become more varied after midweek under slacker pressure but still somewhat chilly weather overall. Through Week 2 things are shown to warm up with time as High pressure builds to the South with a milder SW flow and the rain more concentrated towards the North and West

 

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

 

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

 

THE GFS CONTROL The GFS Control run follows a similar pattern through the first week with the cold and showery pattern early on giving way to more settled conditions late in the week as a ridge moves East. It doesn't last long in the West though as further Low pressure from the Atlantic brings cloud and rain and still cool weather across Southern and Western areas next weekend gradually extending to all areas through Week 2 as the parent Low complex edges East across the UK.

 

THE GFS CLUSTERS The GFS clusters today favour Low pressure being likely to lie to the West or North of the UK in two weeks time with unsettled or changeable conditions and avearge temperatures in a Westerly flow looking the most likely scenario for the British Isles at that point in time.

 

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 a showery cool Westerly flow midweek slackening off as new Low pressure drifts East to the South of the UK at the end of the week and start to next weekend. Midweek showers will continue in the North but more perisstent rain could threaten the South at the end of the period in conditions remaining generally on the cool side.

 

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

 

THE FAX CHARTS The theme of the Fax charts this week shows a cold North flow backing West by midweek and being complicated by further troughs running into Southern areas. Showers in the North will be wintry on hills and the longer spells of rain looks most prolific across Southern areas on Wednesday.

 

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

 

GEM GEM this morning shows a cold and unsettled period the most likely events to witness over the coming 10 days. Early showery and cod NW or West winds die out towards midweek as new Low pressure edges up to the SW of the UK with more prolonged rain across the South and West later. For the rest of the run the UK falls under a Low pressure complex with rain at times and snow on northern hills where it would feel particularly cold and raw in the fresh East or NE flow

 

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

 

NAVGEM NAVGEM shows an equally unsettled and rather chilly period with showers in the first half of the week on a Westerly flow giving way to more prolonged rainfall across the West and later to all as Low pressure edges acoss the UK in maintained cool conditions.

 

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

 

ECM ECM this morning is a little less dramatic with a showery and rather cool Westerly for the first half of the week as Low pressure meanders down across the North and away East later. A weak ridge shows a drier and brighter period soon after midweek replaced by new Low pressure edging up from the SW next weekend with further rain in places. This gradually then is shown to focus more towards the North and West as Low pressure anchors over the Atlantic with somewhat milder air filtering into the SE at the end of the run.

 

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

 

ECM 10 DAY MEAN(12z) The ECM 10 Day Mean Chart  from last night shows a Low pressure belt lying across the Atlantic and the UK maintaining the risk of showers or rain at times 10 days from now.

 

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

 

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The trends this morning show a common theme of Low pressure driven weather with centres close to or over the UK.

 

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  ties at 88.3 pts over UKMO also at 88.3 pts and GFS at 85.8. At 8 days ECM remains the leader with 61.9 pts over GFS's 58.9 pts. Then at Day 10 ECM retains superiority at 47.5 pts over GFS at 42.8. 

 

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 On face value the charts look quite disturbed and cool across the UK for the next two weeks but actually some places could end up with quite a lot of dry weather when all is added up at the end of the period. Having said that some places will have some unseasonably cool weather especially at night with some very unwanted frosts especially early in the period and a few could see some snowfall on the hills of the north through the showery period early this week. The trend is then for pressure to become slack across the UK late in the week with rather less in the way of showers after the risk passes of a period of more prolonged rainfall midweek for some areas. Then as we look towards the second week it looks very much from all models that conditions will remain on the chilly side of average especially in the North where it looks increasingly likely from some output that a cold Easterly feed could develop. By then more prolonged rainfall could be focused on the South but there are exceptions to this rule such as shown by ECM that the North and West could become more at risk of the wettest conditions while the SE warms up a fraction closest to higher pressure over Europe. Whatever the outcome true Spring warmth and sunny skies are on hold for a while and the main message for gardeners and growers is the continuing risk of night frosts particularly over the coming couple of nights and possibly again under any clearer interludes at anytime through the period while occasional rain will quench the gardens and fields for many. 

 

Next update from 08:00 Monday April 27th 2015

[mushymanrob]

hmmm .... thats one large greenland block, shunting the jet on a low trajectory. seems very familiar (summers 07, 08). could we be in for a similar cool unsettled / wet spell for may/early june?.. that high could sit there for several weeks.

IF this transpires though it might be good news for the heart of summer?...

[johnholmes]

Well the anomaly charts now seem to be suggesting a similar trend post 6 to 10 days from now. That is a 500mb flow from south of west into the UK, see links below. NOAA had this a coupole of days ago but the EC-GFS variants did not. Now they too follow this idea.

I would think this is now the most likely upper air pattern from early May.

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

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

 

This idea has been picked up by both synoptic models around 168h on their recent 00z output.

So a colder interlude then a lessening of this with a milder and rather changeable outlook perhaps?

[Captain Shortwave]

hmmm .... thats one large greenland block, shunting the jet on a low trajectory. seems very familiar (summers 07, 08). could we be in for a similar cool unsettled / wet spell for may/early june?.. that high could sit there for several weeks.

IF this transpires though it might be good news for the heart of summer?...

Looking at the models and especially the ensembles, perhaps there is hope as John says above, looking like low pressure might set up shop west of the UK with a cyclonic flow between the south and west developing. This would raise the temperatures to near or even a little above normal.

GFS

 

ECM

 

So the outlook looks unsettled but after a cool week this week, perhaps something a little warmer might develop, but still with spells of rain interspersed with showery intervals.

 

Regarding the Bank holiday weekend, at the moment we might get lucky with a weak ridge perhaps bringing drier weather during the weekend.

Edited April 26, 2015 by Captain shortwave

[knocker]

Running this forward in the ext period to around the 9th May both the ECM and GFS are leaning towards a height build up in the eastern Atlantic much along the lines of the last EC32 update so the prognosis is looking not bad.

Chart weatherbell

 

[Stuie]

Looking at the models and especially the ensembles, perhaps there is hope as John says above, looking like low pressure might set up shop west of the UK with a cyclonic flow between the south and west developing. This would raise the temperatures to near or even a little above normal.

GFS

 

ECM

 

So the outlook looks unsettled but after a cool week this week, perhaps something a little warmer might develop, but still with spells of rain interspersed with showery intervals.

 

Regarding the Bank holiday weekend, at the moment we might get lucky with a weak ridge perhaps bringing drier weather during the weekend.

 

It does and a further LP system spawns behind it like a conveyor scenario.

Edited April 26, 2015 by SaffW

[seaside 60]

I see we have the same pie in the sky forecasts being produced.

Yesterday being a prime example.

Frosty gave run down of the 00hrs and showed a chart for 10th may, large heap of pretty pink snow based mainly over north east and rain else where.

Then on the 12 hrs he showed some lovely temps charts with temps topping 22c over south/south east, oh and the snow fields had now 18c.

With huge numbers in the winter on here that would have been mayhem, however it just goes to show the models just dont produce eye candy in the heart of dec to feb.......

[Frosty.]

The Ecm 00z shows warmer air than currently by the BH weekend so temperatures could return to the mid to high teens celsius across at least the south of the UK, it won't be settled, there are likely to be some sharp showers dotted around but in the sunny spells it would be pleasantly warm once again, not the dull very cool damp conditions London has today for example.

Edited April 26, 2015 by Frosty.

[Frosty.]

The Gfs 6z shows a steady improvement through early / mid may with temperatures becoming rather warm again, into the high teens celsius with some spots nudging into the low 70's F. The BH weekend shows higher temps than currently, more like where they should be at the start of May, into the low 60's F and there is likely to be some dry and sunny weather next weekend but with a few showers around too, BH Monday shows rain pushing north and east but the far east and north escape fine for longest but after the holiday it becomes warmer, still a risk of heavy showers for a while but with a gradual rise in pressure it eventually becomes more settled and the end of the run looks great.

Edited April 26, 2015 by Frosty.

[Milhouse]

BH weekend still looking fairly pleasant with light winds and temps a little below normal with night frosts. Signs that a southerly wind will develop by BH Monday which will raise temperature to more seasonal values. The models not looking as horrific as they were a few days ago.

 

 

 

 

[Milhouse]

The GEFS 6z mean shows the window of settled weather nicely for next weekend. On into FI its the perfect set up for pulses of very warm air to move northwards.

 

 

[Milhouse]

Bank Holiday Monday looking increasingly mild but Breezy as warmer air pushes up from the south.

 

[summer blizzard]

Bank Holiday Monday looking increasingly mild but Breezy as warmer air pushes up from the south.

 

 

A lovely bank holiday before the deluge..