Model Output Discussion - 17th Oct Onwards

[Frosty.]

Thanks for replying to my post PM..have to say i'm looking forwards to winter now, it's coming...

[winter snow]

the latest GFS model keeps it mild till Thursday in northern areas then it becomes colder with even hill snow. on the 6z latest GFS run it becomes very cold in Scotland and northern England by Friday and onwards. the south on this run stays mild but I wouldn't rule out the colder weather reaching there. hopefully we have some sunshine to go with the cold weather. a good run for coldies and good GFS run for mild fans if you live in the south.

[Frosty.]

The Ecm 00z ensemble mean looks very interesting, initially it's very mild and unsettled with strong winds at times through to around the middle of next week, thereafter,  polar maritime /arctic maritime air begins to push southeast into scotland but is held up or forced north again by another depression pushing in from the southwest, so it may turn colder and clearer across at least the far north of the uk later next week with overnight frosts and perhaps a few wintry showers but generally it remains unsettled, however, the mildness does begin to drain away and by T+240 hours onwards, it shows much cooler north atlantic and then probably polar maritime nw'ly winds pushing towards the northwest of the BI..it would mean the showers which push in off the atlantic would begin to turn to snow across the high ground of northern britain if the ecm mean did follow through with this pattern.

[Cloud 10]

The gfs 06z is very similar to the ecm 00z at 168 hrs with its height rises towards Iceland,which then turns into a brief Scandi high before the inevitable flattening.

 

gfs..  ecm..

 

 

The south-west tip of Greenland should provide some interest for Mr Murr on those 2 charts!

[Frosty.]

The GEFS 06Z control run develops a rather colder and unsettled spell beyond the mild, unsettled week ahead with a more amplified pattern for a time, lots of showers and longer spells of rain with sleet and increasingly snow across northern hills & mountains plus overnight frosts where skies clear and winds drop...it's nice to see and it does have support. 

[Frosty.]

GEFS 06z perturbation 2 shows the type of pattern I would like to see through late october / early november with the jet becoming aligned more towards nw/se with frequent depressions crashing southeastwards across the uk followed by a backwash of cold air with showers turning more and more wintry, then a cold ridge with a fine day and a frosty night before the next low races in and with occasional enhanced amplification drawing increasingly cold arctic air south, hopefully a more sustained wintry weather pattern can evolve through early to mid november.

[Frosty.]

 

In the meantime - it looks distinctly unpleasant.

Agreed with your post tamara except for the last bit..for those of us who were utterly bored towards the end of the benign, warm and stagnant autumn which went on for weeks and weeks, I would say the outlook looks distinctly pleasant in comparison.

Edited October 19, 2013 by Frosty.

[Summer Sun]

The ECM monthly average temperature for Glasgow shows average or above average (some times well above average) temperatures to around November 11th

 

 

Its not until around November 12th we see the temperature average falling below average

 

Max temperatures follow a similar pattern to above well above average at times next week peaking at around 16c the average for this time of year is around 12c

 

Edited October 19, 2013 by Summer Sun

[Frosty.]

Just to add some much needed balance to those cool and unsettled charts I posted above, the GEFS 06z perturbations also include a fair number of very anticyclonic outcomes for the early november period, a few very warm for the time of year too, so the outlook remains very uncertain beyond next week.

[Snowman.]

The gfs 06z is very similar to the ecm 00z at 168 hrs with its height rises towards Iceland,which then turns into a brief Scandi high before the inevitable flattening.

 

gfs..gfs-0-168.png  ecm..ECM1-168.gif

 

 

The south-west tip of Greenland should provide some interest for Mr Murr on those 2 charts!

Watch that space I would say I'm feeling a spanner to be dropped soon.

[syed2878]

didn't the incrice in solar activity scuppered some of the wlrf last dec? Also the models gave forecasters a headake because there was a lot of uncertainty?

[Frosty.]

The GEFS 06z mean shows a relatively colder unsettled version of the current pattern later this month with the jet digging further south, the PFJ briefly ends up across northern france but this is followed by a gradual pressure rise from the south which forces the polar front jet northwards again, this is reflected in those more settled looking 6z perturbation charts I posted above. It gives a more balanced view of where we are heading but don't rule out the more extreme outcomes, be it warm and settled or cold with wintry showers and night frosts, it's finely balanced in my opinion although i'm sure most of the experts will say it will just carry on mild and unsettled for weeks to come with very little change in the diurnal temperature range and surface conditions, I say, keep an open mind because something could be brewing through november.

[Timmytour]

 

didn't the incrice in solar activity scuppered some of the wlrf last dec? Also the models gave forecasters a headake because there was a lot of uncertainty?

 Are you trying to say we might be in for a bad spell of weather?

[stewfox]

Looking at the 500mb anomaly charts they are pretty consistent in their idea of the upper air pattern for 6-10 even 15 days time, and have been for 3-4 days or more. Consistent with themselves and one another so this does lead to having reasonable confidence that the pattern shown on the outputs last evening(NOAA) and this morning(ECMWF-GFS) will be close to hwat they show. Just checked their pattern prediction for this morning 10 days ago, (when ECMWF was quite often missing) and NOAA and GFS had it pretty spot on =  the marked trough west of the UK and ridge over the continent with a slight indication of one in the Greenland area. NAEFS also showed a similar idea.

Thus I see nothing to change my view of the last 2-3 days on the general weather out to the end of November.

 

links

http://www.meteo.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

 

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

 

Did you mean end of November or October ? Always take note of your comments

[legritter]

Certainly an interesting outlook going by todays output ,i am very pleased with current mild wet weather as somewhere down the line mother nature could balance things out ,no guarantee mind you ,but from a coldies point of view [which many of us posters are ]it would be nice to ease into late autumn and early winter .must say a thank you to all regular posters who post interesting Data and Charts .

[Frosty.]

Well, that weak blocking signal on the Ecm 00z op run this morning has been cranked up much further on the latest Gfs 12z op run with the formation of a robust looking scandi anticyclone during FI which stops the atlantic juggernaut in it's tracks, forming a solid block against the  atlantic, however, even with high pressure taking charge, it's windy, strong se'ly winds which would make it feel raw and overnight temps close to freezing, still, that's a long way off in meteorological terms but it really goes against the grain of the ensemble mean output. 

 

In the meantime it's a continuation of the mild, unsettled and at times, windy spell but with brighter gaps and scattered heavy showers in between times, feeling rather warm too with  sw'ly to s'ly breezes, occasional heavy bands of rain swinglng northeastwards across the whole of the uk for most of the week ahead but then signs of change, cold air from the north again tries it's luck in pushing south but has similar problems to last time and gets held up across northern scotland, however, high pressure gets a foothold and builds through the uk before slowly drifting east into southern scandinavia and intensifying. So, the unsettled and mild spell gradually morphs into a settled but rather chilly end to the month and early november.

Edited October 19, 2013 by Frosty.

[Cloud 10]

Well, that weak blocking signal on the Ecm 00z op run this morning has been cranked up much further on the latest Gfs 12z op run with the formation of a robust looking scandi anticyclone during FI which stops the atlantic juggernaut in it's tracks, forming a solid block against the  atlantic, however, even with high pressure taking charge, it's windy, strong se'ly winds which would make it feel raw and overnight temps close to freezing, still, that's a long way off in meteorological terms but it really goes against the grain of the ensemble mean output. 

 

In the meantime it's a continuation of the mild, unsettled and at times, windy spell but with brighter gaps and scattered heavy showers in between times, feeling rather warm too with  sw'ly to s'ly breezes, occasional heavy bands of rain swinglng northeastwards across the whole of the uk for most of the week ahead but then signs of change, cold air from the north again tries it's luck in pushing south but has similar problems to last time and gets held up across northern scotland, however, high pressure gets a foothold and builds through the uk before slowly drifting east into southern scandinavia and intensifying. So, the unsettled and mild spell gradually morphs into a settled but rather chilly end to the month and early november.

 

Indeed,the 12z gfs ensemble mean at 240 hrs doesn't bear much resemblance to the op run,still,who knows....

 

gfs op run..  ens.mean..

[Frosty.]

The GEFS 12z mean shows a generally west to east pattern throughout with low pressure dominating the weather across the north of the uk for most of the time, just a brief quieter and rather cooler interlude later next week as a ridge extends southeastwards from iceland, but then the pattern soon flattens out again with a generally w'ly to sw'ly flow blowing mostly mild air across the uk, especially for the south, northern uk having a cooler oceanic north atlantic flow at times, the PFJ is constantly on the move, it's pushed south and pulled north due to the persistence of high pressure to the south/se of the uk across mainland europe ebbing and flowing against the lower heights to the north. Looking further ahead, rather more benign weather with a slow pressure rise begins to extend northwards across southern uk with dry and brighter weather and gradually lighter winds but that's a recipe for thick fog and a touch of frost, the northern half of the BI continues unsettled with a stronger wsw'ly flow and spells of rain interspersed by sunshine and showers and temperatures closer to average, milder further south but with chilly nights.

Edited October 19, 2013 by Frosty.

[Summer Sun]

ECM once again shows cooler air trying to get in but the milder air wins out in the end

 

 

A bigger view of things at t192

 

[syed2878]

well we r in a bad spell atm proper autumn weather. I was talking about increasing solar activity we could c some effects straight away or later on. It's worth keeping a close eye on the models to c what's bruing. Although some of the outputs showing blocking signal so lets waight and c if mor runs shows it.

[damianslaw]

A gradual cooldown is shown by the models today as we head into next weekend, thanks to more of a westerly flow and the introduction of cooler uppers for the north.

 

Before then, very much more of the same, rainy very cloudy weather for all and windy especially in the NW with very mild conditions, nightime minima holding into double digits for most.

 

By this time next week, temps should be much nearer average and fog may become more of an issue.

 

I'm not too sure about heights building to our east as suggested by GFS. ECM probably more likely evolution, with further low pressure moving in from the west as we head into the last week of the month, but a cooler airstream compared to now and a possible NW blast before the month is out with the azores high migrating more to the west.

 

I said a couple of days ago, the synoptics at present are very normal for the time of year in terms of the atlantic being in control, and the signal for the jetstream to buckle more as we head towards end of the month into November will allow temporary ridging and cooler polar maritime air to make there presence felt allowing it to feel more seasonal temperature wise with fog and frost featuring in our forecasts. Met forecasts have hinted at such a development for a number of days now as we head into November proper.

[Jason T]

Wow, What an old weather chart, This is an elite fax chart, Todays ones are just black and white, Must have taken ages to compose it. Sorry folks had to post it. 

 

 

 

[Frosty.]

The Ecm 12z op run shows a gradual cool down from midweek, initially only across the northwest corner of the uk, it's progress southeast is hampered by low pressure and fronts pushing northeastwards across the southern half of the uk but eventually the cooler air wins briefly with a cool ridge pushing east into the uk next saturday, so this would potentially bring the first widespread frost across the uk of this autumn, apart from the far south, but then as the ridge subsides, low pressure starts to gang up to the southwest/west with milder air again beginning to swamp the uk, at least the southern half anyway and high pressure building across the near continent. In the nearer timeframe, it stays mild or very mild and unsettled with  bands of heavy rain spreading up across the uk but separated by brighter and showery interludes, more wet weather pulsing northeastwards through midweek and then a cold front pushing cooler and fresher air southeastwards for a day or so, rather longer than that across the far north where there could be a risk of a touch of frost from midweek onwards with drier and brighter weather compared to the south, then trending unsettled and cooler across all parts of the uk from T+240 hours with a strengthening cooler westerly airflow.

[Summer Sun]

Latest from Gibby

 

Good evening. Here is the report on the midday outputs from GFS, UKMO, GEM, NAVGEM and ECM for today Saturday October 19th 2013.All models show Low pressure remaining in control of the weather over the UK through the next week. Innitially, centres to the West and then NW will keep mild SW winds blowing across the UK carrying spells of rain and thundery showers NE at times. later next week sees most models with a new Low feeding up from the SW approaches, crossing England and Wales and giving a good deal of rain in places with temperatures decreasing to more average levels by next weekend.

 

GFS then shows a ridge of High pressure building over Northern Britain with dry, cooler and brighter weather while a hang-back of Low pressure over the South maintains unsettled weather here through the weekend too. Through the latter half of the run  SE winds bring rather warm air NW from Europe and while very breezy with a lot of cloud temperatures would again be well above average before more unsettled and cooler weather spills back in off the Atlantic late in the run over the North with a cooler Autumnal quiet spell developing right at the end.

 

UKMO shows a marked cold front pushing South next Friday on the rear side of an exiting Low pressure to the East. A band of heavy showers or more persistent rain will move South over England and Wales through the day with colder and brighter weather following with some sunshine and just more scattered showers in the North.

 

GEM evolves into a very stormy period after next weekend as a vicious system of Low pressure crosses NE over England with storm force winds briefly coupled with heavy rainfall before things calm somewhat but still with rain at times in trailing Low pressure over the British Isles. Temperatures would fall back to average levels beyond the first week.

 

NAVGEM shows pressure rising later next week and weekend from the South with dry and fine weather extending across Southern areas. Northern areas will stay more unsettled but generally mild with some rain at times in fresher West or SW winds.

 

ECM shows a brief drier interlude too later next weekend before the Atlantic wind and rain returns, this time with somewhat lower temperatures as the strong Westerly flow that develops has a much colder air source to accompany frequent bands of rain and showers.

 

The GFS Ensembles show the operational as a warm outlier in the second half of the run while most members shows nearer to average values when taken as a whole with a mix of milder and colder options. Rainfall remains quite a common occurrence suggesting a continuation of Atlantic Low pressure dominance.

 

The Jet Stream shows the flow crossing the Atlantic towards the UK over the coming week with a troughing of the flow South of the UK next weekend.

 

In Summary there is little overall change in the outputs tonight from this morning. The highlight's have to be the vicious storm system that GEM passes across Southern England next Monday morning which if evolved as shown would give damaging winds to Southern England. On a more general note the pattern remains basically unsettled and wet at times with the chance of a drier interlude at some point next weekend while all models predict a temperature fall of several degrees on current values as we move through next weekend and the following week.

 

http://www.norton-radstockweather.co.uk/Model-Analysis%282859336%29.htm

[johnholmes]

Did you mean end of November or October ? Always take note of your comments

 

thanks for spotting that, it should have read October, I certainly do not pretend to be able to predict that far ahead.