Model Output Discussion 1200 hrs 30/09/14

[knocker]

With reference to the comments above there does appear to be a tendency for the depressions to travel the Atlantic in a SE/NE dirction and this could allow a height build up in the east. But this is all really pie in the sky

Edited October 12, 2014 by knocker

[knocker]

And now for the encore, basking in Cornwall.

 

[Frosty.]

There is a rather wintry flavour to the Gfs 00z op run beyond the next week or so, looking at the bigger picture with NE Europe in particular having a major cold snap bringing snow and strong winds with a cold high bringing widespread frosts to the uk..I like the way FI is trending, a bit more tinkering could unlock a more substantial early wintry outbreak for the uk. In the meantime, the reliable timeframe looks unsettled, more unsettled than yesterday's gfs with that huge atlantic low having more impact so although it does become much milder later next week, it also looks very breezy and unsettled but with drier, sunnier gaps with most of the rain pushing through overnight..and then it turns colder. I hope the bottled up arctic air way to the north becomes uncorked and brings coldies a taste of winter, this autumn has been summery on the whole, time for a change me thinks

[Captain Shortwave]

The Euro models look good for one last spell of warm weather this morning

UKMO

Some very warm air reaches the UK in week 2 on the ECM before the Atlantic breaks through.

 

GFS and GEM make much less of this and introduce a more mobile westerly set up.

 

so who is right on this one?

[Gibby]

HERE IS MY LATEST ANALYSIS FROM THE OUTPUTS OF THE WEATHER COMPUTER PREDICTION MODELS FOR TWO WEEKS FROM 8AM TODAY SUNDAY OCTOBER 12TH 2014.

 

NEXT UPDATE MONDAY OCTOBER 13TH 08:00

 

THE CURRENT GENERAL SITUATION. An area of Low pressure will move slowly North over France and into Southern England later tonight and tomorrow.

 

MODELS-2 WEEK HEADLINE  Changeable weather with some rain at times but with some dry and very mild weather likely in the South and East for a time from later this week.

 

THE JET STREAM ENSEMBLE FORECAST The rather weak Jet flow currently lying to the South of the UK is predicted to strengthen later this week and ridge North to lie SW to NE across the North of the UK next weekend before reverting back South again through week 2 while maintaining a basic sine wave structure.

 

GFS The GFS operational today shows complex Low pressure moving up into Southern Britain over the next few days before filling close to the East coast in a day or two. This is then absorbed by deep Low pressure slow moving over the Atlantic but sending an active trough NE across the UK midweek. This then brings a mild SW flow with showers as pressure builds from the SE. The weather could turn quite pleasant in the SE for a time before the Atlantic Low moves North of the UK and brings a cooler Westerly flow with bands of rain and showers for all later while at the end of the run pressure builds strongly as High pressure develops over or near to the East of the UK with cool and settled conditions with a fog risk night and morning takes over from wind and rain.

 

THE GFS ENSEMBLES. The GFS Ensembles are decreasingly similar to the operational as time passes this morning with the broad structure and sequence of events basically the same as the operational with just differences in timings and depth to the more unsettled phase as we enter week 2. This then leads on to a different end to the run as potentially stormy conditions for a time are followed by colder air being drawn down across the UK from the North towards the end of the run with the operational's late run High pressure held further West by the Ensembles and keeping a cold Northerly flow over the UK with potential for wintry showers in the North and frost at night generally.

 

UKMO UKMO this morning shows Low pressure held back well into mid Atlantic at the end of the week and start to next weekend. After an unsettled midweek period mild SW and later warm South winds bathe the UK with any rain only for the North and West while the South and East become fine, warm and dry for the most part.

 

THE FAX CHARTS  The Fax Charts show Low pressure early in the week and a trough midweek all bringing rain before a trend towards mild SW winds if rather cloudy and damp weather looks poised to move up across the UK later with pressure rising steadily across the UK.

 

GEM The GEM operational today shows the mid Atlantic Low being drawn closer in towards the UK late in the coming week making any reliable dry weather harder to find even in the South as spells of wind and rain are then drawn across the UK from the SW and then West. After a period of relatively mild weather late in the week things turn cooler and fresher to start Week 2 as winds veer more Westerly and become strong.

 

NAVGEM NAVGEM as some other output holds Low pressure further away to the West later this week with pressure becoming High to the East setting up a very mild Southerly flow for the UK with fine and dry conditions for many with any rainfall restricted to Northern and Westernmost parts by next weekend. 

 

ECM The ECM operational today continues this basic theme of an unsettled first half to this week before mild and less unsettled weather follow a trough NE by Thursday. The deep and complex mid Atlantic Low then feeds slowly NE later and the mild or very mild if rather cloudy SW flow across the South and East slowly gives way to more unsettled weather across all of the UK again by the end of the run as winds become more Westerly, stronger and cooler with rain at times for all by the end.

 

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The trend is still showing a conflict of interest in whether Low pressure to the West and North overcomes the power of High pressure to the SE and East in the longer term outlook this morning. This conflict has still to be resolved from the latest outputs today.

 

MY THOUGHTS  There seems reasonably good agreement on the next 4-5 days weather before the models differ somewhat in where we go from then. In the short term the Low currently coming up into Southern England from France looks like giving a couple of inclement days of cloud and rain in cool weather over England and Wales with Scotland fairing best. Then the mid Atlantic Low pulls an active trough NE midweek with more heavy rain in places before it more importantly introduces the UK to increasingly mild and less unsettled weather towards the weekend as High pressure builds to the SE. It's then the discrepancies between the solutions shown by the models come into play with some output showing a period at least of potentially warm weather affecting parts of the South and East though cloud amounts could temper this somewhat. Other output shows the Low to the West moving in closer to keep the unsettled if milder theme going late this coming week and weekend before a general consensus for a dip into more generally unsettled weather in week 2 is supported. This then heralds the usual array of wild and windy scenarios offered by GFS in the low resolution period who eventually shows an excursion into late Autumn by the end of the run with cold North winds, widespread frost and wintry showers in the North possible. All speculative at this range of course and I think the more likely scenario is something close to what ECM offers this morning being quite likely meaning after an unsettled start to this week a period of mild or very mild and dry weather for the South and East could hold on quite a while before the unsettled conditions held to the North and West become more widespread again next week as the Jet tilts more West to East across the UK or to the South and sinks back South. In Summary despite some wind and rain for all in the next few weeks given it is October there is nothing to suggest anything disruptively unpleasant in the longer term this morning with potentially very mild weather being the most noteworthy parameter to be the weather headline to be talked about over the period especially in the SE.

[summer blizzard]

So both the GFS and Euro flatten the flow to a westerly at day 8 and 10 respectively.

 

Into FI and the GFS gets much cooler, a northerly followed by an inversion high producing classic frost and fog weather most likely.. Winters coming.

 

[johnholmes]

So both the GFS and Euro flatten the flow to a westerly at day 8 and 10 respectively.

 

Into FI and the GFS gets much cooler, a northerly followed by an inversion high producing classic frost and fog weather most likely.. Winters coming.

 

 

Until the 3 main 500mb anomaly charts show some possibility of this then I would discount it. Of course 1 in perhaps 50 times GFS synoptic has shown the way but it is rare for this.

So far the anomaly charts are pretty solid in keeping a fairly major trough west of the UK. EC-GFS do keep trying the idea of building a ridge in the Greenland area but not consistently yet and so far the NOAA 6-10 and 8-14 versions have not shown any inclination towards this idea.

[MR EXTREMES]

indeed the polar vortex is slowly making its trip around the pole ecm model in fi has it located well away from this side of the arctic more over the russian side and not to far from the nw side of canada. 

glad its still there but slowly doing its rounds id expect its going to be a slowly progression around towards canada.

 

but heights around the greenland area does look likely be on the higher side than low side.

but looks likely for us looks like the kitchen sink just about sums it up.

 

wind rain showers warm cooler perhaps snow for scotland later in the runs.

still i expect the models to deal with its out puts very well in this sluggish slow moving atmosphere.

[summer blizzard]

Until the 3 main 500mb anomaly charts show some possibility of this then I would discount it. Of course 1 in perhaps 50 times GFS synoptic has shown the way but it is rare for this.

So far the anomaly charts are pretty solid in keeping a fairly major trough west of the UK. EC-GFS do keep trying the idea of building a ridge in the Greenland area but not consistently yet and so far the NOAA 6-10 and 8-14 versions have not shown any inclination towards this idea.

 

Aye, i'm just getting excited at these good looking charts. Inversions are one of the best weather phenomena.

[Newberryone]

Just wondering if anyone's cast an eye on that pesky little feature down to the southwest on day number 10 of the Ecm 00z  

Unlikely to be still there on the next update but interesting all the same.

[Summer Sun]

ECM ens shows the potential for some warmer wetter weather as winds shift to a south westerly towards next weekend temperatures would widely in the high teens maybe even just into the 20's for some southern areas

 

 

By day 9 & 10 winds begin to come in from the west again so temperatures begin to ease back down towards the seasonal average

 

[damianslaw]

Very typical conditions for the time of year look set for the foreseeable timeframe. Overall its an unsettled set up and very changeable, through the week we exchange the rather cool conditions of current for a much milder windier theme with tropical maritime air descending upon all in time for next weekend - a classic long draw southwesterly fetch with all its associated misty cloudy gunk.. away from the far SE a very dank dull set up with copious rainfall. We saw a very similar set up around the same time last year.

 

Longer term - the jet stream is forecasted to track southerly again after a temporary northerly shift, this no doubt will help to quickly kick aside any ridge/height developments over SE parts returning a cooler unsettled them once again, a northwesterly/northerly certainly not out of the question. GFS is showing this possibility, much will depend on the position of core low heights over north pole, if they stick where they are currently, this would certainly help increase chances of something much colder from the north as we enter the latter part of the month.

[Frosty.]

The GFS 06z op run throughout FI is classic british autumn with the jet digging further south, spells of milder, wet and windy weather interspersed with brighter, colder and showery days and probably cold enough on northern hills for a wintry mix, also a risk of frost during quieter interludes. It's a very mobile pattern with a chance of occasional upstream amplification bringing the risk of more potent polar maritime or even arctic outbreaks later in the month if the jet tilts more towards a northwest / southeast alignment.. and into november.I hope we don't see limpet euro high's with benign warmth any more this autumn, I want cold 

Edited October 12, 2014 by Frosty.

[Polar Maritime]

Yes some cold synoptic's keep showing towards the end of the runs of late by the GFS, With Pm/rPm air establishing.. Nice to see in the output as we draw closer to Winter, And very interesting watching the changes in the Northern Hemisphere.

 

 

Edited October 12, 2014 by Polar Maritime

[Milhouse]

Warm moist air being dragged up from the Azores. Expect a lot of cloud but temperatures could reach the low 20s if winds manage to veer more southerly as the ECM is suggesting.

 

 

 

Balmy for mid summer, never mind October!

 

[Bobby]

The PV around Greenland is showing to strengthen and move S with time

 

ECM mean day 10 compared to the present state. NAEFS which goes further shows more progression

 

   

 

850 temps cool down back to normal values also, exceptionally warm at the moment

 

 

Would seem to suggest a fairly active Atlantic and jet and a more zonal pattern into the later part of the month and early Nov. Indeed the main models OPs are looking like that by around day 10.

 

ECM

 

 

All looking rather typical October fare!

Edited October 12, 2014 by Bobby

[Iceaxecrampon]

Yesterdays Scottish cool plunge progged for around the 22nd (FI  - I know) backtracked further north with no wintery ppn as such - yet.

 

980mb Low

 

 

Temps still around 7 degrees  - snow risk down at 25% for the NW Highlands on the 24th.

 

Welcome to the journey that is Winter 2014....!

 

Can't wait

 

Ian

Edited October 12, 2014 by Iceaxecrampon

[Frosty.]

It's getting there, it's getting there, good strong signals from Gfs today for a colder, windier unsettled further outlook and we may even use the S word before nov...no not that S word. I mean the one where everything turns white and crisp and even.

Edited October 12, 2014 by Frosty.

[knocker]

Where exactly are these strong signals coming from? I ask because it's not that obvious to me?

 

Looking at the day ten anomalies and surface analysis doesn't indicate to my uneducated eye cold weather in the near future.

 

 

.

[Gibby]

I find looking at charts more than 10 days out for specifics is quite futile really. I know I state what the charts are showing in weather terms at that distance within my reports purely to inform those less able to read charts but it's only my evaluation summary at the end which I hope gives a cross model, balanced and unbiased view of the most likely scenario taking all output as a whole. Despite isolated mouth watering charts from our old friend GFS in FI in recent runs I see nothing to indicate any slant of note towards winter anytime soon..quite the opposite in the short term actually.

Edited October 12, 2014 by Gibby

[phil nw.]

I find looking at charts more than 10 days out for specifics is quite futile really. I know I state what the charts are showing in weather terms at that distance within my reports purely to inform those less able to read charts but it's only my evaluation summary at the end which I hope gives a cross model, balanced and unbiased view of the most likely scenario taking all output as a whole. Despite isolated mouth watering charts from our old friend GFS in FI in recent runs I see nothing to indicate any slant of note towards winter anytime soon..quite the opposite in the short term actually.

Yes agree Gibby.

Certainly the overall Atlantic pattern is evolving into a typical Autumn,changeable outlook.some quite mild days at the end of the week as the next Atlantic low stalls and draws in some muggy tm air into the UK.

The mean charts showing continental heights and Atlantic low pressure as we go through the nextwek/10 days.

[Frosty.]

 

 

 to my uneducated eye cold weather in the near future.

 

 

.

I'm sure the eye in the sky will be on soon  , i'm looking beyond the mild mush towards the last ¼ of october into november, the gfs has frequently shown colder zonal patterns in that range, usually good at spotting longer term trends, yes the next 10 days bring plenty of mild mush but there is a chance of colder weather later on.

[Polar Maritime]

Yes Frosty, The GFS has been hinting for a cooler more unsettled Pm/rPm flow out in the runs towards the end of October. As you say it's interesting to spot trends/signals at this range, As it's intended for.

Edited October 12, 2014 by Polar Maritime

[Iceaxecrampon]

I find looking at charts more than 10 days out for specifics is quite futile really. I know I state what the charts are showing in weather terms at that distance within my reports purely to inform those less able to read charts but it's only my evaluation summary at the end which I hope gives a cross model, balanced and unbiased view of the most likely scenario taking all output as a whole. Despite isolated mouth watering charts from our old friend GFS in FI in recent runs I see nothing to indicate any slant of note towards winter anytime soon..quite the opposite in the short term actually.

Yes - understood Gibby - the perennial Chesnut - but you have to have a base and start somewhere and pick up on any signals (like potential snowfall for the Scottish tops - my favourite time to log in on the Community and looking forward to the rollercoaster and your excellent summaries

 

Ian

[IDO]

I'm sure the eye in the sky will be on soon  , i'm looking beyond the mild mush towards the last ¼ of october into november, the gfs has frequently shown colder zonal patterns in that range, usually good at spotting longer term trends, yes the next 10 days bring plenty of mild mush but there is a chance of colder weather later on.

 

 

Interestingly the CFS monthly has been strong on a settled November anomaly with above average temps. Little sign of anything cold from them for a while:

 

 

 

JMA week 4 of October to end week 1 November suggests Uppers above average: 

 

The GEFS mean in FI also showing seasonal average T850s for Aberdeen: 

 

The odd op run does show something a bit cooler like the 06z but the Control offers a milder perspective:

 

 

So no real sign of any consistent sign of a cool spell yet alone anything cold but lots of uncertainty so things may change. Looking at the moment from week 2 a trend towards a westerly flow but not on full throttle so maybe brief ridges for the south for some drier weather. Late on in October signs are that pressure will rise and at least the S/SE/E should benefit from this.