Model Output Discussion 1st Nov.2013

[Summer Sun]

Latest from Gibby

 

All models show a deep depression crossing Ireland and Northern Britain through today and tonight. After a fair start a band of squally rain will push quickly East followed by squally showers and clear or sunny intervals in very strong winds with severe gales in places this evening and tonight. this weather eases slowly tomorrow as the Low eases away East. Later a wave depression will form down to the SW crossing Southern Britain over Sunday night with a spell of heavy rain here. Clearer, colder weather in the wake of today's storm over the North on Monday slips South to all areas later with the risk of a frost in calmer weather for a time on Monday night. Things stay very changeable though and renewed wind and rain soon sweeps in across all areas on Tuesday with the midweek period seeing a strong to gale Westerly flow with showers across the North and possibly more prolonged rain at times in the South as wave disturbances on the Polar front cross East on occasion.

 

GFS then trends towards quieter weather in the second week of it's run as High pressure builds across the UK from the West. The weather would become much calmer and probably colder too as overnight frost and fog which could become widespread and dense would probably fail to clear some days.

 

UKMO closes it's run this morning with an unstable and strong Westerly flow still blowing over the UK with showers or spells of rain, the latter most likely in the South. Temperatures will remain close to average.

 

GEM brings back the mild South-westerlies at the end of next week and weekend as the week's wet and windy Westerly weather type relaxes in the South to a dry if rather cloudy period with rain restricted more towards the NW, all this due to High pressure building over Europe.

 

NAVGEM looks more likely to maintain the windy and wet theme on past the term of it''s output this morning as further deep low pressure areas up to the NW push bands of wind and rain East and NE over the British Isles through next weekend. It would be relatively mild though.

 

ECM today is at ease with keeping wet and windy weather going through the end of next week, the weekend and beyond as the conveyor belt of Low pressure areas continue to feed across the Atlantic on the back of a continuing strong Jet flow over the UK. A few brief ridges could give a 12-24hr period of dry weather on occasion but this remains the exception to a very unsettled rule.

 

The GFS Ensembles show that there is still no particularly cold weather on offer from any member of the run today with a Westerly flow by far the most likely weather type across the UK. However, what is shown is a reduction in rainfall amounts in the second half of the output and should this mean High pressure moving into Southern Britain which s hinted at then fog and surface cold could develop over the UK should skies clear and the upper winds remain light later.

 

The Jet Stream shows the flow still remaining strong and on a collision course with the British Isles for the coming week before a definitive trend for it to move North of the UK in Week 2 in response to a strong rise of pressure to the South and SE late in the run.

 

In Summary it's just variations on a theme this morning with more wet and windy weather to be experienced for all over the coming week. There are subtle hints at a rise of pressure still taking place in a week or so to the SE with GFS leading the way on a full blown High pressure area transferring the weather into a chillier and foggy scenario later. However, trends towards this type of outcome are tentative at best from the other models with many preferring to keep the wet and windy theme in relatively mild conditions for at least a while into Week 2 as well.

 

http://www.norton-ra...is(2859336).htm

[Frosty.]

Thanks pm, as for the ecm 00z, I think it's much better than seeing long draw sw'ly mush and I hope the mods deal with individuals who openly dissrespect other posters who are doing their best. : - )

[Polar Maritime]

Thanks pm, as for the ecm 00z, I think it's much better than seeing long draw sw'ly mush and I hope the mods deal with individuals who openly dissrespect other posters who are doing their best. : - )

 

Yes Frosty, some posters need to read Phil's opening post to this thread and take note... Keep up the good work regarding your analysis on every model run and what they are showing 

[phil nw.]

Let's avoid the personal criticism guys.Post differing views by all means but stick to chart discussions please.

 

There is more of a trend to dig low pressure into Europe on the 00z runs at times which tilts the flow into a cooler direction so the prospect of more average temperatures over the next week or so with more polar maritime air in the zonal mix.

 

http://www.meteociel.fr/modeles/ecmwf/runs/2013110200/ECM0-48.GIF?02-12

http://www.meteociel.fr/modeles/ecmwf/runs/2013110200/ECM0-168.GIF?02-12

 

Some snow over the Scottish mountains this weekend in the colder air over the north of the UK.

 

I would sum it up by saying that It is an unsettled,mobile typical westerly pattern so there will changeovers of the airmasses with no mild/cold domination with the mean jet running across the UK for much of the time.

Edited November 2, 2013 by phil nw.

[Frosty.]

Yes phil it's proper very autumnal november weather, I will happily take that over endless sw'ly dross.

[bluearmy]

A more settled period being picked up markedly in the extended ECM ens for London. precip signal drops out along with the wind and the mean maxes drop below 10c. beyond next weekend at the earliest. This fits in with john's musings re the LW upper pattern and anomalys.

[Severe Siberian icy blast]

Yes Frosty, some posters need to read Phil's opening post to this thread and take note... Keep up the good work regarding your analysis on every model run and what they are showing 

Thanks pm, as for the ecm 00z, I think it's much better than seeing long draw sw'ly mush and I hope the mods deal with individuals who openly dissrespect other posters who are doing their best. : - )

Just to clarify , there was no disrespect intended , and my comment was not offensive as far as I can see.

We all want to keep this thread on topic , and importantly , realistic so when people read the thread they get a realistic idea of what type of weather we can expect , I was simply adding a touch of realism so ones don't read too much into what your post said at the end because lets face it fantasy island had 0.1% chance of coming off .

I do appreciate your comments frosty , and they are always very informative if not a little over the top sometimes. :-))

[Summer Sun]

Nice to see the GFS ensemble showing something more settled around mid month

 

 

ECM ensemble also showing a rise in pressure just south of the UK

 

 

Pretty good agreement between ECM and GFS ensembles at t240

 

Edited November 2, 2013 by Summer Sun

[Frosty.]

The Ecm 00z ensemble mean is very unsettled indeed and for most of the next 10 days, the PFJ is to the south of the BI and although there are occasional milder warm front sectors pushing east across southern uk, they are followed by much cooler wnw'ly winds which actually have arctic origins if you follow the isobars back to their source, it just becomes much more modified as it crosses the relatively warmer atlantic ocean but still has some bite to it and is cold enough for a wintry mix of sleet and snow at times across the hills and especially the scottish mountains, it's good news for some early snowcover in the scottish ski resorts as they prepare for what will hopefully be a bumper season. Even towards the end of the run, almost mid november, there is no real end in sight to the unsettled weather with a powerful jet stream and atlantic lows sweeping across the uk. The only change I can see is the jet pushing a little further north which would take the worst of the rain and gales on a gradually more northerly track, high pressure to the south of the uk across mainland europe edging north but there is the possibility that the very unsettled pattern might just be having a time out across the south before cranking up for another full scale assault on the uk during the second half of the month with perhaps more chance of polar maritime incursions by then rather than a settled spell.

Edited November 2, 2013 by Frosty.

[IDO]

Do not see a pattern change at the moment; the LR models suggesting this flat pattern will take us into December and beyond.

GFS T384 mean:

So it looks like a westerly flow with the jet closer to its normal latitude, nearer to Scotland, so a drier outlook the further south seems possible. Mean jet:

The CFS has been trending to a continuation of this zonal flow through December:

Yesterday's JMA for week 3-4 suggests the high trying to build from the south, with a bit more emphasis on the jet being north of Scotland giving most of the UK a period of drier weather:

but the 28 day mean sums it up:

So no sign of any early cold for November and keeping an eye on the December trend.

[ribster]

Do not see a pattern change at the moment; the LR models suggesting this flat pattern will take us into December and beyond.GFS T384 mean: gens-21-1-384.pngSo it looks like a westerly flow with the jet closer to its normal latitude, nearer to Scotland, so a drier outlook the further south seems possible. Mean jet:gens-21-3-384.pngThe CFS has been trending to a continuation of this zonal flow through December:cfs-2-12-2013.pngYesterday's JMA for week 3-4 suggests the high trying to build from the south, with a bit more emphasis on the jet being north of Scotland giving most of the UK a period of drier weather:Y201310.D3112.png but the 28 day mean sums it up: Y201310.D3112 (1).pngSo no sign of any early cold for November and keeping an eye on the December trend.

Do we need a pattern change, strikes me as being an autumnal pattern. Things seem to be moving long just nicely...

[Tuxedo]

Isn't it around this time we expect a winter forecast from GP ( Glacier Point)?

[Nick L]

Isn't it around this time we expect a winter forecast from GP ( Glacier Point)?

 

GP is sadly no longer part of the NW team.

[Tuxedo]

Oh that's disappointing as his analysis was always interesting and informative... A great loss to a great team!

[johnholmes]

A more settled period being picked up markedly in the extended ECM ens for London. precip signal drops out along with the wind and the mean maxes drop below 10c. beyond next weekend at the earliest. This fits in with john's musings re the LW upper pattern and anomalys.

 

nor is there anything in the past 24 hours to change my view, 500mb flow as indeed the 300 and 250mb flow largely remaining from a westerly direction, between 240 and 300 degrees, so never over mild but never over cold. Brief incursions of Tm and Pm air to show the 'extremes' around average temperatures. The probability that for a day or maybe 3 the SE will be under the influence of a temporary surface ridge over the continent. Nothing in the anomaly charts to suggest this is becoming something more permanent. Nothing either to suggest that in the next two weeks any longer than 24-36 hour 'cold' from a northerly area is any more likely.

[BlueHedgehog074]

I have to admit, looking at various models from the likes of the GFS, ECMWF, and UKMO that most of our snow shields will likely to stay rather robust for the next week or so with a continuation of the classic 'Lows racing from West to East' scenario. As mentioned, a mixture of heavy rain, showers, windy weather and brighter spells are likely to dominate our weather for a while as approaching Lows to our West bring the changeable and disturbed weather conditions. Maybe a small chance of the Scottish snow shields (and/or the Highland's snow shields) collapsing briefly during moments where the winds turn more North-Westerly, although I'm not sure if any possible Polar Maritime airflows shown on the models will be potent enough for snowflakes to penetrate the low level Scottish snow shields (unless we see upgrades in regards to the potency of the Polar Maritime airflows happen along with the -5*C 850 hPa temperatures reaching further South-East).

[Frosty.]

The Gfs 06z op run, on balance, shows a lot more relatively chilly weather than mild, the mild air is confined to small segments between the warm front and cold front with a backwash of much cooler air then sweeping down across the uk from polar regions, the north is most prone to polar maritime incursions but the south is also included with some chilly days and some frosty nights but generally there would be too much wind and cloud for frost to occur. It's a very unsettled seasonal run, the type of weather we would normally expect between early and mid november, lots of rain and gales, some snow for northern hills and mountains and occasional frosts during the few settled interludes between depressions, later in the run, high pressure bulges up from the south which forces the PFJ northwards for a time and draws milder tropical maritime air around the top of the high but it remains unsettled and windy, especially further north, the run ends with colder nw'ly winds digging in with wintry showers across the far north.

[UV-RAY]

The Gfs 06z op run, on balance, shows a lot more relatively chilly weather than mild, the mild air is confined to small segments between the warm front and cold front with a backwash of much cooler air then sweeping down across the uk from polar regions, the north is most prone to polar maritime incursions but the south is also included with some chilly days and some frosty nights but generally there would be too much wind and cloud for frost to occur. It's a very unsettled seasonal run, the type of weather we would normally expect between early and mid november, lots of rain and gales, some snow for northern hills and mountains and occasional frosts during the few settled interludes between depressions, later in the run, high pressure bulges up from the south which forces the PFJ northwards for a time and draws milder tropical maritime air around the top of the high but it remains unsettled and windy, especially further north, the run ends with colder nw'ly winds digging in with wintry showers across the far north.

The JEM and CFS have both been showing a cool down from mid month for the last two weeks with temps below the seasonal average, maybe they are onto to something Frosty

[Bobby]

Looking at the NAEFS anomalies the coolest upper air temps are about now, up to 4c below average today and tomorrow. Beyond day 7 they remain generally above average out to +384.

 

 

Day 10

 

 

Could be some frosts if we get some high pressure building but there's been hints of that for a while into FI but doesn't seem to be getting much closer. Just the mountains of Scotland have a chance of snow it would seem for the forseeable.

Edited November 2, 2013 by Bobby

[Gael_Force]

GFS going for three in a row.

 

[cooling climate]

I think the UKMO t120 and 144 charts are worthy of a comment or two.

the Meteociel northern hemisphere charts for the time frames above show

heights making their way into the Arctic. Very good news lets see what the

ECM has to say.

[Summer Sun]

Whilst the bulk of Europe is above average for the next 8 days all but the south west and south coast of the UK is below normal according to GFS

 

Edited November 2, 2013 by Summer Sun

[Cheshire Freeze]

I think the UKMO t120 and 144 charts are worthy of a comment or two.

the Meteociel northern hemisphere charts for the time frames above show

heights making their way into the Arctic. Very good news lets see what the

ECM has to say.

UKMO 02.11.13.gif

 

Yep the PV was looking quite disrupted on the later frames of the ECM yesterday.

[Cloud 10]

12z ECM for today,compared with 168 hrs = groundhog day.

 

today..  168 hrs..

 

 

[Cheshire Freeze]

Finally by 216 hours we start to see slightly more amplification in the hemispheric flow. Just starting to appear around the suggested (by some) mid month pattern change

 

Edited November 2, 2013 by CreweCold