Model Output Discussion - Late October Onwards

[Grimsby Snow Lover]

528dam 500mb-1000mb as far south as Southern England on latest GFS run.

I noticed that too, the run even finishes with an easterly with the Scandinavian high extending towards Greenland. A real shame however as any chart that far out is very unlikely to materialise. In the shorter term the opening few days of Novemeber look well above average, especially the further south you go.

[snow drift]

528dam 500mb-1000mb as far south as Southern England on latest GFS run.

http://www.meteociel...&ech=276&mode=3

Yes your correct. Even if it is unlikely to materialise, its what I like to view as we move into the "show time" part of the year.

[Zakos]

Interesting to see that 3 out of the 4 last GFS runs have a northerly blast around the 7th of November.

I know its FI, but the consistency could mean something.

[feb1991blizzard]

I noticed that too, the run even finishes with an easterly with the Scandinavian high extending towards Greenland. A real shame however as any chart that far out is very unlikely to materialise. In the shorter term the opening few days of Novemeber look well above average, especially the further south you go.

I agree it is not going to happen, i think the best we can hope for now regarding timeframe of the first cold spell is december and after reading the stratospheric warming watch thread and GPs pre forecast thoughts thats starting to look less likely. As per John Holmes and GPs post this is a more likely pattern for early November and ties in well with the Met Offices monthly update.

http://www.meteociel...map=0&archive=0

Edited October 26, 2011 by feb1991blizzard

[Snowstorm1]

528dam 500mb-1000mb as far south as Southern England on latest GFS run.

http://www.meteociel...&ech=276&mode=3

Round 3? Yes I know its FI but these charts have a taste of last year with them could it just could it happen again... (Even I admit this run is far too progressive and quick though personally give it another two or three weeks ).

Anyways at least now there is something starting to show in the models to spice things up on here ; yes its FI but over the years I have noticed it picks up things then drops them then picks them back up at closer range so just an eye to keep things on instead of this mild dross

[BlueHedgehog074]

Interesting to see that the GFS is trying to bring back a bit of a Northerly wind in FI, as a Low-Pressure system tries to push itself East:

(arrows indicating the wind direction)

This appears to be a short-lived affair lasting for about 2/3 days as thin area of High-Pressure then attempts to knock the Low-Pressure sytem out to the North-East and another Low-Pressure system spills in from the Atlantic. In the deepest FI part of the run, the GFS models the approaching Atlantic Low-Pressure sytem to sink South-Eastwards as the Southern part of the Jet Stream goes to the South of the UK, and we end up with an Easterly towards the end of the run.

Clearly, it's very likely to change within the next run, but I do wonder if the GFS may be trying to pick out new trends. It could, however, that the GFS is still trying to be too progressive with this pattern breaking away that big block of High-Pressure to the East.

Edit: Was almost tempted not to post this since others have beaten me to the outlook with the GFS (lol).

Edited October 26, 2011 by Rainbow Snow

[summer blizzard]

I think that there are several things to take away from todays runs.

On the one hand we lose the high to the east which results in a much more mobile pattern and by day 9 the ECWMF has a polar maritime flow.

On the other hand the upstream pattern is not good and other than a brief period, we see a SW/NE tilted Jet Stream giving mild and wet weather.

The big difference between the GFS12z and ECWMF0z in my opinion is that after the polar maritime shot (GFS says day 11), the ECWMF goes back to a northerly tracking Jet Stream while GFS has a NW/SE tracking Jet Stream.

The ensembles do show some support for a polar maritime shot from about the 3rd.

[Frosty.]

At last there are faint signs of a colder pattern emerging beyond T+240 hours but it could just be white noise and amount to nothing. Next week is looking unsettled, mild and windy with the european high being shunted further southeast but it would take over 10 days for the troughs to push far enough to the east to allow colder winds to arrive, both the gfs & ecm show a lot of bottled up arctic air well to the north of the uk but no route for the cold air to reach the uk until well into november and even that is probably very optimistic. This weekend looks best in the southeast closest to the high with the north & west more unsettled with strong sw'ly winds so at least it will be mild.

[MP-R]

I think some people need to remember 2009. The charts at the moment are showing a gradual movement of the jet southwards which will not only bring more exciting weather over time with wind, rain, hail, thunder and snow to the north but also a possible eventual transition into something colder. The first sign of cold in 2009 came from a brief northerly on Nov 30th / Dec 1st so perhaps that's what we should be looking for rather than the Siberian or Scandi high.

[Aaron]

That's what I've been saying.. who cares if November is mild.. it isn't a winter month so is not important.

[Grimsby Snow Lover]

That's what I've been saying.. who cares if November is mild.. it isn't a winter month so is not important.

Totally agree. A lot of places in the east really need the rain. So if November does turn out to be as unsettled and mild as the models suggest then hopefully the places that need the rain will get the rain. The cold can hang on until WINTER when its more use.

Edited October 26, 2011 by Grimsby Snow Lover

[Gibby]

Hi folks. Here's my look at the 12zs.

GFS tonight shows Low pressure moving slowly in from the NW over the weekend while a temporary weak ridge of High pressure gets nudged away East from Southern Britain. After a rainy day tomorrow Southern and Eastern regions dry up for the weekend with milder temperatures developing yet again. Further north and West rain arrives by saturday and gradually over the next few days this makes its way slowly and erratically SE to the remainder of Britain. As we move through next week the weather becomes more deeply unsettled everywhere with heavy rain and showers for all with temperatures reverting to normal values and maybe somewhat below in Northern regions at times. This weather type continues through FI before a change to cold Easterlies develop in response to High pressure over Scandinavia very late in FI.

The GFS Ensembles for both London and Aberdeen show fairly normal uppers for the oncoming two weeks. The operational was something of a cold outlier at the end of FI with the majority of members maintaining a more Westerly weather type right to the end with plenty of rain events for all.

UKMO tonight shows a trough moving NE into Southern areas later tonight and tomorrow. This weakens later tomorrow as a ridge moves in ahead of a SW flow which takes over through the weekend. After rain for many tomorrow friday will see a better day after fog clearance. Winds will freshen in the NW with rain there by Saturday, a process which continues through the following days. By 144hrs things look like turning wet and windy if mild for all areas by midweek next week.

ECM follows UKMO tonight so that by midweek deep Low pressure has closed in on the UK bringing gales and heavy rain at times for all. Things remain relatively mild, though by the end of next week a few colder incursions of air look possible chiefly in the North.

In Summary tonight the weather looks unsettled and often windy with rain or showers for all. temperatures would in general be close to average though a few milder interludes are shown in the SE to begin and some colder weather is possible in places later in the North as the Low pressure areas move on progressively more southerly latitudes.

Edited October 26, 2011 by Gibby

[Isolated Frost]

Big cold bias on here now. We need more impartial posts instead of FI every other post. I don't mind it, but its getting annoying now.

Merid. flow with jet moving about with Tm, rPm and Pm flows throughout. Tomorrow generaLly looks wet and cloudy. Friday and Saturday warmer and sunnier. Looks a very unsettled theme will lows nearby and the high possibly falling by day 8-11.

[johnholmes]

Big cold bias on here now. We need more impartial posts instead of FI every other post. I don't mind it, but its getting annoying now.

sadly IF its the pattern for the next x months I'm afraid-I'm sure by now you already have a list of those who try and post objectively.

In all honesty nowt has changed since my post this morning-no sign of anything other than brief temporary cold behind lows tracking west to east or if any temporary ridge coincides with overnight for frost in places.

Looking at every run and hope casting is a waste of time but then I've lost count of the number of times I've posted this with some disliking my view.

Look at all available outputs, take just one run, for each model each day, stick with it, check the 500mb anomaly charts for any continuous trend, check the NAO and AO, the MJO, read the technical thread for ouputs from those well known for their understanding.

Otherwise it can be a very very long and frustrating winter, but to a lot its fun watching the changing charts at long time scales and is of course what a lot want to do.

Edited October 26, 2011 by johnholmes

[ANYWEATHER]

To be Honest, Im certainly not looking for Winter cold right now. Last Novembers Wintry cold spell was a "fluke", and not likely repeated for "some" time. The models are bringing us the real true "BestOfBritish" Autumn weather for the forseeable future. Wind and Rain look pretty certain in the near future hopefully alleviating some of the Uks driest areas although im certain that many folk around the Uk dont wanna see any more rain! Anyway a normal service of true British Late Autumn weather

[Isolated Frost]

Yes John I will look at them a bit more now and hope others heed your advice.

Very zonal flow I meant on my last post. (Edit)

Snow only likely above 300m in the north at the best of times; run of the mill Tm and rPm weather for the halloween-bonfire weather. Temperatures about 2-4c above average by day and maybe more at night until bonfire night at least; quite mild and at times very mild but when that polar influence comes in, closer to average and maybe a touch below when a clearer, showery polar maritime flow as lows track further south and east than nornal.

[gottolovethisweather]

I don't often post in here, as I try not to pollute this thread with my unscientific guesses. However, like others, I often get a hunch or two from time to time, when viewing my favourite model's output (mine, tending to be the GFS). Well, I posted this on my status update just 2 days ago and it still seems valid, as far as I can tell.

Just to think that in about 30 days time we were about to enter the coldest final week of November on record. And what's more, the coldest December for over 100 years was to follow. This time around, we're not there yet, BUT, I believe the GFS output in particular is hinting at the first Northerly toppler due for the 2nd week in November. It's until such time, I cannot foresee any wintriness of any note in the UK? All in my humble opinion.

As per above, purely using the GFS (eg: 06z consecutive runs) it's been picking up a consistent signal since it's dropped the High Pressure down south idea. It now indicates (as do GP, GIbby, JH, IF etc.) that we are locked into an unsettled period right through to the 2nd week of November, at least! albeit, with occasional colder NW'ly flows. HOWEVER, it's not beyond the realms of possibility/probability that from the FULL MOON period 7th-13th we will see MUCH COLDER PROSPECTS. Maybe? If, this is to be the case, my gut instinct would be a Northerly Toppler then, after this, back to westerly driven wind n gales.

Before then, some more wet weather for the southwest and parts of the south, a brief HP visitation and then back to the westerly flow for a few days.

Anyhoos that's my input for what it's worth.

Cheers

gottolovethisweather

Edited October 26, 2011 by gottolovethisweather

[Mark Parsons]

Have to agree with John. My take on the current weather patterns is of a "normal for this time of year "trend. There has been to much hope balanced on the previous 2 winters and to be honest there seems not much to support anything the same ATM. Fair enough if one wants to believe in FI but this also should be compared with the more serious technical side.

The pattern does seem set on a generally mild Nov with the short lived cooler spells which is what I would expect, so be patient cold lovers!!!!

[nick sussex]

The GEFS is still reluctant to move that ridge to the east too far and it looks like the stalemate will continue for a while yet.

However some of the later outputs of the ECM and GFS do suggest a little more interest in terms of a return to more average temps with the chance of something a little colder for the nw but any colder interludes still look brief here.

We really need to see the back of that limpet ridge and a big shift east in the pattern but this still looks like it will take some time.

We're just about heading into November so we should just be patient and see what happens when we break out of this stalemate.

[johnholmes]

At the moment all the models are showing much the same ideas out into the start of November, be it the synoptic model, see below for GFS, almost identical to the ECMWF chart for the same day;

or the 500mb anomaly charts you hear me go on about so much, see below

I do prefer a daily look at these rather than the hour by hour dissection at times of each GFS run. All 3 main models swing about at times but the 500mb anomaly charts are much much less prone to do this. They are often a much better indicator of if the pattern is going to stay much the same or if there is an indication of a pattern change.

Both the above show the major upper trough in about the same place and about the same height value and other major items are very similar-a strongish 500mb Atlantic flow for one suggesting its going to be unsettled with the air Pm at times and at other times Tm, so mild with short bursts(chiefly for the more noerthern areas) of colder air. Although unsettled it does not preclude the temporary development of a surface high between the surface lows.

When the synoptic models, GFS, ECMWF, GEM etc at the 10 day time scale are pretty much like the 500mb anomaly charts then we can usually expect that the overall upper air pattern is pretty certain to be close to what is showing. What can and often does happen is that the models 'fine tune' the lower 18,000ft of the atmosphere and the actual surface pattern may differ somewhat from what the synoptic models show out at day 10.

For a solid belief in the 500mb type chart then they need to be showing a similar upper air pattern, all 3 of them, NOAA, GFS and ECMWF, to be really confident in using them.

Remember they are only valid out to about 10 days, NOAA to 14. Beyond that then AO, NAO, MJO are the firt things to look at along with a daily peek at the 500mb charts.

Edited October 26, 2011 by johnholmes

[Snowmad79]

From what I can tell, in the early parts both the ECM and GFS have the polar vortex strengthening with LP the dominant factor over the poles, however at 144hrs both show some sort of split occuring along with a degree of height rises at the pole after this apparent split. This paticular feature being modelled in the reliable could acutally have a significant impact on the over global pattern post 150hrs couldn't it ?

For example, wouldn't the net result of that be less energy being added to circulation around the pole (reduced westerlies), thus weakening the jet stream if hieghts do rise over the pole?. It could lead to more meandering of the jets track especially where deep low forcing occurs (the tough forming and moving west to east over the uk around 168+) ?

http://91.121.84.31/modeles/gfs/run/gfsnh-0-192.png?12

This is less so on ECMWF, as per the stratospheric veiw of winds in the north inc the jet (from chinio's thread) the ECM is biased towards a quick jump north in the average lattitude of the jet in deep FI) which would be a strengthening of the westerly component assocaited with LP over the pole rather than a weakening that you would get if heights did rise over the pole.

Not desperate to see cold synoptics, I'm just trying to figure how the over all pattern may or may not change later down the line Thanks.

[ITSY]

well the GFS 18:00 output has put the cat amongst the pegions!! Albeit in the unreliable range, but from around +192 all the way through to +348, it has the northern HALF of the UK in a week long cold spell, with northern england the coldest place in Europe by night with temps upto -5c and with day max's between 3-5C. transient snow events definately possible for higher elevations, with sub 528 air over northern Britain for at least 3/4 days in that period. definately a cold outlier, but very interesting possbility for all those (including me) who thought anyway significant cold would be weeks away - particularly given that the 12Z started a 3 day cool spell over the same period.

First properly cold(ISH) run of the autumn for northern Britain from GFS, there.

[Liam J]

ECM outputs remain consistant that the weather is about to turn much more unsettled especially next week, potentially stormy times ahead as the jet increases in strength. Wet and windy with gales or severe gales likely at times further N & W, relatively mild for the time of year but it won't feel like that in any wind and rain.

Perhaps something cooler on offer later next week with the GFS showing a cool down in FI on the 18z run which is no doubt a cold outlier but it would produce wintry weather on the hills over Scotland perhaps N England which isn't out of the ordinary for late October, the -5c isotherm stays over Scotland and the 528 thickness reaches further south briefly, GFS low res has shown a few cooler outputs which never seem to progress out of FI.

Edited October 26, 2011 by Liam J

[summer blizzard]

Snowmad is correct that the split in the Polar Vortex does allow the low to move east of the UK with a polar maritime shot, ECWMF and GFS have the cold front clearing southern England at day 9 which seems to be a maintaining trend.

Despite the wonders of the 'GFS pub run' as it is known, i am doubtful that this cold shot will last long and snow still looks unlikely outside Scotland (very similar to the previous 2 polar maritime shots in October). There is also disagreement as to what happens afterward with GFS having a reload scenario while the ECWMF has the jet orientated in a way which would likely lead to a washout over central and northern England a few days afterward.

We have a trend, we now need to maintain that in the high resolution phase.

[Radiating Dendrite]

Nice to see an increasing amount of Ensemble runs starting to go colder in FI now. Will be interesting to see if this maintains itself and gets closer to the reliable.

I think we can expect a bit of a pattern shift in around 14-18 days time I believe.

Edited October 27, 2011 by Radiating Dendrite