Model Output Discussion

[Spurry]

Hi , haven't posted for a while , i tend to be out and about once the spring arrives , anyway....last night on the countryfile forecast Laura Tobin was suggesting a washout on friday as the fine spell breaks down, but no matter how many times i look at the GFS Charts all i can see is HP dominated weather thru'to Sunday...am i reading the charts wrong?..i would really like an accurate interpretation as it is my (49th) Birthday on Saturday and i was planning on spending it outdoors.

Thanks

Ian

Edited May 31, 2010 by Spurry

[johnholmes]

After watching this forum for over a year and experiencing all the ups and downs of model watching I have decided to join.

I agree its only the 0z GFS op run and its one of the coldest members and is unlikely to be correct , still plenty of warmer members.

We will wait and see what 06z brings

oh dear, I thought following every run for what FI showed was just a winter addiction-life is going to become very tedious if you go down this path for every day of every year, I fear!

[SP1986]

Even I too am quite baffled at the comments, I would have thought the selection of outputs on offer for the 0z is better than previous days. The Euros go for a slight extension of the settled spell, whilst with the GFS its as you were but some fairly decent weather to come.. still typically summery from a UK perspective.

For the youngens who have never experienced what a typical 'average' UK summer can be like, next week will be a great experience of it. We havent seen much typical UK summer over the last decade afterall.

[Cecil Hogmanay Melchett]

Even I too am quite baffled at the comments, I would have thought the selection of outputs on offer for the 0z is better than previous days. The Euros go for a slight extension of the settled spell, whilst with the GFS its as you were but some fairly decent weather to come.. still typically summery from a UK perspective.

For the youngens who have never experienced what a typical 'average' UK summer can be like, next week will be a great experience of it. We havent seen much typical UK summer over the last decade afterall.

Here here Ste,the 0z runs are much better,esp the ukmo model which has done a flip from the idea of the Atlantic roaring in on Fri to

settled warm weather.

Laura Tobin might have to revise the forecast for fri if the ukmo/ecm are correct.

UKMO

http://www.wetterzentrale.de/pics/Rukm961.html

http://www.wetterzentrale.de/pics/Rukm1201.html

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

The last chart would be introducing some very warm air from the SE.

ECM

http://www.wetterzentrale.de/pics/Recm961.html

http://www.wetterzentrale.de/pics/Recm1201.html

http://www.wetterzentrale.de/pics/Recm1441.html

Maybe not as warm as UKMO but certainly a flow from the SE albeit rather slack,potential for some thunderstorms.

[fine wine]

For those that come onto the forum for an unbiased opionion of the models it must be very difficult to read this thread at the moment . It seems we have constant talk of downgrades, poor weather and summer 2007 like patterns. The charts for this week show a warm and sunny 5 days after Tuesday. Great summer weather. The reality is the temperatures are usually 2-3c higher than predicted by the GFS. Look at the last warm spell we had - gin clear skies and temperatures as high as 29c but temperatures only predicted to max at 24 - 25c. Even during that spell of perfect late spring weather last week we had members on this forum going on and on about it wasn't that warm, wasn't that nice, wasn't that exceptional, was only localised etc etc etc.......... This week gone by has actually been rather nice, sunny spells most days (look at yesterday) and reasonable temperatures. If the weather improves further this week as predicted by the models then in my book that has been 3 weeks of good weather with just a couple of poor days thrown in.

The latest models (ecm) are hinting at prolonging this settled spell taking us well into June. Ofcourse, the unsettled charts may move out of FI, but for the time being they are staying the right side of T120.

[SP1986]

6z is having none of the UKMO/ECM outlook, wants to bring the unsettled weather into the west by Monday. Wonder who will win out?

[lukemc]

6z is having none of the UKMO/ECM outlook, wants to bring the unsettled weather into the west by Monday. Wonder who will win out?

Indeed thier does seem to be some quite autumnal looking deep lows in that FI but that's all it is - FI and the tendancy in the summer especially is for the lows to be downgraded nearer the time and I would not really consider those lows to be that viable at this time of year I would imagine a low of that depth and extent in June would be a rarity in itself so maybe it is GFS going of on one in FI again.

Anyway a few warm days to enjoy is in the bag even if that did occur. The only thing that would possibly worry me is that we were looking at similar charts this time year that moved into the reliable timeframe after initially being in FI during the warm spell at the beginning of June, but the positive thing was the unsettled spell did not last that long before warm settled weather again returned in later June/early July. I am not sure if we had cross model agreement then on the unsettled weather coming of - we don't at this present time as it is only the GFS that is going for this more unsettled option at present.

Anyway do you think that this summer could be at least more thundery than the last few is thier much potential for thunderstorm activity as I believe some poor/cool summers have also been quite thundery I believe that summer 1985 had some quite potent thundery outbreaks.

Luke

[snowlover2009]

thank god that unsettled weathe ris in FI!!! you can bin that must be a big outlier, all gfs has done in FI has brought incredible messy messy pictures with lows everywhere. in france the temps dont get above 20c! it is a joke. I think the americans need to consider doing the runs from 0 to 240 like ecm.

Indeed thier does seem to be some quite autumnal looking deep lows in that FI but that's all it is - FI and the tendancy in the summer especially is for the lows to be downgraded nearer the time and I would not really consider those lows to be that viable at this time of year I would imagine a low of that depth and extent in June would be a rarity in itself so maybe it is GFS going of on one in FI again.

Anyway a few warm days to enjoy is in the bag even if that did occur. The only thing that would possibly worry me is that we were looking at similar charts this time year that moved into the reliable timeframe after initially being in FI during the warm spell at the beginning of June, but the positive thing was the unsettled spell did not last that long before warm settled weather again returned in later June/early July. I am not sure if we had cross model agreement then on the unsettled weather coming of - we don't at this present time as it is only the GFS that is going for this more unsettled option at present.

Anyway do you think that this summer could be at least more thundery than the last few is thier much potential for thunderstorm activity as I believe some poor/cool summers have also been quite thundery I believe that summer 1985 had some quite potent thundery outbreaks.

Luke

nice to here your opinions, but why do you repeat the questions of the regards to how summer will pan out compared to other months. there has been plenty of opinions and you still ask and this is not the right thread for your question. you might get more answers if you put it in the appropriate thread, liek the summer thread.

Edited May 31, 2010 by snowlover2009

[MR EXTREMES]

please remember fi is fi its very unlikely it will pan out as shown for now it looks like improving.

[Rob]

please remember fi is fi its very unlikely it will pan out as shown for now it looks like improving.

agreed, too many people over-react to the FI when it's only an idication of possible developing theme

[SP1986]

please remember fi is fi its very unlikely it will pan out as shown for now it looks like improving.

I dont think it's always wrong to overreact to FI.. yes it can make people look ridiculous if it changes and leaves them red faced, however sometimes even FI can foretell of a potential trend or pattern.

Afterall this warm spell and the one before it turn up in what may be deemed as FI.

So I don't think concerns raised about FI are necessarily off the mark.

[Wilxy]

FI is only good if a trend has been developing for some time but when it shows something completly different i dont pay attention

[MP-R]

I dont think it's always wrong to overreact to FI.. yes it can make people look ridiculous if it changes and leaves them red faced, however sometimes even FI can foretell of a potential trend or pattern.

... perfect example being the heavy snow event of 16th/17th December 2009 being shown on the 3rd December.

[johnholmes]

the term FI is often bandied about, sometimes T+72 is used sometimes much further out.

The plain fact is that the further from T+00 then the more likely the prediction is to be not correct, sometimes not even remotely near the actual weather.

One must use, alongside the 2 main models out to T+240, what the larger scale models are showing, 500mb anomaly charts for the hemisphere, the AO and NAO, along with what the Tropics are showing and suggesting. The further out one goes then the more use of these teleconnections has to be used, out into ENSO, QBO and the outer atmosphere all help, note the word, help, to try to get a reasonable idea of what the major synoptics may end up. Beyond about T+120/144 and the best one can usually see, although as others have suggested GFS can sometimes be stunningly accurate, is to watch the upper air pattern, forget the surface, at least at first. In the 3 years I did checks on GFS at T+168 and beyond I would estimate it was nearly right or actually correct in some detail at the surface on about 40% of occasions using the 12z output.

Its an interesting exercise in seeing what the model at its furthest suggests but often nothing more, certainly without fairly solid back up from some of the teleconnections I've mentioned. Even when everything seems to agree things still turn out differently. Remember winter 2009 and how certain everything from the Stratosphere warming event right down to GFS and UK Met with ECMWF showing cold continuing only for February to become mild or very mild.

So caution is the word!

[Kentish Kiwi]

Remember winter 2009 and how certain everything from the Stratosphere warming event right down to GFS and UK Met with ECMWF showing cold continuing only for February to become mild or very mild.

So caution is the word!

And similarly how confident many were of December 2009 continuing the mild theme set in place through November with its extremely active Atlantic, only for a dramatic, rather surprising turn around to the easterly around the 18th and subsequent northerly that turned December into a cold, below-average month with above average snowfall and a 'snookered' Atlantic.

[glosteroldboy]

... perfect example being the heavy snow event of 16th/17th December 2009 being shown on the 3rd December.

Could that be a bit of luck/co-incidence? What were the models showing in the days after the 3rd of December, did the snow disappear for a while?

[MP-R]

Could that be a bit of luck/co-incidence? What were the models showing in the days after the 3rd of December, did the snow disappear for a while?

Obviously they did wobble slightly changing from a long-drawn easterly to a Scandinavian low but the general theme was a switch around to cold.

[rmc1987]

FI has been showing low pressure and cooler temps etc although not yet in the reliable. I think the trend is that it will become much more unsettled from Sunday/Monday.

Edited May 31, 2010 by rmc1987

[Backtrack]

Looks like a week of long sunny spells and temperatures peaking around 24c. High pressure dominating throughout the first week of June.

Finally some decent weather on the school holidays lol.

[Cecil Hogmanay Melchett]

Hum rather poor gfs 12z operational.Model has gone back to the unsettled theme after Thursday.

Hopefully the Euro's,esp the UKMO model will stick to the morning output.

[SP1986]

Correction: The GFS becomes unsettled after Saturday, however the persistence of the GFS for breaking down this pattern around the weekend suggests that this is definitely the pattern to go with. The GFS has actually been rather consistent with its detail over the last 2 days or so, so they ever changing ECM and METO may have to concede this one to the GFS.

However a thoroughly enjoyable week to come with a few days of warm settled weather.

The GFS in my opinion is right on the money with its breakdown date.

[fine wine]

The 12z shows a slightly warmer spell than the 06z with higher 850's but brings in the breakdown 6hrs earlier. It will now be interesting to see what the other 2 big models do.

[Cecil Hogmanay Melchett]

Correction: The GFS becomes unsettled after Saturday, however the persistence of the GFS for breaking down this pattern around the weekend suggests that this is definitely the pattern to go with. The GFS has actually been rather consistent with its detail over the last 2 days or so, so they ever changing ECM and METO may have to concede this one to the GFS.

However a thoroughly enjoyable week to come with a few days of warm settled weather.

The GFS in my opinion is right on the money with its breakdown date.

Yes i meant after Fri ste.A thoroughly awful run from gfs as we head into the weekend.If the model has a handle on the evolution we can expect a sustained spell of unsettled weather.

Not sure whether i agree with you about gfs being correct though,euro's this evening will be very interesting.FWIW GME looks quite similar to gfs at around 108h maybe the ukmo will have to back down this evening afterall.

[SP1986]

Yes i meant after Fri ste.A thoroughly awful run from gfs as we head into the weekend.If the model has a handle on the evolution we can expect a sustained spell of unsettled weather.

Not sure whether i agree with you about gfs being correct though,euro's this evening will be very interesting.FWIW GME looks quite similar to gfs at around 108h maybe the ukmo will have to back down this evening afterall.

I think up to 144 hours will be quite pleasant, warm and sunny, but thereafter it does look like things could turn unsavoury, but yes I would say the outcome is from decided between all the model outputs.

Ironically however in the scenario where the low moves over, the GFS presents quite a thundery showers scenario.

[Thundery wintry showers]

I think thunder potential prior to the breakdown is indeed pretty low on the GFS 12Z- possibility of some cells developing over the Midlands and heading into NE England but the SW flow is always the main issue for those hoping for some electrical fireworks. However the returning polar maritime regime following the initial frontal system contains large levels of CAPE and heavy showers, so as Stephen suggested a "thundery showers" scenario though too far out at this stage to pin down precise details.

It continues to appear that some will refer to an outlook as "awful" unless there's a big fat high constantly over the UK between T+0 and T+240. The outlook within the reliable timeframe sees high pressure in charge for a good few days, and as a result we are likely to see sunshine and temperatures come out well above the seasonal average for the first week of June with rainfall rather below in most places. The breakdown, though "knocking on the door of FI", does look likely to come off with a cyclonic regime following- then the strength of the jet will determine whether the results are predominantly dull & wet or bright & showery with thunder. I suspect the latter will apply initially especially in southern districts.