Jump to content
Thunder?
Local
Radar
Pollen
IGNORED

12z Model Comparisons Results


Recommended Posts

Posted
  • Location: Lincoln, Lincolnshire
  • Weather Preferences: Sunshine, convective precipitation, snow, thunderstorms, "episodic" months.
  • Location: Lincoln, Lincolnshire

    Test 1: Evaluating Thursday 9th March at T+96. An easy starter for the models.

    Actual Synoptic Situation: Low at 985mb just west of Britain. 1015mb Scandinavian High, southerly winds over the British Isles and low pressure in charge. Shallow low at 1000mb to the East of Britain.

    GFS: Had the low that currently sits to our west, over the top of the British Isles at T+96. S winds in the southwest of England were shown as NW winds by the GFS at T+96. However, apart from the error in positioning of the low, other features were spot on. I'd give it 7/10.

    UKMO: The UKMO had the low too far northwest, with high pressure closer to the east, and a broad SW flow over Britain, rain moving east. Probably a 6/10.

    ECMWF: Had the Scandinavian High slightly closer than it turned out to be, but otherwise a near perfect prediction. I give it 9/10.

    NOGAPS: Shallow low stuck over Britain with Icelandic Low was the NOGAPS prediction- quite a way off, 3/10.

    JMA: Almost identical to ECMWF, with 9/10 the score.

    GEM: Almost identical to UKMO, hence 6/10.

    Thus, the first comparison seems to have the ECMWF and JMA score highest, with the GFS in third, the UKMO and GEM doing okay, and the NOGAPS well off. My inkling, however, is that the JMA won't score as well in the next few results!

    Link to comment
    Share on other sites

    • Replies 541
    • Created
    • Last Reply
    Posted
  • Location: Upper Tweeddale, Scottish Borders 240m ASL
  • Location: Upper Tweeddale, Scottish Borders 240m ASL

    Great summary TWS ;)

    Link to comment
    Share on other sites

    Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks

    thanks for that Ian, very useful. I hope you keep a running total so that in a few months time, if you are still doing it, we can see which is doing the better out of them.

    John

    Link to comment
    Share on other sites

    Posted
  • Location: Lincoln, Lincolnshire
  • Weather Preferences: Sunshine, convective precipitation, snow, thunderstorms, "episodic" months.
  • Location: Lincoln, Lincolnshire

    Yes, I completely agree with that, it is certainly my intention to keep a running total.

    Link to comment
    Share on other sites

    Posted
  • Location: Lincoln, Lincolnshire
  • Weather Preferences: Sunshine, convective precipitation, snow, thunderstorms, "episodic" months.
  • Location: Lincoln, Lincolnshire

    Friday 10th March 2006: Models had to get T+96 and T+120 right this time.

    Current Scenario for 12Z: Low pressure at 995mb off East Anglia, slack pressure gradient over Britain but with cold easterlies extending into Scotland via the Scandinavian High at 1020mb over NW Scandinavia. Westerlies in southern England.

    GFS: Very good at T+120; there was a secondary low west of Ireland progged at T+120 that didn't materialise, but it had a slack pressure gradient over Britain, westerlies in the south and cold easterlies flooding into Scotland.

    At T+96 there was a low over Britain that had been deepened to 990mb and was progged very close to where it actually ended up. The general pattern of easterlies in Scotland, westerlies in southern England and a slack gradient over the rest of Britain remained.

    A solid 9/10 for me, and a good performance from the GFS.

    UKMO: At T+120 there was a deep low at 985mb over Britain with strong winds and heavy rain, and no Scandinavian High influence.

    However, at T+96 it was falling into line with the actual outcome, with a slack 1000mb low over Britain. It had a secondary low west of Iceland that didn't materialise, but the Scandinavian High, easterlies for Scotland and southerlies for S England were intact.

    Given the discrepancy at T+120 I can't rate the UKMO as highly as the GFS for this one. 6/10.

    ECMWF: A good performance at T+120 with a 1000mb low progged over the Midlands and easterlies extending into Scotland, and at T+96, it had the low intact in roughly the right position with easterlies for Scotland and southerlies for southern England.

    Probably about level with the GFS, so a score of 9/10.

    NOGAPS: Well off at T+120 with the low that ended up over us, progged to be over NW Scotland with attendant south-westerly winds across Britain. At T+96, however, NOGAPS came into line with the correct outlook.

    Only a 5/10 from me I'm afraid, at T+120 it was even further from the reality than the UKMO, but at least it got T+96 right.

    JMA: Accurate at T+120, with an almost identical outlook to ECMWF, at T+96 the general pattern was still there although it had the main low over Britain centred a bit too far south, with the primary centre just off south-east England. Still good on the whole.

    Probably 8/10 for the JMA; not quite as good as GFS and ECMWF but certainly very close.

    GEM: Way out at T+120, with the Azores High projected to start dominating the weather and westerly winds over Britain. It did, however, fall into line at T+96 with broadly the correct pattern.

    Overall a 5/10 because of the T+120 cockup, of similar magnitude to that of NOGAPS.

    Overall, today ended in a tie between the GFS and ECMWF both of which were close to perfect at both T+120 and T+96. In the overall standings ECMWF, GFS and, surprisingly, JMA, are the models that performed best over the past two days.

    Link to comment
    Share on other sites

    Posted
  • Location: Exeter, Devon, England
  • Location: Exeter, Devon, England

    That's interesting Ian, thanks for putting it together.

    ECMWF is my model of preference when looking at the T120 - T168 timeframe and to see it score 9/10 is indeed very encouraging. I think it's also had a pretty good handle on the situation for next week, but time tell will I suppose. Interesting to see the JMA score high- usually one of the less seriously taken models in that timeframe.

    Link to comment
    Share on other sites

    Posted
  • Location: Lincoln, Lincolnshire
  • Weather Preferences: Sunshine, convective precipitation, snow, thunderstorms, "episodic" months.
  • Location: Lincoln, Lincolnshire

    Sadly I was out late last night, so I didn't get all of the results in for yesterday's model comparisons, which will have implications further down the line- one run will be missing for next Tuesday, Wednesday and Thursday.

    However, today's model test involves all three timeframes- evaluated to T+96, T+120 and T+144.

    Actual Situation on Saturday 11th March: 1025mb high centred over western Scandinavia with a ridge into north-eastern Britain, light east winds over Britain, 995mb lows to the S and W of Iceland and southerly winds pushing eastwards into western Britain.

    GFS: T+144 had a low at 980mb over SE England and a 995mb low off western Scotland and cold east winds flooding in. The main error was the 980mb low. At T+120, we were sandwiched between an Azores and Scandinavian High, with little wind across the country, so it underdid the Scandinavian High a little but was pretty accurate. At T+96, the GFS went for a far too progressive outlook with strong SW winds, mild temperatures and the Scandinavian High being pushed away eastwards.

    Only a 6/10 from this one- the projections were broadly similar to what happened, but it was still having difficulties at T+96 and underdoing the Scandinavian High.

    UKMO: At T+144 there was a weak low to our east at 1000mb and a deeper low to our W. Cold east winds were forecast to flood into the north; the 1000mb low was its main error. T+120 was quite good, with light E winds over Britain, the highs and lows in similar places to the outcome, although the Azores High was slightly overdone. At T+96 the Azores High was again overdone a little but the outcome remained broadly correct, with light E winds over Britain and a southerly flow moving E at the battleground.

    I'd give it 8/10- a dodgy T+144 output but it was good at T+120 and T+96.

    ECMWF: At T+144 the evolution was remarkably accurate with light E winds for Britain and the Scandinavian High and Azores High of correct intensities, although the westward extent of cold air was underdone. A bit of a wobble at T+120 though as it showed mild westerlies over Britain already pushing the cold block away eastwards. T+96 was better but with the battleground with southerlies a bit further east than actually happened, and the Scandinavian High underdone.

    I'd have to mark this one down at 7/10 for although ECMWF was very accurate at T+144, it fell down at T+120 and T+96.

    NOGAPS: At T+144 it was broadly accurate with Britain sandwiched between Scandinavian and Azores Highs, the Scandinavian High slightly underdone. T+120 was a slight wobble with a strong NE flow projected for SE England but the highs, and low to the NW, were close to the right places. T+96 again good.

    8/10 for the NOGAPS- there were slight errors particularly at T+120 but it was broadly correct at all three timeframes.

    JMA: At T+144, it was as NOGAPS- broadly correct, just the Scandinavian High slightly underdone. However at T+120 the outlook was far too progressive with SW winds sweeping across Britain, and remarkably at T+96 it had low pressure over Britain!

    I'm afraid, only a 4/10 this time- I don't think I would be justified in awarding a model 50% or above if it got T+96 completely wrong, even if T+144 was accurate.

    GEM: Had a far too deep Icelandic Low, no close-proximity Scandinavian High and south-westerlies at T+144; a complete write-off. At T+120 it was quite accurate though with the Scandinavian High only slightly underdone, but at T+96 the outlook was too progressive with the mild air having already arrived from the west.

    About 5/10 I think, too inconsistent again, slightly worse than the GFS.

    So in today's outlook, it appears that the UKMO and NOGAPS handled the Scandinavian block reasonably well, while the ECMWF had some problems but was fairly okay. GFS, JMA and GEM all had problems with a tendency to bias towards a progressive outlook, which is consistent with what people say about the Euro models handling eastern blocking better than the GFS.

    Link to comment
    Share on other sites

    Posted
  • Location: Lincoln, Lincolnshire
  • Weather Preferences: Sunshine, convective precipitation, snow, thunderstorms, "episodic" months.
  • Location: Lincoln, Lincolnshire

    Just had a quick glance through my analysis for tomorrow's charts at T+96, T+120 and T+144 in the other thread, and I think you could well be right. :lol:

    Link to comment
    Share on other sites

    Posted
  • Location: Lincoln, Lincolnshire
  • Weather Preferences: Sunshine, convective precipitation, snow, thunderstorms, "episodic" months.
  • Location: Lincoln, Lincolnshire

    So, now for today's results (heh heh heh)...

    Actual Situation at T+6 today: 1030mb high extending from Scandinavia into the North Sea. 990mb lows around Iceland. Strong southerly winds across Britain.

    GFS: A write-off at T+144, with a 980mb low off NW Scotland and gale force westerlies and not a Scandinavian High in sight. It was no closer at T+120, with a low north of Scotland and a secondary low over central Britain and westerly winds. The low was still there at 990mb to the north of Scotland at T+96, with westerly winds, and that secondary low remaining across central areas. Still not a Scandinavian High in sight.

    I don't like being overly harsh but I feel I have to give it a 1/10, it was never even near the correct outcome.

    UKMO: A bit closer than GFS at T+144, with a 1035mb high off SE England, and a 975mb Icelandic Low. However, the outcome on the UKMO was a broad south-westerly, rather than southerly, flow, due to the lack of highs over Scandinavia. T+120 was further off, with LP to our NW, high pressure to our SE and a west to south-westerly airflow.

    However T+96 was quite close to the actual outcome, with a 1025mb Scandinavian High and 1020mb Euro High and SSW winds across Britain.

    A 6/10 for the UKMO, it had the low and high positioning not far off at T+120 and T+144 but the specifics over Britain were very different (SW winds), then at T+96 it was quite accurate.

    ECMWF: At T+144 it committed a similar error to the UKMO; the lows and highs were in approximately the right places, but the Scandinavian High was underdone and Britain had south-westerlies. At T+120 it gravitated towards the GFS outcome with a low north of Scotland and WSW winds, and stuck with it at T+96 although the Scandinavian/North Sea block was there, just too far east.

    A 4/10 for this run from ECMWF, it didn't fall into line with the correct outcome at all, but at least it had the lows and highs in approximately similar places to the actual outcome.

    NOGAPS: Way out at T+144, low to the north, high to the south, WSW winds. At T+120 it had the battleground too far east and gave us SW winds, but at least there was a 1030mb Scandinavian High on the chart. At T+96 it went completely off the rails with low pressure and north-westerly winds.

    A 2/10, simply because T+120 looked vaguely similar to the actual outcome.

    JMA: At T+144 it was nowhere near with a blustery showery westerly and low pressure over NE Scotland. However the T+120 chart was recognisably similar to the correct outcome, it had the lows and highs in roughly the right places but overdid the Icelandic Low, giving SW winds to Britain. At T+96, however, it had broadly the correct outcome with high pressure to the east and south and southerly winds over Britain, though the high to the south was overdone.

    A 5/10, it at least got close to the right outcome by T+96.

    GEM: At T+144 it had an overdone Icelandic Low and highs to our east and SW winds, but the positioning of highs and lows was similar to the actual outcome, just that the battleground was further east. However at T+120 it was way off with a showery north-westerly regime. At T+96 it was broadly correct though the high pressure to the south was overdone, and the battleground was displaced a bit to the east of where it should have been with SSW winds over Britain.

    A 5/10 also for GEM, it had a bad wobble at T+120 but T+96 was pretty accurate.

    Awarding scores today was very difficult as the performance was generally poor. The UKMO, JMA and GEM finally stumbled on the correct outcome by T+96, while the GFS was never anywhere near the correct outcome. The UKMO just shaves it because as well as finding the correct evolution at T+96, the charts at both T+120 and T+144 were at least recognisable relative to the actual outcome. ECMWF consistently showed a WSW flow over Britain but it did have the lows and highs in recognisable positions.

    At the moment, after 4 days, the ECMWF is in the lead with an average of 7.3/10, followed by UKMO and JMA, with GFS in fourth and GEM 5th. NOGAPS, with an average of 4.5/10, has performed worse so far.

    Link to comment
    Share on other sites

    Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks

    tks for doing this Ian. I know its a lot of work but it will be highly useful to see these scores over the weeks ahead, if you can keep it up.

    thanks

    John

    another comment relevant to the T+168 from GFS is, take a look at the competition No 20 for Eskdalemuir. Most of us were not too near the real weather for today.

    John

    Link to comment
    Share on other sites

    Posted
  • Location: Lincoln, Lincolnshire
  • Weather Preferences: Sunshine, convective precipitation, snow, thunderstorms, "episodic" months.
  • Location: Lincoln, Lincolnshire

    Monday 13th March 2006 Situation at T+6: 995mb low to the west of Scotland, SSW winds over Britain. 1040mb Scandinavian High.

    Results:

    GFS: Quite a way out at T+144 with a Bartlett High situation, 1000mb/990mb lows to the north of Scotland and westerly winds veering to the SW. It showed the same thing at T+120. However by T+96 it had the 995mb mid Atlantic low quite well positioned, though overdid an Icelandic Low and had the Scandinavian High placed over Germany. Winds over Britain were mild SWs though with the battleground much further east.

    A 3/10 here- at T+96 it finally latched onto something similar to the correct outcome, but overall poor.

    UKMO: A long way off at T+144, with similar output to the GFS and no sign of any Scandinavian Highs. However at T+120 it had the SSWs correctly over Britain, though with the Scandinavian High underdone, but at T+96 it went off the rails again with low pressure over NW Scotland and a very progressive, SW'ly outlook.

    A poor output from the UKMO also, though I will give it a 4/10 as it at least got T+120 vaguely correct, and T+96 was no worse than on the GFS.

    ECMWF: Had the Scandinavian High underdone at T+144 with mild SW winds over Britain and a strong Atlantic influence. At T+120 and T+96 it persisted with this outlook, with high pressure over the Baltic, lows to the N and W and a south-westerly influence over Britain. The continental air input was strongly underdone.

    Probably a 5/10 for this one, it had the lows and highs in vaguely similar position but the outcome was Atlantic south-westerlies.

    NOGAPS: Similar to GFS at T+144, "Entire Grid Undefined" at T+120 and then a low pressure dominated, westerly regime at T+96. No Scandinavian High in sight.

    This time it is NOGAPS' turn to get 1/10 without anything remotely resembling the correct outcome.

    JMA: At T+144 it went for a very low pressure dominated outlook with SW winds. However at T+120 it had the evolution broadly correct, and similarly at T+96, but with the high centred over the Baltic rather than Scandinavia resulting in much milder SSW winds.

    Probably another 5/10; the T+120 and T+96 were similar to the correct outcome but at T+144 it was well out.

    GEM: Low pressure in charge at T+144 with westerlies. It was similar at T+120 with westerlies, but at T+96 moved into line with a similar outcome to the correct one, albeit with SW winds and less continental influence than there should have been.

    Similar in terms of accuracy to the GFS so I give it 3/10.

    A very poor set of results for the models today, showing that they had great difficulty with underestimation of the Scandinavian High. Not to worry, marks are likely to pull upwards again once the easterly gets underway. The ECMWF is still in the lead in the current standings.

    Link to comment
    Share on other sites

    Posted
  • Location: Lincoln, Lincolnshire
  • Weather Preferences: Sunshine, convective precipitation, snow, thunderstorms, "episodic" months.
  • Location: Lincoln, Lincolnshire

    Today's comparisons, and here's hoping for some better performances...

    Situation: 1015mb low over NW Scotland with light southerly winds for most, 1045mb high over Russia extending into Scandinavia. Mild air extending E (but due to be pushed back W tomorrow, of course)

    GFS: At T+144 it had an over-deepened 995mb Low over NW Scotland with SW winds over Britain, and no Scandinavian/Russian High in sight. T+120 was closer, with 1005mb over NW Scotland, SW winds, and a large high centred over the Baltic. Similar at T+96.

    5/10 for this one, the low to the NW was consistently positioned correctly but it took until T+120 to find the high to the east, which it promptly situated too far south.

    UKMO: Was pretty close to the mark at T+144, low to the NW slightly overdeepened at 1005mb, but had a 1045mb high around Murmansk (very close to where it actually ended up) but it did have the cold continental air further east. However at T+120 it had fallen into line with the GFS output, with a Baltic High and the mild air way too far east. T+96 unavailable.

    I give it 6/10, it was closer than the GFS at T+144, but about as far away at T+120.

    ECMWF: Way off at T+144 with 1000mb low over N Scotland sweeping mild WSW winds in, and no sign of the Scandinavian High. T+120 as GFS and UKMO. T+96 unavailable.

    Again 5/10- similar level of accuracy to GFS.

    NOGAPS: 1000mb low over SE England and 1015mb high to the north at T+144 with north-easterlies over Britain- way out. At T+120 it had a progressive W'ly outlook with a long drag of south-westerlies approaching. T+96 unavailable.

    1/10 I'm afraid, it was nowhere near.

    JMA: A bit out at T+144, low positioned over N Scotland, W winds, and highs to the W and E, the high to the E underdone. T+120 not so good, WSW winds over Britain and signs of a mild southerly drag taking over.

    I give this run a 4/10.

    GEM: Slack low over N England at T+144 with slack highs to the W, S and E, quite a way out overall. Closer at T+120 with a high over Scandinavia, but again the low too far East with westerly winds.

    Another 5/10.

    I scaled marks up a little because of the lack of a T+96 output (I was out late on Friday night), in general the models underdid the continental block but a better performance than before. UKMO just shaves it, unusually, due to its greater accuracy at T+144 than the others.

    Current standings after 6 days: ECMWF 6.5, UKMO 6.0, JMA 5.8, GFS 5.2, GEM 4.8, NOGAPS 3.3. I am very surprised at how well the JMA has been doing, I expected it to be well down there with NOGAPS.

    Link to comment
    Share on other sites

    Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks

    excellent Ian.

    Note to Paul

    I really think what Ian is doing needs to be kept safe as over a period the cumulative marks, along with his assessments may be extremely useful.

    Can you ensure all his posts are put somewhere safe please?

    I also make the point in the forecasters thread.

    regards

    John

    Link to comment
    Share on other sites

    Posted
  • Location: Lincoln, Lincolnshire
  • Weather Preferences: Sunshine, convective precipitation, snow, thunderstorms, "episodic" months.
  • Location: Lincoln, Lincolnshire

    model_comparisons.xlsToday's comparisons.

    Actual Outcome: ESE winds covering Britain, with ENE'lys in the North Sea. 1040mb High from Scandinavia to Russia.

    GFS: At T+144, high was located over Britain rather than Scandinavia, with 1015mb Scandinavian Low (!) shown on the chart. T+120 was similar. However, at T+96 the GFS was completely spot on with its prediction.

    I give it 5/10, because T+144 and T+120 were totally out from the correct outcome- but T+96 was excellent.

    UKMO: Similar error to GFS at T+144 with the high over NW Britain and little wind, apart from slight NNE wind for the East. No data at T+120 sadly, but at T+96 it was spot on.

    5/10 again, for the same reasons as GFS.

    ECMWF: It wasn't too bad at T+144, with a 1030mb high north of Scotland, and chilly east to north-easterly winds. Highs and lows were in the wrong places but at least it showed a continental regime. No data for T+120, but spot on again at T+96.

    A 7/10 for the ECMWF, having picked up on the easterly regime quite early.

    NOGAPS: No resemblance at T+144 with a long draw of mild southerlies. However, accurate at T+96, so another 5/10 mark.

    JMA: At T+144 had southerlies over Britain and a strong high over the Baltic, although at least it did have the continental blocking in place. It struggled at T+96 with the high centred too far SW, over northern Britain, and not much of an easterly regime.

    Because of its underperforming at T+96 I will only give the JMA 4/10.

    GEM: Similar to ECMWF at T+144; lows and highs in the wrong places, but correctly identified a continental regime. At T+96 it was spot-on.

    A 7/10 for GEM, it performed the same as the ECMWF.

    Looks like the models finally came into line with the continental block by T+96, with only JMA having some problems. Marks should be a lot higher come tomorrow.

    Link to comment
    Share on other sites

    Posted
  • Location: Lincoln, Lincolnshire
  • Weather Preferences: Sunshine, convective precipitation, snow, thunderstorms, "episodic" months.
  • Location: Lincoln, Lincolnshire

    model_comparisons.xlsComparison for Thursday 16 March 2006: I expect some decent marks this time.

    Actual situation: ENE winds over Britain, 1040mb high centred to the N and NE of Scotland, just west of Scandinavia.

    Note: T+144 runs are missing because of my late night last Friday. Complete sets resume tomorrow.

    GFS: Performed very well at T+120 with ENE winds correctly situated over the British Isles. The high pressure was correct in terms of intensity, positioned further east than the actual outcome (centred over Scandinavia at both T+96 and T+120) but the general pattern was spot on both times.

    A 9/10 for the GFS, apart from a minor quibble about high positioning it was spot on, a dramatic turnaround from the last few days.

    UKMO: Another accurate set of runs. At T+120 it had the evolution almost perfect, and at T+96 although the high was positioned a bit further east than the actual outcome, it had the pattern spot on.

    Also 9/10 for UKMO.

    ECMWF: This model positioned our high, if anything, a little to the west of where it ended up, but the pattern of east to ENE winds was spot on at both T+120 and T+96.

    Also 9/10 for the ECMWF, little to fault.

    NOGAPS: Correct at T+120, but at T+96 it underdid the easterly flow, having the high to our north too dominant and giving us only slack easterlies.

    Only 7/10 for NOGAPS due to its veering off-course at T+96, though it still kept us in an easterly.

    JMA: At both T+96 and T+120, the high to our north was positioned too far south, and the easterlies were underdone- indeed, at T+120, only southern Britain actually had much in the way of wind at all.

    Only 5/10 for JMA: poor positioning of the high, and is ranked lower than NOGAPS because T+120 was also quite a way out.

    GEM: Pretty accurate at T+120, but with the high too far east, the flow over Britain was spot on. However at T+96 it had the high too far south, so while southern Britain was correctly predicted easterlies, northern Britain was stuck underneath high pressure.

    Only 7/10 for GEM, similar accuracy to the NOGAPS.

    Link to comment
    Share on other sites

    Posted
  • Location: Lincoln, Lincolnshire
  • Weather Preferences: Sunshine, convective precipitation, snow, thunderstorms, "episodic" months.
  • Location: Lincoln, Lincolnshire

    model_comparisons.xlsComparisons for Friday 17th March 2006. Who will win this time?

    Actual synoptic situation: 1040mb high just to the N of NW Scotland, easterly winds over Britain.

    GFS: At T+144 had the high over Scandinavia rather than to the N/NW, but had ENE winds over Britain so not too far off. At T+120 and T+96, apart from minor quibbles about specific wind direction and the high positioning, very accurate.

    I give this run an 8/10, it was good. Maybe the GFS returning to its former glory.

    UKMO: Was closer than the GFS at T+144, unusually, with the high centred north of Britain and easterlies. Apart from minor quibbles about high positioning it was accurate also at T+120 and T+96.

    9/10 for UKMO, because it was closer than GFS at T+144, and about the same at T+120 and T+96.

    ECMWF: ECM made the slight mistake of positioning the high a little too far west at T+144, but the outcome of easterlies over Britain remained. At T+96 it was pretty spot on.

    I give this run a 9/10 also.

    NOGAPS: At T+144 it was accurate enough, with a high to the NW of Britain and easterlies. At T+120 it was a case of "Entire Grid Undefined" but at T+96 it remained good with high to the N and easterlies.

    This run, too, gets 9/10.

    JMA: Had the high too far south at T+144, with easterlies over southern Britain but not northern Britain, but at T+120 was accurate, then at T+96 also accurate.

    8/10, and the models are doing well today.

    GEM: Accurate all the way through.

    A 9/10 for GEM.

    Very good scoring from the models today, and little to choose between them.

    Link to comment
    Share on other sites

    Posted
  • Location: Lincoln, Lincolnshire
  • Weather Preferences: Sunshine, convective precipitation, snow, thunderstorms, "episodic" months.
  • Location: Lincoln, Lincolnshire

    So, onto today's comparison- today had a 1035mb high just south of Iceland and a 1050mb Greenland High, and easterly winds over Britain, veering northerly over NE Scotland.

    GFS: Not too bad at T+144, had the high to our north extending further east than it did and giving us ESE winds, but the general pattern was there. At T+120 the high still extended too far east, but ESE winds over the country remained, and by T+96 it was pretty spot on.

    I give the GFS 8/10: not excellent, but it had the correct general pattern nailed on from the start.

    UKMO: At T+144 it committed the same error as the GFS with too much of an eastward ridging high, and ESE winds over Britain. It found the correct pattern and positioning of the high by T+120 though, and continued accurate at T+96.

    I give the UKMO 9/10 because it was more accurate than GFS at T+120, and about the same at T+144 and T+96.

    ECMWF: It was accurate at T+144, T+120 and T+96 with easterlies over Britain, high pressure to the NW and northerlies starting to push into Scotland. It did over-egg the northerlies coming into Scotland a bit at T+144 and T+120.

    The ECMWF was very close to being perfect so it gets 9/10.

    NOGAPS: Similar error to UKMO/GFS at T+144, high too far east. At T+120 it had a strong ridge of high pressure over us that failed to materialise although the general easterly setup was there, and at T+96 it was spot on.

    I will mark this down at 7/10 because T+120 wasn't as good as the GFS, which got 8/10.

    JMA: It had too much Arctic influence at T+144 with cold north-easterlies already extending to Britain, though the Icelandic High was correctly positioned. Like NOGAPS, a ridge of high pressure over Britain was strongly overdone but the setup of ESE winds was still there, but at T+96 it was spot on.

    I give this 7/10 also.

    GEM: Pretty much as JMA, had too much Arctic influence at T+144, and high pressure too far east at T+120 and spot on at T+96, but the general pattern was recognisable throughout.

    7/10 for GEM also.

    So far it has gone very well for the ECMWF, but before any conclusions are made about it possibly being the best of the models, the ECM's phantom north-easterlies are coming up, and I think UKMO and GFS may well start to catch up with ECMWF as we get into the northerly evolution.

    model_comparisons.xls

    Link to comment
    Share on other sites

    Posted
  • Location: Lincoln, Lincolnshire
  • Weather Preferences: Sunshine, convective precipitation, snow, thunderstorms, "episodic" months.
  • Location: Lincoln, Lincolnshire

    model_comparisons.xlsAnother model comparison- this time for Sunday 19th March 2006. We have light northerlies over Scotland and light easterlies elsewhere, with a 1055mb Greenland High and quite a strong 985mb low over the north-east of Scandinavia.

    GFS: At T+144 it hadn't shifted our continental high far west enough and there was still a strong ridge over to Scandinavia and light ESE winds. At T+120 it had a near-accurate evolution but with the Arctic air too far south, such that the north-easterly winds over Britain looked quite cold, bright and showery. By T+96 it was accurate. Surprisingly it kept underdoing the Greenland High.

    It wasn't bad, but not great either, so I think I'll give it a 7/10.

    UKMO: Same as GFS at T+144. However, at T+120 and T+96 it was very accurate, and T+120 was closer to the mark than the GFS.

    Hence, I give the UKMO 8/10.

    ECMWF: At T+144 there was a low in the North Sea, propelling cold, showery north-easterlies to Britain. The low had been displaced to the Baltic by T+120, still with the cold showery north-easterlies and the -5C 850hPa air well over the whole country. At T+96 it was close to the correct outcome.

    Not one of the ECMWF's better runs, with strong evidence of that phantom "north-easterly that never was". Only a 5/10.

    NOGAPS: Same error as ECMWF at T+144. At T+96 it had a low in the North Sea and potent cold northerlies.

    Only 3/10 for NOGAPS: it wasn't accurate even at T+96. T+120 was missing ("Entire Grid Undefined")

    JMA: Consistent outlook by JMA throughout with light, not especially cold NE winds for Britain and 1040-1045mb high over Greenland slightly underdone but to no great consequence.

    Surprisingly, I'd have to give the JMA a 9/10, it's been the most accurate of the models today.

    GEM: About as accurate as JMA, with slack and non-potent north-easterlies over Britain throughout, so 9/10 for GEM.

    UKMO has already pretty much caught up with ECMWF after today's scores, with GFS down there with JMA and GEM, and NOGAPS performing rather poorly.

    Link to comment
    Share on other sites

    Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks

    thanks again Ian, certainly seems ecmwf and met are nicely in the lead during this blocked period.

    John

    Link to comment
    Share on other sites

    Archived

    This topic is now archived and is closed to further replies.

    ×
    ×
    • Create New...