12z Model Comparisons Results

[johnholmes]

current scoring since 08/05/07

GFS=7

ECMWF=9

Met O=1

with 15 marked as even between the three.

[Thundery wintry showers]

1 June

992mb lows to the west, 1024mb high to the north, and for most parts it was a dry sunny day. Exceptions included a few areas that had showers, and east-coast counties that had fog.

GFS scores only 6/10; surprisingly it was excellent at T+144 and then got progressively worse at T+120 and T+96. T+96 had a shallow low over Britain, while T+120 had much overdone low pressure to the west giving strong southerlies.

UKMO also scores only 6/10; low pressure too far east at T+144 giving SW winds, T+120 had a shallow low over Britain, while T+96 was relatively okay, but had southerlies and low pressure still a little too far east.

ECMWF scores 5/10; T+144 had a deep low off W Scotland giving strong SW winds, T+120 and T+96 had a shallow low over Britain.

NOGAPS scores 6/10; T+144 unavailable, T+120 was poor with a low over N Scotland giving westerlies, but T+96 was then very accurate.

JMA was slightly better scoring 7/10; T+144 had a low off NW Scotland giving moderate SW winds, T+120 was very accurate, and T+96 also accurate but had low pressure slightly too far east, with SSE winds for all.

GEM also scores 7/10; T+120 and T+96 both overdid high pressure to the south, with SSW winds in the south, but otherwise was accurate, with a slight easterly drift in the north.

Surprisingly JMA and GEM were the most accurate, with the three main models rather struggling, positioning Atlantic lows too far east and overdeepening them.

[Thundery wintry showers]

2 June

984mb low to the SW of Iceland, and a moderate southerly flow for most, finally fending off the sea fog in some eastern coastal areas, and giving most a warm dry sunny day.

32nd anniversary of widespread snow in June; 5th anniversary of a massive thunderstorm across N England.

I award GFS a 7/10; it was very accurate at T+144 and T+96, but had low pressure much too far east at T+120, giving a cyclonic/southerly flow.

UKMO scores only 6/10; T+144 had high pressure too dominant with low too far west, T+120 was similar to GFS's T+120 with low pressure too far east giving a cyclonic/southerly flow, then T+96 was accurate.

Also 7/10 for ECMWF; low pressure too far east at T+144 and T+120 giving a southerly flow, but the low was only about 200-300 miles too far east, so not too inaccurate; T+96 was then superb.

NOGAPS unavailable again.

JMA poor at T+144 giving an anticyclonic/NE flow, but accurate at T+120; overall 6/10 (T+96 unavailable)

GEM unavailable except T+120 when it had high pressure too dominant in the east.

Overall a decent set of runs.

[Thundery wintry showers]

3 June

1024mb highs to the SW and NE, with a slack region of pressure over Britain. A weakening cold front moved east with some heavy showers and local thunder up the central strip of Britain. Sea fog continued to affect some eastern coasts.

GFS scores 6/10; an Atlantic low was overdeepened at T+144 giving strong WSW winds, T+120 had a weak low off N Scotland giving weak WSW winds but was fairly accurate otherwise, and T+96 was very accurate.

UKMO scores 6/10 also; T+144 was fairly poor with a strong Atlantic low giving a cyclonic/southerly flow, although it was better than GFS; T+120 and T+96 were similar to GFS T+120 with a weak low off N Scotland pushing weak WSW winds in.

ECMWF was slightly better, scoring 7/10. T+144 had an overdeepened low to the NW giving SW winds, but T+120 and T+96 were both accurate.

NOGAPS available at T+144 (westerlies, LP to north) and T+96 (high pressure to south, weak W winds, LP off N Scotland). Overall 5/10.

JMA also unavailable at T+120; however it was reasonable at T+144 with LP off N Scotland and a slack westerly, and T+96 was accurate. Overall 7/10.

GEM unavailable except T+96 so no mark, but at T+96 high pressure was too far east and Britain had southerlies.

Overall the models were rather too progressive, especially at T+144.

[Thundery wintry showers]

4 June

1032mb high off northern Scotland with ENE winds across most of the country; most parts were dry with cloud breaking up except near the east coast.

I award GFS 7/10; it had high pressure too far south at T+144 with the high mostly over SW Britain, T+120 was more accurate with the high to the W & NW giving northerlies in the east, T+96 was accurate.

UKMO unavailable at T+144; scores 8/10 in view of T+120 and T+96 which were slightly more accurate than GFS and had Britain in NE winds.

ECMWF also scores 8/10; high to NW at all three timeframes giving NE winds, but T+120 was a bit dodgy (strong E flow and high too far north).

NOGAPS and JMA unavailable.

GEM scores 7/10; it had high pressure generally to our west giving N/NNE winds at both timeframes.

Overall a fairly accurate set of outputs (although NOGAPS and JMA playing up on WZ), the GEM was also quite good.

[johnholmes]

current scores since 08/05/07

GFS 7 correct and 8 even

ECMWF=9 and 6 even

Met O=1 and 7 even

[Thundery wintry showers]

5 June

1032mb high off N Scotland with ENE winds over Britain. Many places were warm and sunny but it was dull near the east coast.

GFS scores another 7/10; T+144 and T+120 had high pressure in charge with the high too far south, giving easterlies only for the south. T+96 was better with the high accurately placed giving easterlies for all.

UKMO scores 8/10; T+144 was similar to GFS with high over NW Britain giving NE winds over the SE, but T+120 and more especially T+96 were accurate.

ECMWF scores 9/10; perhaps slightly too cyclonic a bias on the easterly flow at T+144 but otherwise spot on at all three timeframes.

NOGAPS scores 6/10; unavailable at T+120, T+144 had high pressure way too far south covering the British Isles, but T+96 was accurate.

JMA scores 8/10; T+120 unavailable, T+144 was good with high slightly too far west giving NE winds for most, and T+96 was very accurate.

GEM had high too far south at T+120 giving slack winds for all, but was fairly accurate at T+96; overall 6/10.

The ECM and UKMO, as is often the case with easterly setups, handled the situation most accurately with JMA also very good.

Model Comparisons spreadsheet updated to cover the whole of April; May should be out too within the next few days:

model_comparisons.xls

[Thundery wintry showers]

6 June

An uncomplicated chart- 1028mb high off N Scotland and easterly winds, very slack easterlies, but enough to bring a significant amount of low cloud westwards.

I give the GFS another 7/10; T+144 and T+120 were fairly accurate but had too strong an easterly flow over Britain, by some way in the case of T+144. T+96 was very accurate.

UKMO also scores 7/10; T+144 unavailable, T+120 and T+96 much the same as their GFS counterparts, too strong an easterly flow at T+120.

ECMWF scores 8/10 because it overdid the easterly only at T+120, and was very accurate at T+96 and T+144.

NOGAPS was unavailable at T+144. Scores 8/10 on account of very good outputs at T+120 and T+96, with dodgy high positioning but very accurate over Britain with slack easterly flow.

JMA scores 7/10; easterly flow overdone at T+120, but accurate at T+96 (T+144 unavailable)

GEM scores 7/10 also; T+120 okay but had a shallow low over SE England that didn't materialise; reasonable at T+96.

A good set of outputs, with ECM and NOGAPS being most accurate.

[Thundery wintry showers]

7 June

1024mb high off N Scotland, an easterly flow, with many places dry and cloudy, surprisingly with some storms over E Scotland.

GFS scores 7/10 again; pretty good, but T+144 and T+120 overdeepened low pressure to the south, giving strong ENE winds, whereas T+96 was very accurate.

UKMO scores a 8/10; it was very accurate at T+144, but T+120 overdid low pressure to the south and high to the north giving stronger E winds, then T+96 was accurate again.

ECMWF was splendid, scoring 9/10, and was very accurate at all three timeframes.

NOGAPS scores 8/10; accurate at all three timeframes but T+144 had high pressure too far south.

JMA scores 7/10; good, but T+120 in particular had the high too far west, with NNE winds in the east. T+96 and T+144 were very good.

GEM scores 6/10; T+120 had a large high over Britain, but T+96 was accurate giving easterlies.

Another good set of outputs, with ECMWF heading the way. The impression I'm getting is that the 'upgrade' to GFS hasn't had any significant effect, and that GFS still has some catching up to do in order to bypass the ECM.

[johnholmes]

would agree with your summation there Ian; its certainly outdoing GFS and the Met O computer over the past month, like 12 to 7 for outright winds with Met having just 1.

But then the idea of ECMWF being set up in the late 70's early 80's was specifically for this taking or trying to take T+48-72 accuracy out to T+240 if possible.

So far its doing near enough what they wanted of it to T+168 but I have no idea beyond that. And still a lot of occasions when after T+96 its not as good as had been hoped for. Nevertheless its improving if you look at their own statistics.

I have no real belief in there being 70%+ accuracy on a regular basis beyond about the 10 day mark.

That is until we have a much better idea of the interaction between ocean and atmosphere and other elements outside those two that MAY be having an effect.

Edited June 8, 2007 by johnholmes

[The PIT]

would agree with your summation there Ian; its certainly outdoing GFS and the Met O computer over the past month, like 12 to 7 for outright winds with Met having just 1.

But then the idea of ECMWF being set up in the late 70's early 80's was specifically for this taking or trying to take T+48-72 accuracy out to T+240 if possible.

So far its doing near enough what they wanted of it to T+168 but I have no idea beyond that. And still a lot of occasions when after T+96 its not as good as had been hoped for. Nevertheless its improving if you look at their own statistics.

I have no real belief in there being 70%+ accuracy on a regular basis beyond about the 10 day mark.

That is until we have a much better idea of the interaction between ocean and atmosphere and other elements outside those two that MAY be having an effect.

Just a slight word of caution. We're into summer now so forecasting for the models tends be as little easier, until the hurricane season gets into full swing. It wasn't all that long ago that all the models were struggling to get 72 hrs right let alone T168.

[Thundery wintry showers]

8 June

Weak 1024mb high off N Scotland. A weak 1016mb low off the coasts of East Anglia and the SE brought a band of thundery rain northwards across the area, although storm activity was largely restricted to the south coast.

I give the GFS another score of 7/10, because it had the pattern of slack easterlies pretty accurate, but it had the weak 1016mb low too far to the north-west at all three timeframes. At T+144 the low was covering NE England, and at T+120 and T+96 it was touching the coast of East Anglia, probably resulting in an overestimation of storm activity.

UKMO at T+144 showed no sign of the low with a 1025mb high over northern Britain. T+120 had a moderate ENE flow and the trough only just picked out, but T+96 was then quite accurate but like GFS had the low off E Anglia slightly too far west, overall 6/10.

The ECM scores 8/10 as it was very accurate with the low positioning at all three timeframes. However, at T+96 the high to the north was rather too far west, giving a NNE flow for most other parts of the country.

NOGAPS unavailable at T+144 and scores only 6/10; the trough off the SE/East Anglia was not picked up at all, and Britain was in moderate ENE winds.

JMA scores 6/10 also; T+144 had a weak trough over Britain, T+120 was okay but had the SE trough too far west, covering the SE, and T+96 was reasonably accurate.

GEM was quite accurate at T+120, but at T+96 failed to pick out the low to the SE, giving high pressure and a light easterly flow. Also 6/10.

I reckon the ECM would have probably been best at modelling the storm system over the SE, while the GFS did slightly better than the UKMO at the T+144-T+96 range.

[johnholmes]

interesting that Ian and another point to ECMWF, its well ahead over the past month

[Thundery wintry showers]

9 June

1024mb high to the north, slack easterly flow. Some showers developed in the south, many western areas were dry and sunny, many eastern areas were stuck under low cloud.

I only give GFS 6/10, the reason being that it kept putting an area of low pressure over eastern England (esp. T+144 and T+120) suggesting a more unsettled outlook with pressure 5mb lower everywhere. T+96 was more accurate but had a low off East Anglia giving NE winds.

UKMO scores 8/10; it was fairly accurate at all three timeframes, only T+120 was slightly dodgy with a low off East Anglia (similar to GFS at T+96)

ECMWF scores 7/10. At T+144 it was very accurate, but at T+120, though still quite accurate, an Icelandic Low was shown, with low pressure heading for north-west Scotland. T+96 was similar to GFS at T+96. Overall better than GFS but not as good as the UKMO.

NOGAPS scores only 6/10 as although it had easterlies over Britain, at all three timeframes, a low was shown to the west, giving southerlies over western Britain, and fronts trying to come into the west.

JMA also scores 6/10- T+144 was poor with low pressure over Britain (albeit slack low pressure), then T+120 was good, and T+96 decent but had a weak low off East Anglia like the GFS and ECM.

GEM was reasonable at T+120, but at T+96 it had a low centred over north-east England, and looked rather out of kilter with what happened, so scores only 5/10 overall.

The UKMO was the most accurate this time around.

[Thundery wintry showers]

10 June

A late update, because my internet decided it fancied a spell of juicy scrumptious downtime. Slight easterly drift with pressure between 1015 and 1020mb, and large 1004mb low to the south-west, starting to extend towards south-western Britain.

GFS scores only 6/10. Low pressure was too far east at T+144 giving a cyclonic/southerly flow, and at T+120 a low was shown off East Anglia giving north-easterlies, but it was very accurate at T+96.

UKMO scores 7/10; dodgy T+144 with no high to our north and slack lows to the SW and SE, but T+120 and T+96 were both reasonable- T+120 if anything overdid the high.

ECMWF also scores 7/10- main failing at all three timeframes was placing high pressure too far north and giving too much of an influence from the low to the SW, but the easterly/slack flow was accurately shown.

NOGAPS scores 7/10; almost identical to UKMO with T+144 dodgy, no high pressure, but T+120 and T+96 were good.

JMA was probably the best of the models- an 8/10- because it had easterlies over Britain at all three timeframes, the high positioning was suspect at T+120 (too far south) but otherwise very good.

GEM had low pressure too far east at T+120 giving a southerly flow, but T+96 was accurate; overall 6/10.

Overall surprisingly the JMA was the most consistently accurate this time.

[Thundery wintry showers]

11 June

1000mb low creeping closer to the south-west, very light southerlies for most, but still some low cloud clinging onto those North Sea areas. Parts of western, central and northern Britain had thunderstorms late on.

GFS only scores 6/10 again- T+144 had a low off eastern Scotland giving northerly winds for all, T+120 had Britain in a slack region of nothingness, and T+96 had Britain in an easterly flow.

UKMO had low pressure too close to the SW at T+144, giving a cyclonic/south-easterly flow. T+120 had low pressure too far south giving an easterly flow, but T+96 was accurate. Overall also 6/10.

ECMWF also scores a 6/10 because low pressure was a long way too far north at T+144 and T+120, almost touching the SW, but T+96 was very accurate.

NOGAPS also scores 6/10; easterlies at T+144 and T+120, with low pressure to our south, but accurate at T+96.

I give JMA a 7/10 because it was fairly accurate at all three timeframes, but overdid high pressure to our north, giving easterlies.

GEM also scores 7/10- T+120 and T+96 were both decent, though the low to the SW was slightly overdone.

Overall a mediocre set of outputs from all models, overdoing high pressure to the north and low to the S/SW, often giving moderate easterlies.

[Thundery wintry showers]

12Z Model Comparisons graph updated to 31st May:

model_comparisons.xls

[Thundery wintry showers]

More model analysis for 12 June.

1000mb low staying to the SW, with slack 1012mb region of relatively low pressure over Britain. Winds were westerly in the south and easterly in the north. Storms occurred over N Ireland, N England and Lincolnshire. Low North Sea cloud occurred in east-coast areas of the north.

GFS scores 7/10; good T+144 (though with low slightly too far north with westerlies for most), T+120 had low too far south with easterlies for most, T+96 spot on.

UKMO was very good at T+144, but T+120 and T+96 were less good, with no ridge of high pressure to the south of Britain, a complex set of lows over Britain and the low to the SW too far east, encroaching into the south-west. Also 7/10.

ECMWF also scores 7/10; poor T+144 with low pressure coming into the west and bringing strong southerlies, but T+120 and T+96 were very accurate.

NOGAPS scores 6/10; poor T+144 with low pressure too far south giving easterlies, then T+120 and T+96 similar to the UKMO, with a complex set of shallow lows over Britain.

JMA scores 7/10; generally accurate at T+144 and T+96 but dodgy at T+120 with the low to the SW too far east, giving southerlies in the west.

GEM scores an 8/10- very accurate, though with the low marginally too far north with westerlies across the south.

Overall a decent set of outputs.

[Thundery wintry showers]

13 June

Some bad news:

1) In a few days' time I will probably end up missing out a few days because my internet has decided to play up on evenings.

2) I won't be around from 5 to 23 July.

1000mb low, by now, not very far from the south-west of England. A shallow 1008mb low over England & Wales, notably chilly northerlies coming into N Scotland, and a slow-moving band of rain over northern England.

I give GFS an 8/10; it was very good, especially at T+144 and T+96. T+120 was less good in that it didn't have the finger of low pressure at 1008mb, instead giving no isobars over Britain. The pattern was generally correct with N winds just coming into Scotland.

UKMO was poor at T+144; low a long way too far north, giving a cyclonic, showery southerly regime for all. However T+120 was reasonable (though with low still slightly too far north, giving SE winds for all), then T+96 very accurate. Only a 6/10.

ECMWF scores 7/10- T+144 was poor with south-westerly winds and showers across Britain but it was accurate at T+120 and T+96.

NOGAPS scores 6/10- it wasn't bad, but at all three timeframes high pressure was overdone to the north, and low pressure to the SW too far north, giving easterly winds. Only T+96 had the northerlies coming into Scotland.

JMA scores 7/10- it got the northerly coming into Scotland right, but easterlies were shown for the south at all three timeframes- particularly at T+144 the low to the SW was too far to the NE.

GEM scores 7/10 also- pretty good but again with easterlies shown for all, northerlies just coming into Scotland.

A reasonable set of outputs, with GFS producing the best T+144 output and as a result getting the highest mark.

[Thundery wintry showers]

14 June

996mb low now just off SW England, with a strong easterly flow across most of Britain, but southerlies in the extreme south. Most places were cloudy and wet and it was notably cold in north-east England.

GFS scores only 6/10. T+144 was okay but the low was too far north, giving SSW winds for England & Wales and easterlies only for Scotland. T+120 had the low too far west as well as north, giving southerlies for all. T+96 was okay but had the low underdone, with moderate easterlies for the north, and high pressure over northern Scotland.

UKMO was surprisingly good at T+144, but T+120 was poor, similar to GFS, with the low too far west giving southerlies for all. T+96 was reasonably accurate, so overall 7/10.

ECMWF was okay at T+144 but had lowest pressure slightly too far north with southerlies over the southern half of Britain. The low was too far west at T+120, giving easterlies in the north but southerlies in the south. T+96 was accurate. Overall 7/10.

NOGAPS was poor at T+144 with a very slack easterly flow, and vastly underdone low pressure. T+120 was good, but then T+96 had the low vastly overdeepened with winds in south-west England approaching gale force, and cold northerlies in Scotland; overall 5/10.

JMA had low pressure too far east at T+144 giving ENE winds. T+120 and T+96 were good, however, with the easterlies over most of Britain and southerlies in extreme south; overall 7/10.

GEM only available at T+120 so no mark. It wasn't bad, with the low perhaps slightly too far north.

A decent set of outputs, but particularly at T+120 there was a tendency for the models to position the low too far west and north, giving a warmer, more showery southerly regime. The ECM was the most accurate of the main three models at T+120, but UKMO was best at T+144.

[Thundery wintry showers]

15 June

1000mb low over the south with strong easterlies in the north. It was very dull, cold and wet in N England.

GFS was fairly poor, good enough only for 6/10. T+144 had the low pressure significantly to the west, giving southerly winds for most, and the rainband clearing N Scotland. T+120 was also fairly poor, the low too far east this time giving NE winds. T+96 was good though.

UKMO scores 7/10; it was similarly poor at T+144 with a low to the west and a cyclonic/southerly flow, but T+120 was reasonable, low only slightly too far north, and T+96 was very good.

ECMWF scores 8/10- some quibbles over low positioning but it was reasonably accurate at all three timeframes. T+144 had the low too far west but an extension over the south which translated to easterlies and a slow moving front over N England anyway.

NOGAPS scores 7/10- unavailable at T+144, good at T+120 and T+96 but with low pressure slightly too far west, giving southerlies for the southern half of Britain.

JMA scores 6/10- T+144 had lows too far south, with easterlies for all, T+120 had the low slightly too far north giving southerlies and westerlies for England & Wales and easterlies for Scotland, and T+96 was similar.

GEM unavailable except T+96 when it was not good- low vastly overdeepened, and southerlies for most.

Overall a reasonable set of runs. GFS and UKMO were dodgy at T+144 showing southerlies and low pressure too far west, indicating a warmer, more bright/showery type of regime for northern areas.

[Thundery wintry showers]

After some missing data, we progress to 19 June.

992mb low off SW England bringing a cyclonic/south-easterly flow, caused by trough to the south which made the flow SE'ly rather than southerly. Many areas were sunny and warm but low cloud plagued North Sea areas. Thunderstorms broke out widely in the south and south-west and these tracked north during the latter part of the day. I don't have any T+144 outputs.

GFS was good enough for 7/10; low positioned accurately enough, but errors in the orientation of the flow, with more of a SSW flow shown for most at T+120 rather than a SE'ly (I think the elongated trough to the S was too far north). T+96 was more accurate but still had less of an easterly component to the flow in the north than actually occurred.

UKMO also scores 7/10; again the positioning of the low was very good, but southerlies were shown instead of south-easterlies at both timeframes.

ECMWF likewise; 7/10.

NOGAPS also scores 7/10; same issue, low accurately positioned but with southerly, rather than south-easterly, winds shown at both T+120 and T+96.

JMA was the most accurate at T+120 with a cyclonic/SE flow and it picked up the trough to the south, unfortunately T+96 was relatively poor with high pressure clinging onto the east and the low too far west; only 6/10 because of the poor T+96.

GEM also scores only 6/10; southerlies shown at both timeframes and low pressure slightly too far west.

Overall a middling set of outputs. All of them, except JMA at T+120, showed southerlies rather than south-easterlies, which would have had a major bearing on both storm distribution and the existence (or lack of it) of low cloud in North Sea areas.

[johnholmes]

sorry you will be away Ian, but I'm sure you are not, thanks again for all the hard work.

Current scoring, since the GFS update is,

GFS=8

ECMWF=14

Met O=3

there are a lot of 'ties' between them as well as the scores above.

GFS=11

ECMWF=11

Met O=11

so ECMWF clearly leads even after the GFS update.

[Thundery wintry showers]

Although I will be away from 5-23 July, these summaries will continue after 23 July. Regardless of them being quite a lot of work, there's no way I'd stop these altogether; the most that could possibly happen if my PhD got very busy is that I'd stop the written summaries on the site but maintain the Excel log of the scores. That in itself would be unlikely to happen regularly until next year.

20 June had an unsettled picture with a 996mb low over SW Ireland and a cyclonic/southerly airflow for most. Western areas had sunshine and showers while most eastern parts stayed dry. For some North Sea areas of the north, the first warm sunny day for a long time.

GFS scores 8/10; it was very good, at T+144 the low was slightly too far west, giving a relatively slack southerly flow, but T+120 and T+96 were both very accurate. A much better GFS run than of late.

UKMO was poor at T+144; a slack low over southern England with easterlies in the north. However T+120 and T+96 were very accurate; overall 7/10.

The ECM was not as good as GFS, and almost identical to UKMO; slack low over the south at T+144, accurate at T+120 and T+96.

NOGAPS was poor at T+144 with a slack low off the SW giving a warm humid SSE flow, but T+120 was quite accurate and T+96 reasonable; overall 7/10.

JMA scores only 6/10- low over Britain at T+144, and too far south at T+120 with easterlies over the north; good at T+96.

GEM was unavailable.

Overall, a good set of outputs. I gave the GFS the nod on this one; ECM and UKMO were further out at T+144.

[Thundery wintry showers]

21 June

1004mb low off SW England. Showers and thunderstorms were particularly prominent over western and south-western Britain where there was flooding at Boscastle, and there were many storms over Lincolnshire and eventually up into Yorkshire. A cyclonic/southerly flow.

GFS was very accurate at T+144 and T+120, though with the low positioned very slightly too far west. However T+96 was not so good, positioning the low over southern England and giving easterlies for the north, so 7/10 overall.

UKMO had the low way too far north at T+144, giving westerlies in the south. T+120 and T+96 were better but T+96 had the low over central Britain- i.e. way too far north again. Only 6/10.

ECMWF was poor at T+144 with the low centred over north-east England, but T+120 and T+96 were reasonably good, though with low pressure generally too far north; overall 7/10.

NOGAPS unavailable.

JMA was very poor at T+144; a low over SE England and north-easterlies elsewhere. T+120 unavailable, then T+96 was reasonable, so scores 6/10.

GEM also unavailable.

It was a decent set of outputs, but with a tendency to position the low too far north and east. GFS was best at T+144 and T+120, but was a letdown at T+96.

22 June

A shallow 1008mb low centred over Lincolnshire-ish, with very slack winds and slow moving showers and thunderstorms.

GFS was reasonably accurate at T+144, though the low was slightly too far south (centred over S England) giving a pronounced easterly flow in the north. T+120 had the low too far east, giving a NNE airflow for most. T+96 was okay but again had the low too far south, centred over the southeast. Only 6/10.

UKMO had the low much too far north at T+144. T+120 and T+96 were okay but had the low too far east, centred off East Anglia with north-east winds for many. Only 6/10.

ECMWF was good at T+144 but at T+120 the low was too far east, giving northerlies for western Britain, then T+96 was remarkably accurate. Because of the excellent T+96 I give this 7/10, but it was still unconvincing.

NOGAPS unavailable except at T+96, when it had the low positioned slightly too far west but was otherwise fairly accurate.

JMA had the low much too far south at T+144. It was better at T+96 but still with the low too far south giving NE winds for most, then T+96 was reasonably accurate. Overall just 6/10.

GEM had the low too far north at T+120, centred over NE England, then accurate at T+96, so scores 7/10.

A mediocre set of outputs- there was much uncertainty over the positioning of the low. I analysed this output to death because minute differences in low positioning were ultimately the difference between the whole of the North East getting sunshine, showers and storms, and everywhere except a narrow strip of the east coast getting them. Looking over these outputs, the writing was on the wall that the latter would happen, for if anything, the models tended to position the low further south and east than it ended up.