12z Model Comparisons

[Thundery wintry showers]

From today, I will be doing 12Z model comparisons for the ECMWF, UKMO and GFS, taking the 12Z runs of each, and comparing them at T+96, T+120 and T+144.

I won't have enough time to get a hold of images for every chart, so the analysis is likely to consist of describing what the charts show at 12Z. This will then be compared to the actual outcome.

The idea of this is to provide some kind of objective evaluation of which model is performing better in its 12Z runs, and with it being displayed on the forum, people can decide for themselves whether or not they agree.

I won't be including the likes of NOGAPS, GEM and JMA due to time constraints, and my lack of confidence in those models (NOGAPS and JMA: unreliable, GEM: sometimes good but lacks detail)

Edit: ignore the above paragraph, Evo's links have been sufficiently helpful for me to end up including those models anyway, at least for the time being.

Edited March 8, 2006 by Thundery wintry showers

[johnholmes]

excellent Ian

John

[Evo]

TWS

I don't know if this will be of any use to you. I fixed it up from an old semi-broken page I found on the Internet.

This is for T+96 but if it's useful I can do other timebases too. I think they will all line up timewise with 12z data just before the 18z GFS comes out?

T96 Comparison

Sometimes the fader breaks. Just hit the refresh button to fix. Best viewed at 1024x768 screen resolution or greater.

Let me know...

[Thundery wintry showers]

I think it will be very useful- the other two timebases I would be interested in are T+120 and T+144. It allows a straightaway comparison between the charts and would probably save a lot of time (as well as enabling me to add NOGAPS in after all!)

[Evo]

Hi TWS

I've done the other times and added the other oddball models in - it's obviously up to you which ones you use!

Here are the links:

T+96 500s

T+120 500s

T+144 500s

T+96 850s

T+120 850s

T+144 850s

Only Nogaps, GFS, JMA & GEM have 850s on Wetterzentrale, with the GEM 850s only going out to T+120.

If you can, save the above pages to your hard drive by using the File -> Save As menu item in your browser, as they may not stay on the above links forever. If you save them to your desktop, you'll have ready made shortcuts.

Hope this helps!

Oh and one last thing, try to check the model shown is correct (at the bottom of the image) as once or twice the radio button on the right has said one thing but the Nogaps has been displayed! I think this only happens when using the refresh button. The image goes back to Nogaps but the radio button on the right will stay on whatever it was before you press refresh.

Edited March 5, 2006 by Evo

[Thundery wintry showers]

Thanks a lot- will be very useful indeed, and I was able to save them to my hard drive.

[johnholmes]

Hi TWS

I've done the other times and added the other oddball models in - it's obviously up to you which ones you use!

Here are the links:

T+96 500s

T+120 500s

T+144 500s

T+96 850s

T+120 850s

T+144 850s

Only Nogaps, GFS, JMA & GEM have 850s on Wetterzentrale, with the GEM 850s only going out to T+120.

If you can, save the above pages to your hard drive by using the File -> Save As menu item in your browser, as they may not stay on the above links forever. If you save them to your desktop, you'll have ready made shortcuts.

Hope this helps!

Oh and one last thing, try to check the model shown is correct (at the bottom of the image) as once or twice the radio button on the right has said one thing but the Nogaps has been displayed! I think this only happens when using the refresh button. The image goes back to Nogaps but the radio button on the right will stay on whatever it was before you press refresh.

hi Evo

I'll put this into our forecast forum as it will be very useful to use when we do Close Ups or are considering Alerts.

Many thanks for that

John

[Thundery wintry showers]

12Z Model Comparison No. 1: Sunday 5th March 2006.

T+96 (to Thursday 9th March)

GFS: Low at 990mb situated over British Isles, SE winds across much of Scotland, gusty NW winds across Wales and southern England. Probably dull and wet for most.

UKMO: Low at 985mb just off western Scotland. Strong south-westerly winds across the country. Probably rain moving NE leaving sunshine and showers.

ECMWF: Low at 985mb just to the west of Britain. Scandinavian High already bringing cold easterly winds very close to northeast Scotland, with southerlies covering Britain.

NOGAPS: Britain under flabby low pressure at 1000mb, with low pressure over Iceland. Low-index pattern with little wind but probably a lot of cloud and rain.

JMA: Very similar to ECMWF, with low at 990mb just to the west of Britain, southerlies over Britain and the Scandinavian High centred over the north-western tip of Scandinavia.

GEM: Similar to UKMO, strong low to the NW and south to south westerly winds over Britain.

T+120 (to Friday 10th March)

GFS: Low at 990mb approaching western Ireland, band of rain moving E. Light westerlies across southern Britain. Scandinavian High with attendant cold easterlies very close to northeast Scotland.

UKMO: Big low pressure at 985mb situated over Britain. Wind and rain.

ECMWF: Low pressure (1000mb) centred over the Midlands, with rain. Easterly winds over Scotland pulling in some continental air.

NOGAPS: Weak low pressure at 1000mb to our NW with light westerly winds. On the cool side, probably with some sun and some showers, wintry on hills.

JMA: Again similar to ECMWF, the only difference being that the low over the Midlands is deeper at 995mb.

GEM: Low pressure at 985mb over SE Iceland, growing Azores High to our south, westerlies over Britain.

Thus, there are already large discrepancies at T+120!

T+144 (to Saturday 11th March)

GFS: Big low at 980mb just off south-east England, weaker low (995mb) off western Scotland. Cold east winds flooding into northern Britain.

UKMO: Weak low (1000mb) to our east, a deeper low to our W. Cold east winds flooding into the far north of Scotland, mild westerlies for southern England.

ECMWF: Britain sandwiched between 1030mb Azores High and 1025mb Scandinavian High, but with the latter ridging into Scotland, and light easterlies for Britain. Not particularly cold easterlies though.

NOGAPS: Britain sandwiched between a 1030mb Azores High and a 1025mb Scandinavian High. Very little wind. Pressure uniform at 1020mb.

JMA: Britain sandwiched between 1030mb Azores High and 1025mb Scandinavian High. As NOGAPS.

GEM: 970mb Icelandic Low and strong to gale force south-westerlies. Mild and wet.

[johnholmes]

Ian

I like this, like the idea of it being short, sharp to the point. Keep it this way and it will be very useful for all of us doing Close Up and looking at Alerts.

Many thanks

John

[Roger J Smith]

Good idea, but to have any real idea which models are performing better than others, you would need about three months of data at the very least. It may be the case that some models handle certain situations better than others, so that there wouldn't just be one "superior" model but the forecaster should be attuned to which models handle given situations better than others.

Here's my subjective opinions of these models based on about a year of fairly regular 7-day forecasting (which I do off-site more regularly than here) --

GFS -- Like NW, I regard the GFS as the least of all evils. It is often the most accurate of the lot. I have come to suspect that it has an inherent bias to overdevelop Scandinavian highs and extend them too far across the North Sea too quickly. A case in point will be available for review Friday-Saturday.

GEM -- This model has proved itself to be better than the GFS over most of North America. Therefore its solutions for the western Atlantic are always worth holding up for comparison. Although the GEM has a reputation for being too progressive over Europe, this tendency has shown signs of reducing since October. I can think of three situations this past winter where the GEM had a better solution than the GFS. Therefore would say always be cautious about differences such as this weekend's depicted warming.

UKMO -- I find that it often sides with the GEM when there is a model discrepancy, but I would admit limited contact with it so far, and I plan to consult it more in the future. So no qualified opinion on it yet.

EURO -- Hit or miss. Either it goes off on a tangent that is off-side with other models and proves to be wrong, or it spots a trend early and develops it faster.

ALL THE REST -- Seldom improve on these three, in my admittedly limited experience looking at them. Can't remember a major outlier in them succeeding.

MY RESEARCH MODEL -- Coming up fast from behind, you may be using it by 2010 at the rate things are going. Not computerized therefore remains a subjective adjustment technique using GEM or GFS, as preferred. Has one demonstrated 30-day map forecast success (30 Dec 2005) as well as one documented 28-day verbal forecast (23-24 Oct 2005). I am working on parameters for at least systematic placement of highs and lows with subjective detail added.

Edited March 6, 2006 by Roger J Smith

[Thundery wintry showers]

I don't know how long I'll be able to keep this up, but I intend it to run for quite some time, for instance it would be useless if I stopped it before Thursday, as there wouldn't be any data at all!

Some could also view it as a kind of substitute for Paul B's excellent 12Z Model Summaries, which would probably have been made a lot easier for him if Evo had been around then, with those model comparison sites.

[Thundery wintry showers]

12Z Model Comparison No. 2: Monday 6th March 2006.

T+96 (to Friday 10th March)

GFS: Low at 990mb stuck over the British Isles, with a High at 1015mb over western Scandinavia. A wet outlook. Windy in the north (easterlies) and south (westerlies).

UKMO: Low at 1000mb right on top of the British Isles, with 1015mb Scandinavian High, similar positions to the GFS, but more flabby. Also 995mb low just off western Scotland, not shown on GFS. Very little wind.

ECMWF: 1000mb low over Britain, similar position to UKMO, but with less N-S extent giving strong (and cold!) easterlies over Scotland, and westerlies over southern England. Low at 990mb off SW Iceland, 1015mb Scandinavian High.

NOGAPS: Low at 995mb just off western Scotland, shallow 1000mb low over Britain. Very little wind anywhere. 1020mb Scandinavian High. Overall very similar to UKMO.

JMA: 995mb low just off southeast England pulling in light easterlies, but not from an especially cold source. 1020mb Scandinavian High, 995mb Low just SW of Iceland.

GEM: 1000mb low over SE England pulling in strong easterlies. 1020mb Scandinavian High. 1000mb low just west of Iceland. Overall similar to JMA.

Some reasonable agreement on the T+96 charts for low pressure stuck more or less over Britain. Seems that the ECMWF and JMA, followed by GFS and UKMO, have maintained the most consistent outlook for Friday, so far.

T+120 (to Saturday 11th March)

GFS: Sandwiched between 1025mb Scandinavian High and 1030mb Azores High, pressure around 1010mb over Britain. Low at 1000mb approaching from the west, light westerlies over southern Britain, rain approaching from the west.

UKMO: 1025mb high over northeast Britain, being swallowed up by 1030mb Azores High, 990mb low SW of Iceland. Light easterlies over Britain, moderately cold.

ECMWF: 1025mb high over S Scandinavia, 1030mb high ridging from the Azores, 995mb low SW of Iceland. Westerlies extending over to Britain, becoming mild.

NOGAPS: 1030mb highs over NE Scotland and coming out of the Azores, 995mb low SW of Iceland. Cold NE winds covering the SE of England, light E winds elsewhere.

JMA: Low at 990mb over NW Scotland and strong SW winds over Britain, rain sweeping NE, mild. 1025mb Scandinavian High.

GEM: 1030mb High to east of Britain, 1030mb Azores High, mild southerlies starting to approach in association with 995mb low SW of Iceland.

Good agreement from all of the models apart from the JMA, which is on its own. With respect to yesterday, very consistent outputs from ECMWF and NOGAPS, reasonable consistency from UKMO, GFS backing away from the cold easterlies, and GEM and JMA changing significantly.

T+144 (to Sunday 12th March)

GFS: Big low at 980mb over northern Scotland, strong to gale force westerlies over Britain.

UKMO: 975mb Icelandic Low, 1035mb High over SE England and mild SW winds sweeping in.

ECMWF: 975mb low east of Iceland, 1025mb highs to the S and E of Britain and mild SW winds sweeping in.

NOGAPS: 980mb low east of Iceland, 1030mb high to the south of Britain, mild WSW winds.

JMA: 980mb low over NE Scotland and strong, showery west winds over Britain.

GEM: Strong 980mb Icelandic Low, 1035mb High to our east, and strong mild S/SW winds.

Sunday is clearly one to watch, with GFS and JMA going for blustery showers on a W airflow, and the others going for a broad "warm sector" with SW winds.

Edited March 6, 2006 by Thundery wintry showers

[Evo]

In view of the WZ problems tonight, here are some alternate pages which use different WZ links. These are working OK.

T+96 500s

T+120 500s

T+144 500s

T+96 850s

T+120 850s

T+144 850s

[johnholmes]

tks Evo, I'm sure Ian will pick it up and I'm sure he is grateful for your help.

John

[Thundery wintry showers]

In view of the WZ problems tonight, here are some alternate pages which use different WZ links. These are working OK.

T+96 500s

T+120 500s

T+144 500s

T+96 850s

T+120 850s

T+144 850s

Yes, thanks a lot- have saved these to my hard disk also, as backups in case the same thing happens again with WZ.

[Evo]

No problem chaps, glad to help

[Thundery wintry showers]

12Z Model Comparison No. 3: Tuesday March 2006.

T+96 (to Saturday 11th March)

GFS: Low at 995mb to the NW of Scotland with mild SW winds over Britain, looking quite strong too.

UKMO: 1020mb High over western Scandinavia, but swamped by a 1030mb Azores High; an Atlantic low pushing in (centre 990mb W of Iceland, another 1000mb depression just to the W of Scotland) bringing southerly winds eastwards.

ECMWF: Low at 1000mb just off NW Scotland, 1020mb Scandinavian High, southerlies pushing into Britain.

NOGAPS: 1020mb Scandinavian High, light E winds over Britain but a 990mb low S of Iceland starting to spread SW winds towards Britain.

JMA: 995mb low over Iceland, shallow 1005mb low over Britain with little wind, a strong Azores High to the south.

GEM: 995mb low over N Ireland with southerlies over Britain and a band of rain moving in from the west.

A clear shift of the models towards more dominance of the Icelandic Low/Azores High combo, with S or SW winds sweeping eastwards across the country- only JMA out on its own here.

T+120 (to Sunday 12th March)

GFS: Mild westerly regime, 990mb low north of Scotland, secondary 1010mb low over Britain, strong Azores High ridging over towards Europe.

UKMO: 1030mb high to the SE, 975mb low to our north, and mild WSW winds.

ECMWF: 995mb low north of Scotland, mild SW winds across Britain, with 1020mb highs to our S and E.

NOGAPS: 1030mb Scandinavian High being pushed out of the way by 985mb low right over Iceland. Mild SW winds.

JMA: 975mb mid-Atlantic low, highs at 1020mb to the E and S, mild SW winds.

GEM: Low at 980mb just off eastern Scotland with showery north-westerlies over Britain.

All of the models apart from JMA and GEM show mild west or south-westerly winds and the Azores High ridging over to Europe.

T+144 (to Monday 13th March)

GFS: Complex 1000mb/990mb lows to the north of Scotland, strong developing Bartlett High ridging into southern Britain, light winds from the W veering round to the SW with 990mb lows in the mid/southern Atlantic.

UKMO: 980mb Low N of Scotland, moderate W winds over Britain with showers for N and W districts. Strong signs of a developing Bartlett High (1025mb over central Europe, extending into S England) 970mb low quite a way west of Iceland.

ECMWF: 990mb low south of Iceland, 1025mb high to the east, mild SW'ly conveyor belt over Britain.

NOGAPS: 980mb low to our north, westerly winds over Britain, 1020mb high to the south showing signs of developing into a Bartlett and extending into S England. 990mb lows over mid Atlantic, similar to the GFS.

JMA: 975mb Low off W Scotland, with strong SW winds over Britain and high pressure well away to the S and E, no sign of a Bartlett.

GEM: 990mb lows just to our NW and NE, 1020mb Azores High getting closer, westerly winds over Britain but with low pressure the dominant theme.

All models apart from the JMA and GEM want to bring about what looks suspiciously like a developing Bartlett, and a westerly airstream for Britain. The GFS has backed away from its showery westerly and fallen into line with the Euro models and NOGAPS. The ECMWF already has us in south-westerlies; the other models have us in a cooler westerly but with SW winds knocking on our doorstep.

In two days' time there will finally be a chance to evaluate the model output (T+96) for Thursday. Don't worry about the "Entire Grid Undefined" for ECMWF- I went over to WZ and got the alternative ECMWF charts, which worked.

Edited March 7, 2006 by Thundery wintry showers

[wolves78]

great informative post TWS ty

[Thundery wintry showers]

12Z Model Comparison No. 4: Wednesday 8th March 2006.

T+96 (to Sunday 12th March)

GFS: Low at 990mb to the north of Scotland, secondary low (1010mb) over central Britain, strong Azores High to the south. Probably mild and wet in the south, some sun and showers in Scotland. Westerly winds.

UKMO: 1025mb Scandinavian High and 1020mb Euro High. 990mb low SE of Iceland, mild SSW winds over Britain with Atlantic front moving east.

ECMWF: Low at 975mb just off E Iceland, 1025mb highs to S and E, strong mild WSW winds over Britain.

NOGAPS: Low at 1000mb off East Anglia, low at 995mb off SE Iceland. NW winds over Britain, probably wet with some showery weather in between rain bands, low pressure dominant.

JMA: 995mb east of Iceland, high pressure at 1025mb over Scandinavia, mild S winds over Britain with Atlantic front moving east.

GEM: High pressure at 1030mb to the E and S, low at 985mb south of Iceland, strong S/SW winds over Britain. Mild.

The ECMWF, GFS and JMA haven't changed significantly since yesterday; some changes on other models.

T+120 (to Monday 13th March)

GFS: Slack 990mb and 1000mb lows north of Scotland, weak westerly flow, mild SW winds approaching with developing Bartlett High extending influence into southern Britain.

UKMO: 985mb lows east of Iceland and in the mid Atlantic, mild SSW winds over Britain probably bringing a lot of cloud and drizzle.

ECMWF: 990mb N of Scotland, 990mb in mid Atlantic, S/SW winds over Britain. Mild.

NOGAPS: "Entire grid undefined". I think I'll have to give that one a miss!

JMA: 985mb low NE of Iceland, another in the mid Atlantic, mild SSW winds over Britain. Very similar to UKMO.

GEM: Low at 985mb north of Scotland, slackening SW winds across Britain, rain moving east.

This time only the GFS and ECMWF remain consistent with yesterday's output, with UKMO and JMA going for a similar outlook.

T+144 (to Tuesday 14th March)

GFS: Low at 995mb off W Scotland, mild SW winds, but with only 1015mb Euro High and low pressure the dominant factor.

UKMO: 1005mb low centred over W Scotland, light winds in NW of Britain, strong SW winds in SE England. 1020mb Euro High and large 1045mb high around Murmansk, HP developing to our W.

ECMWF: 1000mb low over W Scotland, moderate WSW winds over Britain, Euro High slipping away SE.

NOGAPS: An interesting one for cold/snow lovers, with 1000mb low over SE England, high pressure (1015mb) to the north and a rather cold, showery looking east to north-easterly airflow over Britain.

JMA: 1010mb low over N Scotland, light W winds over Britain, shallow highs to both the W and E.

GEM: 1000mb low over northern England, with high pressure at 1015mb to our W, S and E.

The UKMO and JMA seem to opt for a similar outlook again, while GFS is rather more progressive, and NOGAPS looks quite chilly.

Tomorrow, I will start up another thread detailing the model comparisons results. Tomorrow's task for the models should be an easy starter as it is only covered at T+96!

Edited March 9, 2006 by Thundery wintry showers

[Thundery wintry showers]

12Z Model Comparison No. 5: Thursday March 9th 2006.

T+96 (to Monday 13th March)

GFS: Strong 980mb low NE of Iceland, 995mb mid Atlantic low, and 1030mb high over East Germany. SW winds over the British Isles, probably in a warm sector.

UKMO: 985mb low just off NE Iceland, 990mb low over NW Scotland, strong SW winds over Britain, with 1030mb high centred over northern Scandinavia but 1025mb also over most of Europe.

ECMWF: 995mb low to the N and W of Britain, 1030mb high centred over the Baltic and mild SW winds.

NOGAPS: Low at 985mb E of Iceland, and 995mb low over Scotland, moderate WSW winds across Britain and low pressure in charge.

JMA: Low at 985mb NE of Iceland, 985mb mid Atlantic low, 1030mb high around Baltic, SSW winds. Overall quite similar to the GFS.

GEM: Flabby 995mb low to the N and W of Britain and SW winds. 1035mb high centred over Northern Scandinavia, similar to the UKMO.

Some changes on the GEM but otherwise very consistent with yesterday's T+120 comparisons across the board.

T+120 (to Tuesday 14th March)

GFS: 1005mb low over NW Scotland, a cyclonic SW flow over Britain, 1025mb high centred around the Baltic but generally high to the south and east. Long drag of southerlies just to our SW.

UKMO: 1005-1010mb low over Britain, a very slack affair, with 1030mb Baltic high and 1020mb high to our S, also 1015mb high to our W. Not much wind.

ECMWF: Pretty much as UKMO, with 1005mb weak low over Britain, and highs at 1015mb to the west, 1030mb over the Baltic and 1020mb to the south. Not much wind.

NOGAPS: 995mb low off northern Scotland, westerly winds over Britain, long SSW drag just to our SW.

JMA: 1005mb low well to the north of Scotland, WSW winds, with 1035mb Baltic High and a long drag of SSW winds just to our SW.

GEM: Weak 1005mb low over Britain. Not much wind, with 1030mb high over southern Scandinavia and also 1010mb weak mid Atlantic high.

Some chopping and changing among the models, but similar outlooks to yesterday's T+144 with good agreement on a shallow low over or just to the NW of Britain; NOGAPS has done a big U-turn though, and JMA stands out from the crowd with a milder SW regime.

T+144 (to Wednesday 15th March)

GFS: 1020mb high over Britain, also covering most of Europe, with weak 1015mb low over southern Scandinavia. No significant wind.

UKMO: 1025mb high centred over NW Britain with weak 1015mb low over Germany. NNE winds over the eastern half of England, little wind elsewhere.

ECMWF: 1030mb High off N Scotland, 1015mb shallow lows over parts of Europe, and a chilly looking east to north-easterly airflow over the British Isles.

NOGAPS: Shallow 1000mb Low over W Scotland, 1025mb Euro High, warm SSW winds pushing into southern Britain with a long drag from very low latitudes.

JMA: 1030mb high over the Baltic, with a strong westward ridge covering the British Isles, light southerly winds over Britain.

GEM: 1015mb low over SE England, 1020mb high north of Scotland, and consequently a slack ENE'ly airflow over Britain. Also strong 1030mb high over east Scandinavia.

Some variation in the T+144 outputs tonight; all models apart from NOGAPS bringing high pressure in, but whereas ECMWF and GEM go for a chilly north-easterly airflow, GFS has the high over us and JMA gives us a southerly airflow; the UKMO falling between GFS and ECMWF/GEM.

[Thundery wintry showers]

12Z Model Comparison No. 6: Friday March 10th 2006.

T+96 (to Tuesday 14th March)

GFS: 1005mb low over the northern tip of Scotland. Westerly winds over Britain, a ridge of high pressure from a 1025mb high over Germany giving mild sunny weather to southern England. 1045mb high over Russia.

UKMO:

ECMWF:

NOGAPS:

JMA:

GEM:

T+120 (to Wednesday 15th March)

GFS: 1025mb high over the British Isles with little or no wind, probably sunny and feeling pleasantly warm.

UKMO:

ECMWF:

NOGAPS:

JMA:

GEM:

T+144 (to Thursday 16th March)

GFS: 1035mb high over southern Scandinavia, pulling in easterly winds across the southern half of Britain, light southerlies in Scotland. An anticyclonic outlook, cloud probably streaming into eastern England.

UKMO:

ECMWF:

NOGAPS:

JMA:

GEM:

I am going out this evening so the other models will be updated sometime around midnight tonight.

[Thundery wintry showers]

Unfortunately I was out until 2am last night, so Friday doesn't have data for many of the 12Z runs I'm afraid...

[Thundery wintry showers]

12Z Model Comparisons: Saturday 11th March 2006.

T+96 (to Wednesday 15th March)

GFS: 1040mb high extending from Russia into central Scandinavia, with east to south-easterly winds over the British Isles, easterly in the North Sea.

UKMO: 1040mb high extending from Russia into central Scandinavia with ESE winds over Britain. Slightly different high orientation, with ENE winds out in the North Sea.

ECMWF: 1040mb high over Scandinavia/Russia, ESE winds over Britain, easterly in North Sea.

NOGAPS: 1035mb highs to the N and NE, south-easterly winds over Britain but easterly in the North Sea.

JMA: 1035mb high over the top of Scotland centred west of Scandinavia, light cool easterly winds for southern England.

GEM: 1050mb Russian High with a strong 1040mb ridge to our north. ESE winds over Britain, ENE winds in the North Sea.

Apart from JMA, general agreement on an east to south-easterly airflow, which is likely to be cold.

T+120 (to Thursday 16th March)

GFS: 1040mb high over Scandinavia/Russia remains, with ENE winds affecting the British Isles.

UKMO: 1040mb high centred just north of Scotland, with easterly winds over Britain.

ECMWF: 1040mb High to the North of Britain and easterly winds, ENE in the North Sea.

NOGAPS: 1040mb high to the north of Scotland with easterly winds over Britain.

JMA: 1040mb high over northern Scotland, light easterlies for southern England.

GEM: 1040mb high from Scandinavia to Russia, easterly winds over Britain.

The theme of easterlies continues, with GFS and GEM keeping the high over Scandinavia and other models bringing it west, JMA remaining the odd one out with high pressure over northern Britain instead.

T+144 (to Thursday 16th March)

GFS: 1040mb Scandinavian High, relatively slack ENE flow over Britain.

UKMO: 1040mb high north of Scotland, easterly winds over Britain.

ECMWF: 1040mb high now over Iceland with easterlies over Britain.

NOGAPS: 1035mb high just to the NW of Scotland, with easterly winds over Britain.

JMA: 1040mb high over northern Scotland and easterlies for southern England, these quite strong.

GEM: 1040mb high to the north of Scotland, easterlies over Britain.

Now only GFS goes for the high sticking over Scandinavia with others bringing it west. Remarkable consistency among the models tonight that the winds are going to be coming from the east and that it is going to be quite chilly.

[Thundery wintry showers]

12Z Model Comparisons: Sunday 12th March 2006.

T+96 (to Thursday 16th March)

GFS: 1040mb Scandinavian High throwing up a ridge to our north, with cold ENE winds covering the British Isles.

UKMO: 1045mb high centred over W Scandinavia. Cold ENE winds covering the British Isles.

ECMWF: 1040mb high just to the north of the British Isles, with cold ENE winds covering the British Isles.

NOGAPS: 1040mb high just off N Scotland with a slack easterly flow covering the British Isles.

JMA: As NOGAPS: 1040mb high just off N Scotland with a slack easterly flow covering the British Isles.

GEM: 1040mb high just off N Scotland but with quite a strong easterly flow over the British Isles.

Complete agreement on the overall outlook, some differences in where the models put the high.

T+120 (to Friday 17th March)

GFS: 1040mb high just to the north of the British Isles, easterly winds over Britain.

UKMO: 1040mb highs centred just north of Scotland and over Scandinavia, with easterly winds over Britain.

ECMWF: 1040mb High to the south of Iceland and easterly winds over Britain.

NOGAPS: Entire Grid Undefined. Will have to give that one a miss I'm afraid.

JMA: 1040mb high off northern Scotland with easterlies over Britain.

GEM: 1040mb high off northern Scotland, easterlies over Britain.

More remarkable consistency.

T+144 (to Saturday 18th March)

GFS: 1040mb high over Iceland, extending to S Scandinavia with ESE winds over Britain.

UKMO: 1035mb Icelandic High but extending to S Scandinavia, ESE winds over Britain.

ECMWF: 1040mb Icelandic High, easterlies over Britain, Arctic northerlies filtering towards Scotland.

NOGAPS: 1035mb high just to the north of Scotland, ESE winds over Britain.

JMA: 1040mb Icelandic High with easterlies starting to veer NE'ly and pick up an Arctic influence.

GEM: 1035mb Icelandic High with ENE winds over Britain and Arctic northerlies veering closer.

More remarkable consistency, although there is a disagreement on whether we will pick up a dry and cloudy looking east to south east flow, or whether Arctic northerlies will start to take over.

[Thundery wintry showers]

12Z Model Comparisons: Monday 13th March 2006.

T+96 (to Friday 17th March)

GFS: 1035mb high to the north of Scotland, easterly winds over Britain.

UKMO: 1045mb high to the north of Scotland, easterly winds over Britain.

ECMWF: 1040mb high to the NW of Britain, just south of Iceland, with easterly winds over Britain.

NOGAPS: 1035mb high covering N Scotland with easterlies over Britain.

JMA: 1040mb high just south of Iceland, with easterlies over Britain.

GEM: 1040mb high just north of Scotland with easterlies over Britain.

Anyone for easterly winds?

T+120 (to Saturday 18th March)

GFS: 1040mb high just south of Iceland, ESE winds over Britain. Northerly airstream well away to the north and east of Britain.

UKMO: 1040mb Icelandic High, 990mb Scandinavian Low, and easterly winds over Britain but northerlies pushing into northern Scotland.

ECMWF: 1040mb High SW of Iceland, 1010mb low extending into Scandinavia, easterly winds over Britain but northerlies pushing into Scotland.

NOGAPS: A ridge of high pressure over Britain, light easterly winds. 1045mb Greenland High and 980mb Scandinavian Low sending northerlies southwards towards Scotland.

JMA: Ridge of high pressure over Britain, 1050mb high centred over Greenland, 1010mb low over N Scandinavia and light ESE winds over Britain.

GEM: 1035mb high centred around Iceland, ESE winds over Britain. Northerly airstream well to the north and east of Britain.

GFS and GEM and JMA want to keep us in an ESE regime while other models show signs of bringing in a northerly.

T+144 (to Sunday 19th March)

GFS: 1040mb high over Iceland, extending to Scandinavia, light ESE winds over Britain.

UKMO: 1045mb high centred over Greenland, NE winds for Britain but with high pressure dominant. Quite intense 995mb low over N Scandinavia.

ECMWF: 1045mb Greenland High, 1000mb low in North Sea and rather chilly, showery looking north-easterly winds over Britain.

NOGAPS: A remarkable 1060mb high over Greenland, with cold showery north-easterly winds over Britain.

JMA: 1045mb Greenland High, slack NE winds for Britain.

GEM: 1040mb Greenland High and NE winds for Britain.

Some disagreement on whether we will get a potent, cold showery NE'ly (ECMWF, NOGAPS), a relatively tame NE'ly (UKMO, JMA, GEM) with GFS out on its own in maintaining a east-south-east flow.