Model Output Discussion

[osmposm]

It's on the 6-15 day forecast, Ossie.

http://www.metoffice.gov.uk/weather/uk/uk_forecast_weather.html

Ah yes, there it is. Thanks very much (and sorry Chris). It's weird, I looked at the 6-15 day before I spoke, but must have got an older version still in my cache.

[Thundery wintry showers]

See days 6-15 here:

http://www.metoffice.gov.uk/weather/uk/uk_forecast_weather.html

"Through the weekend and following week there is an increasing possibility of drier more settled weather developing across the UK with cold easterly flow."

To me, that implies high pressure and a sluggish import of cold continental air from the east rather than a full-blown east-north-easterly from Siberia/Russia bringing sunshine and snow showers, and I think it probably represents the most likely scenario given the upcoming synoptic evolution. However, it will only take fractions either way to leave us in a mild cloudy (albeit probably much drier than recently) south-westerly regime with HP stuck to the E or SE, or alternatively a full-blown snowy easterly resulting.

I am pleased to see the Met Office coming on board with the upcoming trends and hopefully helping to dispel allegations of "warm bias" in their forecasts, but at the same time being realistic about it (i.e. not sensationalising with the coldest-case scenario).

[David-kig]

met office 6-15 days forecast aint worth looking at

[londonsnow]

I'm inclined to agree that something is brewing from mid month onwards but it could just be a near miss for the uk although mainland europe looks set for a freeze up. I still think we will get a settled spell from next weekend onwards with frosty nights and some freezing fog, anything more than that will be a nice bonus.

tend to agree. central europe looks like getting a dose of very cold mid month. odds are very long anything bitter hitting the uk

[Thundery wintry showers]

6-15 day forecasts are always prone to considerable error because of the fact that one slight inaccuracy at day 4 can throw the rest of the forecast out of kilter- which is partly why I say the margins between a mild SW'ly, a cold snowy easterly, or the Met Office's in-between scenario, are very small.

[nick sussex]

Alots been made of the ukmo further outlook, that can change as quickly as the models but at least they go with at least the initial euro high extending north and some easterly feed.

[Frosty.]

Im not settling for that full blown cold snow or nothing, we have settled for near misses for years time to deliver!!!

If only the weather would listen to what we want but we might have to settle for the scraps from the table while central & eastern europe have a major freeze up. At least we should get something colder and more seasonal feeling and there is an outside chance of something more potent.

[snowmadchrisuk]

If only the weather would listen to what we want but we might have to settle for the scraps from the table while central & eastern europe have a major freeze up. At least we should get something colder and more seasonal feeling and there is an outside chance of something more potent.

What is worth saying as well is how quick the cold to our east builds. We often say there is no cold to tap into , but in the right conditions cold can build very very quickly , within 48 hours in some cases .

[Frosty.]

tend to agree. central europe looks like getting a dose of very cold mid month. odds are very long anything bitter hitting the uk

I don't think the uk could cope with what central europe is going to get, the models seem to be losing ensemble support for a bitter blast reaching the uk, at least it will save our lousy government some money.

[Solar Cycles]

See days 6-15 here:

http://www.metoffice...st_weather.html

"Through the weekend and following week there is an increasing possibility of drier more settled weather developing across the UK with cold easterly flow."

To me, that implies high pressure and a sluggish import of cold continental air from the east rather than a full-blown east-north-easterly from Siberia/Russia bringing sunshine and snow showers, and I think it probably represents the most likely scenario given the upcoming synoptic evolution. However, it will only take fractions either way to leave us in a mild cloudy (albeit probably much drier than recently) south-westerly regime with HP stuck to the E or SE, or alternatively a full-blown snowy easterly resulting.

I am pleased to see the Met Office coming on board with the upcoming trends and hopefully helping to dispel allegations of "warm bias" in their forecasts, but at the same time being realistic about it (i.e. not sensationalising with the coldest-case scenario).

Aye, but it does mention the possibility of MILDER weather returning towards the end! I'll get my coat!!

I don't think the uk could cope with what central europe is going to get, the models seem to be losing ensemble support for a bitter blast reaching the uk, at least it will save our lousy government some money.

For the time being Frosty. I wouldn't be suprised to see us being under it's influence, by the third week of this month!

[Stu_London]

12z looking like one of the milder evolotions into FI

[cooling climate]

Well going into the 12z's we have the MJO slowing down a bit but still looking likely to enter phase 8 .

http://cawcr.gov.au/....Last40days.gif

Convection still looks strong and progressing across the date line going by the OLR anomalies.

[snowmadchrisuk]

Convection still looks strong and progressing across the date line going by the OLR anomalies.

Yes looking good , all the background signals are good , Just need to convert this into something cold for the UK

[Optimus Prime]

HI THERE SORRY TO BUT IN ON HERE BUT IF ANYONE COULD SOME UP WHATS GOING ON IN ENGLISH PLEASE FOR THIS NEWBIE. HAVE NOT GOT USED TO ALL THE WEATHER JARGON YET

The short term - Unsettled

Medium Term - Settled with a cold inversion high perhaps slight easterly

Long Term ala FI - Potentially cold with an easterly wind

[nick sussex]

That shortwave running off the main trough is very troublesome here, it just makes things more complicated. Get rid of this shortwave and the euro high ridges further north subsequently less can go wrong after this.

Edited December 5, 2009 by nick sussex

[Cecil Hogmanay Melchett]

gfs 12Z Looking like a poor run to me,too much action in the GIN with those blasted lows preventing the high

going north.

Hopefully not the start of a new trend.

[January Snowstorm]

That shortwave running off the main trough is very troublesome here, it just makes things more complicated. Get rid of this shortwave and the euro high ridges further north subsequently less can go wrong after this.

There's always something though Nick.

Every year we have some reason why we dont get cold.

[nick sussex]

There's always something though Nick.

Every year we have some reason why we dont get cold.

The problem here is even if the FI looks good the shortwave earlier means more can go wrong and hence you're relying on more factors to go right afterwards. Notice here the delay in the cold arriving and this begins to resemble chasing the pot of gold at the end of rainbow, this is all to do with the earlier shortwave, i suspect the ensembles will show a clear separation between the cold arriving much earlier without the shortwave and those with the shortwave showing a delay or the jet spilling east off the main trough and scuppering the easterly.

Edited December 5, 2009 by nick sussex

[TEITS]

The problem here is even if the FI looks good the shortwave earlier means more can go wrong and hence you're relying on more factors to go right afterwards.

Don't you find though Nick that at times the GFS over cooks these shortwaves at this timeframe? Or am I suffering from selective memory.

[bluearmy]

we're even getting shortwaves in FI sinking the block!! at least that might prevent too much excitement until later when the ecm is out.

[Iceberg]

There is alot less energy in the northern arm this run, A blend of the 06Z and 12Z would be fantastic.

Agree re the short waves, it's the right time for GFS to be playing with them.

[nick sussex]

Don't you find though Nick that at times the GFS over cooks these shortwaves at this timeframe? Or am I suffering from selective memory. :lol:

It can do but also this is a possibility and it wouldn't be the biggest surprise given recent history, we'll have to see what the euros do but if the shortwave appears and verifies i'm going to put away my ear muffs and bobble hat!

[snowmadchrisuk]

Not liking the 12z 1 bit ... when you think what it produced 24 hours ago. Along way to go still but I think the chances are reducing of a quick start to a cold spell . I.e next weekend.

[January Snowstorm]

The situation remains the same after this run; unless a trigger low runs under the High to back the cold West, then we will be under a mid-latitude High which will probably take a fair bit of shifting.

Yes if that high does take residence over the UK we can wipe out the whole of December inc Christmas.

All or nothing here and the form horse looks like 'nothing'.

If we can't have cold give me a storm. Our interest in weather wasn't founded over high cells sitting over us for weeks

[Cecil Hogmanay Melchett]

There's always something though Nick.

Every year we have some reason why we dont get cold.

Good point.There always appears to be spmething to stop the cold reaching us.

Its no accident when it happens year in tear out,is it?