Model Output Discussion - 2nd March Onward

[summer blizzard]

Interesting output from the models this morning showing two differing outcomes.

My personal opinion is that the default pattern at the moment is the one which we have just seen as in high pressure very close to the UK (be that south or north i don't know) and so i think that other than a few days it is likely that pressure will build in akin to the ECWMF or GEM.

Chart of the day for me is day 10 GEM..

[chionomaniac]

Looking at the London T2 ensembles it does appear that up to day 8-9 things will be distinctly average temperature wise and dry precip wise. there is no doubting that it is the period after that potential for colder weather to arrive exists.

We are seeing again another period of stratospheric led wave 1 activity that is displacing the vortex towards Siberia. Yet again, where any ridge can build will determine exactly where any cold is released. And I suspect it is too early to be too confident to any ridges exact positioning. I still would use every bit of information that we have at our disposal and will still be looking at the H500 anomaly charts. The latest show a positive anomaly towards the south of Greenland.

I suspect that, as shown by the European T850 anomaly, that the cold air will just miss us to the east - but this is close enough to maintain interest as a possible spring arctic blast.

[Cloud 10]

Looking at the 06z GFS ensemble mean reveals quite a fall in upper air temperatures

over the UK around the 10th of March onwards,so maybe a loose date to keep an eye

on for any potential cold outbreak.

Edited March 2, 2013 by Cloud 10

[bluearmy]

the post 10th march drop off in mean maxes has been on the charts since it came within view. of course, as the timeframe comes within higher res, it may well get 'bumped'. ed's london graph shows the split well. i sense an azores ridge trying to makes itself felt at that timescale. whether that becomes mid atlantic, euro or mid lat nw europe, who knows but its a trend from recent suites.

[Panayiotis]

Can anyone answer my question why does the NAE model show a lot of cloud cover for my area, however here there is no cloud in sight!?

Thanks.

Latest radar Weather Europe, Satellite Weather Europe, Weather Forecast, Rainfall, Clouds, Sun in Europe - Source: SAT24.com

Edited March 2, 2013 by Panayiotis

[Frosty.]

Looking at this mornings output a cold E,ly continues to look favourite, how cold is still very uncertain. Appears around the 11th March is when this could occur so only 24hrs later than I suggested many days ago.

I won't bother you with posting the links but the GEFS mean again is very similar to last night and of course todays ECM shows an E,ly flow. If you look at the ensembles below you can clearly see the uncertainty how cold it could be.

http://cdn.nwstatic....bridgeshire.png

The latest met office update doesn't look very encouraging for a cold outlook, it sounds fairly mild to me. I'm disappointed because the arctic is much colder than normal and it seems to be getting harder for us to benefit from it, it could be that the central and western atlantic have an arctic blast but the uk is mild and unsettled, one of the quirks of nature.

[bluearmy]

looking through the 06z gefs, expect anything from low res gfs 12z. almost every conceivable solution was in there and seeing as the ops are lacking any consistency, i expect we will see another low res plucked from the previous ens suite.

[Jason M]

Blimey, no post since 4pm!

Overall its as we were tonight. Opps nothing to write home about but ensembles trending colder and colder. Some epic runs in amongst them.

Yesterday I think I put 15 per cent probability on a very cold spell. I'd up that to about 40 per cent tonight taking the various outputs into account. I'm tempted to say 50/50 tbh but I'm allowing 10 per cent to account for Murphy's law :-)

Jason

[Methuselah]

Oh dear! The dear old GFS is showing 'potential' again...

[Panayiotis]

The latest met office update doesn't look very encouraging for a cold outlook, it sounds fairly mild to me. I'm disappointed because the arctic is much colder than normal and it seems to be getting harder for us to benefit from it, it could be that the central and western atlantic have an arctic blast but the uk is mild and unsettled, one of the quirks of nature.

More than encouraging for me!

UK Outlook for Sunday 17 Mar 2013 to Sunday 31 Mar 2013:

Most areas are likely to be colder than average during the end of March with an east or southeasterly influence most probable. Generally, there are no strong signals regarding precipitation, but taking the period as a whole, in an east or southeasterly regime, some western and northwestern areas of the UK are most likely to be drier and sunnier than normal.

Issued at: 1600 on Sat 2 Mar 2013

[nick sussex]

The ECM refuses to back down at T96hrs with one shortwave heading west the other east with the gap opening up to the ne which means that it will develop differently to the UKMO.

Because of this crucial early difference if the ECM is wrong at that point then the rest of its output can't verify.

It's unusual to see this stand off between the ECM/UKMO from such an early timeframe, the same can also be said for the UKMO, if its wrong re the shortwave then its later output can also go in the shredder.

Edited March 2, 2013 by nick sussex

[Panayiotis]

TEITS, Matt Hugo agreeing with you.....

Matthew Hugo â€@MattHugo81

Details highly uncertain, but a colder E or NE'ly flow looks increasingly likely from around the 10th/11th onwards.#wintrybymidmarch

[cooling climate]

Momentum grows for a cold spell around mid month which is a surprise not.

Been saying it for the best part of two weeks now along with a few others.

How cold is still to be decided though.

[ChartViewer]

Momentum indeed cc

[nick sussex]

The early differences between the ECM and GFS/UKMO are so fundamental for how things develop that I'd put these odds on a colder east/ne flow, if the ECM is correct 50%, if its the UKMO 5%, GFS 30%.

In terms of the ECM it could still be better with more trough disruption and there are some concerns with phasing of energy upstream between the low leaving the eastern USA and that shortwave energy to the west.

But for those hoping for a last wintry shot then you really need the ECM trend to be the right one because the UKMO needs a fiction writer to plot a route to an east/ne flow from its 144hrs output.

[ChartViewer]

One last shot of cold please

[Frosty.]

LOL are we still on page 2..oo page 3 already.

Nice Gfs FI for a change, winter bites back, not the easterly that some crave but a potent northerly for the time of year not to be sniffed at.

Edited March 2, 2013 by Frosty039

[Tamara]

Mmmm - with the right trough disruption as shown by the ECM we could see low pressure squeezing, slithering and snaking eastwards to our south and pulling some of that very cold air to our NE towards us

[cooling climate]

Fantastic t216 chart on the 12z ECM with -12c uppers across a large part of the country

and heavy snow showers I would imagine.

[Panayiotis]

That is beauty! Now lets see if we can get this into the reliable by Tuesday, then I think we can be looking at something noteworthy!

Upper air winds to support some good convection into the South from a ENE flow:

Edited March 2, 2013 by Panayiotis

[nick sussex]

I suppose the only benefit from the ECM tease coming so late in the season is that this place is quieter and perhaps everyone is a bit more laid back about things.

I dread to think of the carnage that could have happened in here if it was mid winter and the ECM got this wrong! But I'd advise people to wait to tomorrow before even getting remotely excited because the GFS and more so the UKMO do not agree with the ECM from as early as T96hrs.

If you don't get that favourable split at T96hrs then theres no chance of the ECM developing how it does. Anyway that's my parenty sensible post for the evening!

Keep an eye out for the fax charts later because if the UKMO think their raw output is cat litter then they might modify them towards the ECM if theres good ensemble support.

Edited March 2, 2013 by nick sussex

[Snowman.]

Liking this new model made by NASA so should be counted as a fairly high performance model. Perhaps this could be used to get a more detailed outlook at a further range than the UKMO.

[SMU]

finally we see the ECM produce a run that I expected to come from the 00z .....

Very very cold unstable easterlies spreading south at 192 with -13 air over the ne.

Large discrepancies against the Ukmo which is unusual for this winter.

Gfs all at sea again.... Which has been the norm this winter

[Frosty.]

I suppose the only benefit from the ECM tease coming so late in the season is that this place is quieter and perhaps everyone is a bit more laid back about things.

I dread to think of the carnage that could have happened in here if it was mid winter and the ECM got this wrong! But I'd advise people to wait to tomorrow before even getting remotely excited because the GFS and more so the UKMO do not agree with the ECM from as early as T96hrs.

If you don't get that favourable split at T96hrs then theres no chance of the ECM developing how it does. Anyway that's my parenty sensible post for the evening!

The ECM can't be trusted at all, last saturday it showed a potent arctic blast for today, hmmm that went a bit wrong didn't it, now we are back to charts closer to T+200 hours, if it gets to T+72 then yes, believe it.

[Panayiotis]

Liking this new model made by NASA so should be counted as a fairly high performance model. Perhaps this could be used to get a more detailed outlook at a further range than the UKMO.

Thats the 00z,the 12z comes out at 10pm.Its also one of the highest res models that goes out to 120hrs.