Model Output Discussion - 2nd March Onward

[john pike]

[nick sussex]

The first hurdle is overcome if you get the ridge extending sw as per the ECM and now GFS 18hrs run, however for the UK to get something worthwhile in terms of snow and cold its essential to tap into the coldest source of air and even if theres agreement tomorrow on the ECM trend that's still uncertain.

So still quite a few hurdles to come even if the UKMO joins the party tomorrow.

[Cheese Rice]

18Z GFS desperate to push the cold towards us, eagerly awaits the rest of the output.

Edited March 2, 2013 by Cheese Rice

[nick sussex]

I think theres been some modification to that but it still looks a bit underwhelming. The 120hrs will be the decider because the raw output threw a lot of energy much further north.

[SMU]

The 18z has the most perfect sausage high at 162... One of the best locales you could hope for in any winter month

S

[mushymanrob]

John Holmes would strongly agree, Steve Murr would strongly disagree. So

if its gonna happen it will show on the anomaly charts, even if they play catch up with the ops. ill wait and see what they show tomorrow morn. even if there is summut nasty (lol)itll be nothing as severe as the ecm suggests this eve, unless its a one in a million chance that actually happens. its all fi so will be tempered as all ecms doom charts have been.

[cooling climate]

when the anomaly charts suggest support for tonights fi , ill start to think summuts happening. until then its fiction

I posted the other day that anomaly charts and Met forecasts can change on a dime

and it very much looks like this will be one of those times.

[bluearmy]

i'm confused - the anomoly charts do support the broad ecm solution.

[SomeLikeItHot]

I think you are right, mush: the ECM has overcooked just about everything this winter, so far...Maybe this time, it won't? That said, I don't recall much, from T+200+, verifying...

Over cooked is an interesting term for too cold... I think in terms of weather the GFS is usually over cooked , but interesting to see the similar cold from scandi which didn't hit the uk in the 12z reaching us this time on the 18z and turning into a N to NEly for most of the low res .

At this range there is still a of course a very good chance of not verify or being toned down considerably. That said I think at this range the ECM has correctly picked out cold spells including the one last weekend, which it only really "over cooked" in terms of its snow potential. Seems to me considerably increased chances of something cold from early next week from this evenings runs.

Edited March 2, 2013 by SomeLikeItHot

[Cheese Rice]

The ECM solution is NOT overcooked, these uppers are wholly expected when you consider the exceptional cold air pushing into NE Europe.

ALL models show this cold pool, the question arises as to whether a.) we can push the cold air south and b.) whether the cold air can be advocated westwards. If we do push the cold air towards the UK then uppers below -10 perhaps even -15 should be expected.

[nick sussex]

Lower resolution GFS gets a bit messy but the higher resolution is a step in the right direction for cold.

So the hurdles to get the cold into the UK are as follows:

Separation of shortwave energy to the north at T96hrs allowing the ridge to edge sw out of the Arctic.

The troughing near the UK needs to disrupt and send more energy se into southern Europe.

No phasing of shortwave energy to the west of the UK with the low exiting the eastern seaboard of the USA, at worst this must happen much later.

A favourably orientated high to the ne.

The Azores high needs to take a hike so you need more energy heading se and flattening it.If not you'll have to go through the stress of it ridging north and then need a shortwave to come into play similar to what the GFS just did.

So that all looks straightforward then, off to order my ear muffs and gloves now for winter part 2!!! Who said getting cold into the UK was easy, oh and finally deep cold uppers to offset that fast increasing solar energy!

Quite a few hurdles to overcome but a chance this evening, the 120hrs fax chart has thankfully been modified, not as good as the ECM but at least the UKMO dropped that raw output.

[No Balls Like Snow Balls]

The Ecm (Birmingham) and Gfs (London) ensembles do show a sharp decrease in daytime temps from next weekend. But they are still nowhere near cold enough to produce snow or any daily express big freeze headlines. Hardly worth getting excited at the moment considering any extreme cold shown in the op runs are 8 days away. I Do find de bilt ensembles pretty pointless when all they really do is confirm the likely hood that de bilt will be colder than the UK 99% of the time.

[john pike]

make of that what you will

very messy and wet

[bluearmy]

http://www.meteo24.fr/fr/home/meteo-france-et-europe/passion-meteo/ensemble-de-previsions.html?eps=london

The less cold fi runs dropping way quickly now. Looks like a period of upper thirties maxes for london approaching and around mid month.

wonder if we can scrape a decent snow event somewhere across the uk once this has passed?

[LomondSnowstorm]

http://www.meteo24.f...html?eps=london

The less cold fi runs dropping way quickly now. Looks like a period of upper thirties maxes for london approaching and around mid month.

wonder if we can scrape a decent snow event somewhere across the uk once this has passed?

I fancy my house:

A rain to snow event from the north followed by a possible convective flow from somewhere between north and east, though the last part is the most speculative both in details and length.

[Cheshire Freeze]

Been a while since we've seen a signifficant cold push in March. Ensembles looking interesting from a cold lover's perspective

[TEITS]

Very surprised at some of the posts this evening.

Firstly why are some surprised by the ECM and then suggesting it wont happen. I have been posting ensemble means these past few days and all of which have supported an E,ly around the 10th March. What has been uncertain is how cold this E,ly could be.

Are upper temps below -10C exceptional and too extreme for the ECM to be correct? Well the answer is no because very cold runs have frequently been appearing on the ensembles and some have been as low as -15C.

[Cheshire Freeze]

some have been as low as -15C.

I suspect that sort of upper air temperature would oversee some very heavy falls of snow

[Weather Boy]

The ECM solution is NOT overcooked, these uppers are wholly expected when you consider the exceptional cold air pushing into NE Europe.

ALL models show this cold pool, the question arises as to whether a.) we can push the cold air south and b.) whether the cold air can be advocated westwards. If we do push the cold air towards the UK then uppers below -10 perhaps even -15 should be expected.

I think that Mushy's language is slightly overcooked ( e.g I would say unlikely, not highly unlikely) but I would broadly agree with him. The point being made is that often it has shown totally classic synoptics and that has not come to fruition.

However in its defence, every time (December debacle aside, when all models were wrong) it got the general pattern right and therefore was (and IMO is) worth more of a look than pretty much any other model, notably the GFS which has been an utter shambles all season. I' d therefore venture that it's likely to be broadly correct even if the detail isn't quite as juicy as it appears, which will be hardly surprising given the range we are contemplating.

Cold snap likely to be coming, I'd say: potency and longevity far more up in the air. Could well be a disappointment compared to some charts. Who knows but that would hardly be a surprise.

[TEITS]

Just add that I don't know why some are suggesting its only the ECM showing this potential.

18Z GEFS mean at +192.

Remember I got some flak last night when I mentioned the JMA was suggesting a big freeze!

[nick sussex]

Just looking at some of the GEFS and some of the 850's shown are astonishing for eastern Europe for what would be getting on for the middle of March.

Even for the UK I think you would be digging around the record books, when you look at March records the majority have come right at the start of the month so to see some of those upper air temps and the cold pool to the east one only wonders what those values would have shown in the middle of winter.

I'm sure most would be happy to just see a final winter fling and a bit of snow so we'll see over the coming days whether the trend continues.

[Thundery wintry showers]

Although I think a generally snowy spell towards mid-March is still odds against, I can't deny that the odds have shortened substantially on the evidence of tonight's model runs, with GFS and ECMWF showing the east-Atlantic trough weakening and sliding SE at around the 7-10 day range, allowing cold airmasses to come down from the NE.

Unlike a stable continental east to south-easterly, a north-easterly type with a cold source is still capable of producing significant convection over the North Sea at this time of year, and if pressure is low enough, showery activity in inland areas can be pepped up due to solar heating from the relatively strong March sun. Frontal snowfalls are also possible in that setup, e.g. when we get renewed northerly blasts or when southerly tracking lows slide across the south.

However, the fact that the snowy setup takes until the 7-10 day timeframe to arise, and that the UKMO looks somewhat different to the GFS and ECMWF at days 5 and 6, mean that it is too early to be able to place much confidence in that setup arising and I still think that some sort of moderately cold, cloudy east to south-easterly is at least as likely as a snowy northerly or north-easterly.

Looking closer to the present moment, cloud cover is currently variable over the British Isles although the satellite images suggest that there have been more sunny areas than cloudy areas today. This is likely to continue until the 5th March with Ireland seeing the cloudiest skies and central and northern England probably sunniest. On the 5th a warm south to south-easterly may send temperatures up into the low teens quite widely, but after that we'll get weather systems moving in off the Atlantic and these will bring somewhat cloudier conditions for most of the country, with light rain at times, although away from the south-west I think rainfall totals will generally be small.

Edited March 3, 2013 by Thundery wintry showers

[Guest pjl20101]

There are hints even that the MJO is going back towards phase 5 after a brief spell in phase 7. That will send the models in meltdown as that will probably mean that our period of unsettled weather maybe short lived. Another thing I picked up on from NCEP is the AO being very negative. Not really good news for people who like their spring weather on the warm side.

[Cheese Rice]

I think many here would be happy with one last winter blast, the overall consensus is winter didn't deliver as much as hoped. It was a good winter for me but I wouldn't say no to a convective easterly. If the ECM comes of we'd see convection of epic proportion, a significantly stronger sun would create a severe unstable flow.

It's easy to get carried away by the current output, and while I'm certain severe cold will be pushing into NE Europe i'm less than confident it'll hit here.

Anyway here's my pick from the ensembles.

Edited March 3, 2013 by Cheese Rice

[Guest pjl20101]

One can hope that those charts are modified a bit. I personally find wetterzentrale a lot more reliable and Gavin p would probably agree with me as he uses it too. Meteociel sometimes acts like it has bugs with it that aren't fixed in time. Those charts cheese rice you have posted are very alarming indeed and weather that isn't even remotely Springlike.