Winter Model Discussion - Cold Hunting - 20th Dec

[Frosty.]

Yes the Aberdeen ensembles are looking much warmer than yesterday as 2013 begins after a cool down between the 26th and 29th or 30th there than becomes a lot of scatter with the members more are trend above zero than they were yesterday

cold hunting will get even harder then, it's a shame because there were hints of a northerly between xmas and new year but it now just looks like a brief cool down after the torrential rain clears. Anything cold shown in FI is sure to downgrade. The models have teased and taunted us so far this winter with phantom easterlies and northerlies, the only thing the models are good at is mild swlys.

[IDO]

Browsing through the GFS ensemble members there is a majority that are picking

up higher pressure (blocking) to the north and over the Arctic in the extended

range. Hopefully this will be a continuing trend in the future.

So thats average for the north and south then lol.

Yes I suppose, normal for the north to have slightly cooler uppers in this set up than us southerners.

[wolvesfan]

Evening all,

I know its not wise to pay too much attention to the models out into fi,but due to the zonal flow thats entrenched itself recently thats where the pattern changer undoubtedly lies.

Nice to see 12z rising heights to our NW as we seem more likely to benefit from that area than any other.

Slight changes to the mets wording today on its LRF and whats developing in the strat leaves me feeling a little more optimistic this evening ,i feel it wont be long before the models start to evolve in showing a colder solution.

wolvesfan.

[chris55]

Although we are in a very wet zonal type pattern for the foreseeable, things look to cool down around Christmas, with a bias for northerly incursions, as opposed to South Westerly ones.

This may bring the risk of some snowfall and some frosty nights (in any lull in depressions) so could be worse IMO.

We'll just have to wait and see if any proper cold patterns follow into the new year and beyond.

[chris55]

A surprise snowfall not out of the question! (as highlighted above)

ECM quite different to the 00z at 144. A slightly more southerly track of the Low approching from the West and places south of Scotland may see some of the white stuff.

Scotland cold, England and Wales quite cold (just not quite cold enough!!)

[nick sussex]

Hero to zero GFS! Zero to a sort of semi hero ECM!

The ECM so far upto 168hrs is an improvement in terms of some colder potential compared to its earlier 00hrs, the GFS has gone the other way in recent runs.

However its always difficult at these timeframes to trust the models in terms of how far south the jet will be, because of the location of the PV you tend to find they over estimate how far south it gets.

[chris55]

+ 10 850s over Scandinavia on the 00z ECM have been replaced with -10 850s on the 12z!!

[Frosty.]

Yes I suppose, normal for the north to have slightly cooler uppers in this set up than us southerners.

Yes it looks rather cold in northern britain for most of next week, nearer average or mild for the south but maybe a chilly start to the new year for most of us with a lot of luck. Nice to see you being more positive than usual.

[Panayiotis]

Differences between GFS and ECM, if you ask me ECM looking much better!

[nick sussex]

Overall a better run from the ECM with the jet further south and a move away from its sw/ne tilt to the jet.

With a few tweeks it could be of even more interest especially for northern areas, but best to not expect much as things could easily move the other way again.

The overall NH pattern at 240hrs is a step in the right direction but well into the future so we'll just have to see over the next few runs.

[cooling climate]

A much more promising sign in the extended range from the ECM tonight.

As with the GFS ens that I mentioned earlier hopefully this is a trend

that we will see continue.

[Frosty.]

Overall a better run from the ECM with the jet further south and a move away from its sw/ne tilt to the jet.

With a few tweeks it could be of even more interest especially for northern areas, but best to not expect much as things could easily move the other way again.

The overall NH pattern at 240hrs is a step in the right direction but well into the future so we'll just have to see over the next few runs.

The ukmo 12z looks good too. Now it's the gfs which is relatively poor, that will be the day when all 3 models show something cold at the same time!

It's good news from the ecm though because the 00z showed the jet buckling sw/ne with pressure rising over europe with low pressure to the northwest

Edited December 21, 2012 by Frosty039

[Man With Beard]

+ 10 850s over Scandinavia on the 00z ECM have been replaced with -10 850s on the 12z!!

If this chart came off it would be like a repeat of this week - low stuck off Ireland

[Methuselah]

The ukmo 12z looks good too. Now it's the gfs which is relatively poor, that will be the day when all 3 models show something cold at the same time!

It's good news from the ecm though because the 00z showed the jet buckling sw/ne with pressure rising over europe with low pressure to the northwest

Didn't we have cross-model agreement on the BFTE, Frosty?? It might be better, on the nerves at least, if there's just a wee bit of disagreement?

Edited December 21, 2012 by Rybris Ponce

[Jason M]

Didn't we have cross-model agreement on the BFTE, Frosty?? It might be better, on the nerves at least, if there's just a wee bit of disagreement?

From memory all the models showed an easterly, but they always seemed to show different easterlies :-)

It struck me at the time that the Synoptics were often completely different both between models and between runs. Perhaps a lesson to be learnt from that episode?

Anyway, today we continue on the trend to zonal. Over the last 24 hours the trend has been for the models to flattern the pattern and reduce the impact of any northerly. With heights to our south the form horse will be that this will continue as in these scenarios the models tend to overstate any colder incursions only to moderate nearer the time.

Jason

[Frosty.]

Didn't we have cross-model agreement on the BFTE, Frosty?? It might be better, on the nerves at least, if there's just a wee bit of disagreement?

LOL yes but it never happened, I should have made myself clearer, what I really mean is will the gfs, ukmo and ecm show a cold spell that actually happens, rather than always in FI although to even see a cold snap/spell in FI is something good when we are in such a horrible wet spell with average/mild temps, for example, 13c is likely in the south tomorrow..yuck.

Edited December 21, 2012 by Frosty039

[Methuselah]

LOL yes but it never happened, I should have made myself clearer, what I really mean is will the gfs, ukmo and ecm show a cold spell that actually happens, rather than always in FI although to even see a cold snap/spell in FI is something good when we are in such a horrible wet spell with average/mild temps, for example, 12c is likely in the south tomorrow.

I did suspect that that's what you meant. And, aye, I would certainly buy that...

[Frosty.]

I did suspect that that's what you meant. And, aye, I would certainly buy that...

Yes and i'm trying to be positive about next week, the big week and at least scotland should have some colder than average weather and hopefully the new ecm trend will bring colder weather further south.

[East_England_Stormchaser91]

Ill say it now, anyone writing winter off now, is like writing the summer off in the middle of June. Yes winter hasn't been great so far, but we still have the whole of January, February and March left, I say March because April can often see some potent snow falls too, one of which about 5-6 years ago, I witnessed thundersnow one morning from a potent snow shower in Lincolnshire. Odds even stack up for Easter to have more of the magical white stuff than at christmas time. I think we are going to see some proper cold from mid January on into February. We even saw a spine chilling low of -16c here in Cambridgeshire during the cold snap in February earlier on this year from the 'deadly cold' snap in Europe. Now had that huge high pressure have been placed 500 miles further west, we would have seen copious amounts of snowfall like Ukraine, Romania and much of the Adriatic. Have faith people, we will see the cold, we just need the right pattern to set itself up. We have 2 solid months yet at least folks.

[Gibby]

Good evening. Here is the report of the 12z output from GFS, UKMO and ECM for tonight Friday December 21st 2012.

All models are showing a very unsettled picture right up to and including the two main days of Christmas. Low pressure and associated troughs are moving towards SW Britain carrying rain already into Cornwall and proceeding further NE overnight to reach all areas by midday tomorrow. Some heavy and disruptive rain is likely with further flooding issues developing by tomorrow. A drier interlude is then shown to cross NE through the middle of the day turning the rain light and drizzly before a further wave brings heavy rain back again later in the day and overnight tomorrow. Sunday looks like a better day as the UK lies between weather systems before Christmas Eve shows another system pulling in from the West with yet another band of rain crossing West to East through the UK. Over Christmas Day and Boxing Day the weather is shown to turn somewhat colder as a more showery couple of days move in from the West with air cold enough for some wintry showers in the North but with some welcome respite from recent continuous rains with even a few sunny intervals in places.

GFS then takes us out of Christmas with next Thursday being another day of rather cool and bright conditions away from showers around windward coasts. Towards New Year a new deep depression wind's it's way NE to the NW of the UK with gales and rain sweeping NE over the UK, this time heaviest in the NW. A broad Westerly and rather mild flow in the South takes us over the New Year with further rain at times, though less heavy than recently. Through FI tonight the trend is for a colder snap for the far North with a few wintry showers before a return to high winds, rain and rather milder weather returns later.

The GFS Ensembles show the wet period is likely to be maintained for some while yet with things turning somewhat chillier for a while before a return to somewhat milder conditions return before the end of the period. There is little prospect of anything seriously cold within the time frame of the perturbations shown.

The Jet Stream shows a continuation of the undulating West to East flow all the way from the States, across the Atlantic and into the vicinity of the UK for the reliable future.

UKMO for midday on Thursday shows a Low pressure area exiting NE England into the North Sea with a strong to gale Westerly flow over the South. Rain would clear East followed by showers. It would feel colder than of late, especially in the North where showers could be wintry.

ECM for the same time shows a similar synopses with Low pressure over the UK, clearing East though the day taking it's wind, rain and showers with it. Towards the end of the run the charts show no abatement in rainfall for the British Isles with the UK being the target zone for further deep Low pressure and further heavy rain and showers right out to the New Year. Temperatures will never be far from normal for most.

In Summary the weather looks like staying very inclement and unsettled with bands of heavy rain interspersed by short drier interludes lasting right through from now until New Year. Some of the rain will be heavy and disruptive with flooding issues continuing over the Christmas and New Year break without doubt and it may also be coupled by strong winds too at times. Temperatures will range from very mild at times in the South to a little on the cold side in the North on occasion with some wintry showers in between the more persistent rain bands. Low lying Britain is more or less guaranteed a green or water covered land surface rather than a white Christmas this year.

[Spurry]

Ill say it now, anyone writing winter off now, is like writing the summer off in the middle of June.

From my memory summer wasn't just written off in the middle of June ,it actually ended there and then!, Good to see the models showing hints of a change but still nothing on the horizon that would confirm that Winter is finally going to wake up and deliver

Edited December 21, 2012 by Spurry

[cerneman]

Ill say it now, anyone writing winter off now, is like writing the summer off in the middle of June. Yes winter hasn't been great so far, but we still have the whole of January, February and March left, I say March because April can often see some potent snow falls too, one of which about 5-6 years ago, I witnessed thundersnow one morning from a potent snow shower in Lincolnshire. Odds even stack up for Easter to have more of the magical white stuff than at christmas time. I think we are going to see some proper cold from mid January on into February. We even saw a spine chilling low of -16c here in Cambridgeshire during the cold snap in February earlier on this year from the 'deadly cold' snap in Europe. Now had that huge high pressure have been placed 500 miles further west, we would have seen copious amounts of snowfall like Ukraine, Romania and much of the Adriatic. Have faith people, we will see the cold, we just need the right pattern to set itself up. We have 2 solid months yet at least folks.

My untrained eye will be scanning models for pattern change in early January,if only to see end of this rain,Think picked wrong time to learn models

[Gavin Hannah]

Differences between GFS and ECM, if you ask me ECM looking much better!

Agreed. I reckon the flatter ECM will be the way forward.

Oh and well done everyone for surviving the Apocalypse!

Edited December 21, 2012 by IBringTheHammer

[Frosty.]

Not very wintry tomorrow, 12-13c in southern england will feel springlike, it brings back memories of last christmas when some areas reached 14-15c on christmas day 2011, no repeat of that this year as it will be turning cooler by xmas day with temps nearer the seasonal average of 6 to 8c in the southern half of the uk but nearer 5-7c in the north of the uk and boxing day looks colder across all areas with a frost early and late.

[Panayiotis]

Agreed. I reckon the flatter ECM will be the way forward.

Oh and well done everyone for surviving the Apocalypse!

Yes I think the jet will be much lower than projected on the GFS, and more probable to look like the ECM. We will see how the 18z will do in terms of cold in a hours time.. I dont want to see anymore downgrades, because this winter we have seen many, it seems like the weather doesnt want to give us the cold and snow. Edited December 21, 2012 by Panayiotis