Winter Model Discussion - Cold Hunting -23/12/12

[Radiating Dendrite]

Hallelujlah (excuse the spelling)!

Lovely looking end to the 00z. The funny thing is the guys in the know have been suggesting the 15th being the sort of date where the fun and games could start!

Hopefully we will start to see some very interesting ensemble options soon. Could this be like 2010, where we just watched it start in far FI and come all the way to the reliable!

I am sure there will be ups and downs, but finally it looks like winter 2012/13 could clear the tower and launch!

[snow drift]

Hallelujlah (excuse the spelling)!

Lovely looking end to the 00z. The funny thing is the guys in the know have been suggesting the 15th being the sort of date where the fun and games could start!

Hopefully we will start to see some very interesting ensemble options soon. Could this be like 2010, where we just watched it start in far FI and come all the way to the reliable!

I am sure there will be ups and downs, but finally it looks like winter 2012/13 could clear the tower and launch!

This is going to be interesting to watch unfold. The thought of watching the charts from T384 and get closer and closer then happen would be great. If they do then this winter will be remembered. If they don't then this winter will also be remembered but not fondly by many.

As good runs are shown and then not so good runs, I just hope for the sanity of most that people will take note of what JH and others have said for many a year. Look at the trends. For all Newbies, let the confusion begin. Not only will the output show volatility from run to run but so will many a poster.

If you are able to look at the output and then view why people are calling it good/ bad etc you can learn a great deal. This will enable you in the future to look at the models and draw your own thoughts, rather than hanging on everyone’s word. From personal experience it is better to try and learn than let your emotions be driven by someone saying its great or not.

This charts will please many. For all newbies, have a good look at it and try and workout why. Remember though it is 384 hours away. In weather terms a light year. But something to look for in future runs. Then we could call it a trend.

[IDO]

As the strat is heading for a Major Warming Event, a great post from Matt Hugo on Twitter, that may help explain why the NH synoptics are about to change:

http://matthugo.word...r-january-2013/

The next seven days look like high confidence, with HP building from Wednesday to Saturday, then the retreat east of the UK high by both ECM and GFS. Timings vary within ensembles. GFS and ECM try to retrogress west but in FI GFS builds heights to the NW with a possible ridging in the Atlantic, as the UK high finally sinks. Plenty of cold uppers ready to head south: http://cdn.nwstatic..../h850t850eu.png

once the heights build over the pole, and if this run confirms, a good chance for the UK for severe cold during the second half Jan.

A mild start for the first half of January though: http://wxmaps.org/pix/temp4.html

No frosts forecast on the GFS op run for England.

Edited December 30, 2012 by i'm dreaming of...

[Gibby]

Good morning. Here is the report on the 00zs from the big four models, namely GFS, UKMO, GEM and ECM for today Sunday December 30th 2012.

All models show a broadly similar pattern on the sequence of events between now and next weekend. Today will see the sunshine and shower mix give way later today to more persistent cloud and rain coming into Northern and Western areas under a rather chilly and blustery West to Southwest wind. Many Eastern and South-eastern areas may have a dry and bright day. Tomorrow sees an active cold front bring a spell of heavy and squally rain SE over the UK with gales on coasts and hills in temporarily milder weather again. Late on tomorrow clearer, colder and more showery weather returns from the NW with the showers heavy and wintry in the North and West tomorrow night. By New Years Day the showers will be migrating away East as pressure will be rising sharply with decreasing winds backing towards the West on what will of been a rather chilly New Years Day. On Wednesday a warm front crosses East with some rain and drizzle, chiefly in the North. The remainder of the week will see rather a lot of cloud with relatively mild conditions. There may be some brighter spells and if these occur at night there is the chance of patchy mist and fog and a touch of frost but probably not much.

GFS then shows next weekend as remaining mostly dry with High pressure slowly relaxing to the East of the UK. With uppers gently lowering the temperatures at the surface would fall back with the incidence of fog increasing with time and patchy frost too. Later in the run pressure begins to fall with time and a Southerly flow develops with rain spreading from the West by the end of the period in association with Low pressure advancing in from the West.

The GFS Ensembles show a much drier period on the way. As High pressure builds next week from the South there is a guarantee of very mild conditions with rather cloudy skies for a time before temperatures relax back towards the seasonal normal with High pressure in general likely to still be in control with much less rainfall than we have become accustomed too of late.

The Jet Stream shows the flow ridging over the Atlantic and eventually over the British Isles behind tomorrows Low and fronts. The High pressure holds it's own for the most part next weekend as the flow remains steered North over the UK and down over Europe next weekend.

UKMO for midnight on Saturday shows High pressure stretching from Spain to Southern England with a ridge North over the UK. The weather would see relatively light winds, dry weather but with a lot of cloud in places, but some clearer spells too leading to fog patches in places overnight. Temperatures would be generally near or above normal.

GEM shows the High slipping away SE more readily with a moist SW flow bringing extensive cloud cover, increasing winds and eventually rain back across the UK from the Atlantic by the end of the run.

ECM shows a similar pattern to UKMO at day 6 with the High then slipping slowly SE into Europe setting up a NW/SE pattern with mild SW winds over the UK with plenty of cloud with some rain at times in the North and West while SE parts stay largely dry.

In Summary today the weather still looks like becoming more settled from the middle of the coming week. Dependant on the location of the High centre will determine how things are at the surface. However, the main body of models keep the main centre just South of Britain keeping a Westerly drift and feeding a lot of low Stratocumulus cloud around the Northern flank of the high and delivering rather cloudy, benign conditions with temperatures well above normal in any brightness in the East though these same breaks could make way for some overnight mist and fog patches. In the longer term the High is shown to drift back SE into Europe with the likelihood of some Atlantic incursion towards the second week when the North and West at least see the return of wind and rain. These conditions may not reach the South and East though during this period giving the saturated grounds here a chance to slowly drain in continuing reasonable temperatures for early January.

There will be no evening report either tonight or tomorrow night but the A.M. reports will carry on as normal and the full twice daily service will resume on New Years day.

[Summer Sun]

UKMO is high pressure dominated again this morning, Scotland is the only exception at first

Likely to be cloudy most of the time but temperatures should be around average for most, with the odd fog patches in clear spells overnight

[Jason M]

Fi on the 00z is looking very good, check this chart out, we wait until that low moves east and it will be 2010 all over again! Remember earlier I said I would keep my eye on perturbation 2 as this was showing lovely Greenland heights near the end of the run,maybe all the members will follow this one!

Just as a point of interest for any newbies, the chart being shown is actually virtually snowless for the UK. The uppers under the low sitting over the top of us are actually well above zero. Assuming that the low moved to our south or south east we would pull in colder air afterwards. Of course the detail at that range isn't worth worrying about, but sometimes snowy looking charts are not all that they seem.

Jason

[UV-RAY]

Who care's Chio ! great to see, and all in line with the stratt..

Would the models pick up on something that hasn't occurred yet though, or I'm I missing something?

[bluearmy]

Whilst the saturday 12z's and 18z were very positive re the pattern pre warming and the gefs in their latter stages seemed to show signs of a quick trop response, the 00z suite from all the models is a swing back on the pendulum. I guess this should be expected.

[TEITS]

Delighted with the GFS +384 chart because that is exactly what I have been hoping to see over the last few days. Im also keeping an eye on the period between +192 & 240 because I feel this period isn't resolved yet and our HP could build further N than currently progged.

Although I love my E,lys via a Scandi HP even I would prefer a more reliable GH. Far less stress and the models seem to handle this better than an E,ly via a Scandi HP.

[snow drift]

Delighted with the GFS +384 chart because that is exactly what I have been hoping to see over the last few days. Im also keeping an eye on the period between +192 & 240 because I feel this period isn't resolved yet and our HP could build further N than currently progged.

Although I love my E,lys via a Scandi HP even I would prefer a more reliable GH. Far less stress and the models seem to handle this better than an E,ly via a Scandi HP.

There is changes over Canada at this time range which is a good example of how output is going to be Volitile moving forward.

[Jason M]

On the 186 chart of the current GFS run that big low is an awfully long way south compared to recent runs. Could we be looking at the bid daddy of undercuts?

Low res will no doubt sent it North again, but something similar is shown on the BOM run.

Jason

[-uksnow-]

Would the models pick up on something that hasn't occurred yet though, or I'm I missing something?

You are, they factor the strat output into the output of the models therefore we may start seeing possible solutions for an almost guarentee'd SSW on the 5th Jan appear in FI.

[Jayces]

Would the models pick up on something that hasn't occurred yet though, or I'm I missing something?

Isn't that what the models do anyway?

They are after all predicting the future possible weather based on future possible events.

[Dampdorset82]

On the 186 chart of the current GFS run that big low is an awfully long way south compared to recent runs. Could we be looking at the bid daddy of undercuts?

Low res will no doubt sent it North again, but something similar is shown on the BOM run.

Jason

There is nothing to undercut. My understanding is to be an undercut the LP system cuts under a HP system to the north and that isnt the case here.

[Duane S.]

The reason the far FI of the GFS 00z op was so good was the vortex had headed away so far NW'wards. The 06z not so keen at the same timeframe but has the same idea of the high being pulled westwards into the Atlantic which looks like it would end up the same way a day or two days on from +384.

[Jason M]

Hi Damp

Take at look at the BOM run as this illustrates what I was getting at. It's unlikely, but you never know.

Jason

Edited December 30, 2012 by Jason M

[TEITS]

You are, they factor the strat output into the output of the models therefore we may start seeing possible solutions for an almost guarentee'd SSW on the 5th Jan appear in FI.

Yep I have a very basic understanding of the Stratosphere but even I understand that what we are seeing in distant FI is the models figuring out how this will impact the troposphere especially what happens to the PV. I imagine were going to see some wild, wacky FI charts from the GFS with little consistency at this timeframe. However all im currently doing is counting the number of runs that point towards cold for the UK and this is especially true of the ensembles.

Im sure the likes of GP, CH, SM will agree that predicting a SSW is much easier than figuring out how this will actually impact our weather on the ground. This is why I would suggest to members to closely follow the Strat thread rather than the inconsistent GFS. Whatever the outcome im going to enjoy following this period over the next few weeks.

We could potentially see a complete reverse of some of our recent winters which have consisted of cold Decembers but milder Febs. We could potentially see a very cold period from mid Jan extending right into Feb.

[nick sussex]

It's a shame the ECM didn't build on last nights 12hrs run, it looks like we're going to have to put up with some underwhelming output seeing as the models are reluctant to show a quick initial response.

I do hope things speed up as even though you often see a timelag of a few weeks to full impact of an SSW it's getting tiresome looking at the same old dire output every day!

Yes Mr Gumpy's back!!!

Edited December 30, 2012 by nick sussex

[TEITS]

It's a shame the ECM didn't build on last nights 12hrs run, it looks like we're going to have to put up with some underwhelming output seeing as the models are reluctant to show a quick initial response.

I do hope things speed up as even though you often see a timelag of a few weeks to full impact of an SSW it's getting tiresome looking at the same old dire output every day!

Yes Mr Gumpy's back!!!

Good news is though Victor Meldrew is the ECM Op was on the mild side of the mean.

http://www.knmi.nl/exp/pluim/vijftiendaagse/Data/15DAAGSE_06260_NWT.png

Only kidding mate I normally refer to John Holmes as Victor Meldrew.

[chris55]

High pressure becoming more dominant is a welcome change to the very wet weather of late, although not especially cold a settled spell will at least allow the ground to dry out a bit for those in the flood effected areas.

Beyond this I am sure we will start to see some more favourable conditions for colder weather appearing in the models as a response to the strat changes, there is bound to be plenty of ups and downs (as always) but hopefully a trend to more blocked conditions will transpire.

Edited December 30, 2012 by chris55

[Polar Maritime]

Would the models pick up on something that hasn't occurred yet though, or I'm I missing something?

Come on 7... That's why we use the models, yes they take in Stratt warmings as they get into the reliable.

[Froze were the Days]

Very consistent modelling for an extensive area of high pressure to become established firstly to the south of the UK and then just to the east or south east of us, so mild fairly calm weather will be the order of the day from towards the back end of this week what happens there after becomes interesting.

[phil nw.]

Yes we will see some differing solutions in the later frames of the models-especially GFS as it goes out to 15 days.The main theme to follow is the weakening and fragmenting of those low heights across the Arctic and the trend to a more amplified pattern.

The 850`s will show nothing of note for a while as we will receive no deep cold whilst in the current setup.We should see 2m temps ease down though as the Atlantic flow slows under the high especially if it builds far enough north.

The real period of interest will be beyond the initial build of this high and where any further heights develop as the vortex shrinks and splits into smaller pieces.

[cooling climate]

It's a shame the ECM didn't build on last nights 12hrs run, it looks like we're going to have to put up with some underwhelming output seeing as the models are reluctant to show a quick initial response.

I do hope things speed up as even though you often see a timelag of a few weeks to full impact of an SSW it's getting tiresome looking at the same old dire output every day!

Yes Mr Gumpy's back!!!

It certainly is frustrating waiting for a model run to come out and then only interested to see what

pops up past t240. As I said yesterday it would be nice if the models gave us something to talk

about in the meantime,something a bit more seasonal.

It could all be worth the wait though if (that word again) things go our way but looking at the strat

charts and the way the vortices displaces and then splits I can not help but feel confident of a

very good second half to winter with at least a couple of notable cold spells or as TEITS says

something far more prolonged and noteworthy.

[Jason M]

Ensemble suite out to 276 and and some nice ones in there. Much better than the earlier run. A couple of good easterlies and some potential undercutters in there. I'd urge people to look at BOM this morning. A trend setter maybe?

Jason

So far number 14 is my fav as in my back yard I'd need a snowplough to get out of my front door with snow showers piling in off the Thames estuary as a deep cold pool encroaches from the SE. :-)

Edited December 30, 2012 by Jason M