Model Output Discussions 18z 31/01/2016

[bluearmy]

The GFSP is incredible consistent post T300 in building a n Atlantic/greeny ridge 

at that timescale, this isn't an evolution you would expect to see repeating, run after run.

 

[winterof79]

16 minutes ago, PerfectStorm said:

If it's any consolation, that chart is for 1am tomorrow morning and is the super-low res version of the GFS 0.5 high-res charts. 

Yes it is I know. This still shows back edge snow.I suppose I am a little bit annoyed with how things have panned out yet again.So on to the N/W flow this weekend then

 

Edited February 17, 2016 by winterof79

[Singularity]

Encouraging to see the strat split at 30 hPa jump forward to day 11 on the 12z GFS run. 

The consistent response in the 12-16 day time is strongly driven by a combination of this sort of thing (not always as pronounced) and MJO phase 7/8 forcing. No surprise then that it brings memories of the run up to the changes in Dec 2010 and Mar 2013, for example. Once the models latches on, they were fairly steady with the broad theme while the details slowly came together in the usual, wavering manner.

[weirpig]

8 minutes ago, winterof79 said:

Yes it is I know. This still shows back edge snow.I suppose I am a little bit annoyed with how things have panned out yet again.So on to the N/W flow this weekend then

 

There it is     cant fail to deliver,,

[pip22]

There is a potential of some significant snow on Sunday night on the latest GFS run.  There is back edge snow across southern England on Sun night. While northern areas are having snow/wintry showers. Another chance for snow starve southerners??

Edited February 17, 2016 by pip22

[karlos1983]

5 minutes ago, pip22 said:

There is a potential of some significant snow on Sunday night on the latest GFS run.  There is back edge snow across southern England on Sun night. While northern areas are having snow/wintry showers. Another chance for snow starve southerners??

Until I see it falling out the sky, I shall not be getting my hopes up. 

 

[Chris.R]

48 minutes ago, lukemc said:

Crewe Cold,

Well wouldn't you count Boxing Day 2014 in that category too? which I would class as a toppler scenario and that brought snow on the ground here in Liverpool upper temps were not amazing btw so it can happen - we also had transitional lying snow in Liverpool from a NW'ly last year in January I can recall so as least as far as my area is concerned that is not correct they can still deliver if the parameters are right.  It can also depend on the intensity and amount of precipitation you get to bring evaporative cooling increasing the risk of snow at low levels.

EDIT - also remember we got snow from a transitional NW'ly again in December 2011.

It might have been different in Crewe but that was for my location in Liverpool not far from the Irish Sea coast even though snow is infrequent at our location it goes to show it is not impossible of course - and the examples above are of toppler type events not even including the likes of 2010.

 

 

Luke

 Yes but boxing day 2014 was a slider low  being undercut by  Cold 850s in a PM setup.  29/01/15 was a  Standard north-westerly with -7 850s but a streamer  developed over us allowing evaporative cooling to give us some temporary snow. 16/12/11 was a trough in a northwesterly  again evaporative cooling played a big part.   North-westerlies with 850s warmer than -10  I have found generally need a catalyst like  A trough or  evaporative cooling to produce snow here.  This has been lacking this winter. We can get  buried if things are conducive. 

Sorry for the IMBY post here,  I just wanted to reply. 

[DR(S)NO]

1 hour ago, CreweCold said:

Yep, 2004 was just a bog standard toppler too. However, it pees all over anything we've seen from that direction over the past few years and anything that's currently showing within the NWP. Even March 2006 saw a decent plunge from that direction. Baffling.

Well March 11th 2006(as described below..courtesy of weather wise) was the heaviest snowfall I've seen in my area since snowfall in the 1980s. Given the right Synoptics we've still got a good few weeks of snow opportunities ...and goodness knows we deserve something after the long Autumn we seem to have had..

 

Disruptive frontal snowfall on the weekend of the 11th-12th March 2006

 

There was further disruption due to heavy snow on the 12th March as Atlantic fronts stalled against a well-established cold block across Scandinavia that extended towards the UK. A very cold air mass moved westward on the 11th to cover all but Ireland and Northern Ireland. Earlier in the week, numerical weather model output predicted the mild air from the Atlantic to make rapid progress eastward bringing a rapid thaw behind a band of snow that was to cross the country on the 12th.

 

As the event neared, there was a sharp turnaround in model output in such a way that hasn't been seen for some time with the block being sustained across the UK, therefore preventing the mild air from progressing further east than the Irish Sea at the surface. Consequently on the 12th, the Atlantic fronts stalled across Wales, Northwest England and Southwest Scotland bringing some significant falls of snow to these areas overnight and during the morning of the 12th. A significant contrast in temperature was maintained across the Irish Sea throughout the day; under the persistent cloud and snow some parts of Northern England struggled to rise above freezing, the lowest maxima are outlined in Table 1 below. However, across the Irish Sea in parts of Ireland in the milder Atlantic air mass it was very mild with the temperature peaking at spring-like 13.8°C at Shannon Airport during the afternoon.

 

Surface analysis by the UK Met Office for 00Z on 12th March 2006:

http://www.wetterzentraleforum.de/archive/2006/brack/bracka20060312.gif

 

 

TABLE 1.  Lowest maxima recorded in the UK on the 12th March 2006

 

Station

Maxima (°C)

Boltshope Park, (County Durham)

–1.2

Fylingdales, (North Yorks)

–0.9

Carter Bar (Roxburgh)

–0.6

Eskdalemuir (Dumfries)

–0.5

Thorncliffe (Staffs)

–0.5

Shap (Cumbria)

–0.4

Ponteland (Northumberland)

–0.4

Lake Vyrnwy (Montgomery)

–0.3

Loftus (North Yorks)

–0.2

Durham

–0.2

Wilsden (West Yorks)

–0.1

Warcop (Cumbria)

0.0

 

The snow fell most heavily across southwest central Scotland (with unofficial reports of 30 to 40cm of lying snow from some locations) in a strong and gusty SE’ly wind, fortunately during the late evening on Saturday and into Sunday when less people needed to travel. However, in Glasgow it left several thousand clubbers stranded during the early hours as the roads quickly became too treacherous and the usual bus and taxi services were suspended. The Garage nightclub and Central Hotel were opened to accommodate those who were stranded waiting for a taxi in the freezing conditions. 

 

Glasgow airport was closed for much of the day as the staff fought a losing battle to keep the runways clear of snow, and rail services were decimated across the areas worst affected as the snow continued to fall thick and fast. The M74 linking Scotland and England was closed for several hours during the day to northbound traffic at Johnstonebridge, and countless minor routes across Scotland were closed for the day as they became simply impassable. Once the snow had stopped falling, there were strong winds, which drifted the snow recently cleared off the roads, back onto them. Thousands of homes were left without power at one point because of downed power lines, though these mainly in the more rural and exposed parts of Dumfries and Galloway.

 

Snow continued to fall through much of the day leading to some large accumulations across southwest Scotland and northwest England. Notably there were several centimetres even at sea level right by the coast in Blackpool, and many areas further inland and slightly higher above sea level had much more. The highest official totals recorded at 09z were 22cm reported at Bishopton (Renfrew), 21cm at Eskdalemuir (Dumfries) and 20cm in Glasgow. The southern extent of the snow appeared to be Manchester where little or none was reported and the extent of the precipitation from the Atlantic fronts was much patchier. Nearer the coast though the precipitation was much heavier, for instance, Liverpoolwas blanketed by many inches of snow by mid-morning.

 

During the late afternoon most of the precipitation died out or changed over to ice pellets and light rain as the mild air started to work its way east, at least above the boundary layer. It remained very cold at the surface on the night of the 12th across much of the UK (apart from Northern Ireland and the extreme west coast of Scotland), the lowest temperature recorded was only –4°C at Buxton (Derbyshire) over the snowfields but with a strong S-SE’ly wind it certainly felt like a bitterly cold night.

 

Surface analysis by the UK Met Office for 00Z on 13th March 2006:

http://www.wetterzentraleforum.de/archive/2006/brack/bracka20060313.gif

 

The block continued to dominate and exert its influence to the east of the country preventing the mild air from progressing much at the surface. This had the result of tightening the pressure gradient across the UK and drawing gale force S’lies across Scotland, which acted to drift the snow that had fallen during the day. Mild air was beginning to move in aloft on the 13th which led to spells of freezing rain at higher elevations under the inversion coating the snow cover in a frozen glaze, and in Scotland a thaw set in as the mild air raced in at the surface. Temperatures were slightly higher everywhere but still cold for March maxing in the 3 to 6°C range and still with the very cold wind-chill.

 

Surface analysis by the UK Met Office for 00Z on 14th March 2006:

http://www.wetterzentraleforum.de/archive/2006/brack/bracka20060314.gif

 

The mild air eventually moved east during the rest of the week, though making slow progress and not before another spell of snow, freezing rain and ice pellets ensued across the north and east of Englandon the 14th. A further 5 – 10 cm fell across northeastern England locally during the morning renewing difficult travel conditions on the roads affected. The heavy snowfall forced the closure of Newcastleairport during the morning causing delays on several flights from the airport, it also forced the closure of many schools in Northumberland, County Durham, Tyne and Wear and Teeside. In south Yorkshire the A57 Snake Pass remained closed for several hours because of ice and the A66 in north Yorkshirewas also temporarily closed near Scotch Corner following a serious incident. Conditions began to improve though on the 15th as pressure began to build from the east and extend a ridge from the anticyclone 

across Scandinavia, the south had some long sunny spells where it felt a bit more like spring out of the wind and most of the wintry mix had changed back over to rain as the milder air mixed through to the boundary layer. However, during the rest of the week there were strengthening easterly winds and further unseasonably cold weather for March.

 

Summary 

 

The snowy spell that occurred on the weekend 11th/12th March 2006 was possibly the worst to hit the UK in March since 1995 in terms of overall extent, snow depths and disruption caused.

[winterof79]

1 hour ago, weirpig said:

There it is     cant fail to deliver,,

Classic back edge.....luurvin it

Lets have a look on Saturday

On a plus note,Louise Lear just showed a graphic with heavy snow for Scotland on Sunday.I take it that is going to move south but the fronts didn't look convincing.Here is the chart before the move south

That is a marked boundary between mild and cold and will have copious amounts of moisture within it.No fizzling this time.

Edited February 17, 2016 by winterof79

[fergieweather]

59 minutes ago, bluearmy said:

The GFSP is incredible consistent post T300 in building a n Atlantic/greeny ridge 

at that timescale, this isn't an evolution you would expect to see repeating, run after run.

 

It's currently a 50-50 split in marked GPH direction by turn of month in EC EPS Cluster anomalies. There's been recent suspicion that until now, extended range ENS might be behind the curve (re potential for more blocked outcome by that period into March). Perhaps now we can see incipient signals emerging for this becoming a bit more likely. 

[nick sussex]

The UKMO have modified their raw output at T120hrs in the fax chart, it looks more like the ECM for that timeframe:

The UKMO did look quite different from the others with that lobe of high pressure to the nw supported by the shortwave low. In terms of the new fax chart, cold windy with wintry showers, some snow possible more especially to higher ground. It would be great to have a chart where you can just say snow showers without any marginality but its been the way of the winter so far.

 

 

[marksiwnc]

Just now, nick sussex said:

The UKMO have modified their raw output at T120hrs in the fax chart, it looks more like the ECM for that timeframe:

The UKMO did look quite different from the others with that lobe of high pressure to the nw supported by the shortwave low. In terms of the new fax chart, cold windy with wintry showers, some snow possible more especially to higher ground. It would be great to have a chart where you can just say snow showers without any marginality but its been the way of the winter so far.

 

 

Hopefully the fronts pushing south would consist more heavy precipitation therfore snow would fall to quite low levels.  Being in North Wales snowdonia should do well but I should think nw England Scotland and Ireland would do well too. Hopefully the likes of Ian would be able to keep us informed. 

[nick sussex]

8 minutes ago, marksiwnc said:

Hopefully the fronts pushing south would consist more heavy precipitation therfore snow would fall to quite low levels.  Being in North Wales snowdonia should do well but I should think nw England Scotland and Ireland would do well too. Hopefully the likes of Ian would be able to keep us informed.

Yes it looks okay for your location, and there should be some heavy showers which of course could bring the freezing level down. Still 5 days out but the models are pretty solid in terms of a nw flow but the 850 temps still could change.

[feb1991blizzard]

The London ECM graph really does back up Ian Fergusson's post, a big shift in 24 hours, never seen as big a shift in that timeframe on the ECM ens before, they are usually very stable and gradually adjust.

 

 

 

Edited February 17, 2016 by feb1991blizzard

[A Frayed Knot]

12 minutes ago, feb1991blizzard said:

The London ECM graph really does back up Ian Fergusson's post, a big shift in 24 hours, never seen as big a shift in that timeframe on the ECM ens before, they are usually very stable and gradually adjust.

 

 

 

Is this a good thing * As in cold with Snow for the UK * Sorry for such A Garbage post ' But i am still trying to learn .

[feb1991blizzard]

Just now, Cloud buster said:

Is this a good thing * As in cold with Snow for the UK * Sorry for such A Garbage post ' But i am still trying to learn .

Yes, last night I'm sure the ensemble mean (yellow line) towards the end was a couple of degrees higher, doesn't sound a lot but the ECM ensemble contains 50 members, there is a tendancy towards the end of the run for the average of those to align more with climate averages, now although there is no massive negative temperature anomaly, the change is significant, when you consider these are for further south than London, that's decent news for the UK.

[Geordiesnow]

4 hours ago, nick sussex said:

I'm frustrated on one hand and relieved on the other! Both the GFS and ECM agree on a diving low se'wards. Both also agree on lifting those deeper low heights n away from Scandi, the effect is to give a signal for pressure to rise there.

The issue at the moment is how much cold will be on tap. I seriously don't want to see another on the face of it good synoptic set up ruined by the lack of cold.

Its at times like this that you want to bang your head against a wall because as we enter the end of winter we're chasing those more elusive deeper cold pools which of course with the same set up its easier to find earlier in the winter.

So the key going forward is to see deeper cold setting up to the east/ne.

It might be that these better synoptics may well continue to evolve with higher latitude blocking especially in light of the MJO.

Unfortunately I think any hopes of an easterly with deep cold are nearly more or less over for this winter, the developing Scandi/Russian high which looks like will occur will pump a lot of WAA towards the higher latitudes/Arctic with the PV all the way situated in Eastern Russia/China, in other words, a long long way and unless there is a major pattern change then its just not going to happen. Also the Arctic looks like it will go through what can only be describe as a "heatwave" with the PV totally broken up and those warm southerly winds via the strong Russian high so even if the russian high does slip away, any Northerlies into Scandinavia are very much modified. 

Basically the outlook for deep cold is not a good one for the UK and the outlook is boarding on disaster for the Arctic, as Karyo says, sad times indeed and it probably does somewhat explain why any NW'lies don't sustain themselves and keep getting mild sectors embedded although I think other meteological reasons do come into play also. 

[Standfree 1903]

10 hours ago, Grimsby Snow Lover said:

Agreed! we are currently nearing the end of a cold spell and what amazes me is that the temperatures have been average at best. Since when has average temperatures been classed as a cold spell? when was the last time Shetland and Aberdeen got hammered by frequent heavy snow showers in a northerly flow?

Being an Aberdonian I can tell you it's been quite a few years since we've seen big snow fall.Yes the city has  had minus temps and some small amounts of snow but nothing to get excited about.I've moved 35 mile to the north west of the city with good elivation so see much more snow when it's around.This year we've had around 20 odd days of snow on the ground and -7 the coldest temp,I'm really looking  forward to seeing a proper winter with 2-3 week cold spells with double didget minus temps.

[That ECM]

ECM would be nice viewing and would normally have people discussing how good it looks but after months of disappointment enthusiasm wanes I guess!!!

[chris55]

UKMO looks like it could deliver snow to the northern edge of that low, it's very slow moving!! 

Big differences in the way the big three handle the low into next week. With UKMO sending it south, ECM building a small ridge ahead of it leading to some trough disruption later and GFS keeping it a bit further north.

certainly something that will keep us busy watching how it unfolds.

 

 

[Polar Maritime]

Both ECMWF and GFS show a cool/cold end to the Month as the Jet sinks South filtering polar air over the UK and a much more disrupted PV than of late.

 

Edited February 18, 2016 by Polar Maritime

[Day 10]

51 minutes ago, That ECM said:

ECM would be nice viewing and would normally have people discussing how good it looks but after months of disappointment enthusiasm wanes I guess!!!

My sentiments exactly, some good charts this morning and 'MAYBE' something can be salvaged from this rubbish effort of a winter. I have still been looking at the charts but gave up posting them a few weeks back in here as it just seemed a waste of time, as the only thing that seemed to verify was rain! Here's hoping for different this time around AGAIN...

[Timmytour]

Yes some good FI outlook again, but that's been a constant theme of this winter, a winter of promises but precious few deliveries.

tbh I think fewer and  fewer people can get themselves excited about such charts popping up in FI now. Not even the Daily Express can be bothered with them any more!!!!

[Alexis]

Big story this morning is how the UKMO is doing its own thing and disagrees with all the rest 

 

 

Edited February 18, 2016 by Alexis

[IDO]

1 minute ago, Alexis said:

Big story this morning is how the UKMO is doing its own thing and disagrees with all the rest 

 

 

UKMO D6 charts should have a health warning like the ECM D10 charts IMO.

There are no signs of any pattern change to March 5 on the GFS 0z run. The Azores every 5 days will try to build north but gets flattened by the PV lobe off Canada, so the potential for toppler after toppler, but as this "cold spell?" testifies to, much ado about nothing! Poor synoptics for most of the country as you need a lot to go right to get anything worthwhile.

The CFS w3 and w4 are showing this theme maintained: 

Looking at the GEFS for the next 16 days for London and overall pretty average fare:

  

Not sure the strat PV will be killed off by a Major SSW; its demise has been much exaggerated this Winter, and probably too late for us the way its going. After the last few winters it was hard to think this could be any worse, but its up there with the worst of them for cold. What we don't want now is a Spring dominated by a cool flow with cold rain, though I suspect that is what is upcoming.