Model Output Discussions 18z 31/01/2016

[Cheshire Freeze]

10 minutes ago, fergieweather said:

Latest EC Monthly lends some additional weight to notion of a cold start to March. One to watch. 

Wouldn't at all be surprised if this 'winter' offers a final kick in the 'nads by offering winter in spring.

Cheers for the input

[nick sussex]

In terms of the medium term outlook I'd be dubious of the GEFS because it takes the MJO into phase 6 but then hurtles towards the COD for several days thereby weakening the impact of this.

The MJO is likely to be a  factor as we head through towards the end of Feb start of March. USA forecasters at NCEP think this could develop an eastern USA troughing and west USA ridge set up in their latest update.

Much depends on the amplitude of any east USA troughing but this if amplified would correlate with some high pressure to the nw/n of the UK.

At this time I think we're more likely to see a more eastern based negative NAO if the MJO does force that upstream change.

 

[Cheshire Freeze]

5 minutes ago, nick sussex said:

In terms of the medium term outlook I'd be dubious of the GEFS because it takes the MJO into phase 6 but then hurtles towards the COD for several days thereby weakening the impact of this.

The MJO is likely to be a  factor as we head through towards the end of Feb start of March. USA forecasters at NCEP think this could develop an eastern USA troughing and west USA ridge set up in their latest update.

Much depends on the amplitude of any east USA troughing but this if amplified would correlate with some high pressure to the nw/n of the UK.

At this time I think we're more likely to see a more eastern based negative NAO if the MJO does force that upstream change.

 

Given the rumblings from Fergie and the general consensus of seasonal modelling throughout winter, I think a blocked March looks the form horse at this point. Pretty typical that as we start thinking of warmer days, winter may well decide to play a trump card.

Yes it can still snow in March but for the majority of the population away from elevation, March snowfall is about as useful as a knitted condom.

Edited February 15, 2016 by CreweCold

[feb1991blizzard]

3 minutes ago, nick sussex said:

In terms of the medium term outlook I'd be dubious of the GEFS because it takes the MJO into phase 6 but then hurtles towards the COD for several days thereby weakening the impact of this.

The MJO is likely to be a  factor as we head through towards the end of Feb start of March. USA forecasters at NCEP think this could develop an eastern USA troughing and west USA ridge set up in their latest update.

Much depends on the amplitude of any east USA troughing but this if amplified would correlate with some high pressure to the nw/n of the UK.

At this time I think we're more likely to see a more eastern based negative NAO if the MJO does force that upstream change.

 

This is beginning to look more and more the form horse to me, timing uncertain of course but this ties in with the stratosphere forecasts, ive been thinking this for a while now.

[Allseasons-Si]

15 minutes ago, CreweCold said:

Wouldn't at all be surprised if this 'winter' offers a final kick in the 'nads by offering winter in spring.

Cheers for the input

I would take a kick in the nad's if a dumping of snow was on offer

let's be patiant and see what the rest of this winter has in store for us,i know we keep saying this but we are only in mid feb,plenty of time for snow before winter is out,

thu 6 am

with light winds,evaperative cooling would be the form horse to get snow down from elevations.

 

Edited February 15, 2016 by Allseasons-si

[nick sussex]

Just now, CreweCold said:

Given the rumblings from Fergie and the general consensus of seasonal modelling throughout winter, I think a blocked March looks the form horse at this point. Pretty typical that as we start thinking of warmer days, winter may well decide to play a trump card.

Yes I'm sure the perfect winter charts will pop up as we head into spring! If those pop up early in the month then still a chance for something interesting but you'd need some very good synoptics. We'll see but I think it is down to the MJO to help deliver that change.

[Frosty.]

Some look like waking up to a snowy Thursday morning according to the Gfs 18z but then a few days later the weekend looks very spring like across the southern half of the uk with low teens celsius but low res shows some potent wintry shots...Hope we do have a cold march which puts this feeble winter to shame!

[Nick L]

9 minutes ago, Allseasons-si said:

I would take a kick in the nad's if a dumping of snow was on offer

let's be patiant and see what the rest of this winter has in store for us,i know we keep saying this but we are only in mid feb,plenty of time for snow before winter is out,

thu 6 am

with light winds,evaperative cooling would be the form horse to get snow down from elevations.

 

Unfortunately, the air is looking too moist for evaporative cooling to take place. RH will be approaching 100%, so you're not going to get much evaporation. Cold rain is still looking the form horse for this event for the vast majority. It's starting to come into range for the Euro4 for southern areas though so we'll see how it goes.

[Nick L]

Also, several off topic posts have just been removed.

[feb1991blizzard]

The latest Euro4 is absolutely dyer.

[Cheshire Freeze]

7 minutes ago, feb1991blizzard said:

The latest Euro4 is absolutely dyer.

Time to put this winter to bed now I think- for everyones' sanity. Won't be long until we're in the throes of summer....nowt like a stiff westerly, partly cloudy skies and temps of 18C! 

Edited February 15, 2016 by CreweCold

[NorthYorksWeather]

10 minutes ago, feb1991blizzard said:

The latest Euro4 is absolutely dyer.

The difference between the Euro4 and the 10.30 BBC graphics is quite large, BBC looks like its snow widely above 200m ish wheras Euro4 looks like highest tops of Pennines..... hmmmm

[Frosty.]

Just now, vizzy2004 said:

The difference between the Euro4 and the 10.30 BBC graphics is quite large, BBC looks like its snow widely above 200m ish wheras Euro4 looks like highest tops of Pennines..... hmmmm

That's just one timframe though, what happens a few hours later...maybe those pink blobs get bigger

[Banbury]

1 hour ago, Lukesluckybunch said:

Horror looking 18z Into f1 with lows moving in a north east direction, instead of taking a southerly track. Keeps us in mild west to south west winds!

Really????

[IDO]

The latest Dr Cohen blog ties in with the way the models have been showing with the trop response splitting its PV and the cold axis is from W.Asia to East US. For the UK a continuation of PM air, with scraps of cold if we can get the right shortwave movement. Pretty unlikely for an Atlantic Block/Ridge so a prolonged cold spell doubtful: https://www.aer.com/science-research/climate-weather/arctic-oscillation

The D16 chart from this morning mirrors this (trend has been there a while): 

I believe the SSW effects will be complemented by the MJO signal as it is not clear that the minor SSW will bring a negative AO.

Still not seeing much to the decaying front Wednesday and Thursday, despite the BBC teasing with "watch this space" rhetoric.

EG: T44 from Arpege:  Backedge snizzle c T52: 

However very localised and probably dependent on height and falling on wet surfaces, so really a rather tame affair. Of course all subject to change. With some mild uppers moving in on Friday any settling snow will be gone quickly as we get 36-48 hours of milder weather in a zonal westerly flow, so not really dry for many.

With the x-flow/split after D10 there is potential for the strong Azores High to maybe push a bit further north as the PV lobes respond to background signals. Not sure this is a precursor to HLB (ridge) due to lows spinning off the Canadian lobe perpetuating the westerly/NW'ly flow, but maybe enough for the high to be a cooler variety with winds originating from the NW quadrant. For most south of Birmingham that is the worse case scenario for Spring; cool with cold rain, but March looks like starting that way unfortunately.

 

[Polar Maritime]

GFS 00z Wed/Thursday snow risk..

Edited February 16, 2016 by Polar Maritime

[Man With Beard]

Euro4 a little on its own this morning, but nevertheless, here it is:

http://expert-images.weatheronline.co.uk/daten/proficharts/en/euro4/2016/02/16/basis00/ukuk/prty/16021800_1600.gif

[Lukesluckybunch]

7 hours ago, Banbury said:

Really????

It is just fleeting cold though, each time a high trys to build in Atlantic it just gets totally flattened!

[winterof79]

42 minutes ago, Man With Beard said:

Euro4 a little on its own this morning, but nevertheless, here it is:

http://expert-images.weatheronline.co.uk/daten/proficharts/en/euro4/2016/02/16/basis00/ukuk/prty/16021800_1600.gif

Looks fine to me, but then it would.

Seriously though, it shows the front slowing and mixing with the cold air. Lets hope it grinds to a halt. BBC watching it closely. Southern Pennines could get battered.

[Luke Best]

9 hours ago, The Enforcer said:

I wonder whether the development of a low pressure cell along the line of the front along the channel coast (as can be seen on the fax charts) could re-vitalise the front to keep the moisture levels going once the temperatures/dewpoints/DAM/WBFL have become more conducive to snowfall?

Here's an example of the biggest snow event here in recent decades when a LP (shown over the channel) developed in a decaying front coming down from the north. Temperatures/dewpoints/DAM/WBFL had all been favourable - the issue up to that point was lack of precipitation, so granted not the same scenario, but the LP 'made' the event.

Remember that - the Met Office had Bournemouth on a Red Warning for Snow but the LP moved just too far east before it stalled and we totally missed out, whilst the A3 corridor got absolutely pasted. 

I'd be interested to understand what made the LP stall and reinvigorate if anybody can explain.

[Banbury]

14 minutes ago, Lukesluckybunch said:

It is just fleeting cold though, each time a high trys to build in Atlantic it just gets totally flattened!

There isn't much in the way of SWly winds as you suggested, perhaps a chart to show this would be good

[Frosty.]

The Gfs 00z shows a weekend of stark contrasts with Saturday very mild with temps into the low teens celsius in the southern half of the uk but with some rain and then turning colder through Sunday, much colder across Scotland with snow showers piling south, showers becoming wintry in the south later on Sunday..yesterday, the gfs was showing a very spring like Sat/Sun, indeed the 18z showed 15/16c for favoured spots in the E/NE on sunday.. not now it doesn't! 

[Banbury]

That's quite a turnaround Karl......................no complaints from though

[Frosty.]

1 minute ago, Banbury said:

That's quite a turnaround Karl......................no complaints from though

Indeed it is..until the next gfs run, the gfs is like a box of chocolates, you never know what you're gonna get.

[Severe Siberian icy blast]

I'm surprised nobody has mentioned the ECM this morning ,  t144 onwards sees high pressure heading toward Greenland with another slider of sorts , be interesting to see if models develop this particualarly as it fits into what Ian f said they expect as we head into March .