Model Output Discussion - 21st - 28th November

[MR EXTREMES]

there is possitives to take from the gfs run beyond t144 notice heights building around greenland and alantic block being sucked up towards greenland aswell although before that a very active set of low heights moving west to east across the alantic.

notice beyond t144 on the gfs the euro high moves slightly south so a possible more southerly track of low heights from west to east be nice to see stronger blocking move south out of alaska.

but the assembles dont seen keen.

but then in fi its a nightmare if the gfs charts were to be correct forget december being a winter wonderland.

Edited November 22, 2011 by badboy657

[Paul]

Chilly too, this at 168 :o

I love those charts - a cold lovers dream, 850 temps which start the blue at 0c and make everything look a lot colder than it really is!! Problem is though, if you're looking for even a small risk of snow on lower ground you need them to be -5c, so once you take that into consideration what's being shown is not quite so cold & the reason why the majority of weather maps start the blue at that point.

[Isolated Frost]

I love those charts - a cold lovers dream, 850 temps which start the blue at 0c and make everything look a lot colder than it really is!!

Yep exactly! The netweather and wetterzentrale ones are better because the blues actually mean cold! You can't beat the GFS in extra though...

[Bobby]

I love those charts - a cold lovers dream, 850 temps which start the blue at 0c and make everything look a lot colder than it really is!! Problem is though, if you're looking for even a small risk of snow on lower ground you need them to be -5c, so once you take that into consideration what's being shown is not quite so cold & the reason why the majority of weather maps start the blue at that point.

Cold enough for Snow on high ground in Wales, which is relevant for some

Edited November 22, 2011 by Barb-

[The PIT]

Away from the arguments of whether it's cold or mild or not I'm surprised nobodies picked up that nice little feature just entering the reliable time frame at t93 and lasting to t117. Some very windy weather with that and a rare autumn storm as well. Another one soon after well in FI land though

Deep FI shows a nice tease of some cold weather just keep the pulses going.

[Radiating Dendrite]

Cold enough for Snow on high ground in Wales, which is relevant for some here....

The GFS snowfall maps tend to be........how to put this.........optimistic!

Maybe highland Scotland, above 400-500m but I would be surprised if Wales saw any, apart from the very highest peaks.

[Bobby]

The GFS snowfall maps tend to be........how to put this.........optimistic!

Maybe highland Scotland, above 400-500m but I would be surprised if Wales saw any, apart from the very highest peaks.

Even the 1000 mile march beings with a single step B)

[Summer Sun]

Looking quite unsettled next week for just about all, deep FI brings high pressure back but I guess it will soon vanish.

http://hw.nwstatic.co.uk/gfsimages/gfs.20111122/12/360/h500slp.png

http://hw.nwstatic.co.uk/gfsimages/gfs.20111122/12/384/h500slp.png

[reef]

Away from the arguments of whether it's cold or mild or not I'm surprised nobodies picked up that nice little feature just entering the reliable time frame at t93 and lasting to t117. Some very windy weather with that and a rare autumn storm as well. Another one soon after well in FI land though

Deep FI shows a nice tease of some cold weather just keep the pulses going.

Yes its looking quite stormy in the more reliable timeframe. Theres quite a rapid fall in the 850hPa temperatures as the cold front passes over, so you couldnt rule out a gusty squall line with damaging winds, hail and very heavy rain:

Whats notable aswell is how the polar maritime air behind has steadily warmed on the models as we get closer to the time. The -5C isotherm barely makes its way into Scotland now with much of England and Wales in 850hPa air that is just around average for the time of year. It reminds me a little of mid-January 2008 where such bursts were shown on the models quite regularly but failed to materialise.

[Harsh Climate]

Really boring charts at the moment but like people have been saying, most great winters didn't start until after christmas and 1947 didn't start until late january, so there's absolutly no need to worry just yet I think last year we was really spoiled with a terrific start to winter. November was probably a 1 in 100 event! So we need to be realistic and accept most probably nothing great will happen until a tleast after christmas and even then chances are our winter will be mild because statistically that is our norm.. .

Looking back through the archives on wetterzentralle you will struggle to find exceptionally COLD and SNOWY winters (together), 1963 being the obvious choice and little much else. For me 1947 wasn't one, it was just an incredible cold spell that lasted 6/7 weeks, really the holy grail of synoptics!

look how quickly a rubbish bartlett high set-up can turn into something good..

http://www.wetterzentrale.de/pics/archive/ra/1947/Rrea00119470117.gif

http://www.wetterzentrale.de/pics/archive/ra/1947/Rrea00119470119.gif

Then we know what happens after . So even the worst looking set-ups can evolve into a snow fans dream.

My thoughts on the current output is that we should expect more west to east tracking depressions rather than south west to northeast which we are currently getting. This should allow much cooler polar incursions with snow from time to time on the mountains of scotland, with snow eventually falling from time to time on the mountains of england and the highest hills of scotland..

http://www.wetterzentrale.de/pics/Rtavn301.png

http://www.wetterzentrale.de/pics/Rtavn1201.png

This is about as much as we know at the moment, a typical atlantic driven start to winter.

I will be keeping a close eye on the ECMWF and NAO/AO as I believe these are the key players in picking up blocking in the northern hemisphere and any future easterly type set-up.

[Frosty.]

Some stormy weather is due to hit the nw corner of britain on thursday night into friday and then again across the far north during the weekend with 70-80mph gusts, maybe even higher than that and with colder air sweeping in, there will also be wintry showers across the far north of the uk on friday and then again from sunday onwards, some wintry weather on the gfs 12z but mostly for the northern half of northern britain only which is no use for the majority of the uk as the jet looks flatter further south and lacks that northwesterly element with more of a mixture of rPm and Tm air, not cold enough for wintry ppn in other words. High pressure close to the southwest later in the run, waiting for the last low to push away before it builds into the uk but a very unsettled outlook, temps mostly around average but some warm front sectors bringing milder interludes but also some Pm or rPm air, mostly for the north.

[Geordiesnow]

Yes its looking quite stormy in the more reliable timeframe. Theres quite a rapid fall in the 850hPa temperatures as the cold front passes over, so you couldnt rule out a gusty squall line with damaging winds, hail and very heavy rain:

Whats notable aswell is how the polar maritime air behind has steadily warmed on the models as we get closer to the time. The -5C isotherm barely makes its way into Scotland now with much of England and Wales in 850hPa air that is just around average for the time of year. It reminds me a little of mid-January 2008 where such bursts were shown on the models quite regularly but failed to materialise.

Theres a reason why the cold uppers are getting mixed out and thats because the high pressure to the South is being more of an influence stopping the polar westerlies hitting us. The UKMO has been fairly consistant with this whilst the GFS and ECM were more keen for a WNW'ly hence these two models predicted the -5hpa line to cross the country.

One thing the GFS appears to be correct on in recent runs is to really deepen that low that will hit the far NW on Thursday, the Shetland isles could see some damaging winds from that low pressure system especially with the UKMO now on board with this now.

Looking at the output, I hope the GFS is right regarding the deep low and its positioning but too me, the UKMO has been less keen on any polar outbreaks and having the lows influencing us but it goes to show that even a slight change in the jet can make a heck of a difference.

Lets see what the ECM brings.

[Frosty.]

IMO the Gfs 12z has upgraded the storm systems for later this week, not just the stormy winds for nw britain but increased the winds for other areas too, there looks likely to be a lot of damage caused by these two souped up depressions but at least it will be mildish.

[nick sussex]

The GEFS ensembles have shifted with more now at least taking the troughing further east but still a question mark regarding shortwaves.

Although the pattern flattens out again on the operational run into the later output it's certainly a small step in the right direction.

I must admit to a little bias here, anything that produces snow for the Pyrenees is very welcome, and I'm sure there will be people in the thread who might be planning a skiing trip in December to Europe so at the moment thats the key aspect of the model output I'm concentrating on.

In terms of the UK its essential the trough clears far enough east and digs into central Europe to give a chance of some PM air. Theres still uncertainty though with shortwave activity near Iceland and for this reason we should be cautious in viewing the ensembles, these aren't great for modelling them well at this range.

Edited November 22, 2011 by nick sussex

[BLAST FROM THE PAST]

I think you've misunderstood what I meant.

I meant because it didn't really start untill late january and lasted about 6 weeks, I wouldn't class the WHOLE of 1946/47 winter as been bad. It was just a normal winter untill the end which brought an AMAZING cold spell! I class a spell as the length of cold without at anytime mild weather completley breaking through.

Very quick one on that Dec '46 cet 3.1, Jan '47 2.2c and Feb sub zero. Notable cold in mid Dec and notable cold 5/6 to 12th then mild then WHAM from around 20th.

Now more changes on 12 z. Goes to show run from run, let the picture develop.

BFTP

[IanM]

Can we please keep on the Models, past winters are interesting, but don't need to be analysed here, thanks

[BLAST FROM THE PAST]

Decembers are normally to and fro with a bit of everything thrown in, but it will still end up average to mild from what I can currently see...you I assume, as I asked earlier are saying average to cold??

Not the last one and the ' record cold ' events came on cue last Dec. Depends how long the anticipated cold spell around mid month [3rd week] digs in for and its severity will determine if above or below IMO. What can you see that derermines averagte to mild for Dec? Model output?

BFTP

[Frosty.]

Not the last one and the ' record cold ' events came on cue last Dec. Depends how long the anticipated cold spell around mid month [3rd week] digs in for and its severity will determine if above or below IMO. What can you see that derermines averagte to mild for Dec? Model output? BFTP

Hey fred, do you expect the ukmo to jump on board with the gfs 12z and bring cold weather further southeast later next week?

[No Balls Like Snow Balls]

It's nice to see the 850 ensembles getting below the average. What I have noticed is that the mean has been slowly but steadily falling over the past couple of days with each run. Long may the cooling trend continue.

Edited November 22, 2011 by No balls like Snow Balls

[nick sussex]

The NH profile makes it very difficult to get height rises over Greenland, so I would expect secondary features to limit the incursions of colder air to the far North.

Yes those shortwaves are always likely to pop up as we enter the 144hrs timeframe, at the moment though I'll take anything down here that includes snow for the mountains.

I see the ECM is painfully edging the trough east at 168hrs.

Just as the snow shield was about to be breached the ECM decides to track the low due north and delay further my chances to go skiing! the ECM is seriously beginning to get on my nerves now!

Isn't there a moan thread on netweather, I need to get over there!

Edited November 22, 2011 by nick sussex

[Cloud 10]

Yes those shortwaves are always likely to pop up as we enter the 144hrs timeframe, at the moment though I'll take anything down here that includes snow for the mountains.

I see the ECM is painfully edging the trough east at 168hrs.

Just as the snow shield was about to be breached the ECM decides to track the low due north and delay further my chances to go skiing! the ECM is seriously beginning to get on my nerves now!

Isn't there a moan thread on netweather, I need to get over there!

http://forum.netweat...-winter-thread/

[nick sussex]

http://forum.netweat...-winter-thread/

Thanks, it looks like I will be spending alot of time over there in the coming days!

The only frame of the ECM that didn't make me want to chuck my laptop out of the window was the 240hrs output.

Let's see what happens to the downstream pattern once the east Pacific ridge has set up.

[SuttonStorm]

Nick - not sure why but I am feeling a little more optimistic tonight (as said in the Alpine thread) with the models showing a downward trend in both pressure and temp for Bern (that is the closest venue to the Alps I can find unless you know better?). The only caveat being this trend has been pushed back 2 -3 days with the eurohigh deflecting any possible incursion north/north west.

Small steps................

SS

[nick sussex]

Nick - not sure why but I am feeling a little more optimistic tonight (as said in the Alpine thread) with the models showing a downward trend in both pressure and temp for Bern (that is the closest venue to the Alps I can find unless you know better?). The only caveat being this trend has been pushed back 2 -3 days with the eurohigh deflecting any possible incursion north/north west.

Small steps................

SS

Well it's like pulling teeth at the moment to get that trough sufficiently east to deliver snow to the ski resorts. I was just about to become even more grumpy than I have been recently until the last frame of the ECM 240hrs output!

Also interesting things can happen even with mediocre teleconnections!

http://www.meteociel...&nh=1&archive=0

I'm willing to wait and see how the models forecast the downstream pattern once that ridge sets in over in the western USA.

I see GP's arrived in the thread to probably deliver yet more bad news! I only put up the JMA as a means to lighten the mood! I love your posts GP and you're a bit of a star in here but just for tonight please don't tell us that Santa Claus doesn't exist! let us stay in deluded contentment for a while longer!

Being serious now if you have bad news to deliver could you wait till after 8pm UK time as I'll be off to watch Masterchef then!

Edited November 22, 2011 by nick sussex

[SuttonStorm]

Well it's like pulling teeth at the moment to get that trough sufficiently east to deliver snow to the ski resorts. I was just about to become even more grumpy than I have been recently until the last frame of the ECM 240hrs output!

Also interesting things can happen even with mediocre teleconnections!

http://www.meteociel...&nh=1&archive=0

I'm willing to wait and see how the models forecast the downstream pattern once that ridge sets in over in the western USA.

I see GP's arrived in the thread to probably deliver yet more bad news! I only put up the JMA as a means to lighten the mood! I love your posts GP and you're a bit of a star in here but just for tonight please don't tell us that Santa Claus doesn't exist! let us stay in deluded contentment for a while longer!

Being serious now if you have bad news to deliver could you wait till after 8pm UK time as I'll be off to watch Masterchef then!

Yes please JMA.....not too much to ask?