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Model output discussion - Winter has arrived and the hunt for cold is on

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Anomalies though, aren't they. Not that great when looking at the actual 500hPa mean:

gensnh-21-1-360.png

 

 

 

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GFS beginning to back away from the Euro high and ECM not so keen in the 8 to 10 day range.All still up 

in the air regarding Christmas period weather.

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15 minutes ago, Anthony Burden said:

GFS beginning to back away from the Euro high and ECM not so keen in the 8 to 10 day range.All still up 

in the air regarding Christmas period weather.he 

Take a look at the 06z gfs at 198 hours!!i think regardless of how slack or deep that low coming of the eastern seaboard is we we will not be able to evade that pressure rise to the east!just gota hope after this little cold spell that sceuro high gets further west as quick as possible to keep us frosty and cold at the very least!

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With respect to the handling of the US low the GFS moves a step closer to the ECM 0z:

ECM>24414482_ECE1-192(2).thumb.gif.0b576aa00bc551b3163de49c30098dce.gifGFS 06z1983455516_gfseu-0-186(4).thumb.png.1d01033cdfea494557cc0e9a68cbcef6.png

Compare to the GFS 0z:

2102767903_gfseu-0-192(1).thumb.png.e23cb4506676d1dd69677a42f742b602.png

This brings the milder air into the UK 18h earlier and we are closer to the warmer air after D8. No shock there as the GFS 0z op had very little cluster support. Can it avoid the ECM D10 chart that sucked the trough west and introduced some exceptionally mild air? 

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Still not a done deal by day 10 - lots to sort out with the Atlantic trough/euro high positions:

image.thumb.png.3d08f78d521d5994c44bf80b483240e4.png

By day 15 there is no really clear signal for any pattern at all, with any outcome still possible:

image.thumb.png.6a3648af1d0f1912cf0923424646d669.png

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8 minutes ago, mb018538 said:

Still not a done deal by day 10 - lots to sort out with the Atlantic trough/euro high positions:

image.thumb.png.3d08f78d521d5994c44bf80b483240e4.png

By day 15 there is no really clear signal for any pattern at all, with any outcome still possible:

image.thumb.png.6a3648af1d0f1912cf0923424646d669.png

The de Bilt ensemble unfortunately show a very large majority something between west and southeast but most south, southwest 

Screenshot_20191210-115323_Samsung Internet.jpg

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Another issue that I have pointed out on the new GFS is its propensity to have wedges at higher-latitude in FI and then next run or two later kill them all off. That is not very helpful and we see it again when we compare the 0z and 06z:

1316557691_gfsnh-0-312(5).thumb.png.91f15652844037cb01a4d47f45dc0ee2.png2105186801_gfsnh-0-300(5).thumb.png.04d30b76e92e5dfa23544d9f778633e1.png

The contrast is evident and if the new GEFS show this trait then we shall have some eye-catching ensembles in 2020!

A pretty flat FI on the 06z but all JFF till we get consistency. Though taking into account the likely coupling with the strat, seeing the core cold migrate back to the Arctic region would be a soluble solution:

T6gfsnh-1-6.thumb.png.940de420345648ed3719b9ab2a45957c.png T324: 131451470_gfsnh-1-324(2).thumb.png.9cc48bb4639a4a217d764cc76f1e2540.png

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The next couple of days showing good snow potential for Ireland, Scotland and Wales based on the updated Euro4

29F3BADD-D2F8-4B81-B356-40FA9AF2DA74.gif

A32382BA-3520-4EC9-A523-5DD5996435E6.gif

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Yes plenty of snowfall filled charts for some this weekend but as ever these are just raw model charts from the GFS they are never going to come off like for like - hence why the best 'tool' to use this weekend in terms of working out whether it's going to snow or not is probably to just look out of the window.. 

Nontheless; 

Here's Wendesday at 15:00 but this really does look high/highest ground stuff

image.thumb.png.9944978dbd4d89bceccdd94560ff509a.png

Saturday looks a little more interesting for some; 

06:00

image.thumb.png.4eef39598eb785b41f20380e3481520c.png

and still lingering showers throughout the day for some in the N/W

image.thumb.png.36a41311a69d6da1f8d1a147d4bee27c.png

image.thumb.png.9052977de50ad16f833ab338656bcb90.png

I suspect all these would just be wintry showers with accumulations only for high ground, though lower levels could still see some snow falling

Looking ahead and the GFS is just sodden from D8 onwards to the end of the run. But still think a change could take place towards the back end of the month - just doesn't look too likely

image.thumb.png.d5244d982b1910bdc26f3244fd443d2f.png

image.thumb.png.730dab3d3b997cfec82c7cf846d46c86.png

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25 minutes ago, IDO said:

Another issue that I have pointed out on the new GFS is its propensity to have wedges at higher-latitude in FI and then next run or two later kill them all off. 

It's like the EC in that respect then, maybe it's a feature that makes forecasts shorter term more reliable? 

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I would take the pipe-burster at the bottom.

image.thumb.png.2820e129baeac0407d270742ffabb85b.png

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15 minutes ago, StretfordEnd1996 said:

is probably to just look out of the window.. 

:oldrofl: 

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2 minutes ago, Iceaxecrampon said:

:oldrofl: 

Yes well not look out the window to see whether there's precipitation falling out the sky - I think a good portion of the country will see that - but more to look out to see whether its rain, sleet or snow..!

Actually seen some people post charts recently that highlight the snow 'level' - these are interesting to see but not sure if they are accurate?

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26 minutes ago, StretfordEnd1996 said:

Yes well not look out the window to see whether there's precipitation falling out the sky - I think a good portion of the country will see that - but more to look out to see whether its rain, sleet or snow..!

Actually seen some people post charts recently that highlight the snow 'level' - these are interesting to see but not sure if they are accurate?

Looking at the GFS and EURO snow acc chats for Sat into Sun, I would say they are probably about right in that they show some (between 1-5cm MAX) accumulation on mountainous regions such as Snowdonia, Brecons, Lake District and Scottish areas.  Nothing at all outside of that.  

1683296666_Screenshot2019-12-10at12_10_32.thumb.png.2e101e3178eecc7dd5bec8429f35cee0.png

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40 minutes ago, StretfordEnd1996 said:

Yes well not look out the window to see whether there's precipitation falling out the sky - I think a good portion of the country will see that - but more to look out to see whether its rain, sleet or snow..!

Actually seen some people post charts recently that highlight the snow 'level' - these are interesting to see but not sure if they are accurate?

.....and with all those weather supercomputers the size of Swindon.

 

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4 hours ago, Iceaxecrampon said:

Exciting? - well looking at Thursdays pressure ensemble the phrase "Cabin Up" springs to mind :blink2:

Looking at the surface pressure, IF it is close, then a definite fall to the 13 th with a rise thereafter but becoming totally unreliable after a further few days?

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image.thumb.png.95ba236ce2485502fa0e1f0270ccc626.pngwith the forecast for tomorrow its a cool start of thursday morning

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39 minutes ago, Dennis said:

image.thumb.png.95ba236ce2485502fa0e1f0270ccc626.pngwith the forecast for tomorrow its a cool start of thursday morning

Yes indeed. And with each run in the last 36 hours the pivot has increased. Latest fax charts are showing almost an easterly on the stalled leading edge.

281784674_Screenshot2019-12-10at14_04_54.thumb.png.c1304bedeacc2ba6fbd10c9e98317740.png

1589602361_Screenshot2019-12-10at14_05_03.thumb.png.a33ee9d0f6343c0d211e638cac97b9c3.png

1040425561_Screenshot2019-12-10at14_05_17.thumb.png.c0c5870cc94626890eb11d6029920700.png

 

So does anyone think the snow potential for the borders / north is being slightly under-estimated?

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3 hours ago, Weegaz said:

The next couple of days showing good snow potential for Ireland, Scotland and Wales based on the updated Euro4

29F3BADD-D2F8-4B81-B356-40FA9AF2DA74.gif

A32382BA-3520-4EC9-A523-5DD5996435E6.gif

Sorry only just saw this. Ties in with my question 😁❄️

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48 minutes ago, West is Best said:

Yes indeed. And with each run in the last 36 hours the pivot has increased. Latest fax charts are showing almost an easterly on the stalled leading edge.

281784674_Screenshot2019-12-10at14_04_54.thumb.png.c1304bedeacc2ba6fbd10c9e98317740.png

1589602361_Screenshot2019-12-10at14_05_03.thumb.png.a33ee9d0f6343c0d211e638cac97b9c3.png

1040425561_Screenshot2019-12-10at14_05_17.thumb.png.c0c5870cc94626890eb11d6029920700.png

 

So does anyone think the snow potential for the borders / north is being slightly under-estimated?

Richard

yes I do, and the UKMO model has been edging and edging colder over recent days, and that’s the one I’ll go with, couple more days too for further small steps.  
 

BFTP

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7 hours ago, northwestsnow said:

Christmas still remains a bit of an unknown at the moment.

 

 

 

hmmm... not so sure, if this chart verifies, and its evolution has been consistent and plausible, the run up to Christmas is looking mild and unsettled with a mean southwesterly. Id have thought this chart is about as far away from a cold spell as you could expect.

 

814day.03.gif

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40 minutes ago, mushymanrob said:

hmmm... not so sure, if this chart verifies, and its evolution has been consistent and plausible, the run up to Christmas is looking mild and unsettled with a mean southwesterly. Id have thought this chart is about as far away from a cold spell as you could expect.

 

814day.03.gif

I think the most important word in that post was 'if' 

Given we're 14 days (336hrs) away I think it's amazing that anybody would hang on a one model forecast alone..    

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2 minutes ago, booferking said:

Saturday looking nasty up north wind snow cold the lot.

gfs-0-96.png

gfs-14-96.png

gfs-1-96.png

gfs-2-96.png

Early doors but snow further south on this run for the weekend:

12zgfseu-16-120.thumb.png.44fa4d84a319c16a0df64d6d388827ca.png06z:gfseu-16-126.thumb.png.3322546a78b9753662b8ffa0c03b9a5a.png

 

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