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Model Output Discussion 01/09/17

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Memories are funny things - fortunately, every run is on Meteociel archive for you to watch exactly what happened 7 years ago .......

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Who was right at Feb 2012? I can't remember

 

 

 

 

Edited by Jonan92

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22 minutes ago, tight isobar said:

Oi oi ...

Its all going top..

And the scandi wrap is also a feature...

850s dropping like tottenhams form!!

-in prem-

gfs-1-162.png

gfs-0-162.png

Obviously one or more mods tottenham fans....

Where me little love heart..??? 11 likes 😂😂😂

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Well this would be a great result (If the GFS is right of course)

gfs-0-144.png?12

This would deliver conditions that would bring snow to low levels even in the south for a time. 

Unfortunately the other models are starting to steer away from a strong block that could bring increasing cold and eventually snowy conditions. The models are starting to favour a very common late Autumn pattern. 

UKMO/GEM

UW144-21.GIF?23-17   gem-0-144.png?12

The ridge is unable to push into the Arctic and eventually the high will topple towards the UK, probably setting up something more settled across the UK with the potential for surface conditons to become very cold but with little precipitation.

ECM ens from this morning tend to push towards anticyclonic conditions, though with many members potentially saying something colder.

EDM1-144.GIF?23-12   EDM1-192.GIF?23-12   EDM1-240.GIF?23-12

We could go milder again if westerlies manage to push across the UK, but the high could drift over the UK with a cold and settled spell, but equally we could see another low sink south east into Europe with another push of cold northerly winds.

Edited by Captain Shortwave
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In fairness looking at the UKMO run on Wetterzentrale, it perhaps look more better than it perhaps first appears and that a very slow topple ridge may not actually happen but wait and see on the 168 hour chart to be sure. Obviously uppers are the issue here so any showers will likely to be of mainly rain but some good convective weather nonetheless I would of thought.

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Guest

Further to my long post yesterday (on page 192), it does seem that we might manage some much lower 850s. "If" this 12z GFS run is anywhere near accurate, it is now getting very close to the 2010 set up.  I show the reanalysis charts below + the website so you can run through the following days. The pattern then becomes much more polar continental. The likeness does persist for over 5 days and I could just as easily have posted several other 2010 charts running in to that cold spell.

                25/11/2010 Pressure                              25/11/2010 850s

archivesnh-2010-11-25-0-0.png   archivesnh-2010-11-25-0-1.png     http://www.meteociel.fr/modeles/archives/archives.php?day=25&month=11&hour=0&year=2010&map=4&region=&mode=2&type=ncep

 

           GFS 12z T+192 Pressure                        GFS 12z T+192 850s

gfsnh-0-192.png?12?12  gfsnh-1-192.png?12?12

 

CAUTION: It is dangerous to assume that we might see anything like the epic 2010 cold spell and these charts are simply to illustrate some similarities.

Edited by Guest
Correct typos

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npsh500.png

So yes it did its best to make a mess of things. Entertaining to see a 1070 mb high over Asia though!

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4 minutes ago, tight isobar said:

Obviously one or more mods tottenham fans....

Where me little love heart..??? 11 likes 😂😂😂

Can we please get back on topic please this is not the place to discuss Tottenham can we :Ddiscuss models and not about lovely spurs thank you...

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FI - No organized vortex in sight, that's nice

gfsnh-0-384_nkk5.png

Edited by Jonan92
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Another 2 positives - GFS control following the Operational 

- Also the Mean @102 has the svalbard shortwave more alligned SW instead of west- thus increasing the probability of the deep cold filtering south theough Scandi -

S

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42 minutes ago, Steve Murr said:

Just to add to how deep the cold is-

thats a nice toasty -9c @850 over london.

IMG_1312.thumb.PNG.19219948ae77f3b2f6f03654fdf31821.PNG..

 

The GFS run is superb, a wee bit more energy under the Greenland high in the later frames and we would be getting some even colder air towards us eventually. Good to see -9C 850s already.

Do models sometimes overestimate upper air temps? and could colder pockets appear closer to the time?

Either way the good thing about this time of year is that the weak solar input means temperatures at the surface can drop very quickly especially in slack winds. During 18th-25th December 2010 for example uppers were at a similar level (maybe a tad colder). Probably won't be as cold as that this time round at the surface but it just illustrates how we develop our own cold pool.

UKMO very similar to GFS earlier on but differ in the level of strength of the Greenland high. If we can get the GH to develop more on the UKMO then it may stay more securely to our NW. Either way its still a very good run.

Edited by Quicksilver1989
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For those wondering what ecm might bring, yesterday’s ICON run was very similar off the Eastern seaboard at the end of ts run 

was hoping this might get resolved by tomorrow morning but very doubtful now. 

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We have a 1030mb mean high just to the west of Ireland at T180 - my favourite sign of confidence in the outcome:

gens-21-1-180.png

A high usually verifies when that strong on the mean chart. But could still verify a little west or a little east of where it is situated. Either cold and dry, or cold and wet/snowy. Cold either way.

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One of the issues re the UKMO is the weaker low and then a shortwave runs ne and stops the ridge getting further north. You want a deep clean low over east Canada at T96hrs.

The UKMO is a continuation of this mornings messier ECM run.

The offending shortwave is that kink in the flow at T120hrs:

UN120-21.thumb.gif.aa5b559f1df49c18f26511375bd3e44a.gif

 

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48 minutes ago, Captain Shortwave said:

Well this would be a great result (If the GFS is right of course)

gfs-0-144.png?12

This would deliver conditions that would bring snow to low levels even in the south for a time. 

Unfortunately the other models are starting to steer away from a strong block that could bring increasing cold and eventually snowy conditions. The models are starting to favour a very common late Autumn pattern. 

UKMO/GEM

UW144-21.GIF?23-17   gem-0-144.png?12

The ridge is unable to push into the Arctic and eventually the high will topple towards the UK, probably setting up something more settled across the UK with the potential for surface conditons to become very cold but with little precipitation.

ECM ens from this morning tend to push towards anticyclonic conditions, though with many members potentially saying something colder.

EDM1-144.GIF?23-12   EDM1-192.GIF?23-12   EDM1-240.GIF?23-12

We could go milder again if westerlies manage to push across the UK, but the high could drift over the UK with a cold and settled spell, but equally we could see another low sink south east into Europe with another push of cold northerly winds.

Agreed, all coulds, if, buts and maybes. However, I'm liking the trend towards something we haven't seen much of in Novembers past, i.e. something colder than the norm and with some snow potential. I won't even bring up that year we all talk about. Expect the usual inter-model and inter-run upgrades and downgrades and focus on the 0z and 12zs daily, would be my suggestion to the less knowledgeable and experienced forum readers in here. Maybe save a chart or two to your pc, laptop etc. and see if you can see which way things are set to be developing into the end of November and beyond. Here's to the ECM 12z, will it be a :drunk-emoji: moment to celebrate for coldies, even if the actual timeframes are still some days ahead.

Edited by gottolovethisweather

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Ensembles for the 12z. Following a similar theme. Never really deviating from the -5 line. Pretty impressive.  Birmingham ensembles IMG_1066.thumb.GIF.6232586db2a5e31f28952744c34a8c3e.GIF

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4 minutes ago, weirpig said:

Ensembles for the 12z. Following a similar theme. Never really deviating from the -5 line. Pretty impressive.  Birmingham ensembles IMG_1066.thumb.GIF.6232586db2a5e31f28952744c34a8c3e.GIF

Looks like the Op was a bit of an outlier with the depth of cold upper air later next week.

A good clustering throughout suggesting below average temps but not well below average temps that southern UK would need this early in the season, re wintry PPN.

Edited by AWD
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7 minutes ago, Paul said:

Back to shorter range again - I'm intrigued by this little feature on the 12z Netwx...

pl1.png

Animation

Nov 23 2017 5_44 PM - Edited.gif

Looks like the time has come, close enough to the time where these features start to pop up :) 

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So just before the ECM runs we have the JMA to 84

if you compare the 84 today V the 108 yesterday ( same times ) you see the key trends of today emphasized -

* Better atlantic ridging & clearence through Iceland-

* Svalbard shortwave tilted south instead of west

IMG_1314.thumb.PNG.0bcc486d66d0622393811c9512d5dfca.PNGIMG_1315.thumb.PNG.f6352a82ce03dfb31934d8909ab55684.PNG

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The ECM at T72hrs looks better upstream than the UKMO for that time.

AT T96hrs much better, not that flabby low but a cleaner deep feature.

 

Edited by nick sussex
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Off out for a wee shop...keep a beady eye on that pesky Svalbard shortwave for me, will you?:good:

Edited by Ed Stone
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Nice clearing around greenland..

And pv-canadian area findind suitable placing.....

The back-edge of the ridge looks a tad dodgy...but lets see.

ECH1-96.gif

Edited by tight isobar

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