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Model output discussion 8th Feb - Cold for now, but then what?


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1 hour ago, Ali1977 said:

MJO and strat can't do it then maybe the key was the out of sync QBO - should have been Easterly not westerly!! Maybe a diff story if the other way round.  We had great early Siberian snow cover too, another fail!!  

Incorrect re: the snow sorry. Siberian snow cover is seen as increasing the chances for cold weather for Europe. Not just a little island on its fringes. And much of Europe has indeed had a chilly winter. So snow advance cannot be called a fail.

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Evening All- ive been offline for a week taking a little break- monitoring the progress of the strat mainly- Things are homing in nicely now on the second SSW of the season ( a final warming

the possibility of a prolonged cold spell towards late November the possibility of a prolonged cold spell towards early December the possibility of a prolonged cold spell towards mid December the poss

Rather disappointing that the obsession over cold and snow excludes some fascinating weather over the next 72 hours. This is the deepening low, not yet even formed. It is due to begin to develop in th

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There's been lots of generic winter posts in here tonight, which don't fall into the model discussion category, so if you want to carry on with that side of the debate, please head to the winter thread:

 

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13 hours ago, Steve Murr said:

Morning All-

Just a quick update from the other nights post- nothing much has really changed -

The second wave of warming is really coming into view now - very similar to the way the last one was modelled, initially progged to send the zonal mean into deep negative territory, the last 48 hours have seen the overall forecast to continue to run along the same timeline with a 'slight' moderation of the negativity of the zonal winds-

The mean (GFS) drops to + 2M/S on the 22nd- however as with the first warming assisted by the MJO the tropospheric response could well be more immediate -last time relating to the height anomalies - they had responded & built when the zonal wind had reached the +10M/S line (ave for mid Feb is ~ +23M/S)

The CFS again is very bullish about negative territory & whilst modelling wise it doesnt deliver 10HPA resolution particularly well - generally overall this winter in terms of its forecasts of 'shape' of zonal wind trending V actuals has been pretty good- so it could all be sematics as to whether we actually tick the 'final warming' box- its the steep decline towards zero M/S thats important & of course hopes of a slower / non existent PV recovery....

( CFS is in pink - GFS ens in Green )

IMG_2435.thumb.PNG.c4012ccc4830dc9c3770f1e4e5186991.PNG

As highlighted then the numbers look good & the magical 0M/S line may yet again be breached- however from a trop point of view the guide for me in terms of what we may well see develop @500MB is the 10M/S time line ( again assisted by the MJO ) - forecasts for this are 17/18 Feb so allowing for the slight lag of height anomalies building we would see the NH profiles to start to look on 17-19th- focussed on positive heights over greenland & in the atlantic with of course deeper troughing trying to filter into Scandi- a relative rarity this winter-that should put the UK in the frame still for getting cold late next weekend ( timed nicely for my 3 weeks off !!)

 -The ECM strat forecasts are mostly onboard with the forecast although im expecting lower zonal wind forecasts at day 10 when berlin updates today - yesterdays 10 day 100HPA forecast perfectly depicted the flow allignment highlighted above..

IMG_2437.thumb.PNG.93f5a2cfe408fc68b605fee066ed114c.PNG

If we also review the last few days modelling ( without posting to many pics ) - the ECM in particular has been to progressive with the South easterly warm up, initially progged for Sunday- its now more Monday & we keep a continental influence for the whole week, so frosts by night however a higher diurnal range-

Snow over the weekend again looks more widespread than first modelled.. I guess somewhere at elevation in the UK will breach 10cms - Im expecting a dusting here - with peak availability over the UK being Friday 00z to sunday 12z before the slightly less cold uppers filter NE from Kent...

have a good day :)

S

 

 

Really hope Steve is right with his forecast because there is no sign of it in the output this evening. Surely the models factor in the start warming and zonal wind forecasts? If so why do they not agree with the notion of Greenland height rises in 8-10 days time? 

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For a few days earlier this week the ECM mean was showing hints of dropping back to or below 0 later next week that has disappeared on the past couple of updates whether it shows up again in the coming days who knows

graphe_ens3_php.thumb.png.04ea98b166270394eec9f035399ac4ab.png

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39 minutes ago, mcweather said:

Well I'm glad I didn't hang my hat on the current cold snap being anything more substantial. While it is always exciting to see the Scandi high appearing in forecasts. Unless the positioning is just right and the genoa low is sturdy the high nearly always slips away southeastwards or simply morphs into mid latitude high. As more learned posters have already pointed out the genuine article is a rare beast indeed.

Looking forward I have not yet completely given up on a decent cold/snowy spell between now and mid march and with the jet practically non-existent there is always the chance of some unusual or unexpected developments but at the same time I'm not holding my breath.

Yep MC, the Genoa low is all too often crucial when it comes to a good Easterly and usually one of the early building blocks to HLB. As has been proven again, energy sliding south under the block just doesn't cut the mustard if it doesn't make it far enough east, certainly loitering around Portugal usually does us few favours.

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32 minutes ago, damianslaw said:

I'm not passing much comment on the models at the moment, as I think they are prone to wide margins or error beyond the 96-120 hr timeframe, as we have a predicted very weak floundering jetstream, and thus no major forcing feature, hence expect varied output in the days ahead. 

The 18z is desperately trying to listen to you :)

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18Z upto 132hrs is just showing inactive Atlantic and HP just slowly sinking from its current position to Central Europe leaving UK with a quiet spell of weather with temps in Northern UK i would guess in 4-6 degrees and those in South 7-10 i would guess with night frosts for most if skies clear.No sign of retrogression og Heights moving to our North or NW but this is the pub run so who knows what FI will show lol!!Clock ticking on Old Man Winter now ..

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Louise Lear on BBC seems confident for snow overnight Friday into Saturday morning but as temps rise on Saturday snow will turn to sleet/rain during the day although high ground may still see snow.She then alluded that PERHAPS things may turn more springlike as next week progresses.We shall see!! 

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1 hour ago, blizzard81 said:

Very impressed at the continuity between the gfs 12z and 18z ops. Both runs very similar at day 9. This leads me to think that the dye may not be cast yet on cold phase 2 for next weekend :)

Agreed. As @damianslaw has pointed out, such a weak jet stream and Atlantic is bound to have an effect. After all the models simulate a predicted progression of the weather based on data and if one of the big forcing factors inherent in the starting data and subsequent evolution is quiescent then dare I say unpredictability increases.

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3 hours ago, North-Easterly Blast said:

What has happened is that after a good cold winter in 2009-10, the severe December 2010, then another decent winter in 2012-13 and the cold end to that winter, the last three winters have gone significantly downhill and mostly back to almost rubbish again, (2013-14 was a complete write off, and an absolute shocker for lack of cold weather).  Winter 2016-17, although so far looking less mild overall than 13-14 and 15-16; unless we see a decent cold spell later this month or even into early March, winter 2016-17 will still be overall disappointing for most.  So surely the law of averages ought to suggest that we will see another decent winter before 2020.

Yes for sure...I do suggest we will have a decent/XCELLENT winter before 2020...:D :yahoo::cold: :hi:

Couldn't resist :)

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14 minutes ago, Man With Beard said:

Best news of the night - ECM monthly rock solid above average temps till mid-March. Going by its form this winter, get those sledges back out of the loft!

The one time its right all winter i should bet. its been hopeless since October so it will probably be spot on now...

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25 minutes ago, Man With Beard said:

Best news of the night - ECM monthly rock solid above average temps till mid-March. Going by its form this winter, get those sledges back out of the loft!

CFS says 'Pah!'

cfs-4-3-2017.png?00

cfs-1-3-2017.png?00

Seriously, the way the ECM monthly has behaved this winter, I would take its +ve temperature outlook as a good thing if it's snow/cold you're after.

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Not really much to get excited about this morning so far. The GFS OP is on the mild side of things again, but the general consensus is for temps to recover to average/above average by the 13th for a few days, before perhaps a small chance of something cooler re-appearing by the 17/18th. A small number of very cold runs by the 3rd week, but nowhere near enough evidence to push this agenda at present.

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ao.sprd2.gif

Just to add the AO forecasts - most of which are sharply heading back to0 or positive. I guess this ties in with the models now showing pressure falling over the pole and the PV regaining some strength from its current state. How the projected second SSW will effect this - I'm not sure at all.

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5 minutes ago, mb018538 said:

ao.sprd2.gif

Just to add the AO forecasts - most of which are sharply heading back to0 or positive. I guess this ties in with the models now showing pressure falling over the pole and the PV regaining some strength from its current state. How the projected second SSW will effect this - I'm not sure at all.

Yes, GFS, GEFS, ECM and yesterday EPS showing broadly similar AO and NAO. Doesn't mean it will happen though ;-)

Personally looking forward to an early Spring, but the longer range models haven't covered themselves in glory this season, so I'm not counting my chickens just yet.

 

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9 minutes ago, mb018538 said:

ao.sprd2.gif

Just to add the AO forecasts - most of which are sharply heading back to0 or positive. I guess this ties in with the models now showing pressure falling over the pole and the PV regaining some strength from its current state. How the projected second SSW will effect this - I'm not sure at all.

Looks like a very similar evolution high up. Given the zonal flow is weaker than last time to begin with, I wouldn't expect anything coming from the strat to interfere too much with whatever is driving the trop at the time. In any event, for us in the south, march is generally not a month to bring lying snow and I would rather have spring than slush! 

Sad for coldies that this promising synoptic scenario is going to deliver so poorly., given its potential. I guesss we've done well to get a pseudo cold pool to get here but it's origins are not great and it doesn't pack a big enough punch ire depth of cold uppers or lowness of thickness. maybe this weekend sums up winter 16/17 pretty well - no luck for the UK coldies! 

 

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Volitle model outputs indeed a split average zonal or heights over the uk or north south split dryer in the south but what is noticeable it's the polar vortex trying to get over to the siberian side.

But there's no clear evolution very dissapointed plenty of egg on my face that's for sure.

But anyway might as well hunt for some early spring warmth.

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Well there we have it. The worse possible chart possible as we head towards winters end. Looks like most models heading this way now. Maybe time for a another chance of cold but will need a quick flip in MRFs. Although we have had extensive cold periods in Central Europe, very little snowfall and that's the way it looks for the next 10 days here. Sorry for you snow lovers back in blighty , its drawn blank again for most and very frustrating considering the lack of zonal Atlantic flow this winter. Anyway hope some of you see a bit of snowfall during the next 48 hours. Defeated and deflated yet again for lovers of real deep winter cold and snow of course!

 

C

ECMOPEU00_240_1.png

Edited by carinthian
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