Model output discussion - proper cold spell inbound?

[chionomaniac]

It's small, but slight change for the better this run regarding Scandi. More jet stream undercut compared to previous run at T+180. That will help any Scandi block to form.

[nick sussex]

NOAA have updated their MJO outlook:

An active MJO continues as the enhanced phase propagated across the West Pacific.

 Dynamical and statistical models strongly support continued MJO activity, with the GEFS maintaining a signal near the Date Line due to Rossby wave activity in the Pacific, while the constructed analog is more progressive. 

 A robust West Pacific MJO event favors potential transition towards cooler temperatures over the eastern U.S. while a warming trend is favored over the West. Odds also tilt towards below-normal precipitation across the U.S. as the MJO continues towards the Western Hemisphere.

Buried deep in the update was this:

Lastly, the shift from retraction to extension of the jet over East Asia appears to be underway.

 

[chionomaniac]

Look towards Svalbard.....

[Allseasons-Si]

1 minute ago, chionomaniac said:

Look towards Svalbard.....

All looks good on this run Fred+chunk of pv split over NE Canada,trough to our NW going under u think.

[bluearmy]

5 minutes ago, chionomaniac said:

Look towards Svalbard.....

I’m thinking back to the days when we have seen a  ssw downwelling and I recall the Atlantic low heights  filling quite rapidly as those purples and blues went to light blue and then yellows and greens within a coupe days. To use your analogy from earlier - as if someone just let the air out of the balloon. Given that we start with a strong vortex extension from Canada, I wonder if we will see something similar over the next couple of days in the week 2 output ?? 

Im not talking about a surge of WAA pushing heights north but imagine the day 9/10 ec op today and that upper low just can’t make eastward progress - then it just fills in situ within 48 hours ! 

Edited February 5, 2018 by bluearmy

[Nick F]

Just noticed this tweet showing next 4 weeks temps anomalies for Europe from today’s EC monthly forecast system run, below average for the UK and much of Northern Europe for next 4 weeks, quite a -ve departure this far off for week 4 at the end of Feb into first few days of March. Need to start saving for the quarterly heating bill ...

 

Edited February 5, 2018 by Nick F

[chionomaniac]

7 minutes ago, bluearmy said:

I’m thinking back to the days when we have seen a  ssw downwelling and I recall the Atlantic low heights  filling quite rapidly as those purples and blues went to light blue and then yellows and greens within a coupe days. To use your analogy from earlier - as if someone just let the air out of the balloon. Given that we start with a strong vortex extension from Canada, I wonder if we will see something similar over the next couple of days in the week 2 output ?? 

That's certainly my thinking,,,,,

Nice cold pool building to our east too

Compare where the lowest heights are as well to our NW - they have receded further west on this run - the trend is our friend....

Edited February 5, 2018 by chionomaniac

[supernova]

10 minutes ago, bluearmy said:

Ec 46 shows week 3 and 4 low heights and slp nw Europe and high heights and slp to our north and nw. Tough to see how high heights are over scandi until global picture revealed. What is noticeable is -4c upper across midlands weeks 3 and  4. That’s a long way off for such a mean. 

Interesting Blue. Various people here and on Twitter comparing upcoming SSW with the 1985 warming. That event took place in Dec and appeared to impact the weather throughout Jan and Feb which were both cold months (with significant snow for many). Not sure the comparison is a good one but, if so, EC46 as mentioned above and @TEITS's earlier comment about keeping an eye on Greenie (or Icelandic) heights seemed well considered. This is what happened in Feb 1985 after said warming.

 

Feb 3rd. Feb 5.  Feb 7.  

By Feb 10..a snowy Easterly.  

Frankly I'm cynical of anything GFS shows us much past 144 (or any other model) but if we're looking for trends I'm temped to suggest a Greenie rather than Scandi high might well be an interesting call if history repeats itself. No complaints from me if so.

  

[ANYWEATHER]

Evening, as long as a lobe of the polar vortex remains over north America as in the ecm a gfs output at T+240 forget looking east for any major cold . We need a major change in synoptics for any massive change here ,as far as I'm concerned  we need to keep looking west not east for our westher

[Allseasons-Si]

32 minutes ago, Sweatyman said:

How many fronts crossing us???

That's a fourfront conclusion....

the 18z 10hpa looks a bit toasty demolishing the Canadian pv.

[Frosty.]

I'm happy to look west / northwest in the short / medium range as it looks like some very decent cold zonality sourced from canada has our name on it..then hopefully we will be looking east / northeast!!

 

 

[Snowy L]

I know the models have had upgrades since then but I still think they are missing something. In Jan 2013 they were showing nothing great then as soon as the SSW actually happened out of nowhere a gap appeared in the raging Atlantic and high presure built over the UK then into Scandi. I think the same will happen again in 10-12 days time. Yes the Greenland vortex lobe is incredibly strong but the fact is a massive stratospheric high is about to separate it from the Russian lobe.

So I think we will see something after the intital split and we wont have to wait until the next warming weakens the Greenland lobe, but we wont see it modelled until the split has actually happened.

Edited February 5, 2018 by Snowy L

[karlos1983]

15 minutes ago, ANYWEATHER said:

Evening, as long as a lobe of the polar vortex remains over north America as in the ecm a gfs output at T+240 forget looking east for any major cold . We need a major change in synoptics for any massive change here ,as far as I'm concerned  we need to keep looking west not east for our westher

But if you keep looking West your gonna get a cold back! 

Are you expecting westerly winds to dominate for the foreseeable? I think charts at 240 need to be taken with a pinch of salt! More so now than usual! 

Upcoming SSW is going to change the NH pattern in a major way!

[bobbydog]

just a comparison of the GFS snow chart for midnight against the current radar image- (close enough timing)

lots more precip than GFS shows...

 

 

[ITSY]

Not as many blocked members as I’d hoped for after the earlier EC46, but more than a few to wet the appetite...especially as this only flirts with the beginning of the period likely to feel the downwelling effects of the SSW

 

Edited February 5, 2018 by ITSY

[BlackburnChris]

53 minutes ago, ANYWEATHER said:

Evening, as long as a lobe of the polar vortex remains over north America as in the ecm a gfs output at T+240 forget looking east for any major cold . We need a major change in synoptics for any massive change here ,as far as I'm concerned  we need to keep looking west not east for our westher

that comment may come back to haunt you.... Look East 240hr Plus

[Paul_1978]

 

[Daniel*]

It looks currently we’re in model ‘no mans land’ I bet by the end of this week things will look decidedly more inspiring. What’s going on in the atmosphere is really chaotic, it’s like a snow globe that is soon to be shaken the snow is yet to settle down, expect large volatility to come. I see some folk bashing others for hyping of no fault of our own for instance the uppers were toned down there was a time when UKMO / GFS & ECM had -12 uppers over London as a result it’s not been quite as cold. Possibly why convection was not as vigorous as it could have been, last night, some localised areas had 2” in Kent so not a complete no show. I also reckon the SSTs being above average, further moderated the cold uppers crossing North Sea. I as a matter of fact have seen snow flurries 2/2 days out of this current cold spell, and I may see some snow later on today that would make a third consecutive day of snow falling. Nothing significsnt yes but it has been highly unusual to see that in recent years. It’s the signals which drive model output and if our teleconnection ‘experts’ are hopeful then we too should be. 

[BlackburnChris]

2 minutes ago, Daniel* said:

It looks currently we’re in model ‘no mans land’ I bet by the end of this week things will look decidedly more inspiring. What’s going on in the atmosphere is really chaotic, it’s like a snow globe that is soon to be shaken the snow is yet to settle down, expect large volatility to come. I see some folk bashing others for hyping of no fault of our own for instance the uppers were toned down there was a time when UKMO / GFS & ECM had -12 uppers over London as a result it’s not been quite as cold. Possibly why convection was not as vigorous as it could have been, last night, some localised areas had 2” in Kent so not a complete no show. I also reckon the SSTs being above average, further moderated the cold uppers crossing North Sea. I as a matter of fact have seen snow flurries 2/2 days out of this current cold spell, and I may see some snow later on today that would make a third consecutive day of snow falling. Nothing significsnt yes but it has been highly unusual to see that in recent years. It’s the signals which drive model output and if our teleconnection ‘experts’ are hopeful then we too should be. 

my bet is models dont have a clue due to ssw

[Allseasons-Si]

The end of the control run looks a peach to me with lows diving SE with height's developing to our NE,i know this is FL but this is where we should start looking for our next cold spell as other have noted

the second half of Feb-beginning of march and maybe beyond is looking good at the moment,and no it won't be too late as we go into march as i whitnessed this on march 2013,and no it wasn't on the tops of the peak district,it was almost IMBY just 10 miles away where the road was competely cut off by several foot snow drifts.

i think it was around this time

 

Edited February 6, 2018 by Allseasons-si

[Cheshire Freeze]

10 minutes ago, Allseasons-si said:

The end of the control run looks a peach to me with lows diving SE with height's developing to our NE,i know this is FL but this is where we should start looking for our next cold spell as other have noted

the second half of Feb-beginning of march and maybe beyond is looking good at the moment,and no it won't be too late as we go into march as i whitnessed this on march 2013,and no it wasn't on the tops of the peak district,it was almost IMBY just 10 miles away where the road was competely cut off by several foot snow drifts.

i think it was around this time

 

And, as I have said before, March 2013 was a 1 in 50ish year event- literally everything aligned perfectly (as it needs to for prolonged cold in March). 

I'm not counting any SSW chickens yet as the outcome of the SSW is a mystery at present. We could just as easily end up with a deep Atlantic trough and a mild S'ly/sse'ly waft. 

[Allseasons-Si]

1 minute ago, CreweCold said:

And, as I have said before, March 2013 was a 1 in 50ish year event- literally everything aligned perfectly (as it needs to for prolonged cold in March). 

I'm not counting any SSW chickens yet as the outcome of the SSW is a mystery at present. We could just as easily end up with a deep Atlantic trough and a mild S'ly/sse'ly waft. 

Yes very true

we are a tiny island and we look at the NH profile and is so vast,where the downwelling goes to the mid lats is anyones guess,but i look at this way,at least we have a shot at this,it could be memorable or it could be miserable.

[snowfish1]

3 hours ago, Daniel* said:

It looks currently we’re in model ‘no mans land’ I bet by the end of this week things will look decidedly more inspiring. What’s going on in the atmosphere is really chaotic, it’s like a snow globe that is soon to be shaken the snow is yet to settle down, expect large volatility to come. I see some folk bashing others for hyping of no fault of our own for instance the uppers were toned down there was a time when UKMO / GFS & ECM had -12 uppers over London as a result it’s not been quite as cold. Possibly why convection was not as vigorous as it could have been, last night, some localised areas had 2” in Kent so not a complete no show. I also reckon the SSTs being above average, further moderated the cold uppers crossing North Sea. I as a matter of fact have seen snow flurries 2/2 days out of this current cold spell, and I may see some snow later on today that would make a third consecutive day of snow falling. Nothing significsnt yes but it has been highly unusual to see that in recent years. It’s the signals which drive model output and if our teleconnection ‘experts’ are hopeful then we too should be. 

This post gets my vote. Thank you lets hope so

[Mucka]

Another marginal improvement on this mornings 00z by 144. Azores a little further SW and Russian high at tad further East.

Possibly of more interest is the embedded trough in V cold PM flow. It is just an illustration of what could happen at this range though

Likewise UKMO improved with trough digging SE and very cold PM flow.

Edited February 6, 2018 by Mucka

[That ECM]

Just a random few gefs. This is more to illustrate to newer members that the position of heights can be different for us to get an easterly flow. Flicking through them all and looking at the mean upto t300 there is a move towards heights building to the ne. Clearly the one below is the most extreme.