Model output discussion 25th Jan - The final third of winter beckons..

[Weather-history]

1 hour ago, Weather-history said:

Would that not fit in with the MJO heading towards phases 8 around that time?

Any MJO analysts around to give the possible impact of the MJO later in the month?

Any thoughts on this?

[Frank Trough]

2 hours ago, CreweCold said:

Yes...it has been trailed on the CFS for yonks...

A Greenland ridge stands a better than average chance as we head towards latter Feb. We'll see if the 0z GEFS continue where the 18z suite left off at the tail end of the run.

Here's the latest offering for March...again excellent consistency with its SSW induced outlook, just as it was March 2013...

I think we're going to hear a lot of references to March 2013 over the coming weeks, especially given charts like that. Worth considering that the chances of a repeat are statistically unlikely. Very unlikely. March 2013 was the coldest since the 1880's or something. So we have to ask ourselves how likely a repeat would be 4 years later?

stranger things have happened though. Maybe it will be the new normal?! There will be plenty of hope for that if the current snow chances keep reducing.

[Wayneywoo]

 

What with the MJO as a "forecast", coupled with the SSW, you will expect to see NWP vary.  Still plenty to play for...

[MR EXTREMES]

2 minutes ago, Weather-history said:

Any thoughts on this?

yes at least its not near cod.

other than that im back on the fence purely because of the strong vortex segment in the atlantic over greenland and to add to the complicated pattern we have the azores heights flapping around like flappy bird.

im not especially impressed although maybe once the next bigger low out to our west makes its mind up where its going then until then im on the fence trouble is the azores just wont bugger of.

and to top it of theres a pretty good vortex split.

but gfs see the vortex rapidly reform was also hoping for 09/10 southerly tracking jet just not southerly enough to be honest.

the pot of gold seems to be a hologram,

my frustration is almost at the point of pram full of toys ready for launch.

[bluearmy]

Was rather hoping to relieve the pressure on my backside this morning but alas, I'll have to stay there a while longer. I would still be looking for short term upgrades re snow potential. 

[Decemberof2010]

Be careful how long you sit on the fence for. You may end up falling off into deep potential.

Anyhow let's see what the 6z has in store. I'm hoping for some upgrades for a chance  of snow later next week. 

Looking forward to the 12z's already as well

[Hammer50]

This happened yesterday only for the later models to change to colder we should just wait and see.

[Mr_Pessimistic]

All looks a bit boaring to me, a brief south easterly, no decent uppers, no cold pool rushing towards us, and a reforming of the PV afterwards, now people talking about charts I'm march lol. Optimism, or just kidding yourselves/others, yet again. I'm commenting on the model output before this gets moved.

[TEITS]

My memory might be playing tricks here. However I do seem to recall back in the 1980s how E,lys often started dry, frosty and snow was never immediate. I am still however looking to see whether the cold pooling can be upgraded because even within +72 hrs this can occur in the output.

I do agree with Steve M the longer term prospects have improved in this mornings 0Zs.

[Tristrame]

8 minutes ago, TEITS said:

My memory might be playing tricks here. However I do seem to recall back in the 1980s how E,lys often started dry, frosty and snow was never immediate. I am still however looking to see whether the cold pooling can be upgraded because even within +72 hrs this can occur in the output.

I do agree with Steve M the longer term prospects have improved in this mornings 0Zs.

Aye a week of dry flurries here in February 1991

Then the Irish Sea streamers started dumping a good 8 inches in my area of Eastern Ireland 

we're way further west than you guys obviously but do well in very cold easterlies or northeasterlies  due to the often amazing shower production on the Irish Sea

 

[Man With Beard]

ECM ensembles assessment:

2 or 3 days of deepish cold from the east at the end of next week, not clear at the moment where the snow chances are though the SW looks to have a fair shout as the Atlantic trough passes nearby - and naturally eastern areas more favoured than western in such a setup.

Beyond that, same trend as for the previous 48 hours, a slow sink of the high - will be quite some time before "mild" again, though. The models may be overdoing their signal to remove a Scandi block as they have done many times this summer, so we could see a continuation of SElys for longer than we currently see - could still be cold if Mediterranean influence is cut off.

[Summer Sun]

Looking at UKMO extended most of the UK looks settled with high-pressure building in the far maybe the odd snow shower if the cloud is thick enough the south might get some colder winds too

Edited February 4, 2017 by Summer Sun

[The Weather Dragon]

9 minutes ago, Summer Sun said:

Looking at UKMO extended most of the UK looks settled with high-pressure building in the far south might get some chillier winds though

Still appears to be rather cold - cold easterly for the south in particular. 

[Guest]

DAILY EUROPEAN TEMPERATURE AND PRESSURE CHECK No.2 - SOME VERY GOOD PROGRESS

In the build up to phase 1 of next week’s “probable” cold spell, I feel that it will be useful to keep up-to-date with the current and trending  temperature and pressure changes in Europe. I will try to produce these on a daily basis for the next few days. This should help to show if the pattern is likely to evolve favourably (for coldies) and to monitor the extent of the cold that we might expect.

Firstly, I shall more or less repeat what I said yesterday. I will make a brief comment on the current model 0z output which mostly seems to have downgraded somewhat from yesterday’s 12z runs.  Expect further adjustments in the D4 to D7 period.  This is a complicated pattern transition with changes in the strength and path of the Jet Stream, questions over how quickly the Scandinavian HP builds, exactly where it sets up and its orientation, to what extent will Atlantic LPs undercut the HP and the position of any LP in the Mediterranean. Remember this is all in phase 1. With another (one or two) warming impacts likely to follow in the D10 to D15 period. Phase 2 may well be stronger and have longer lasting impacts. There continues to be a suggestion of a switch from easterlies to northerlies later on, especially when the predicted MJO goes through the key phases 7, 8 and 1 in much higher amplitude.  The models are likely to struggle with the second transition until it becomes clearer. There may be a continuation of the cold spell or there might be a very brief milder interlude. Even if the easterly fails to deliver deep cold and some snow, this may well turn out to be the precursor to a proper cold spell. Of course most of us would like to see both phases produce an epic cold spell!

Now, I shall pick up from my first “check” on page 65. This took us to February 3rd.

European Surface Temperature Charts:

                     Current "live"                                        Feb 4th 0650                                        Feb 3rd    1250                                          Feb 3rd  0650                                         Feb 2nd 1250 

           

Note that it is important to allow for min/max temps when comparing the charts. The 0650s are usually close to the minimums and the 1250s are usually close to maximums. 

COMMENT:    The good news is that the cold over north-west Russia is deepening and expanding. Compare the two "0650" and "1250" charts and note the expanding of "purple" colours. This is really important and a key area to watch over the next few days. The cold in central and southern Europe has eased but this is not relevant at this stage,         

GFS 6z February 4th T+6 European Charts:  

                2m Surface Temps                                       850 Temps                                           500 hPa Temps

   

COMMENT:   Compare today's charts (above) with yesterday's (below). The "purple" area of sub -20c surface temps has expanded as has the "white" area of sub -32c temps  in the far north of Russia - this pool has spread slowly south-westwards too.. The pool of sub -20c 850s has also expanded with a wider area to the north and north-east. This has not yet pushed south-westwards but the synoptics to encourage this have yet to develop.This will be highly important over the next few days. The "green" warmer area is being steadily squeezed out.

GFS 6z February 3rd T+6 European Charts:  

                2m Surface Temps                                        850 Temps                                         500 hPa Temps

    

European Surface Pressure Charts:

                   Current "live”                                         Feb 4th 0650                                          Feb 3rd    1850                                         Feb 3rd  0650                      Current Met Office Fax: 0600 Feb 3rd                                             

        

COMMENT:   The main cell of HP has moved slightly eastwards to the east of the Black Sea. The strong ridge north-north-westwards is developing a separate cell over northern Russia with a further ridge starting to build north-westwards into Finland and westwards towards the Baltic Sea. There is also a stronger ridge of HP building southwards from the Arctic which just shows up in the far north of the chart off the north-west Russian coast. I believe that this is the beginning of the formation of the Scandinavian HP that we desperately need to verify.

Overall, the building blocks are there and most of my indicators are moving in the right direction for coldies.   

                     

Edited February 4, 2017 by Guest
Correcting typos and to ensure that all the links and charts work properly.

[Daniel*]

I expected worse going by some on here GFS op definitely on the the milder side for London in terms of 850hpa temps. The crazy cold runs have depleted. Still a small few 'potent' ones.

UKMO 96hrs is that a snow event for the south? Similar to ECM in fact, cold enough for snow possibly.

I think by Sunday 12Z output things should become more clearer. Am I concerned not yet...

Edited February 4, 2017 by Daniel*

[blizzard81]

The main problem we have is the scandi high is too bottom heavy. It's backside needs to be propped up lol. It's slumber towards the back is what causes it's poor orientation. This is one of the reasons a classic easterly is not being modelled. 

[EML Network]

Looking at the ECM +240 Pressure chart, IMO that it's a pretty good ending point, absolutely loaded with all sorts of possibilities thereafter. 

associated uppers...

 

The ooz ECM is probably the most plausible chart I have seen at handling the probable evolution of the coming ''cold spell''.

 

And make no mistake we are about to head into a colder spell of weather, IMO next week will be a near miss for most, but for the usual places along the NE Facing coasts then there may be some snow potential, but it's the week after that that I am beginning to get excited about, everything looks to be falling into place for a very cold 2nd half of Feb. 

First time this Winter that I have been excited. 

[blizzard81]

The GFS 00z ensembles are far more pleasing on the eye than the 18z ones from a coldies perspective. 

[winterof79]

58 minutes ago, TEITS said:

My memory might be playing tricks here. However I do seem to recall back in the 1980s how E,lys often started dry, frosty and snow was never immediate. I am still however looking to see whether the cold pooling can be upgraded because even within +72 hrs this can occur in the output.

I do agree with Steve M the longer term prospects have improved in this mornings 0Zs.

Your memory serves you correctly,snow graupel swishing along the road for a few days before the main course

Edited February 4, 2017 by winterof79

[Weathizard]

It looks like the same story of winter so far, high pressure edging in from the Azores just when we don't want it too! It's been a pest all winter, that being said I'm still happy with a cold and dry Easterly if that's what we get, you never know what can happen.

The 0z ENS show the split between the NE/Scotland and my location or southern areas with northern areas at a mean of around -8/9 for a good 4 days whereas in southern areas it barely gets to -5

ECM mean ar 144 is very good with less of a saggy bottomed high, but at 168 shows the Azores ridge sticking its unwelcome oar in again.

Edited February 4, 2017 by Weathizard

[SMU]

Nothing spectacular out to T78 in the 06z however small trends to the colder allignments means the upper air cold is further SW in europe - not massive however we only need 100/200 miles per run over 24 hours to see a big change for UK come day 6-

S

[snowray]

Pretty clear cut really, these pesky Atlantic lows are simply too strong and thats why the initial easterly fails of course. What we wanted ideally is for these areas of LP to have been toned down a bit, but if anything they are a little stronger and further east. We never really recover our easterly afterwards as the high starts to sink and the easterly is thinking ok, stuff you I'm off!

Edited February 4, 2017 by snowray

[snowice]

3 minutes ago, snowray said:

Pretty clear cut really, these pesky Atlantic lows are simply too strong and thats why the initial easterly fails of course. What we wanted ideally is for these areas of LP to have been toned down a bit, but if anything they are a little stronger and further east. We never really recover our easterly afterwards as the high starts to sink and the easterly is thinking ok, stuff you I'm off!

It will correct west by 120 patience required! 

[snowfish1]

Couldn't put it better myself hoping for some westward correction on that score to allow the Scandinavia high to form snow ice beat me there lol

Edited February 4, 2017 by snowfish1

[snowray]

53 minutes ago, snowice said:

It will correct west by 120 patience required! 

Yes it does in the end of course move in, we are already a fraction further west on this run.

Edited February 4, 2017 by snowray