Model Output Discussion 29th December - Into mid-Winter.

[Frosty.]

3 minutes ago, nn2013 said:

I hope this does materalise and the ECM are right. Potential 1979 repeat on the cards. 

That day 10 chart is stunning, bone chillingly beautiful :- )

meanwhile, Sidney is praying the Ecm is wrong!

[Nouska]

7 minutes ago, radiohead said:

There's an awful lot of snow for NW Scotland in that flow eg. 84 hours - sorry no snow charts for further south.

[Dancerwithwings]

12z ENS GEFS Control vs 12z ECM...both at 240h

The only differences are what's happening in the Atlantic but pretty much the same......  I wonder

Edited January 9, 2017 by Dancerwithwings

[The PIT]

So tonight folks it's ECM V GFS V UKMO Two mild runs ukmo is going GFS way v very cold ECM. Well ECM is the top model but it's being bullied by it's no.2 and no3. Hopefully the other two will switch next run

[Hotspur62]

ECM is consistent in bringing in an Easterly in FI.I think it has shown it now on last 5 runs!!. Just amazing how different GFS is on same timeframes. Hope ECM trumps GFS but wouldnt bet much on it.Such big differences at T96 onwards that just get wider as time goes on.Fascinating watching though

[Jason M]

With an easterly like shown ice days would be easily achievable in mid Jan. Pressure looks a little bit high for much in the way of convection though with 1030 & 1035 pressure across southern England and would want it more in the 1020 range ideally. I'd imagine that it would be a stratus fest rather than a snowy easterly BUT get the cold in and you are in the game for snow. Nothing marginal about those charts.

The ECM is bringing these charts nearer which is a big positive but I still think its ECM over amplifying things so personally I'm not buying it. Show me some cross model agreement over a couple of days then maybe, but I still think its heights are modelled too far north and a trip up the garden path beckons. Regardless of my scepticism still nice to have some interest though .

[chris55]

After the swings and differences between the GFS/ECM/UKMO of the last 36/48 hours I would be happy to place a bet on the ECM tonight.

It's consistency with the easterly element has been steadfast (including the ens), though the positioning and severity of any colder conditions from the east are open to debate, id say a cold surface high at least looks the form horse.

 

[Arthur1882]

5 minutes ago, Frosty. said:

That day 10 chart is stunning, bone chillingly beautiful :- )

meanwhile, Sidney is praying the Ecm is wrong!

Think this will be Sidney if the ECM verifies, bone chillingly cold, with the potential for heavy snow showers if we get any instability or troughs

 

[❄️❄️❄️❄️❄️❄️❄️❄️❄️]

ECM once again being a total block tease in FI. 

[Summer Sun]

ECM and the GFS control at d10 both have the same idea with the high building over Scandi

Edited January 9, 2017 by Summer Sun

[nick sussex]

As much as the ECM is an excellent run I should add a note of caution. We still don't have agreement between the big 3 and as much as we like to deride the GFS its not like ignoring the NAVGEM. We do need the GFS asap like starting with tonights 18hrs run to start moving towards the ECM solution.

Theres another point of contention and that's shortwave activity in the Atlantic , we want the weakest possible shortwave. Even if the ECM is correct with its overall evolution. You see the shortwave circled red at T96hrs, this gets picked up by the elongated PV to the west and runs ne'wards at T120hrs. Its a ridge inhibitor, its trying to suppress the ridge, the more vertical we can get this ridge the higher margin for error there is moving forward.

 

Edited January 9, 2017 by nick sussex

[Hotspur62]

Where is Mr Murr? Would like to hear his comments on latest ECM. I think as NS has just stated the shortwave in the Atlantic is crucial on how things move forward.Nothing is ever simple in trying to get Long Term cold in for the UK!!

[nick sussex]

1 minute ago, Hotspur61 said:

Where is Mr Murr? Would like to hear his comments on latest ECM. I think as NS has just stated the shortwave in the Atlantic is crucial on how things move forward.Nothing is ever simple in trying to get Long Term cold in for the UK!!

I think he passed out with excitement and was stretchered away! lol The GFS makes a mountain out of shortwaves in the Atlantic and you can see how that ended up. Yes and it is like pulling teeth anytime theres a chance of a more extended spell of colder weather. Until the GFS is on board then I'm going to refrain from any ramping although that's difficult because the ECM is such a good run and given the crud winter so far would be fully deserved by all the long suffering NW members.

[tight isobar]

Yes nick 'shortwave' lol

Nick Sussex. 

Shortwave drama is applicable atm' and you're v-noteworthy in exactions of these scenarios. 

However' the back-banding of height format at Scandinavia' looks atm..to beat'-non comply- with Atlantic lp/waving. .that's why im very enthusiastic about the ecm mod......as it stands. 

However' I'll keep tight with your posts regarding above as its an area I fully respect you in...

[Frosty.]

5 minutes ago, Hotspur61 said:

Where is Mr Murr?

Charging his phone battery perhaps

Again, the Ecm is proudly flying the flag for a prolonged very cold extended outlook..I pray its on the right track!

[Man With Beard]

25 minutes ago, Day 10 said:

The ECM in a bit more detail for thurs/fri.

Great posting, that T78 chart is interesting for the south coast, lots of precipitation well inside the -5 uppers line.

[nick sussex]

1 minute ago, tight isobar said:

Yes nick 'shortwave' lol

Nick Sussex.

Shortwave drama is applicable atm' and you're v-noteworthy in exactions of these scenarios.

However' the back-banding of height format at Scandinavia' looks atm..to beat'-non comply- with Atlantic lp/waving. .that's why im very enthusiastic about the ecm mod......as it stands.

However' I'll keep tight with your posts regarding above as its an area I fully respect you in...

My obsession with shortwaves is well known in here! I've always viewed outputs with potential for cold from an expectation of problems and margin for error which is probably a good thing because of our terrible luck at getting any to verify. Rest assured that I won't be giving the green light until I'm certain or as much as one can be that its all systems go!

[Singularity]

Unusually, we're reliant on a strong trough to get the Scandi ridge, as it throws WWA well north of the UK.

Or at least it does if it's able to direct the flow on its eastern flank right up into the Arctic. The solutions in which it does so tie right in with the tendency since Dec 2015 for Atlantic storms to invade the high Arctic much more readily than in past years. Seemingly a consequence of so much heat and moisture in the overall climate system.

So I believe we're in with a good shot - but only if the lowering of heights doesn't end up strung out in a line such as GFS keeps on doing. 

To avoid that it appears critical that the shortwave near Iceland stays separate from the approaching trough out of Canada. Tense times!

[Guest]

WINTER 2016/17 FULL REPORT No. 7 (PART 1) WITH JANUARY 9TH INPUT

Please note that some of the charts that I refer to in this post are through “live” links which update periodically. So, if you are reading this a few days or even hours after publication (on Monday, January 9th at 1945), some of the charts may already have updated. My comments relate to what the charts were showing at the time of this posting. I am just starting to learn how to cut and paste charts into my posts so please bear with me as I increasingly use these in future reports. @Mucka thank you for all your help with these. I am still having some problems with getting charts to freeze in time and I will be getting further help from another member in the coming days.

I have decided to split my reports into two parts from now on. One of my main features is always on Judah Cohen’s latest Arctic Oscillation report. These are always published around 2300 on a Monday evening which means that my report posts are delayed until around midnight and editing continues for at least another hour after that. So, the Judah Cohen analysis will be in “part 2” and the main “part 1” report, with my other regular features, will go live much earlier in the evening. I hope that this will be useful for everyone and it will certainly allow me to get to bed at a more reasonable hour.

My Take On The Current Model Output And My Reporting Dilemma:

As some of you “may” have noticed, I like to produce occasional but long reports, too long I hear some of you say but this presents a problem. Most posts on the MOD are directly responding to a particular model run and in a specific time frame. The preparation and much of the textual commentary in my reports are spread out over 8 to 12 hours (in between my business commitments). The model output can swing hugely over this short period potentially rendering some of what I say as out-of-date when my post goes live. I usually make more general points and take an overview which takes some account of the fluctuating output. If I make a direct comment on one or more of the models I do usually quickly check for any recent/concurrent changes.

After last night’s 12z (UKMO & ECM) + the 18z from GFS, I was thinking that I will go with my usual cautiously optimistic approach and managing expectations but this morning, following something of a downgrade, I was thinking of being more upbeat. I am a self-confessed coldie and I love snow like the majority of us in this forum. So, just for a change, please permit me to indulge myself. I am releasing the safety belt and will put a very positive spin on things without any undue ramping.

Barring some sort of last minute calamity, we can expect the Arctic cold to move into the UK later on Wednesday and through at least Thursday and Friday. It appears that almost anywhere could see at least a little of the white stuff. The big 3 models have “mostly” been showing quite a clean north to north-north-west flow. There does seem to be potential for one or two small disturbances forming within the flow and as, most of us appreciate, any minor troughs cannot usually be pin-pointed in terms of position and timing until we are much closer to the event (D1 to D2). As @Nouska pointed out as early as last Thursday evening (before anyone else, I think) the conditions may well be ripe for possible Polar Low development, probably from late Thursday and through Friday. With the 500mb temperatures probably still below the key -40c threshold and easily lower enough 850s (update: may be more marginal) the potential still seems to be there. Others with more experience than me on assessing the upper flows can comment on the finer details and requirements. Overall, there is plenty to keep us occupied during the next 5 days and shorter term model watching will be extremely exciting.

Now, there is still much uncertainty over the longevity of this cold snap/spell as well as the intensity. I have some good news on the latter in my Arctic temperature analysis later in this report. For a few weeks now, we have seen a quite extraordinary period of model uncertainty with some wild swings, upgrading, downgrading, lack of consensus and sometimes utter confusion. I have commented extensively on this in my last few reports. As always with this wonderful science, there is a whole array of possible outcomes. I shall attempt to group these into four broad categories, starting with the least attractive for coldies:

i) The cold snap breaks down quickly and the Atlantic piles in:

The GFS 0z operational run output indicated a rapid end to the cold snap, perhaps as soon as Saturday, with a strong westerly or perhaps a south-westerly being pushed in on a much more zonal flow on a powerful west to east jet stream. This being supported in part by the strengthening upper flow. The run was later proven to be a big mild outlier but is a possible outcome. The GFS is often very progressive when it decides to bring in a zonal flow. I feel that it completely underestimates the massive strength of the central European cold block. Although the low heights over Scandinavia (which help to bring in the Arctic airstream in the first place) may displace the deepest cold slightly eastwards for several days, the Arctic cold will spread down over much of western mainland Europe with some pretty widespread snowfall. By next weekend, our European neighbours will have temperatures at or below freezing over a wide area. History tells us, that even in the most zonal of Winters, if these blocks become established, they rarely give up without at least a fight. This could leave us right in the centre of the battleground for a few days.

ii) The cold spell breaks down more slowly with a very mixed period ahead:

Carrying on from what I just said above, the cold snap or spell (it might be useful if we could actually come up with a time definition of each to prevent ambiguity) might last a little longer, perhaps well into the following week (say to around D10 to D12 or around January 20th for example). It’s surely more likely that once the cold is established, that it will take a while to shift and perhaps several attempts at milder incursions to finally clear it. Some of each of the recent models’ ensemble members suggest this type of scenario. There could even be some fronts stalling producing some additional boundary edge snowfall before the milder air takes hold. Thereafter we might see a return to climatology, although with all the mixed and seemingly conflicting northern hemisphere signals we have seen recently, this is a far too general term and rather a cop out. For now, let’s take it in its more literal sense, with predominantly average to mild conditions but with some colder interludes.

iii) The cold spell temporarily breaks down but with renewed cold spells to follow:

I’ve seen a few posters mention more than once, that the D6 to D10 period might be critical in deciding the outcome of the rest of the Winter. Whilst it might be crucial in terms of the next couple of weeks through to late January, these types of dismissive statements are almost always wide of the mark with no evidence provided at all to back up this emotional viewpoint.

In this scenario (as with all the others but a special point to be made here), we have to weigh up some of the uncertainties of the background signals, any areas of warm air advection into the Arctic, the degree of any amplification, the continuing strength and position of the polar vortex, the strength and direction of the jet stream and will it split, the development, speed and track of certain short wave activity and various other factors. Following the two North American cold snaps/spells (the first a very cold one) we are about to see the opposite with an extended period of widespread warmth in that continent. Although other factors are also involved, it occurs to be that with greatly reduced thermal contrasts (east US and west Atlantic) that this might well lead to an abrupt weakening of the jet stream with some favourable (for blocking and more likely colder patterns) downstream consequences for us. Probably a rather too simplistic assumption.

I was also delighted to see @Tamara in her post yesterday, to be able to report more optimistically on the recent changes and movements in the Pacific at last allowing a greater “likelihood” (not a definite forecast) of rather more enhanced HLB as we proceed though the second half of January and into February. Just a little comment here – a few of you guys seem to think that Tamara takes pleasure in destroying all hopes of possible colder weather patterns developing. This couldn’t be further from the truth as she is a Winter coldie and loves snow like the majority of us. So, please be far more respectful of her posts and let’s avoid this bickering over the relative merits of teleconnections, whichever side of the fence that you sit on. Right, no more on disrespectful behaviour in this report – there is far too much exciting weather around to discuss anything else!   

I feel that there is enough evidence to suggest that even if we have a temporary warm up that there will be plenty of further opportunities for more cold spells during the remainder of this Winter. I firmly believe that January, at least, will turn out to be a below average month for both temperature and rainfall. Just how extreme, is still very much undecided.

iv) The cold continues and develops into a prolonged and memorable period of cold:

While my third scenario is the one that I currently favour, let’s really indulge ourselves now with a little FI ! In my last few weekly reports I’ve drawn attention to how unusual the weather patterns have been throughout most of 2016. Record strengths and weaknesses in the PV, record low Arctic sea ice build-up (see later for an important update) and a highly anomalous belt of high pressure close to our shores or right over us, just to name a few. Recently, we have seen some extreme cold developing over central, eastern and southern Europe with a widespread pool of very low temperatures. The imminent Arctic outbreak is quite a potent one in comparison to anything that we have seen in the last couple of Winters. So, unlike almost anything since March/April 2013,  we at last have some very cold pools close by to potentially lock into.

It is quite possible that the Atlantic will not succeed in shifting the cold block to our east. It may not matter initially if we do not lock into this block. As long as it holds back any milder weather, we can retain the cold over us for longer. We might be open to one or two more Arctic incursions to top up the cold. Some of the model ensembles have shown high pressure hanging on close to our east (I’m not referring to a Scandi high right now). Our own cold might be allowed to stagnate right over us. I can recall many times in the 1960s and 1970s when we drew in a south-easterly off a cold continent and these conditions persisted for a long while. With near record cold over southern Europe we could actual maintain pretty cold conditions even on a more southerly flow with the winds coming in on a south-south-easterly having  crossed a quite icy France (within a week or so). I appreciate that it can only take a very small veering of the flow to pull in some much milder air from a more tropical source.

As I said earlier, this type of pattern can also produce a prolonged period where we are in the centre of the battle zone. Between the cold to our east and the mild and wet conditions to our west. Here, the east can remain cold or very cold while the west can often be on the mild side (not so good for me down here in Exmouth or our friends over in Ireland). Some of our greatest blizzards have developed in southern England on the narrow margin between the two when we have seen undercutting where mild air is unable to penetrate the cold block and rides over it producing some very heavy snowfall. The blizzards are quite rare events but more localised decent snowfalls are much more frequent (or used to be).  

So far, I haven’t mentioned the possibility of us seeing a proper easterly set itself up and drawing in some of the extremely cold air. The ECM has consistently hinted at this evolution towards the end of a number of runs. Mostly recently (on the 0z) just failing to achieve this. Some of its own as well as other models’ ensemble members still lead us to an easterly flow. So, this cannot be discounted even if the probabilities are still quite low. The longer the cold block remains close enough to us, the greater the opportunity for this type of evolution.

There are also one or two other more positive hints for coldies. There are signs of the MJO at last coming to life and as the likes of @Singularity and @nick sussex tell us, if this cycle gets us into the important phases (7,8 or 1) at the right time, then this should assist in favouring or enhancing greater HLB.

I’m not going for scenario four, which is probably rather more in the way of wishful thinking. In this unusual Winter none of the four can be ruled out with the second and third scenarios much more probable than the two extremes. Why can't that anomalous area of high pressure set up and stick around in a much more favourable position? I am going to write a warning to myself to stop the ramping and to manage my own expectations! The message is that there is plenty of potential and a lot of exciting model watching ahead. Compare all this to what we saw for much of last Winter. Now you can all criticise me!

Update 1 at 1630: Whilst writing this report, I just had a quick look at the 12z. GFS, which was looking to be going for scenario (i) but ends up closer to scenario (ii). UKMO looks much more like scenario (ii) but only out T+144. Both could still hang on to enough surface cold to get closer to scenario (iii) but a less cold interlude is indicated. I’m not excepting any model to go all out for scenario (iv), at least not at this stage.  It is best to expect more quite large swings. It’s looking like FI was yesterday!.  

Update 2 at 1830: Several more ensemble members and the GEFS mean suggesting a possible easterly. It would be highly ironic if the deep cold pool was displaced a lot further east before the pattern develops. It might still, however, bring back the cold westwards if it becomes a persistent new pattern.

Update 3 at 1900: Gosh, I was wrong – the ECM12z has chosen my scenario iv. Even though I allowed myself some bullishness, I did not expect this type of evolution to show this far out but they have been pretty consistent. This is their patch, ie: home territory – does this give them an unfair advantage? So at least you can blame them if it doesn’t verify! Who will be right?

Dr Judah Cohen’s Latest Arctic Oscillation Report:

As I said earlier, this will now appear in part 2 of my report, probably around 2300. Now I move on to my regular features.

Arctic Sea Ice News and Analysis:

The latest full monthly report was published on January 5th. This is a fascinating read and includes a review of the whole of 2016. Please note that the current ice extent map and the comparison chart to the mean are updated daily and are always of interest. Here’s the link for the latest updates:

http://nsidc.org/arcticseaicenews/

This chart shows the current extent of the sea ice (as on January 8th) in relation to 30 year means.

There are two extraordinary points to make here. The “rate of recovery” during December was very close to a record but despite this the overall ice extent is still at record lows and remains just below the previous low set during Winter 2012-13. Perhaps this is not so extraordinary, as there was highly likely to be a strong recovery from such a low base during November. I have been speculating during the last few weeks as to when (and if) 2016-17 will finally overtake 2012-13. I thought that it might have occurred by now but with temperatures up there much lower now than this time last January we should see a further rapid increase and may be we’ll be there by next week.

Arctic Oscillation (AO) 14 Day Ensemble Charts (updated January 9th): 

The Arctic Oscillation, which is moving from positive to neutral or slightly negative this week goes mostly positive again during week 2 but with a few ensemble members remaining negative and trending down at the end.

CAUTION:  this is in line with the current GFS model output (probably today’s 12z) but is liable to further fluctuations in line with changes in that model’s output. It does not reflect any decisive swing to greater HLB but does paint a very uncertain outlook. Here’s is the link for future reference:

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao_index_ensm.shtml

...and here’s the current chart:

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/ao.sprd2.gif

North Atlantic Oscillation (NAO) 14 Day Ensemble Charts (updated January 9th):

The NAO is also mixed and rather uncertain, trending from positive towards neutral with some members going negative next week. This trend may be slightly reflective of GFS modelling higher pressure a little further north than usual (in our vicinity).

Both the AO and NAO reflect the very mixed GFS output. Here’s the NAO link:

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao.sprd2.gif

...and here’s the current chart:

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao.sprd2.gif

Please note that both the AO and NAO charts I show are based on GFS ensembles so are indicative of their modelling and not the ECM and UKMO output.

MJO Ensemble charts:

Here are today's MJO ensemble charts for the big 4 (all updated on January 9rd) with the live links below should you wish to check any future changes (hope they work properly!). 

UKMO (7 day forecast): 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/UKME_phase_23m_full.gif

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ukme.shtml

ECM (14 day forecast): 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ECMF_phase_MANOM_51m_full.gif

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ecmm.shtml

NCEP/GEFS (14 day forecast):

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/NCPE_phase_21m_full.gif

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/ncpe.shtml

JMA (9 day forecast):  

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/JMAN_phase_51m_full.gif

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/jman.shtml

Please note that last Winter I reported on Kyle MacRitchie’s specialist MJO predictions which seemed to always differ somewhat from the big 4. I have been in contact with Kyle during the summer and he feels that his charts are not adjusted frequently enough and should not be compared to the others. So, unless Kyle improves his updating standards, I shall discontinue reporting on his predictions for the time being (given the current uncertainties I may have a closer look again shortly and report back later or in next week’s report).

COMMENT:  A rather mixed picture yet again but slightly more encouraging signs with all 4 models bringing the MJO to life again. The UKMO with it's shorter forecasting period moves through the COD and points towards a later emergence into phase 8 or 1. The ECM just breaks into phase 1 with a few ensemble members suggesting slightly increased amplitude. The GEFS goes more strongly into phase 1 but almost overshoots into phase 2. The JMA currently shows the best outcome moving more directly into phase 8, close to the phase 1 boundary at good amplitude.  We need this general  trend to continue and for stronger amplification in the important phase 7, 8 and 1 to help assist with some greater HLB. This is definitely one to watch. These charts will probably automatically update daily around 1600 (if not, then please use the link which I also provide).

Northern Hemisphere Snow Cover:

I show animations for snow cover and sea ice changes. These are produced by the National Ocean and Atmospheric Administration (NOAA).  When you go to their site you can change the date range and go back over 10 years. You can change the speed and pause on any particular day. These are brilliant, very informative charts and great to play around with. I’ve have re-set the links below to show the last 2 weeks from December 26th  to January 8th but you can change these again:

a) Animated Northern Hemisphere Snow Cover Changes (updated by NOAA January 9th):

https://www.ncdc.noaa.gov/snow-and-ice/snow-cover/nh/20161226-20170108

I’m not sure if this will work but I have tried to freeze the most recent chart.

http://www.natice.noaa.gov/pub/ims/ims_v3/ims_gif/ARCHIVE/NHem/2017/ims2017008.gif

b) Animated Europe and Asia Day Snow Cover  (updated by NOAA January 9th):

https://www.ncdc.noaa.gov/snow-and-ice/snow-cover/ea/20161226-20170108

As above, I hope this shows the most recent chart

http://www.natice.noaa.gov/pub/ims/ims_v3/ims_gif/ARCHIVE/EuAsia/2017/ims2017008_asiaeurope.gi

BRIEF COMMENT: 

Just look at the rapid build-up of European snow cover during the last few days and the renewed rapid growth in the Arctic sea ice extent. There continues to be well above average snow cover over northern Asia and this has continued to expand southwards and south-westwards. Scandinavia is once again fully snow covered, including the south (the high central plateaus usually have pretty complete snow cover for most of an average Winter).

Current Arctic Regional Surface Temperatures:

GFS – Northern Hemisphere Current Temperatures for January 9rd 1900 (12z – 1300 T+6):

http://modeles.meteociel.fr/modeles/gfs/run/gfsnh-9-6.png?12

and here’s the link to live charts if you wish to view future changes (updated 4 times a day):

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=6&mode=9&carte=1

North Pole:  -24c to -28c (little change).

Barents Sea/High Arctic:  -4c to -24c (-4c to -12c).

Scandinavia: south -4c to -8c (-4c to -12c; north -12c to -16c (-20c to -24c).

Northern Siberia: -28c to -40c and below (-32c to -40c and below).

North West Russia:  -20c to -32c (-24c to -32c)

North-east Europe: -8c to -20c (-4c to -12c).

Greenland: -20c to -40c and below (-16c to -40c)

Canadian Arctic: mostly -12c to -40c (mostly -12c to -28c).

Alaska: -8c to -20c (-4c to -12c).

Please note:  For land masses I have tried to focus on readings away from the coasts and away from any mountainous areas.   You can follow the trends by looking at the latest data at any time from now on. It is vital to note the time of day to take account of daytime/night time variations. So for like for like comparisons, for example the 1900 charts for each day should be available to view from the 12z (T+6) updates which are published around 1600 to 1700 or about 4 to 5 hours later.

Svalbard Daily “Maximum” Temperature Forecast for 10 Days:

Here are the links to the 3 Svalbard stations that I am monitoring.

Central/West Svalbard – Longyearbyen 28 m asl:   

http://www.yr.no/place/Norway/Svalbard/Longyearbyen/forecast.pdf

January 10th   -12c;    January 14th  -9c;       January 18th  -6c.

North-West Svalbard – Ny-Alesund:  

http://www.yr.no/place/Norway/Svalbard/Ny-Ålesund/forecast.pdf

January 10th   -12c;    January 14th  -12c;       January 18th  -8c.

Central South Svalbard – Sveagruva:   

http://www.yr.no/place/Norway/Svalbard/Sveagruva/forecast.pdf

January 10th   -19c;    January 14th  -16c;       January 18th  -11c.

Please note that the links above will update automatically at frequent intervals throughout the day. They are the Norway met office’s predictions. We need to be aware that these are only a forecast that is subject to change and I am told that the Arctic surface temperature forecasts are not completely reliable even at quite short range. 

BRIEF COMMENT:

Special Note: These Arctic surface temperatures are at their lowest at the ideal time around Wednesday, January 11th to Saturday, January 15th just when we will be locking into to that Arctic airstream. A real bit of good luck for a change! So, I’ve done my bit, who’s going to get those 850s below -8c across the whole country on Thursday and Friday. This may give us a slightly higher chance of snow rather than rain or sleet in lowland areas further south given any favourable but marginal synoptics.

To put the above figures into context, here is a link to the main Longyearbyen site:  

http://www.yr.no/place/Norway/Svalbard/Longyearbyen/statistics.html

This shows monthly means and actual highest/lowest temperatures recorded during this winter and goes back further. Svalbard has been seeing “maximum” temperatures often running at 8c to 10c above their long term average throughout most of 2016. This has been the pattern for several years and is reflective of the warming Arctic and record low sea ice cover. The very recent trend has been slightly more encouraging with temperatures falling to slightly below their long term averages for 4 days in early December  which is the longest period of below average temperatures for about 3 years! Then maximum temperatures rose to around zero over Christmas and have trended somewhat lower again since then.

Final Comment:

What more can I add. Uncertainty – yes; a very exciting period for model watching – yes; is there cold and snow around – yes; will we have a prolonged cold spell – who knows!

Next Update:

Part 2 of this report with Judah Cohen’s latest update should be posted around 2330 this evening.

My next weekly report should be on Monday evening, January 16th.

 

 

Edited January 10, 2017 by Guest
Correcting typos and to ensure that all the links and charts work properly.

[mpkio2]

Once more, hello peeps!

Well, well, well! What ever has occured over the last six days since I posted?

Verification time!!!! In my last post I said that all four models (GFS/ECM/UKMO/GEM) were all in agreement with seeing this type of NWP:

Posted by mpkio2 3rd January 2017:

"2. However, if the high sticks around the top of us and collapses south, an evolution which is predicted through all the models, with cross-model agreement, will most probably occur:

06z GFS t120:

All models singing from the same hymm sheet there! Very good cross-model agreement . Positives to take? Well, the PV is centered, but not the "Monst-ball-like-monster", and appears to be being pulled at different parts around the world - especially down the Pacific Ocean, North Pacific Ocean and Europe. With Low heaights around Europe, this enables for any HLB to establish to be cut off, support it and to (Hopefully!!!!) allow for an easterly for the UK further down the line. . Don't take my word for it though!!!!"

(I didn't post all charts from models).

And this is where we stand now:

12z GFS t0:

Very happy with how the modles panned out with that!!  Theres a lesson here to learn for all old and new on here; if all models don't have cross-model agreement, nothing is pinned down!!!! Looking for potential (As many of us do - as do I!!), is all fine and dandy, but is never guaranted for anything really. Just take everything else for fun! (And hope you preffered weather pattern comes to pass!! )

So, what is to come?

Erm....the cold from the NW! and it looks strong!!!

All modles show a Low pressure system coming off the Atlantic and falling down to the East of the UK with a small mid-Atlantic block allowing a cold NW/N flow.

Congrats guys!! We've got our first cold spell down to t48!!!  I thought I would never see the day this Winter!!!!

What isn't nailed down, however, is the finer details and what occurs after the initial NW flow. All modles showing something different with various outcomes atm.

But whats that you say? Theres one model thats being consistant?!

A potential cold spell being predicted by a consistant ECM, with some support from UKMO?

What, no way!!!!

12z ECM t144 6th Jan 2017:

12z ECM t144 7th Jan 2017:

12z ECM t144 8th Jan 2017:

OK, despite the little hick-up from yesterday (I think the ECM was on some post-Christmas wine ), ECM has been perfoming very consistently with its Easterly trend - Easterly predicted to take shape around 15th - 17th Jan as Atlantic high nudges NE to Scandy.

How about UKMO:

12z UKMO t144 (Today):

Well not as amplified as ECM, but the trend is there.

GFS, well its a mess, but, as many have been commenting, its improving with each run...

12z GFS t168 (Today):

Funny enough, the GEFS Controll sees amplification towards Scandy around the same period....

12z GEFS Control t168:

Meanwhile JMA and GEM see the trend but don't wanna follow all the way...

12z GEM t168:

12z JMA t168:

So, to conclude: It seems the models are seeing the height rises, even if they don't go on to develop a true Scandy high - they at least see the trend from the ECM and GEFS (Wasn't it the GEFS that initially picked up this trend to begin with? ). Some have too much strenght in the northern jet which disallows any proper amplification. Whats most important is that they SEE it which, of course, does'nt give us any clue to what will verify and whether a true Scandy high will develop. But its a start I guess!

Funny how I mentioned a few days ago......"With Low heaights around Europe, this enables for any HLB to establish to be cut off, support it and to (Hopefully!!!!) allow for an easterly for the UK further down the line. . Don't take my word for it though!!!!" And now the modles are starting to show this exact pattern!!!  Perhaps the weather Gods are actually listening to our prayers this season! Hey I can wish, can't I?

Anyway, Met Office putting out those Early Weather Warnings and the papers have already started printing their "Snowmegedon" articles!

No-one knows what will happen, but things are looking up. I'm very optimistic, and what ever we get, I'm gonna enjoy it, no matter how short or long this cold spell will last!!

~mpkio2~

Edited January 9, 2017 by mpkio2

[phil nw.]

A switch in the 12zGEFs clusters towards a high further north at t180 compared to yesterday's bunch

http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&CONT=euro&MODELL=gefs&MODELLTYP=2&VAR=cslp&WMO=&ZOOM=0&RES=0&PERIOD=&PANEL=0&ARCHIV=0&BASE=201701091200%26HH%3D180

click on the day/run to compare.

Also the clusters are all now modeling an area of low pressure around Italy/E.Med which wasn't there yesterday(Genoa Low,Nick S?).So a nod towards the ecm model with a better aligned high but not yet far enough north for an easterly-still it's all about trends.

Edited January 9, 2017 by phil nw.
corrected spelling-again

[Methuselah]

I can see only three alternative scenarios: Either that shortwave simply drifts east and makes no impact on next-week's mild dross, or it deepens enough to drag in an ENE'erly in off the nearby Continent; the third, of course, is a more painful/gradual slide into WSW'erly dross...?

Ye can take yer pick, really...It'll make not a ha'peth of difference!

[chris55]

7 minutes ago, Ed Stone said:

I can see only three alternative scenarios: Either that shortwave simply drifts east and makes no impact on next-week's mild dross, or it deepens enough to drag in an ENE'erly in off the nearby Continent; the third, of course, is a more painful/gradual slide into WSW'erly dross...?

Ye can take yer pick, really...It'll make not a ha'peth of difference!

Or it gets entangled in the Newfoundland Low and helps to build the scandi high in the longer term?

Edited January 9, 2017 by chris55

[snowice]

24 minutes ago, nick sussex said:

My obsession with shortwaves is well known in here! I've always viewed outputs with potential for cold from an expectation of problems and margin for error which is probably a good thing because of our terrible luck at getting any to verify. Rest assured that I won't be giving the green light until I'm certain or as much as one can be that its all systems go!

How long can the drama go on for 72hrs to go? It can't go further than the ooz can it

[Ali1977]

On 09/01/2017 at 20:10, snowice said:

How long can the drama go on for 72hrs to go? It can't go further than the ooz can it

If the EPS support the ECM Op I think the  pub run will bring in the goods, and head towards the ECM.