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


Paul

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Posted
  • Location: Windermere 120m asl
  • Location: Windermere 120m asl

Reliable timeframe, a milder spell as high pressure sinks into central europe throwing up an increasingly milder southerly flow, nothing expectional for mid February, but come middle of the week it will feel very pleasant I imagine for most, especially where any sun shines - as the sun begins to gain a bit more strength at this stage in the year.

Longer term, noting GFS this morning, perhaps a signal of projected impact of the Sudden strat warming end of Jan which typically takes about 3 weeks to have an effect (i.e. around next weekend), signs the atlantic may waken up somewhat with a more mobile flow, but importantly deeper trough /low pressure systems anchoring down through scandi as there is a shift in the position of the PV, azore high nosing NE for a time, but perhaps being forced to backtrack and head NW, hence a northerly episode to end Feb looks very plausible to me, indeed northerlies at the end of Feb/early March have been a common feature many occasion last 25 years, a winter bookended by colder spells (late Nov into start of winter), late Feb into March was what happened in winter 05/06, not saying this will happen, but just a hunch it will this time. 

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Posted
  • Location: Castle Black, the Wall, the North
  • Weather Preferences: Spanish Plumes, Blizzards, Severe Frosts :-)
  • Location: Castle Black, the Wall, the North
8 minutes ago, shane303 said:

Shame the forecast is for plenty of cloud then 

It will feel like spring has sprung later next week if the Gfs 6z is correct with increasing amounts of sunshine from the south and light winds from a southerly point..very pleasant for the snow..drops:D

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06_153_ukcloud.png

06_153_uk2mtmp.png

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th.jpg

Edited by Frosty.
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Posted
  • Location: SE Oxfordshire
  • Weather Preferences: Any extremes
  • Location: SE Oxfordshire
5 hours ago, snowsummer said:

What is this 'VP200' please?  

I think it is 200hPa velocity potential anomalies.

WTF that is, I don't know. If someone out there can please explain... :unknw:

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DAILY EUROPEAN TEMPERATURE AND PRESSURE CHECK No. 8 - ONE OFF BUMPER EDITION INCLUDING DEW POINTS AND NORTH-WEST FRANCE FOCUS 

THE COLD IS MORE MARGINAL THAN ORIGINALLY EXPECTED BUT IT IS NOT ALL BAD NEWS

In the build up to and during our 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 several more days around 0800 - although I was away on a business trip from Thursday (so no report Friday) and just got back at 1100 today until Saturday (so this one is around 1400. We can see how the pattern is evolving and monitor the extent and the severity (or lack of it) of the cold.

Firstly, when I drove back from Warwick to Exmouth this morning there was almost continuous very light snow (with patchy settling). This is not the thread to expand on this - so for those interested, at 1215, I added a post to Tamara's "single status report" that she started yesterday. I also congratulate NetWeather on their latest radar, which seems to be much more accurate for differentiating snow (pink) and rain/sleet/snow (green). Whilst driving back, I thought that we should have a closer look at the dew points and the temperatures in north-west France which might be crucial in dictating which side of the two "marginality" thresholds we might sit on in respect of snow (rather than less wintry precipitation) and whether any snow settles. I will not have the time to do this every morning but it's really important right now.

Now, I shall pick up from my last “check” (on page 10 of this thread). This took us to February 8th.

European Surface Temperature Charts:

               "Current "live"                                  Feb 11th 0650                                  Feb 10th    1250                                  Feb 9th  0650                                   Feb 8th 1250

temp_eur2.png  temp_eur2-06.png  temp_eur2-12.png  temp_eur2-06.png  temp_eur2-12.png

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:  Well isn't this just so very frustrating! The cold block has now extended all the away to western Europe and most of the UK and Ireland but at the expense of the deep cold. As I said in my last two daily updates (on Wednesday and Thursday) there is one unwelcome intrusion. A wedge of less cold air is located between eastern Scandinavia and the coastal part of north-west Russia. This air travelled around the top of the HP and pushed southwards on its eastern flank. As it comes off a relatively warm sea it has effectively divided the block and prevented the really deep cold from spreading further west. Now that the HP has moved very marginally southwards (not nearly as far as predicted - see below) you can the gap closing again. Will this be a little too late or might we see a new westward progression by tomorrow? The sub -8c and sub -4c temps have moved further west across into central Europe. Looking at the current pattern, there is a good chance that these might move even further west during the next two days - that'll make the short-term forecasts more interesting. 

All this can be seen by comparing the two "0650" and the two "1250" charts.

European Surface Dew Point Charts:

                "Current "live"                                   Feb 11th 0650                                 Feb 10th    1250                                 Feb 9th  0650                                   Feb 8th 1250

 pointrosee_eur2.png  pointrosee_eur2-06.png  pointrosee_eur2-12.png  pointrosee_eur2-06.png  pointrosee_eur2-12.png

COMMENT:  Given how marginal conditions are for snow in lowland UK, I am including some dew point charts for the first time. The European charts above for dew point temperatures show a similar pattern and progression to the surface temperatures. The sub -4c and sub -8c dew points were at their most extensive and further west on this morning's 0650 chart. The critical sub 0c temps cover most of France and some of the UK. I also show the current "live" and the 0650 charts for UK surface temps and dew points below. The dew points are not quite as low as yesterday morning but are generally between -1c and +1c. There are some lower values just across the Channel. If the winds do veer more easterly from north-easterly later today (as predicted first thing this morning - I haven't checked the latest forecast for those fine details) then the south-east will immediately benefit from lower surface temps and lower dew points - these may then spread across most of southern England.  More on this below.

UK Surface Temperature Charts:                                                                              UK Surface Dew Points Charts:                                                      

              "Current "live"                                        Feb 11th 0650                                              "Current "live"                                Feb 11th 0650   

temp_uk.png        temp_uk-06.png            pointrosee_uk.png  pointrosee_uk-06.png

GFS  0z February 11th T+6 European Charts: 

            2m Surface Temps                                  850 Temps                                      500 hPa Temps

gfseu-9-6.png   gfseu-1-6.png   gfseu-13-6.png

COMMENT:   Compare today's charts (above) with yesterday's  (below).  Note that the "purple shades" area of sub -20c surface temps (and lower temps) remains towards the north-east of the block. The area of sub -4c and sub -8c temps over Europe has changed little (finer detail described above).

The 850s are a little more interesting and slightly better news ("if" the pattern persists). The pool of sub -20c temps in the north-east has intensified again with a wider area below -24c and even some sub -28c and sub -32c temps appearing . The area of sub -16c temps has also expanded. The sub -12c temps are little changed in the main pool but have weakened slightly in the breakaway pool over Scandinavia and Denmark. There is still a good area of sub -8c and particularly sub -4c temps in our vicinity. These have pushed southwards through Ireland.

GFS 0z February 10th T+6 European Charts: 

           2m Surface Temps                                   850 Temps                                   500 hPa Temps

gfseu-9-6.png   gfseu-1-6.png  gfseu-13-6.png 

  Focus On North-West France (+ links to forecast charts):

  Current "Live" Surface Temps                0650 Surface Temps                       Hourly Forecast Precipitation                                         Hourly Forecast Surface Temps

                                                                                                                   http://www.meteociel.fr/modeles/arome.php    http://www.meteociel.fr/modeles/arome.php?ech=3&mode=141&map=0             

temp.png  temp-06.png         aromehd-1-1-0.png?11-11                                      aromehd-41-3-0.png?11-11

COMMENT:  I feel that right now we need to focus on the conditions over north-west France as this will directly impact on our short-term changes. I show the current and 0650 surface temps over France (which includes much of England and Wales as well). The surface and dew point temperatures are generally slightly lower in north-west France compared to those over most of England. A veer in the winds to the east will import these across to us. The last two charts are short-term forecast for precipitation and temperatures. I still haven't mastered the techniques to copy across the charts with the 1 hour time change scroll down features. So I show the two recent charts + links to the full "scrollable" charts. I had a look at these yesterday when I was away and I noted that the forecast is for slightly lower temps today. This is good news for tonight and tomorrow (if we get the more direct easterly). More importantly and just confirmed to me by @Nouska (thank you) the large temperature rises forecast for central and northern France have been very much downgraded and delayed. This is where the charts (for most of the models) have been showing the winds veering into the south by Monday. I felt that this was not only far too progressive but also there would still be plenty of surface cold to shift. I still think that there is a possibility of the milder air climbing over the cold surface air (which could possibly produce further snowfall) but would also further delay any warm up.

European Surface Pressure Charts:

                Current "live”                                   Feb 11th 0650                                  Feb 10th    1850                                Feb 10th  0650                                Feb 9th    1850  

pression2_eur2.png  pression2_eur2-06.png  pression2_eur2-18.png  pression2_eur2-06.png  pression2_eur2-18.png                            

    Current Met Office Fax: 0600 Feb 11th        GFS 0z February 11th T+6             GFS 0z February 10th T+6   

       20170211.0659.PPVA89.png     gfseu-0-6.png    gfseu-0-6.png                                  

COMMENT: Yet again, more good news. The HP has only lost a little of its intensity (just 7 mb in 48 hours) and has only moved slightly south-eastwards - far less than predicted by the models only two days ago. it still has that annoying south or south-east ridge (that allowed the north to south flow on its eastern flank that brought in the milder sea air to the east of Scandinavia) but this is far less pronounced now = good news for reducing the amount it holds back the deeper cold to the east. Even better news (perhaps) is the ridge building westwards to the north of Scotland with even signs of a separate cell of HP emerging there. We have lost the Italian LP although lower heights remain across much of the Mediterranean. There is a wedge of LP across central and northern France. It is this that will be critical in determining how long the cold lasts into next week. It may hold up the veer of winds to the south or we may see a more south-easterly flow still import the cold air from central Europe. We might even maintain the easterly. A truly fascinating pattern that needs to be watched very closely. 

Looking further ahead, I see that we have a real impasse with the models in disagreement beyond D6. I think that they will struggle with D2 to D5 as well! No more on this now but I will pick up on it in my weekly report tomorrow evening and look at the Jet Stream and broader pattern changes as well.

Overall, the news is definitely not nearly as bad as some might have been expecting. Can we get some more snow in the next day or so? Will we loose the cold quickly, slowly or not at all? Will we still get the phase 2 cold spell later this month. Keep watching.

I will do a briefer update tomorrow morning.

 

Edited by Guest
Correcting typos and to ensure that all the links and charts work properly.
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Posted
  • Location: South Petherton 41 metres (134 feet)
  • Location: South Petherton 41 metres (134 feet)

It may be milder by Tuesday yes and looks good on the models but it won't be spring like in realty it will be mostly cloudy with rain developing from the west / south west from Wednesday and hill fog too. 

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Posted
  • Location: New Forest (Western)
  • Weather Preferences: Fascinated by extreme weather. Despise drizzle.
  • Location: New Forest (Western)

gfseu-0-120.png?12 UE120-21.GIF?11-17

A vast difference between GFS (left) and UKMO (right) with respect to how the lows in the N. Atlantic and E. Canada are behaving on day 5.

The standoff continues, with the GFS version screaming of southwesterly flows heading our way while UKMO looks more inclined to offer the chance of a mid-Atlantic ridge, but only if the eastern of the two lows can escape cleanly east. As has been said so very often lately - the extent to which the current kick in GLAAM can amplify the upstream pattern will be the deciding factor.

UE144-21.GIF?11-17

Turns out UKMO looks close but not quite sufficient for the mid-Atlantic high, though it seems the one over us could stick around or even grow stronger should the ridge from the Azores merge with it having bridged across to the north of the low dropping down by Iberia. Possibly the overall position for the weekend would be a bit west of what we see from this model for Friday - so a cool, dry weekend with overnight frosts. Just have to ignore the Go For Storms model.

Speaking of which, even as that seemingly unavoidable major blocking signal begins to take shape for the late days of the month, the model still finds a way to hammer at us;

gfseu-0-372.png?12

Looking a few days earlier, it's not hard to imagine what should have happened instead;

gfseu-0-288.png?12

- though the sheer scale of that vortex over Scandinavia is in part a result of its zonal enthusiasm before hand piling unstable air into the region, so something that dramatic seems a bit over the top.

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Posted
  • Location: Castle Black, the Wall, the North
  • Weather Preferences: Spanish Plumes, Blizzards, Severe Frosts :-)
  • Location: Castle Black, the Wall, the North

Much milder more benign spell on the way from the Gfs 12z from next midweek with temps into low double digits celsius and as high as 13c in the south as time goes on..feeling very pleasant in the late winter sunshine..actually feeling like early spring.:)

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ukmaxtemp (2).png

h500slp (1).png

ukmaxtemp (3).png

ukmaxtemp (4).png

h500slp (2).png

Edited by Frosty.
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Posted
  • Location: Castle Black, the Wall, the North
  • Weather Preferences: Spanish Plumes, Blizzards, Severe Frosts :-)
  • Location: Castle Black, the Wall, the North

A bit of a flutter of interest for coldies in deep low res on the Gfs 12z but even that fails for most of the uk as per usual..the outlook is becoming milder with high pressure generally close to or over the south with most if the wind and rain across the northwest of the uk.

hgt500-1000.png

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Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington

ens again going for a colder end to winter

gefsens850London0.png

Less cold from Tuesday till around the 22nd before anything colder you know the cold that looks great then waters down nearer the time

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Posted
  • Location: Cambridge, UK
  • Weather Preferences: Summer > Spring > Winter > Autumn :-)
  • Location: Cambridge, UK

Very quiet in here....I wonder why!

 

the ensembles show that after the 17th they haven't got a clue. Massive variance, so trying to spot a trend is very difficult.

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Posted
  • Location: Castle Black, the Wall, the North
  • Weather Preferences: Spanish Plumes, Blizzards, Severe Frosts :-)
  • Location: Castle Black, the Wall, the North
28 minutes ago, Summer Sun said:

 you know the cold that looks great then waters down nearer the time

Par for the course in a British winter these days Gavin:D Anyway, turning much milder during the week ahead and feeling spring like from midweek.

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Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington

ECM shows the high sinking a bit further south at times later on but we remain on the mild side

Recm1922.thumb.gif.fa9c86bd740dbb2dc263b91ca3c4ad78.gifRecm2162.thumb.gif.c4c70a3c9564016e9ee5be7f8bb352b5.gifRecm2402.thumb.gif.a4de138e7678a9b995532491b23981d0.gif

Plenty of dry weather developing from Monday and dare I say it feeling spring like by mid week in any sunshine

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Posted
  • Location: portsmouth uk
  • Weather Preferences: extremes
  • Location: portsmouth uk
33 minutes ago, Matthew Wilson said:

Support from UKMO and ECM for HP to be in charge on Friday. Then sinks south according to the ECM for Saturday

IMG_0985.PNG

IMG_0986.PNG

IMG_0988.PNG

That's not a bad chart vortex dropping down into Scandinavia ridge aim north north west.

Although I wait for few days or more to see whether it gets any closer to a block.

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Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington

A D9 ECM showed a southerly

ECU1-216.GIF?06-0

Looks now like it will be a south westerly

ECU1-96.GIF?11-0

Good effort from ECM at such a long range it was the 1st to pick up on the change to something milder and it was right

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Posted
  • Location: New Forest (Western)
  • Weather Preferences: Fascinated by extreme weather. Despise drizzle.
  • Location: New Forest (Western)

Phone's not letting me link to it but Fergie has tweeted that the models may be lagging in response to phase 8 MJO. With that in mind I still see next weekend as a good opportunity for at least a cold snap. Failing that, the following week should offer interesting opportunities - or increasingly frustrating if you live in the far south for example where lying snow is as rare as hens teeth by late Feb/early March.

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Posted
  • Location: Bishop Auckland, Durham NE
  • Location: Bishop Auckland, Durham NE

gfs-0-384.png?12

 

Something like this is what im after as want there to be a load of snow up in the scottish highlands for skiing

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Posted
  • Location: Darlington
  • Weather Preferences: Warm dry summers
  • Location: Darlington
3 minutes ago, Singularity said:

Phone's not letting me link to it but Fergie has tweeted that the models may be lagging in response to phase 8 MJO. With that in mind I still see next weekend as a good opportunity for at least a cold snap. Failing that, the following week should offer interesting opportunities - or increasingly frustrating if you live in the far south for example where lying snow is as rare as hens teeth by late Feb/early March.

 

This one?

 

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Posted
  • Location: Wildwood, Stafford 104m asl
  • Weather Preferences: obviously snow!
  • Location: Wildwood, Stafford 104m asl

yes, quite a decent ECM for those wanting dry weather, just hope there will be a bit of sun, temps could feel springlike,

ECM1-144.GIF?11-0

Edited by I remember Atlantic 252
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Posted
  • Location: Camborne
  • Location: Camborne

The anomalies have been looking at a pattern change for a few days now without settling on a definitive conclusion. having said that in the 5-10 day period they are well within the same ball park.

All indicating the vortex near Franz Joseph Land with trough Alaska and eastern Pacific. A ridge north central America with a further trough in the western Atlantic Simultaneously the high pressure to the east weakens and the Azores ridges in the eastern Atlantic leading to an upper flow from the westerly quadrant. There is still some disagreement on how the influence of the HP vis the UK will pan out as the EPS makes more of the vortex/trough over Scandinavia than the GEFs.

So whilst acceptingthat  the detail still needs to be sorted the percentage play is certainly for temps to rise certainly to average, possibly above, and much of England remaining dry with any fronts and rain being pushed NE so only effecting the west and north

ecm_eps_z500a_5d_nh_11.thumb.png.39ee5ca9f3bd82640f6e386e1d3ff4ef.pnggefs_z500a_5d_nh_39.thumb.png.8ad9a118eeb191ff2b19fe764c042a29.png610day_03.thumb.gif.cedb4ce19154fc604038c1c75253a40d.gif

In the 10-15 period although the vortex remains in the Franz Joseph/Svalbard area there are changes upstream. albeit not massive agreement on the detail. There is now a lobe of the vortex over N/.Canada/Greenland and a ridge GOA.with a flat flow across America and the Atlantic In these circumstances we are looking at the proverbial N/S split with temps around average but I suspect this needs to be treated with caution.

 

814day.03.gifgefs_z500a_5d_nh_59.thumb.png.c1f92c787616ea92a6ce2fd75dbf79c4.png

Edited by knocker
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Posted
  • Location: Bishop Auckland, Durham NE
  • Location: Bishop Auckland, Durham NE

GFS looks to be sticking to its guns so far up until 096hrs

12z

gfs-0-96.png?12?18

 

 

18z

gfs-0-90.png?18?18

The cold pool in the atlantic looks to be getting bigger/more intense though

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