Model Output Discussion

[andymusic]

So do you think that even though this winter was the coldest since 1978/79 (I think), we where very close to even exceeding that winter and recording the coldest and snowiest winter since 1963 and 1947 (or even rivaling them?)? What do you think the main reasons are for not achieving a winter rivaling those historic winters of the 20th century? Is it the lack of a prolonged potent easterly spell?

At least we can say that this winter was the coldest of the 21st century so far the UK and Northern/NW Europe, do you think that we could get a winter in our lifetimes that could event beat this one and be on a par with the above? Certainly I do think we will get a 1947 par winter in our lifetimes and it will also be pretty safe to assume we will get a 1976 type summer in our lifetimes too possibly even before 2020.

Anyway how cold can March be? Is it theoretically possible for March to be as cold as December? As in my area one of the largest snowfalls of the last decade came in March and I think that most Marches over the last 10 years or so have seen some snow events with significant falls in some areas so I would be extremely surprised if we do not get at least one snow event this March. I think that some meteorologists define the first half as March as winter is that true especially in North America where severe snowfall and ice days are possible well into March and even April?

Luke

A number of long term forecasters are saying that we are entering a period of earth's cooling (cyclical) - so far from this winter being a one off event for us to wait another 20 years for it to happen again - there is evidence that over the next couple of decades this sort of winter may well become the norm - one of the influences being a downward trend in solar activity over this period.

So - Watch this space

[TEITS]

Trouble is we have seen quite a few extremly bitter Easterlies at the t+144 time-range which have never materilised or have just missed us this winter.The credibility off all weather models beyond t+144 is so poor is best to ignore them.

I think despite this being a cold winter,i still think we have missed out on an exceptionally cold- winter,by just missing out on the extremly cold air out to the N AND E ,apart from mid Dec,and again the early part of Jan.

Close,but still a frustating Winter in my book,and i dont think the models have performed very well either

I agree with everything you say.

Some will disagree but despite this being an excellent winter the synoptics and the actual weather still don't compare to what I experienced in the late 70s/80s. What we have seen from the models is E,lys downgrading in both strength and length. The only exception was the Dec E,ly when the models upgraded this within +72. So for this reason I shall remain cautious until +72.

Looking at the GEFS mean for my location and it currently stands at -10C. If the GFS Ops continue with this trend then the mean will probably end up around -12/13C. The GEFS precip ensembles are rather dry but I wouldn't expect them to predict much convection due to the timeframe and resolution. However in saying this the further S you are the better due to being farther away from the HP and being closer to the LP. The wind chill factor continues to alarm me. A sustained wind speed of 30mph with max temps around 0C would make temps feel around -10C!!

[Thundery wintry showers]

I'm not sure I totally agree there- if the low is too strong it will keep feeding in milder air from the SE, which in an easterly regime would keep southern areas in particular dull, damp and moderately cold. There's a tradeoff between having the low strong enough to stop the high sinking and weak enough to stop the warmer air feeding in from the SE.

It will also help if the low is further east like on the ECM.

[Jason T]

I agree with everything you say.

Some will disagree but despite this being an excellent winter the synoptics and the actual weather still don't compare to what I experienced in the late 70s/80s. What we have seen from the models is E,lys downgrading in both strength and length. The only exception was the Dec E,ly when the models upgraded this within +72. So for this reason I shall remain cautious until +72.

Looking at the GEFS mean for my location and it currently stands at -10C. If the GFS Ops continue with this trend then the mean will probably end up around -12/13C. The GEFS precip ensembles are rather dry but I wouldn't expect them to predict much convection due to the timeframe and resolution. However in saying this the further S you are the better due to being farther away from the HP and being closer to the LP. The wind chill factor continues to alarm me. A sustained wind speed of 30mph with max temps around 0C would make temps feel around -10C!!

Well hopefully TEITS this time next week we will see some new photos of SNOW.

[kold weather]

I'm not sure I totally agree there- if the low is too strong it will keep feeding in milder air from the SE, which in an easterly regime would keep southern areas in particular dull, damp and moderately cold. There's a tradeoff between having the low strong enough to stop the high sinking and weak enough to stop the warmer air feeding in from the SE.

It will also help if the low is further east like on the ECM.

Yeah, the 18z GFS is actually perfect in that respect with the low still having good precip to the north of the low but cold enough air for most of the country to have some fun. Thats the ideal evolution, however odds are it won't be quite that perfect IMO, but we shall see!

[Geordiesnow]

I think one reason why there is no convective PPN on the GFS 18Z run is because it seems to me a weather front will be close to the low thus alot of residual cloud which will stop convection getting going in the North Sea. Mind you, if you are under the PPN and the 18Z run occurs then it will be snow, if not cloudy and dry and very cold in that wind!

ECM looks better regarding convective potential and on a IMBY POV, i would like to see this run to come off.

I think some sort of easterly looks fairly likely to occur but the position of the high is important especially for those living in the North and Scotland in particualar.

[Frosty.]

Well although it's the first day of spring tomorrow meteorologically speaking, someone forgot to tell the weather because it looks like it will be turning colder during next week with a good chance of snow developing and becoming concentrated across southeast britain with strengthening ENE'ly winds which will become bitter and bring snow showers in from the north sea, settling down across the north with high pressure taking control and light winds leading to very cold frosty nights but hints of hp retrogression coinciding with a deep trough dropping into scandinavia could eventually pull down an Arctic blast with potential for reloads as the jet tilts NW/SE.

[snowfish]

Well although it's the first day of spring tomorrow meteorologically speaking, someone forgot to tell the weather because it looks like it will be turning colder during next week with a good chance of snow developing and becoming concentrated across southeast britain with strengthening ENE'ly winds which will become bitter and bring snow showers in from the north sea, settling down across the north with high pressure taking control and light winds leading to very cold frosty nights but hints of hp retrogression coinciding with a deep trough dropping into scandinavia could eventually pull down an Arctic blast with potential for reloads as the jet tilts NW/SE.

Superb post - my take exactly - and where I am positioned, could be very blizzard like if the charts manifest. I reckon by wednesday of the next week, the colder air will take cold, tightly compressed, an easterly that lasts three days wouldn't be out of the question Frosty, what do you think?

[Frosty.]

Superb post - my take exactly - and where I am positioned, could be very blizzard like if the charts manifest. I reckon by wednesday of the next week, the colder air will take cold, tightly compressed, an easterly that lasts three days wouldn't be out of the question Frosty, what do you think?

Thanks snowfish,

Yes I think it's looking excellent for the southeast for the second half of next week with good solid model agreement for a bitterly cold and wintry blast to become established in the SE especially, it could morph into a bitter N'ly beyond that if hp pulls out into the atlantic with a 1045 mb Greenland High and the scandi trough develops as the models currently indicate.

[Duane S.]

Well a quick scan of the overnight models reveals no hint of a backtrack from what is shaping up to be a very interesting end to the working week. Obviously there are plenty of variations on the theme, some not as good and some excellent. Most are in agreement though that high pressure builds to out North which causes the trough to sink down over us, nice tilt, compressed isobars and bingo! A bitter driving Easterly and heavy snow showers for most. But will it be a 48 hour affair or something more prolonged is the question. That is, IF it occurs in the first place at all, as we can expect greater fluctuations over the next 3 days or so as the models sort out the final evolution.

One of the main differences is how different models handle the growing PV over Scandi and whether or not it drops down to cut of the supply from the East or not. I have found that this has been a bit of a recurruing theme this winter and one reason why Easterlies have never really got going, i.e. a robust trough over Norway. Of course, if this were to occur a Northerly maybe on the cards but like yesterday when some models were showing full on retrogression of the HP, I don't really buy that outcome either.

Edited February 28, 2010 by s4lancia

[TEITS]

A bitter driving Easterly and heavy snow showers for most. But will it be a 48 hour affair or something more prolonged is the question. That is, IF it occurs in the first place at all, as we can expect greater fluctuations over the next 3 days or so as the models sort out the final evolution.

Whilst the excellent trend continues the only disappointing aspect of the ECM/0Z GFS is many places would be dry due to the proxmity of the HP. Ideally we need to see the HP centred further than the 0Zs suggest although the UKMO is pretty decent.

I do feel as though the E,ly flow will be cut off fairly quickly and then its a case of looking N. However due to the timeframe much can change with regards to the E,ly and also the possible reload. Lets hope the 06Z is an improvement.

[pureasthedriven]

Well a quick scan of the overnight models reveals no hint of a backtrack from what is shaping up to be a very interesting end to the working week.

Worth mentioning here, if it has not already been done so, that the GFS was showing this very evolution, especially the very favourable angle of the HP to the north, for early March at T384.

[Ben_Cambs]

Worth mentioning here, if it has not already been done so, that the GFS was showing this very evolution, especially the very favourable angle of the HP to the north, for early March at T384.

Yes I remember that and I think this winter GFS has had a habit of showing evolution's like this Deep in FI, dropping it for a while and bringing it back not too far from the reliable timeframe. Lets see what the GFS 06z brings in regards to next week.

[SnOwFeSt]

Trend looking slightly different so far on the 06z. Low pressure to our west meanders northwards, rather then eastwards.

Might this prevent the blocking high to our north/ undercutting low to our south + keep us in a stagnant southerly/ southeasterly feed? Guess we'll have to wait until the model has rolled out fully.

Edited February 28, 2010 by pjb120

[bluearmy]

this upcoming cold snap/spell appears to be a combination of the pre xmas and new year cold periods re preceding sypnotics. pre xmas was an ah ridge into iberia that extended north and then retrogressed to greeny. new year was an ah atlantic ridge extending north to the developing greeny high that shoved the atlantic trough to our southeast. thi time we have the ridge out of europe headed north and a ridge out of the mid atlantic, meeting behind the trough to our west and shoving it to our southeast where it meets the euro trough. the p/v dropping into scandi and arctic high extending into greenland are patterns we have seen before this season on the nwp. quite amazing to see such obscure winter sypnotic patterns repeating in what some considered a time we couldnt se such things occur.

[SnOwFeSt]

uppers not looking as cold, as high is further south + incorporates some less cold air in the south. Still, would give snowfall to the north, though daytime temps would stay above freezing.

[snowray]

[TEITS]

Still, would give snowfall to the north, though daytime temps would stay above freezing.

Not with HP centred over the UK.

Very disappointing run so far. If anything the N of England/Scotland are least at risk whereas the far SE is at greatest risk. This is simply down to the SE being further away from the centre of the HP although even the 06Z rules out snow even for this area.

I fear this E,ly is already going pearshaped and would be surprised if the models backtracked towards a more snowy E,ly.

[MP-R]

After an amazing 10-day forecast for, in this case, this area yesterday with excellent snow chances for thurs, fri and sat - it all seems to have disappeared this morning. I can now see why, that troublesome high to the north will probably give us rather a missed opportunity if it stays as far south as currently progged:

http://www.wetterzentrale.de/pics/Rtavn1381.png

Certainly cold but I would have thought mostly dry almost everywhere from that - does snow fall when the pressure is as high as 1030mb?

One then has to look deep into FI for anything magnificently wintry. However, none of the runs scream the Atlantic taking hold even as far as out as March 16th just at the moment so never particularly mild. Hopefully things will change with regard to that high over coming runs as that could prove a spoiler to some potentially fun weather next week.

[SnOwFeSt]

Not with HP centred over the UK.

Very disappointing run so far. If anything the N of England/Scotland are least at risk whereas the far SE is at greatest risk. This is simply down to the SE being further away from the centre of the HP although even the 06Z rules out snow even for this area.

I fear this E,ly is already going pearshaped and would be surprised if the models backtracked towards a more snowy E,ly.

Yes, you are quite right - I was referring to the earlier part of the run:

showing uppers of -7 to -8 and quite an unstable looking airstream.

I agree that this easterly looks like it could become a non-event. Models have consistently been putting this high further south on every run, and I can't see the trend reversing.

Looks like crisp, sunny days and frosty nights will be the order of the day come thursday/ friday imo!

[bluearmy]

Not with HP centred over the UK.

Very disappointing run so far. If anything the N of England/Scotland are least at risk whereas the far SE is at greatest risk. This is simply down to the SE being further away from the centre of the HP although even the 06Z rules out snow even for this area.

I fear this E,ly is already going pearshaped and would be surprised if the models backtracked towards a more snowy E,ly.

different evolution to the last 'failed' easterly Dave. seeing as we have to take the energy to our nw to our south and we have the developing block behind this, we must get an easterly behind this sinking 'shortwave'. what is obviously at issue is the strength of the easterly which is down to many factors - strength of the block, strength of the euro trough and strength of the sinking energy (plus the orientation of the block and euro trough). i think this will bring a strong flow across at least a fair chunk of the uk. it may be an area that doesnt look to be in the firing line at the moment.

[snowray]

Yes, you are quite right - I was referring to the earlier part of the run:

showing uppers of -7 to -8 and quite an unstable looking airstream.

I agree that this easterly looks like it could become a non-event. Models have consistently been putting this high further south on every run, and I can't see the trend reversing.

Looks like crisp, sunny days and frosty nights will be the order of the day come thursday/ friday imo!

Exactly the same thing happened with the Easterly progged for Early Feb, another will it wont it affair with the high sinking further and further until only the most Eastern Fringes of kent saw any decent snowfall.

Why could't that Greenland High thats been stuck like glue to Western Greenland since Mid Feb have sunk South a bit? Oh no no no.

Edited February 28, 2010 by snowray

[cooling climate]

The UKMO model looks to be the pick of the big three this morning when looking

for a potent easterly. Worryingly the ECM and the GFS 06z coming out now have

the high to far south so rather than bitterly cold and snowy we are looking at cold

and dry.

Looking at the two Euro models and then comparing to the GFS it looks as if the GFS

is being way to progressive. The Euro's have the easterly taking effect at t144 where

as the GFS brings it in a couple of days earlier and by t144 is already trying to bring

in a northerly.

It could of course be just a poor operational from the GFS model, we will see.

Edited February 28, 2010 by cooling climate

[Guest North Sea Snow Convection]

Quite a mix of model output this morning with varying outcomes around a theme of high pressure developing just to our north and pressure staying relatively low over Europe.

The GEM is the most wintry model output this morning, the UKMO and ECM look something in between and the GFS perhaps has the least snow potential.

Plenty to play for in terms of what may happen - but what seems pretty certain is that as we turn into Spring officially - the actual Winter 09/10 pattern still continues with things very much still on the cold side.

Edited February 28, 2010 by North Sea Snow Convection

[bluearmy]

forget the GFS 06z op. there should be a pos anomoly (upper high) around iceland T180. this run has a trough extension sitting there. obviously no one is saying that the NAEFS is right but at T180 it cant be '180 degrees wrong'.

also, there cant be a 'failed easterly' as per last time - read my post earlier.