Model Output Discussion

[TEITS]

Looking at the fax chart at +72 and there is a chance of backedge snow as the LP tracks NE. However I wouldn't expect very much from this wrt to snowfalls.

http://www.wetterzentrale.de/pics/brack2.gif

As for the E,ly and to be honest the model output is rather disappointing. The ECM at +168 does bring -12C uppers into E Anglia/SE and there probably would be a few snow showers. However the main reason im disappointed is the models have the HP too close. Also taking into account the models tend to shift these HPs further S then rather than experiencing an E,ly it looks possible that HP will be centred over the UK.

Ideally we need to see the model output have this HP centred further N. This would make the difference between a forecast of heavy snow showers to around average temps, dry and sunny.

[Guest North Sea Snow Convection]

I am quite content with the model outlook from next week either way and High pressure is a very welcome sight indeed. To see snow showers etc again would be great of course but just to see some quiet weather and plenty of sunshine and overnight frost would be just the ticket once the weekend is out of the way.

[Eugene]

Not sure if you would see much sunshine in kent NSSC if some of the runs are correct, with a northeasterly or easterly dull cold feed.

Next week is March and the averages are climbing every week now so not sure about average temps and it will feel cold anyway in a continental feed.

Some nice northwestward retrogression on the control and other ensemble members.

Edited February 26, 2010 by Eugene

[Guest North Sea Snow Convection]

Not sure if you would see much sunshine in kent NSSC if some of the runs are correct, with a northeasterly or easterly dull cold feed.

Next week is March and the averages are climbing every week now so not sure about average temps and it will feel cold anyway in a continental feed.

Some nice northwestward retrogression on the control and other ensemble members.

It matters not. An easterly is always welcomed by me, cloudy or sunny. To be dry is a big bonus in itself and a nice dry easterly is just the ticket to deal with the saturated ground.

Retrogression is a possibility further on - certainly seems like temps will stay below average as we get into the new month

[TEITS]

Not sure if you would see much sunshine in kent NSSC if some of the runs are correct, with a northeasterly or easterly dull cold feed.

Next week is March and the averages are climbing every week now so not sure about average temps and it will feel cold anyway in a continental feed.

Some nice northwestward retrogression on the control and other ensemble members.

Sorry I should of made myself a bit clearer.

If the +168 ECM chart verified then temps would be below average and in the SE/E Anglia they would be well below average. My comments about average temps is if the HP decided to be centred over the UK. We would still experience frosts at night but max temps would rise to around 7/8C. Infact during this time of year you can experience quiet a difference between max/min temps under certain conditions.

Disappointing ECM extended ensembles. The mean yesterday was 4C but this has now risen to 7C. This suggests to me a reload from the N might not occur. Having said all of this im now at the stage that if it isn't going to snow then give me some lovely warm S,lys!

[Eugene]

A better run for NSSC with more of a clear southeasterly feed by late next week, check out dewpoints for later next week , it would be give lovely widespread sunny skies, we need a southeasterly for more sun esp in the southeast instead of a dull cold northeasterly/easterly feed, nice retrogression to greenland in FI too, great run

http://www.wetterzentrale.de/pics/Rtavn18010.png

Still a risk of more cloud cover in the far southeast at times for next week though if we pull winds more north of east than south of east and we wont know until nearer the time which way it`ll go.

[Eugene]

Excellend trends on GFS 06Z ensembles it must be said, some show the risk of cold easterlies and snowfall for southern areas from mid next week, not sure why the doom to be honest, with HP blocking to our north you always have the chance of wintry weather.

http://91.121.94.83/modeles/gens/run/gens-18-1-144.png?6

http://91.121.94.83/modeles/gens/run/gens-19-1-240.png?6

http://91.121.94.83/modeles/gens/run/gens-0-1-240.png?6

http://91.121.94.83/modeles/gens/run/gens-4-1-252.png?6

http://91.121.94.83/modeles/gens/run/gens-4-1-228.png?6

[Thundery wintry showers]

A better run for NSSC with more of a clear southeasterly feed by late next week, check out dewpoints for later next week , it would be give lovely widespread sunny skies, we need a southeasterly for more sun esp in the southeast instead of a dull cold northeasterly/easterly feed, nice retrogression to greenland in FI too, great run :lol:

I don't agree re. SE'lys vs NE'lys. A north-easterly is more likely to bring air down from high latitudes as many recent runs have showed- this makes any cloud more likely to be convective in origin, so depending on the intensity of the flow, it may be sunny and dry with night frosts, or there may be patchy cumulus, or maybe some wintry showers in a pronounced flow.

South-easterlies are often dull and dry at this time of year, because the upper air is stable and cloud gets generated over the North Sea- I don't have the fondest memories of March 1996 for example. But at the moment, a dull dry easterly flow on the southern flank of HP is looking odds against because the airmass is likely to originate from high latitudes, and so cold and bright is the most likely outcome.

[Duane S.]

I'm getting more and more interested regards the 5th of March (funnily enough 1 year to the day since I last saw disruptive snow in my town).

Scanning through the perturbations there really are some tasty ones mixed in there for the South for that date. The Op seems slightly out of kilter to me showing a SE feed, many, including the mean, are showing more of an Easterly draw with the block further to the North.

The Ens and some Ops have been hinting at this for quite a few days now so whilst it is getting my interest up, I am mindful of the number of occasions my hopes have been dashed this winter so far (we didn't all get 15 feet of snow you know! :lol: ).

[Ian Fergusson]

I don't agree re. SE'lys vs NE'lys. A north-easterly is more likely to bring air down from high latitudes as many recent runs have showed- this makes any cloud more likely to be convective in origin, so depending on the intensity of the flow, it may be sunny and dry with night frosts, or there may be patchy cumulus, or maybe some wintry showers in a pronounced flow.

South-easterlies are often dull and dry at this time of year, because the upper air is stable and cloud gets generated over the North Sea- I don't have the fondest memories of March 1996 for example. But at the moment, a dull dry easterly flow on the southern flank of HP is looking odds against because the airmass is likely to originate from high latitudes, and so cold and bright is the most likely outcome.

You'll doubtless be unsurprised that the UKMO's Med-Range guys totally agree with you..... to cite their latest briefing - -

Re entire 6-10/15 day period: "Hazards & potential warnings - - Mainly nil, but low probs of heavy rain in W’ern and S’ern regions, mainly early in the forecast period. Also low probs of occasional snow, mainly in N’ern, E’ern and Central regions."

Re Wed-Thurs next week: "Many areas fine and dry, but risk of some more persistent rain affecting W’ern, S’ern and, perhaps, some central regions at first, PPN wintry also perhaps at times over higher ground...... Confidence high for a transition to drier, more settled conditions, and for temperatures remaining below normal."

Re Thurs-Sun: "....Increasing confidence for largely settled type persisting and high for temperatures remaining below normal...."

Re Trend beyond that to 15 days ahead: "Good signal for a blocked pattern, anticyclonic circulation bias and bias towards weather types from the broadly E’ly quarter...."

In other words, as you say, it's looking like mostly dry, rather settled but somewhat cold (against the norm) early spring weather for the next 2 weeks once we're past Wednesday (which in itself looks rather iffy at this stage - at least on the UKMO-GM - for any meaningful PPN moving eastwards).

[Eugene]

Yes the origin of airmass is important but i will say you are wrong over southeasterlies because of the shortest sea track possible for an easterly to reach us they mostly bring clearer colder air to southeastern districts that might suffer from cloud cover off the north sea when winds are north of east.

GFS 06Z brings very low dewpoints for next friday, it would produce lots of sunshine for lots of areas not the cloud cover you think southeasterlies do.

Nowhere in that metoffice update does it agree with him regarding cloud amounts in comparision between northeasterlies or southeasterlies, weatheronline are going for sunshine to be at a premium too so they aren't expecting lots of sunshine for all.

[Thundery wintry showers]

Your argument holds true for south-east England and to a lesser extent East Anglia when comparing a stable north-easterly with a stable south-easterly. In those cases the north-easterly will indeed pick up more stable weather cloud over the North Sea resulting in a cloudier picture than we would get from a south-easterly.

But comparing a north-easterly with 850hPa values of -5C or below with a south-easterly featuring 850hPa values well above -5C is a completely different story. The former will usually be bright and showery, the latter dull and dry.

For eastern Scotland and north-east England a south-easterly is just as likely to be cloudy as a north-easterly when "comparing like with like" in terms of airmass stability because the track over the sea from a south-easterly is still quite long.

[johnholmes]

You'll doubtless be unsurprised that the UKMO's Med-Range guys totally agree with you..... to cite their latest briefing - -

Re entire 6-10/15 day period: "Hazards & potential warnings - - Mainly nil, but low probs of heavy rain in W'ern and S'ern regions, mainly early in the forecast period. Also low probs of occasional snow, mainly in N'ern, E'ern and Central regions."

Re Wed-Thurs next week: "Many areas fine and dry, but risk of some more persistent rain affecting W'ern, S'ern and, perhaps, some central regions at first, PPN wintry also perhaps at times over higher ground...... Confidence high for a transition to drier, more settled conditions, and for temperatures remaining below normal."

Re Thurs-Sun: "....Increasing confidence for largely settled type persisting and high for temperatures remaining below normal...."

Re Trend beyond that to 15 days ahead: "Good signal for a blocked pattern, anticyclonic circulation bias and bias towards weather types from the broadly E'ly quarter...."

In other words, as you say, it's looking like mostly dry, rather settled but somewhat cold (against the norm) early spring weather for the next 2 weeks once we're past Wednesday (which in itself looks rather iffy at this stage - at least on the UKMO-GM - for any meaningful PPN moving eastwards).

thanks for that Ian-good to read the senior man's view and his medium range team's views also on developments in the medium term.

Most teleconnections tend to support that idea as well-or they seem to do so to me.

[Iceberg]

Wasn't sure which thread to put this in, but I very much agree with the recent comments added on the in depth thread.

There looks to be a transient pattern established, the mega block over the UK will I think very quickly disappear northwards, leading to various attacking Lp's very similar to the last week.

Any settled spell in other words will be shortlived IMO, particularly for southern areas. This is backed up in part by the 12Z's so far.

Sorry I know this disagree's with Ians and John's posts, both of which I have a lot of respect for, But I just don't see the High hanging about.

[guitarnutter]

First snow of Spring for England and Wales?

[johnholmes]

Well away from the immediate concerns for this weekend GFS has a very spring like run I Don't think!

Wasn't sure which thread to put this in, but I very much agree with the recent comments added on the in depth thread.

There looks to be a transient pattern established, the mega block over the UK will I think very quickly disappear northwards, leading to various attacking Lp's very similar to the last week.

Any settled spell in other words will be shortlived IMO, particularly for southern areas. This is backed up in part by the 12Z's so far.

Sorry I know this disagree's with Ians and John's posts, both of which I have a lot of respect for, But I just don't see the High hanging about.

Not a problem Ice-we are all entitled to our views not matter who-but why do you not think the high, after the next few days, is likely to move away as you suggest?

[The PIT]

If the GFS FI and Deep FI comes off we could end up having four months below average.

However being more realistic this Sunday is the point of interest and whether cold air gets wrapped around the low or not. If it does it could make life very interesting rain snow strong winds just the reason we live in the UK.

[kold weather]

Wasn't sure which thread to put this in, but I very much agree with the recent comments added on the in depth thread.

There looks to be a transient pattern established, the mega block over the UK will I think very quickly disappear northwards, leading to various attacking Lp's very similar to the last week.

Any settled spell in other words will be shortlived IMO, particularly for southern areas. This is backed up in part by the 12Z's so far.

Sorry I know this disagree's with Ians and John's posts, both of which I have a lot of respect for, But I just don't see the High hanging about.

Quite possibly so, most cold spells this winter have developed from the models showing similar set-ups, only for the high to slowly get taken north over time, its happened a decent amount of times now and whilst it may not happen, its happned enough to need to keep a close eye on it.

The transition into any colder spell looks very messy at the moment, I'd hate to have to make a call on that!

[Climate Man]

If the GFS FI and Deep FI comes off we could end up having four months below average.

However being more realistic this Sunday is the point of interest and whether cold air gets wrapped around the low or not. If it does it could make life very interesting rain snow strong winds just the reason we live in the UK.

I remember 18 months ago on here there were those that thought that we would never see two below average months in a row again. There is little trend for warmth which keeps getting put back. The reverse of previous years. In fact I have not recorded double figures here, 100m asl in Warwickshire, since 7th Dec. Model output does indicate another below average month and I see no evidence for any change in the recent below CET trend.

[Ben_Cambs]

Where is everyone tonight?!!? ECM 12z is a lovely run for next week!:

T+168: http://www.meteociel.fr/modeles/ecmwf.php?ech=72&mode=1&map=0&archive=0

T+192: http://www.meteociel.fr/modeles/ecmwf.php?ech=192&mode=1&map=0&archive=0

HP further away than the 0z, allowing the cold to hit us and not dive into mainland Europe!

[yamkin]

Where is everyone tonight?!!? ECM 12z is a lovely run for next week!:

T+168: http://www.meteociel.fr/modeles/ecmwf.php?ech=72&mode=1&map=0&archive=0

T+192: http://www.meteociel.fr/modeles/ecmwf.php?ech=192&mode=1&map=0&archive=0

HP further away than the 0z, allowing the cold to hit us and not dive into mainland Europe!

Snowman0697, To add to your list ECM 12Z 216h & 240h are also lovely runs even though they are in FI :lol: I agree, where is everyone

Edited February 26, 2010 by yamkin

[Tom D]

The problem this evening is some of the biggest disagreement at +120 I've ever seen, so looking further is pointless.

t+120

ECM

UKMO

GFS http://91.121.94.83/modeles/gfs/run/gfs-0-120.png?12

The changes actually start around t+84.

[kev238]

The models look good again this evening but I think everyone is aware after this winter that an easterly can only be described as nailed on at around 72 hours or so, maybe 96. Time and time again this year we have seen tremednous easterlies modelled in the 144 -168 range which have not really come to fruition for large parts of the country. I think this is why people are a little quiet-- FI is much lower this year as compared to past years.

if the same charts are shown by Monday I am sure the forums would be buzzing again!!

[I remember Atlantic 252]

The models look good again this evening but I think everyone is aware after this winter that an easterly can only be described as nailed on at around 72 hours or so, maybe 96. Time and time again this year we have seen tremednous easterlies modelled in the 144 -168 range which have not really come to fruition for large parts of the country. I think this is why people are a little quiet-- FI is much lower this year as compared to past years.

if the same charts are shown by Monday I am sure the forums would be buzzing again!!

yeah sadly I think GFS has this right wednesday onwards, was a very similar thing around 4th Feb when the other models (even gfs at times) were going for a beast, but the outcome was the high too close to the UK,

same will happen here I think, expect a comedown on ecm 00Z more inline with GFS

the nogaps still showing 13th Feb chart at 150, find that odd, a run from the 7th Feb that never came off, as high was closer

Edited February 26, 2010 by mark forster 630

[cooling climate]

Where is everyone tonight?!!? ECM 12z is a lovely run for next week!:

T+168: http://www.meteociel...map=0&archive=0

T+192: http://www.meteociel...map=0&archive=0

HP further away than the 0z, allowing the cold to hit us and not dive into mainland Europe!

Your right it is a lovely run and potentially snowy for some areas but because it does not

have any support for this evolution from the other two models I think its a case of more

runs needed.