Spring Model Discussion 21st March 2013 006z onwards...

[PB22]

We're well and truly in a rut at the moment with the cold spell continuing to gradually be extended day by day. Very unlike the traditional fare of cold synopics in FI never coming to fruition, instead its the milder synoptics which are not getting any closer whatsoever. Easter is looking increasingly cold and could be white for some, and I wouldn't be surprised if the cold continues well into April. Absolutely incredible output and I would place this spell of weather in the same category as December 2010.

[shaky]

Where is ian ferguson?!want to know where he thinks the highest accumulations are gona be over the next 48 hours!

[Tamara]

Looks like a surface high caused by the entrenched cold,which occur quite a lot over Scandinavia.

This means of course that the UK is the new Scandinavia!

There will be quite some feedback effect for sure going on with the omnipresent deep cold pool over North east Europe which is providing significant (and very late) deep snow cover over the land masses, with the sea temperatures chilling further too and all this in turn feeding back into the strength of the overall cold blocking pattern, which, in turn, is keeping us anomalously well below average. Its to be expected in mid winter,(although so often can be elusive then) but synoptics perpetuating like this are truly extraordinary to end March. But you can see how the pattern is recycling itself.

GP mentioned this feedback process at the start of winter as a factor to watch over the season as being increasingly influential, but no-one predicted that it would keep intensifying into Spring to find its peak in March No sign tonight that the initial turn of the month into April is going to promote much change either

[Midlands Ice Age]

MIA try this link - I like this one as it includes the timestamps for when produced. Not the quickest updated if your waiting on the late evening ones though.

http://www.weatherch...kmomslp.htm#t24

also just click on the chart and it jumps to next frame which is good.

ECM = It's February, no really it is actually February. The endless chasing of models has meant we all got caught in a timewarp.

Lorenzo,

Thanks for that. It is a much better chart viewer.

HOWEVER the chart I was looking at was published by Harsh Climate as a direct copy into this thread, so perhaps something else is going on! (see above)

MIA

[mushymanrob]

the cold spell only goes on and on with the ecm. the gfs and ensembles suggest that the next atlantic attack will be successful (yeah its been wrong before)but this time the anomaly charts support it, or are hinting at it, the inevitable.

like the continuing cold, its only a prediction and could be wrong.

meanwhile this is a spell to rewrite the textbooks, the coldest, snowiest late march spell ever?

[phil nw.]

So the modelling of widespread cold just goes on and on.

There appears no respite following the snowfall promised over the next 2-3days with more astonishing late March charts for next week.

Bitter cold easterly setup considering the lateness of the season.-10C uppers across the centre of the UK!

Just look at how extensive the cold is around the hemisphere and no sign of the jet moving north yet.

I can`t recall such a prolonged and cold start to Spring in all my years of chart viewing.

[Methuselah]

^{Looks like a lot of snow showers on} ukmo^/ecm ^120hrs

Aren't the overall SLP values a tad high for anything widespread and heavy?

Where is ian ferguson?!want to know where he thinks the highest accumulations are gona be over the next 48 hours!

He's got an epic accumulation of work to get through...

[Cheshire Freeze]

So the modelling of widespread cold just goes on and on.

There appears no respite following the snowfall promised over the next 2-3days with more astonishing late March charts for next week.

Bitter cold easterly setup considering the lateness of the season.-10C uppers across the centre of the UK!

Just look at how extensive the cold is around the hemisphere and no sign of the jet moving north yet.

I can`t recall such a prolonged and cold start to Spring in all my years of chart viewing.

Yes, also signs of the GEFS wanting to extend the cold tonight. If this trend continues the anomaly charts MMR is talking about will follow suit accordingly.

[cold snap]

January 2010 November 2010 December 2010 March 2013

March 2013 is now up there with the best ,I've had little snow here but it's still been epic

The ongoing cold weather is freakish but should we be surprised ? Maybe not

March has just been very mild over recent winters

ECM continues the cold this evening on a crazy scale , Ukmo will go that way I feel post 144

One thing is for sure once we get mild that we be winter over ,but we have been lucky to see a very interesting long winter

[shaky]

Aren't the overall SLP values a tad high for anything widespread and heavy?

He's got an epic accumulation of work to get through...

Thats a good one man!!lol!!

Aren't the overall SLP values a tad high for anything widespread and heavy?

He's got an epic accumulation of work to get through...

Thats a good one man!!lol!!

[Tamara]

Aren't the overall SLP values a tad high for anything widespread and heavy?

He's got an epic accumulation of work to get through...

The following two days look better for snow shower activity as the wind turns more north easterly and heights lower with the very cold uppers. The North sea and inland heating during the day could promote some good convection I would think (assuming the ECM was right at days 6 and 7 and the UKMO at day 6)

Edited March 21, 2013 by Tamara Road

[Summer Sun]

So ECM ends its run with a sliding low

The one consistent thing at the moment is the northern blocking eases during next week

From this

To this

Expect lots of flipping and flopping over the coming days for Easter weekend could be mid next week before we get any cross model agreement on which route we'll take whether it be the milder one or as we are now

Edited March 21, 2013 by Gavin.

[cooling climate]

Imagine the depth of cold we would of had if the insane synoptics portrayed by the ECM 12z

this evening had taken place during the winter months.

One thing to note is how bad the ens have been in the run up to this upcoming very cold spell

it is only the last two or three days that they have come on board. Several days ago along with

a few others I said follow the ops runs rather than the ens which were continually on the milder

side with the ops runs almost outliers.

[Gibby]

Hi folks. Here is the evening look at the 12zs from GFS, UKMO and ECM for today Thursday March 2013.

All models show a similar sequence of events over the coming 5-6 days. A cold and raw SE wind is blowing between Low pressure to the SW and High pressure to the North. A trough from the Low to the SW is moving slowly and erratically North over the UK with rain in the South moving slowly North and turning to snow in Central and Northern areas from later tonight. Then after a 24hrs or so spell of rain across the South and snow in the North a short milder interlude may affect the far South for a time as the snow weakens in the North. Later in the weekend a cold east flow develops over all areas as Low pressure recedes away from the South of the UK. This cold but mostly dry and windy spell looks like lasting through to the midweek period with a ridge easing down over Northern Britain lightening the winds and increasing the threat of sharp night frosts.

Towards Easter GFS shows little change with a cold Continental flow continuing over the South with some wintry flurries possible in the SE, the North would maintain dry and bright conditions and frosty nights. As Easter progresses a cold SE flow is shown to turn more Southerly on Easter Monday with milder air filtering North with occasional rainfall, especially in the west. The rest of FI then shows increasingly milder weather with temperatures somewhat above normal by the end of the run with Southerly winds, some rain at times with Low pressure out to the west of the UK.

The GFS Ensembles show a cold spell is still very much in control of the member pack. It isn't until the turn of the month and expiry of Easter that temperatures look like recovering nearer to average with rain at times.

The Jet Stream shows a continuation of the flow well South of the average position for this time of year for some considerable time yet. a weak Northern arm may develop from Greenland through the UK to Europe later though this is less pronounced on tonight's run.

UKMO for the middle of next week shows a cold ENE flow over the UK and after a dry start to the week the chance of wintry showers increases later in cold and windy conditions with temperatures well below average.

ECM tonight follows the UKMO in it's NE flow at the middle of the week with some wintry showers here and there. A ridge of High pressure extends down from the North across the west of the UK by Thursday though wintry showers would still be likely in the South and East. Later in the run there is no sign of any improvement whatsoever, in fact the complete reverse with renewed low pressure at Southern latitudes increasing the easterly flow once more with rain and snow renewed across the UK over Easter.

In Summary the weather remains in an unseasonably cold mood with winds blowing from an Easterly quarter for the next week at least. With unusually cold uppers in place over and around the UK temperatures will stay well below average with frosts at night and some wintry precipitation at times, mostly in the form of showers beyond these coming few days of more widespread snowfall. Longer term it looks like any sign of milder weather is postponed until after Easter now, even from GFS who previously showed things warming by Good Friday. The worrying thing is that ECM is determined to bring the cold towards the record books for longevity in Sprng if tonight's synoptics verify.

[Cheese Rice]

You'd be forgiven for thinking it was mid January, incredible synoptics for the time of year.

Forecast for here looks like the depths of winter, sub zero maxes.

[Chess01]

Could this cold march be because of the strat warming and lag time

[Summer Sun]

Could this cold march be because of the strat warming and lag time

I'm wondering if its a lag on effect of the SSW could be wrong but something is causing this

[nick sussex]

Imagine the depth of cold we would of had if the insane synoptics portrayed by the ECM 12z

this evening had taken place during the winter months.

One thing to note is how bad the ens have been in the run up to this upcoming very cold spell

it is only the last two or three days that they have come on board. Several days ago along with

a few others I said follow the ops runs rather than the ens which were continually on the milder

side with the ops runs almost outliers.

Yes I think we're seeing just how much difficulty the ensembles have in these set ups with where to place energy. Inevitably too much goes north.

We've seen this throughout the winter and indeed over the last few years.Even the operationals can make a mess of things but its evident that at least their higher resolutions gives them a better chance of getting things right.

[Methuselah]

I'm wondering if its a lag on effect of the SSW could be wrong but something is causing this

Thermal inertia and extensive snow-cover? There's a heck of a pool of cold air that needs warmed, yet...

[Blake]

I'm wondering if its a lag on effect of the SSW could be wrong but something is causing this

I would go with this too, I think the SSW was about a 6 week period or so. On that basis, today is 7th Feb or thereabouts. Would it have been colder had there not have been a SSW?

[lorenzo]

Below is the up to date zonal wind profile, would think that with the complete deletion of postive zonal winds over such a period of time it is hard to rule out a lagged influence from the SSW, although not an exact fit with expectations at the time of the SSW and the Cohen climatology ideas.

Looking at the balance of probabilities and this March turning out the be exceptional. We had a strong SSW event and therefore a strong response.

In consideration of March temp records 47 /62 / 63 am sure have been mentioned in posts regarding colder March months of previous years, perhaps someone who has links for these can review, I don't have any bookmarked.

Chionos last post in detail is here. Would be good to read his thoughts on this.

[Andy Bown]

Where is ian ferguson?!want to know where he thinks the highest accumulations are gona be over the next 48 hours!

Probably working, doing what he gets paid for weather wise, rather than the superb voluntary posting he does on here.

Your post was made 15 minutes after his live BBC Points West forecast so I expect he was on a break or beginning to work on

the late evening forecast.

Edited March 21, 2013 by Andy Bown

[Lynxus]

Imagine the depth of cold we would of had if the insane synoptics portrayed by the ECM 12z

this evening had taken place during the winter months.

One thing to note is how bad the ens have been in the run up to this upcoming very cold spell

it is only the last two or three days that they have come on board. Several days ago along with

a few others I said follow the ops runs rather than the ens which were continually on the milder

side with the ops runs almost outliers.

I honestly don't think it would be much different if it were December.

[-uksnow-]

ECM mean at 168 fairly distorted - have to wait for graphical representation but doesnt seem to follow the op with oodles of support

[shaky]

ECM mean at 168 fairly distorted - have to wait for graphical representation but doesnt seem to follow the op with oodles of support

In my eyes that ensemble mean is excellent!!to show a clear undercut on a mean chart that far out is brilliant!!looks like it supports the operational to me!