Model Output Discussion - 2nd March Onward

[Bradowl]

On another positive note, on bbc news forecast this morning it was mentioned that the North sea is colder than normal for this time of year.

An extra ingredient maybe just like we had in April 81 if I remember rightly.

[weather eater]

What we always need in the uk is a lot of luck, the good news today is the rubber stamp being applied by the met office, they must be pretty sure if they are now talking about snow.

Hi Karl, yes indeed that’s another good pointer, again I am reminded of last month, the MO never bought into the idea of a severe or snowy spell and they were spot on.

Edited March 3, 2013 by weather eater

[bluearmy]

That a top post SK it really shows just how we need all the ingredients to come together and how this year somehow we always managed to leave the cake out in the rain, close but no cigar. I remain optimistic if for no other reason than we at last seem to have got rid of the PV or bits of the PV stuck over Greenland, something that’s scuppered a special spell of cold all winter, nothing wrong with being optimistic just not blinkered.

if the scandi trough expands far enough sw to encompass the uk, we can live with some residual energy in the greenland area. we would need a height rise, either azores stretched north or the iceland/svaalbard wedge to keep the atlantic on a southerly trajectory into or shortwave energy headed around the top of a ridge and into the general trough. the azores route is risky as it allows warm sectors to get into the trough which is likely tricky at this time of year for decent snowfall. greeny ridge is the safe route but as i posted early today, its been a long time coming and another false dawn wouldnt surprise. the wedge probably brings the atlantic rather closer than we would like to see.

and thanks for posting the neafs anomoly 11/15 day SK. the 8/15 cpc will be a virtual carbon copy later.

Edited March 3, 2013 by bluearmy

[bradymk]

http://www.meteociel.fr/modeles/geose_cartes.php anyone got any more information about the newest addition to meteociel?

[snowmadchrisuk]

Hi Karl, yes indeed that’s another good pointer, again I am reminded of last month, the MO never bought into the idea of a severe or snowy spell and they were spot on.

They did get there predicted SW'ly forecast wrong though ... Even now were still pulling in SE winds.

[snowmadchrisuk]

2 day Cold spell showing on the ensembles but after that , there is a massive amount of scatter again with a lot of milder outcomes. On another note though today is freezing in Somerset , 1pm temps 2deg at Bristol , 0deg at Yeovilton and Liscombe.

Edited March 3, 2013 by snowmadchrisuk

[weather eater]

They did get there predicted SW'ly forecast wrong though ... Even now were still pulling in SE winds.

Well we can allow a little bit of error, they haven't made many this year.

[Frosty.]

Well we can allow a little bit of error, they haven't made many this year.

The signal for cold during mid march has been there for a while but today represents a major upgrade with more detail being provided by the experts which until today was not there. We have some very clever people on this site who have given a good account of themselves time and time again this winter despite the weather tending to do something different, but I do now feel it's game on with the increasing ensemble support and there should be more runs similar to the Ecm 12z last night and this morning's Gfs 00z in the coming days.

[Cheese Rice]

http://www.meteociel...eose_cartes.php anyone got any more information about the newest addition to meteociel?

I'm pretty sure it's this

http://geos5.org/wiki/index.php?title=Main_Page

[nick sussex]

The main interest for me in the set up is seeing whether the UK can tap the coldest source of air and what temperatures are seen if that's the case.

Historically if you look at past records in terms of temperature these have fallen right at the start of the month which isn't a surprise given that you're dealing with a fast increase in solar energy now.

It's for that reason that people shouldn't get their expectations up too high, once you hit this late into the season, timing of any snow events and more importantly sunshine make a big difference.

And crucially dew point, this point is quite interesting because its this that really helps to keep the snow in shaded areas even when your temps are well above freezing.

For example here we saw snow Sunday/Monday then general blue skies and sunshine, my last snow blob didn't disappear till Friday morning. Temps Tue to Thurs went 3,7,8 but importantly dew points below freezing between -2 and -4.

Of course it helped having an east/ne flow here which isn't moderated by sea track but still I was quite surprised at how well the snow in the shade lasted.

I think to get the best out of this for the UK you're certainly going to have to tap at least -10 upper air and that's possible given that cold pool, for snow I think an ene flow but sourced to the ne so then you've got a little less moderation but still enough of a sea track over the North Sea and the key instability because given the increase in solar energy if you can get the depth of cold then some fireworks could happen.

That's still a long way off though and still a few more hurdles to jump and you need to everything to come together at the right time.

In terms of tonights output I think chances for the UK increase greatly if that troughing disrupts much quicker, the ECM operational run was a bit too slow for my liking, there are some ECM ensembles which did have that happening more quickly and hopefully we'll see one of those later.

Edited March 3, 2013 by nick sussex

[chionomaniac]

It is but not sure what that has got to do with one final shot of snow? My point is we do don't know. If let's say it occurs as the models are hinting then we could still have another possibility after that. Parts of the south did see lying snow under Met Office rules in early April 2008. There was the famous late April 1981 snow event. That was my point.

Sorry, I went off at a tangent. If any one knew significant events off the top of their head it would be you and I apologise for trying to utilise that from your post!

So can anyone think of any -10ºC 850's in the southern half of the UK say from 10 March onwards? I can't think of one.

[bradymk]

Sorry, I went off at a tangent. If any one knew significant events off the top of their head it would be you and I apologise for trying to utilise that from your post!

So can anyone think of any -10ºC 850's in the southern half of the UK say from 10 March onwards? I can't think of one.

March 1962 was probably the only one i can think of that came close. Still think if we get a direct hit of the colder uppers, we could rival March 1962.

[damianslaw]

We are seeing changes within the reliable timeframe, after what will have been 3 weeks of relatively very quiet dry weather - some places have barely seen a drop of precipitation since the 13th Feb!.. the atlantic trough is ready to attack from the SW ushering in a spell of more unsettled windy and wet conditions, however, NE parts may still end up quite dry thanks to heights building to the NE forcing the trough on a SE course. The build of heights is the key trigger to the projected change to much colder unsettled conditions from the NE as we move further into March aided by a build of heights to the NW. We've been here before though many a time this winter - but there does appear to be a much greater chance that heights this time will build robustly to the NW in a much more favourable position to advect proper cold uppers from a N/NE quadrant - and with a very cold pool to our NE, some very cold weather is likely to occur with severe nightime frosts.

All eyes as ever on the position of heights building to our NW, and how the azores high interacts with the atlantic trough, it could still be a spoiler despite decent heights building over Greenland, for a sustained cold attack from the NE, the azores high needs to stay far to the south/sw and not be allowed to ridge N/NE - developments over the eastern USA seaboard will be crucial - again some warm air advection over west greenland will help.

[mushymanrob]

Rob,no wonder you are not seeing what some of us are if you are using the anomoly chart you linked to. Thats based on the operational output only. The ens anomlys have been pointing this way for longer than one or two suites.

ahhh my bad, thanks

One final shot at snow is looking increasingly possible for those in the north and east

unfotunately, i dont agree. the pattern this year has been for cold spells followed by less cold, upto average. i dont think that this expected (but not nailed) cold spell will be the last. its not at all what i want to see, but tbh im not expecting a cold trouble free spring.

the 06z typifies what we just might get, flipping in and out of cold, as opposed to a straight lengthy deep cold spell. atm the models just dont know how the expected cold plunge will impact on the uk....if at all... dont forget the last big freezing northerly simply didnt materialise for us.

[Thundery wintry showers]

Sorry, I went off at a tangent. If any one knew significant events off the top of their head it would be you and I apologise for trying to utilise that from your post!

So can anyone think of any -10ºC 850's in the southern half of the UK say from 10 March onwards? I can't think of one.

There have been a few fleeting examples in fairly recent years, but nothing sustained. Some instances:

http://www.wetterzentrale.de/pics/archive/ra/1995/Rrea00219950329.gif

http://www.wetterzentrale.de/pics/archive/ra/2005/Rrea00220050409.gif

For substantial examples we have to head further back within the archives, but there are a fair number prior to the 1990s:

http://www.wetterzentrale.de/pics/archive/ra/1952/Rrea00219520328.gif

http://www.wetterzentrale.de/pics/archive/ra/1978/Rrea00219780411.gif

http://www.wetterzentrale.de/pics/archive/ra/1985/Rrea00219850319.gif

http://www.wetterzentrale.de/pics/archive/ra/1980/Rrea00219800322.gif

http://www.wetterzentrale.de/pics/archive/ra/1962/Rrea00219620315.gif

http://www.wetterzentrale.de/pics/archive/ra/1958/Rrea00219580311.gif

[AderynCoch]

So can anyone think of any -10ºC 850's in the southern half of the UK say from 10 March onwards? I can't think of one.

EDIT - beaten to it

Edited March 3, 2013 by AderynCoch

[March Blizzard]

Not sure if Nick Sussex is talking about upper temperatures or 2M temps, but the March record low temperature occurred on the 14th. While the bulk of low temperatures occur in the first 3rd of the month there is still the possibility for extremely cold weather well into the month. Food for thought in regards of what potential this possible mid month spell could bring.

[Timmytour]

March 1962 was probably the only one i can think of that came close. Still think if we get a direct hit of the colder uppers, we could rival March 1962.

Interesting because a lot of people you look at that and think you meant March 1963. But March 1962 was the coldest of the century. However, it was also marked by being very dry as well as very cold which makes you think talk of great convection and thundersnow, while it exists potentially, is by no means a given in a freezing March

[chionomaniac]

Thanks for thr replies, guys. The main thing is that this has happened enough times in the past as Ian has posted. Good!

[Gael_Force]

Sorry, I went off at a tangent. If any one knew significant events off the top of their head it would be you and I apologise for trying to utilise that from your post!

So can anyone think of any -10ºC 850's in the southern half of the UK say from 10 March onwards? I can't think of one.

Had a look at the NOAA analogues for the March CET competitition and was intrigued by the number of very cold March CETs that were appearing (also included the record warmest as well '57) - a look at the archive showed '55 and '58 both had -10c uppers over the UK in the second half of March. The other years were '69 and '62 but no -tens in second part of month.

[weather eater]

The signal for cold during mid march has been there for a while but today represents a major upgrade with more detail being provided by the experts which until today was not there. We have some very clever people on this site who have given a good account of themselves time and time again this winter despite the weather tending to do something different, but I do now feel it's game on with the increasing ensemble support and there should be more runs similar to the Ecm 12z last night and this morning's Gfs 00z in the coming days.

There are indeed some very clever people but model backtracks have caught them out many many times, my heart hopes not this time, my head says otherwise. For me all the major models have an error built into them when it comes to modelling these types of synoptics, all very lovely but get into high res and its all change, while i hope that doesn’t happen I nevertheless expect it to do so but I’d love to be wrong.

[Panayiotis]

http://www.meteociel...eose_cartes.php anyone got any more information about the newest addition to meteociel?

Here's my post from the other day when the model first came out:

[Panayiotis]

Thanks for thr replies, guys. The main thing is that this has happened enough times in the past as Ian has posted. Good!

There have been a few fleeting examples in fairly recent years, but nothing sustained. Some instances:

http://www.wetterzen...00219950329.gif

http://www.wetterzen...00220050409.gif

For substantial examples we have to head further back within the archives, but there are a fair number prior to the 1990s:

http://www.wetterzen...00219520328.gif

http://www.wetterzen...00219780411.gif

http://www.wetterzen...00219850319.gif

http://www.wetterzen...00219800322.gif

http://www.wetterzen...00219620315.gif

http://www.wetterzen...00219580311.gif

I would say the best match of those charts, for what is forecast are the charts of 1952 and 1980 as they both show the bulk of the cold over Scandi/Europe, compare them with what the models are showing and we have even colder uppers in Europe, so if we can tap into that, -10C uppers can be reached IMO:

Edited March 3, 2013 by Panayiotis

[SMU]

Wow ukmo very fast and progressive with the cold at 72!

Edited March 3, 2013 by Steve Murr

[-uksnow-]

UKMO is very good at just t72!

Edit: Steve beat me

Edited March 3, 2013 by -eded-