Spring Model Discussion 18Z 9/3/13 onwards....

[frosty ground]

And sometimes human instinct is a reasonably good tool in forecasting.

After all, the Met Office use it along with the models

If one run from one model shows somthing yhen I could understand the dismissing of any solution. Because he does not like it? Who cares?

[Captain Shortwave]

Agreed mushy isn't a troll just prefers mild weather.

His view can be sometimes mild biased, but many would be called a hypocrite for saying that because our own preferences to weather cloud most of our judgement to a degree sometimes. Human nature and all that. Certainly not a troll

Anyway the GFS couldn't be bothered to undercut this time. I don't like it's lack of commitment to sending energy south East under the heights. I mean it makes it to just about the west of the UK and then just stops. It might be right but I feel a bit dubious about it myself.

[Paul_1978]

I often see you guys discussing the relative merits of the models and sometimes criticising the GFS model for its poor performance. This article seems to confirm this:

http://www.climatecentral.org/news/storms-highlight-flaws-in-u.s.-weather-forecasting-model-15744

What a great link, thank you. Just shows that the ECM is one of the most highly respected models both here in the UK, and in the US, with the GFS being less and less trustworthy.

To be honest I stopped looking at the GFS weeks ago.

[Purga]

Great runs again this afternoon and this evening - if this had been 2 months ago or at the start of february the synoptics would have been a pretty good match for feb 1947 in snow potential and longevity. Let's hope we get the shift south that we need over the next few runs.

[Purga]

Gavin: "there we are folks I told you so, the snow definately feels warmer in April!"

Only teasing - LOL!

[CongletonHeat]

Much better 18z, keeps the cold up north where it belongs.

[Guest pjl20101]

It seems that the CPC NOAA site has backtracked from the trough moving westwards tonight and still has it a bit over us. Mind you I don't like what the AO teleconnection is doing currently and looking very suspicious for even a glimmer of warmth. Kinda agree with nick Sussex on this as it will become more transparent nearer the time.

[Guest pjl20101]

The problem the CFS has is the way it's presented and used at times - for instance taking the raw charts and picking out a day in 4 weeks/months time to show as a forecast is something that people tend to do and that's not really the way it's meant to work. The raw charts, are not bias corrected so in effect to use them you need a knowledge of the biases in the model and the patience to take several days output to glean a clue as to the general pattern.

Then there's the anomaly maps, these are updated daily for people to see, but no operational centres use the daily output, it needs averaging over several days - for instance NCEP update their CFS forecasts weekly, based on the average of the output across that period.

I think that bejing climate centre were nearer as was mentioned on gavsweathervids.com. Gavin p reiterated that the trough would extend to scandanavia wheras for the CFS it gave a ridge that extended from the north to scandanavia. Miss Gavin p on here come to think of it as what he says is grounded and makes sense.

[syed2878]

once again some amazing charts tonight. A qs when was the last time we had cinopticks like this in march guys? Thanks.

[Guest pjl20101]

once again some amazing charts tonight. A qs when was the last time we had cinopticks like this in march guys? Thanks.

I think this recent stratospheric warming is to blame my friend, hence the cold spell. Basically we are in a catch 22 position with our weather ATM with our NAO and AO both negative currently. Then again I think its evidence that we have been spoilt rotten to our recent nice springs/march months and are paying the price by having a march month that is a dud.

[SMU]

Morning all,

Huge upgrade for snow for the south on the ukmo today 00z has the best type of undercut slicing across the frontal zone at 96 and 120.

T96 is particulary wintry in sub -10c air, also the north is pounded on this run...

S

[rory o gorman]

18Z ensemble suite is showing signs of a good warm up with the OP being again a cold outliner for most parts. seems lightly that heights will fall back over Greenland over the next week .

Edited March 17, 2013 by rory o gorman

[Gustywind]

The GFS ensembles look a complete mess to me, hardly good agreement on a warm up.

[shaky]

Well ecm undercuts again!!infact looks colder than ukmo aswell!!

[Weather-history]

What I see is that any warm up seems to be pushed back to me. It doesn't seem to be getting any closer or looks less and less convincing.

[IDO]

So comparing like with like:

Yesterdays 0z: Todays:

A very clear shift in ens members from milder to cooler runs from around the D7/8 mark. If that trend continues tomorrow then the mean will be below -5c.

That is also for London, the further north the colder the GEFS mean. Again with the clear split it could go either way. ECM ensembles highlight that they are edging towards a mild/milder Easter (12z): and this morning's ECM 0z in the milder runs (less cold) around D9/10:

D9: D10:

So cold next week, and then uncertainty, with the relatively milder options that are both now showing on GFS and ECM probably the favourite, just.

Edited March 17, 2013 by i'm dreaming of...

[tinybill]

http://www.meteociel.fr/modeles/gefs_cartes.php?code=16&ech=192&carte=&mode=0

well any one going away for Easter take the long john's its looking dry and cold at the moment!!

[Frosty.]

A hint of pleasant spring sunshine towards the end of the Gfs 00z this morning, signs we will eventually lose the northeasterly influence and replace it with something more benign at the turn of the month. In the meantime, a cold week ahead with rain, sleet and snow and frosts becoming widespread for a time but low pressure moving up from the southwest after midweek with strengthening SEly winds as the atlantic low forces up against the cold block and wet weather pushing north and east across the uk, turning to snow with significant falls likely in the north and east, the south and west probably becoming milder for a time with rain as winds veer Sly to SWly but colder weather is then set to return as high pressure intensifies to the northeast.

[No Balls Like Snow Balls]

The ECM OOZ has the coldest uppers reaching all but SW Wales and England @ T96. The GFS 00z has the coldest uppers staying North of the Midlands. The cold air line is changing with every run. It looks like everywhere will be below average next week, but favoured spots for any settling/laying snow must still be the Midlands North, but even then the chances of any accumulating snow at lower levels may well be being over hyped. The GFS ensembles still show good agreement for milder uppers into the South next weekend.

The question still is, will the milder air win out at the end of the week and gradually move North or will the HP win out and keep most of us cold.

By the way the ECM T216 chart would give highs of 14c in Southern England if it were to verify.

Edited March 17, 2013 by No balls like Snow Balls

[shotski]

18Z ensemble suite is showing signs of a good warm up with the OP being again a cold outliner for most parts. seems lightly that heights will fall back over Greenland over the next week .

Having read through this mornings posts and viewed the current output the only outlier in here appears to be your post Rory

[mushymanrob]

History shows us all that extrems happen. Saying over and over agin that it won't happen without any charts or links is boring and trolling. Simples

true, extremes do happen, but are highly unlikely as this winters ecm outputs have proven. ive never said they wont happen, but are unlikely...especially when the extreme is in fi.

repeating the same thing over and over again when run after run is showing the opposite is trolling. Objectivity is a good thing. Saying some wont happen based on it being extream is t objective nor is it scientific.

erm... but you snow lovers are repeating the same thing over and over again... you cannot justifiably throw that at me without equaling that criticism at everyone.

appreciate the support guys

To be honest I stopped looking at the GFS weeks ago.

with respect.... thats foolish. whether the gfs is as accurate as the ecm or not is pretty meaningless as they are both very close. the gfs has out performed the ecm, look how many times this year the ecm has produced record cold predictions only to have them tempered and back in line with the more sober gfs's. but note, im not saying the gfs doesnt do that either, they are both guilty, they are both nearly as good as eachother.

....and this morning,the ecm lead big freeze is yet again downgraded to a few hours midweek, returning to what the models were showing prior.

all models agree that itll get gradually colder from today onwards bottoming out wednesday night with a sharp frost. cool, changable showery weather , some heavy, some wintriness, nice in any sun but sun will be at a premium.

the models start to diverge though as to the timing of the expected atlantic incursion thursday onwards. this mornings gfs 00z is possibly the most foreward suggesting a slow but steady progression thursady onwards. the ecm 00z suggests a messier affair with two attempts before the milder wins out. difficult to predict the outcome between attempts, the ecm also delays the timing and agrees with the ukmo fri-sat with a raw southeasterly before milder air 'wins out'. the ukmo doesnt go out far enough but it suggests a biting cold raw southeasterly .

snow chances are possibly greatest on wednesday, but location and altitude will impact on these chances, plus its not likely to settle, melting after the shower has passed.

frontal snow?.... i dont think so, the chances have been downgraded this morning. the progress of the milder air northeastward thursday onward is going to be a slow affair (on this mornings models), the fronts can be picked out where the isobars kink, ecm t144

http://www.wetterzen...n/fsecmeur.html

thats one chart but its not alone, you can see the uppers are milder ahead of the frontal precipitation zone. so IF (and i take heed of john holmes advice on guessing precipitation more then two days ahead) theres and snow, there wont be much before itll return to rain. of course altitude must be considered.

tbh this weeks expected weather isnt far off what id expect for early march, so not quite 'normal' for mid march, but not too far off, below average/cool.

the gfs in fi suggests a pressure rise, sunny days, frosty nights, until the high sinks allowing higher uppers around the top which would probably be cloud laden. but thats fi, fantasy island or forget it.

Edited March 17, 2013 by mushymanrob

[bluearmy]

Tbh, not sure how convincing the frontal incursion form the sw will actually be. The ecm op has the friday/saturday event quite a weak affair. The ukmo also looks to be struggling to push the energy ne. as i said yesterday, this time tomorrow, we should have decent cross model agreeement inc ens. may not be right though!

[Ian Brown]

It's actually a classic set-up for frontal snow Mushy, it may not pan out like that as the position of the HP to the North and how far the Atlantic Low will push in are yet to be determined, but the sort of synoptics shown have thrown up some huge events in Ireland and the South West in the past and further NE depending on the progress of the fronts and the engagement of the cold air.

I think what we have actually seen from the NWP over recent days is milder air continually being pushed back.

[mushymanrob]

It's actually a classic set-up for frontal snow Mushy, it may not pan out like that as the position of the HP to the North and how far the Atlantic Low will push in are yet to be determined, but the sort of synoptics shown have thrown up some huge events in Ireland and the South West in the past and further NE depending on the progress of the fronts and the engagement of the cold air.

I think what we have actually seen from the NWP over recent days is milder air continually being pushed back.

oh i agree that it is a classic model set up for frontal snow... but these breakdowns for me (ok nimby) are hit and miss, even in winter when ive hoped for snow (a long time ago, lol) its often been a disappointment although just to my north, the peak/pennines have had a pasting. plus the time of year, daylength, sun strength. in winter these synoptics would be very snowy, im just far from convinced that its a threat (to me).

and of course things can change either way, we are talking what might happen in 5+ days time in a very unstable atmosphere.

i think the only certainty for the next week is that it wont be warm! lol.

[bluearmy]

In response to the gefs bringing a renewed cluster of cold runs post next weekend, naefs drops the mean uppers back sub -5c again at that timescale. Currently showing as a spread on the ecm ens rather than the mean but given the recent pattern, seems like a return to average could be easter weekend at the earliest.