Model Output Discussion

[bluearmy]

I think a fairy decent chance we're done, cold rain looks a good shout for the large part of March IMO, windy at times.

looks like paul B has overwhelming nwp support beyond the cold troughing. the GEFS seem keen to drift the AH back over us beyond T180. i cant see anything properly wintry as an alternative so would be happy with an early spring.

[Interitus]

:blush:

It's going to snow on Andy's birthday everyone!

The day I was born (9th December 1990) was the great Midlands/Yorkshire blizzard:

http://www.wetterzentrale.de/pics/archive/...00119901209.gif

Although I must say for my 18th although there was snow on the ground I don't remember anything about the day after

The blizzard was the 8th, sorry off topic.

[Timmytour]

My bugbear Paul is really with this general assumption that if the models are conflicting, the milder option is automatically more likely. I am not a fan of this approach to model watching as every thing that gets shown on the models is a possibility else it wouldn't be flagged up in the first place, so it's all worthy of consideration.

And beyond +168, I am uncomfortable with the idea of ruling any scenario out, especially as you say when there are so many possible options.

Unfortunately the milder option has proved to be right time and time again this month...and with head ruling heart the prospects for anything but a brief cold spell look very fragile.

[Yeti]

The blizzard was the 8th, sorry off topic.

Overnight into the 9th - I was born at 8am. My parents got stuck in the ambulance on the way to hospital so somehow I believe it must have snowed then as well!

[mushymanrob]

Worth mentioning that we could well be on for 15C somewhere tomorrow, it really does look like being a stunning late February day in the south and east:

http://www.wzkarten.de/pics/Rtavn2417.html

Nice ramp but just checked the NMM high-res model on NW and skimmed through the hour by hour charts carefully and the highest temp anywhere tomorrow according to that is 13C in a few isolated spots around Kent/London/Essex. Now this model is fairly new but usually quite accurate so we'll see.

Allowing up to 1C margin of error we could see the odd localised 14C I suppose. But as for 15C, that doesn't seem especially likely.

good call paul b, 15c WAS reached yesterday in london i believe.

24 hours later and the models throw up a very interesting set of runs with a large area of low pressure sinking south and east . the upshot is that the coldest air will miss us (although the fax doesnt support the gfs uppers ) . the resultant easterly though looks cool and grey...

[Frosty.]

Looks like the GFS is now catching up to the ECM on the early morning runs, the UKMO is a bit different but overall I can't see anything wintry as such next week now, the Northerly and cold NW'ly has gone and we have cloudy cool winds off the north sea instead with rain and drizzle...pathetic is how I describe it.

[johnholmes]

in fact not just one place and not only London as the values below show, courtesy of Wx Online

Shoeburyness Landw. (3 m) 15°

London-Heathrow AP (25 m) 15°

London-Gatwick (62 m) 15°

Northolt (39 m) 15°

Charlwood (58 m) 15°

London Weather Center (43 m) 15°

Southend-on-Sea AP (15 m) 15°

a change in the offing for next week with markedly colder air compared to the past fortnight for all parts. Snow for the Scottish ski resorts and a smattering for other places, some accumulations likely over the hills from Wales/Peak District north at times.

Still doubt of just how windy it will be and indeed where as the models still try to pinpoint the exact positions of centres through the week.

[Paul]

Just to clarify, the NMM was in fact showing just shy of 15c, certainly didn't have a top temp of just 13c for yesterday. Top temp according to the meto was 15.3 @ Charlwood.

[charlton north-downs]

BBC Weather girl just said that it will become much colder next week with the possible return of snow. She said don't get used to this spring like weather. :blush:

[azores92]

BBC Weather girl just said that it will become much colder next week with the possible return of snow. She said don't get used to this spring like weather. :blush:

i might just add to that because louise lear specified snow to the FAR NORTHWEST OF SCOTLAND TO HIGHER GROUND, and nowhere else. anyway back to the models, and fairly average weather looks to be on its way.

[dice48]

excuse me but all the forecasts have shown heavy snow for other areas beside the NORTHWEST OF SCOTLAND , and even the metoffice our forecasting snow aswell as the gfs charts which our nearly always right and infact they are even forecasting snow for the southwest of england which never gets snow! Im fed up with people on this website coming out with negative commint just because their area isnt getting snow and i also think a few people so sellfish in that they should get more snow just after getting 1 foot a few weeks ago!

Edited February 28, 2009 by dice48

[azores92]

that may be the case dice, but i wouldnt be surprised if many showers were just hail or sleet.

[dice48]

well i suppose but i think that the showers at night will be of mainly of snow

[ANYWEATHER]

Good morning everyone! The models continue to show a "full menu of weather" next week with everything including the kitchen sink thrown in! Also could well be some thunder and lightning in some of those showers next week with a deep cold 500mb thickness and given the strength of the early March sun some showers could well fall of snow ,sleet rain ,and "hail" looks favourable in this situation.Another one to watch is the strength of the wind at some point during late Tuesday/Weds in the southern UK but of course it depends where the centre of the low ends up! Certainly some snow for upland areas especially the north and west ,Snowdonia, the Cambrian mountains The Pennines, The lake district and the Scottish mountains doing picticularly well out of this. Cant wait for some exciting weather , iive had enough of this benign , boring weather! Bring it on....

[Nick F]

a change in the offing for next week with markedly colder air compared to the past fortnight for all parts. Snow for the Scottish ski resorts and a smattering for other places, some accumulations likely over the hills from Wales/Peak District north at times.

Still doubt of just how windy it will be and indeed where as the models still try to pinpoint the exact positions of centres through the week.

06z GFS does show a possible significant snow event Wednesday morning as a front moves SE, but as ever this far off it looks to be uncertain to where the shortwaves will end up as they swing around the primary low that looks to set up somewhere near Scotland, these shortwaves will have a warm sector and can make the snow threat marginal - it won't be very clear cut until much nearer the time. Though I imagine the snow threat will be mainly Wales and Midlands northwards with air further south ending up wrong side of marginal.

ECM and UKMO had the long-wave trough slightly further west on Wednesday with the colder air slower to arrive- though the colder does finally creep in on Thursday. Alot of uncertainty beyond Tuesday atm.

Think I will enjoy it for the convective element with hail and thunder likely in the unstable polar maritime air. Any snow will be a bonus.

[J10]

Looking at the GFS charts, a wintry mix of showers seems likely for next week, with snow over higher ground at times, adn with snow largely confined on lower ground to the overnight period, and maybe during the heavier showers.

For Tuesday night into Wednesday, there remains a spell of sub -5c 850HPA, and sub 528 DAM air with 500HPa closer to 1290-1295, so not ideal for snow on lower ground by day but certainly good enough imo overnight.

Also looking at the charts Wednesday Night into Thursday looks fairly similar as well.

[SP1986]

Looking at the overall broader picture it's very clear the models haven't got a clue where to take the evolution.

Just to sum it up:

GFS shows a westerly

ECM shows an easterly

UKMO shows a northerly

That is quite bizarre, even in the world of unreliable model outputs, there's usually a broad agreement between two models at 144 hours.

Also I am a little humoured at the GFS attempt to match air temperature with the modelled pattern, even at close range the GFS inability to reveal a realistic temperature particularly on the coast is worrying, if we want to use the outputs at close range as forecast indicators.

phew!

Lets hope the models get the act together soon!

[bluearmy]

http://theweatheroutlook.com/twocommunity/...ms/t/25062.aspx

i havent seen this research referred to on here so i've linked to a thread today on TWO from Brian. an interesting read.

[damianslaw]

Models all over the place medium term, with the reliable timeframe of certainty only up to Wednesday. Difficult to call how things will exactly pan out next week, it is a fairly mobile flow with some amplification but with no real height rises at close enough range to give a clear signal of likely trends for later next week, it looks like we are going to be used as a bit of a battleground leaving it unclear as to whether we see a northerly or easterly or whether the azores high comes back or we remain locked in a cold polar maritime airflow, it could do anything later week which all makes for much more interesting model watching than has been the case the past 2-3 weeks , thank goodness!

On the snow front, yes tuesday night looks conducive for delivering some snow alebit of the very wet variety to lower ground of Scotland and perhaps N Ireland and far north england - all dependent on intensity of any precipitation, but the upper temps look like being on the right side marginal, obviously height will play a major part with a high lapse rate, expect the Highlands to get a good pasting in the next few days and also higher parts of the lake district and north Pennines, southern uplands. It will be nice to see the tops white again.

[Snowyowl9]

GFS changes it`s mind like the wind 0z run was showing an easterly like the ECM, with the 6z run not.

Next cold spell to look out for then for next week as another month comes in.

http://www2.wetter3.de/Animation_06_UTC/90_30.gif

Edited February 28, 2009 by Snowyowl9

[johnholmes]

http://theweatheroutlook.com/twocommunity/...ms/t/25062.aspx

i havent seen this research referred to on here so i've linked to a thread today on TWO from Brian. an interesting read.

yes plenty of links I'm awlays open to others views, so will use the afternoon 'tea break' to check those links out - thanks ba

[The Eagle]

Looks good on Tuesday, at least for a time, on this side of the pond. The shortlived potential spreading East to the UK. Possibly some backedge snow

[SNOWPLOUGH]

Looks good on Tuesday, at least for a time, on this side of the pond. The shortlived potential spreading East to the UK. Possibly some backedge snow

If it does snow it will be falling on a wet ground

SP

[Frosty.]

Difficult to know which model to believe today, the track of the fairly large atlantic depression is still not nailed but the latest meto update suggests the low will transfer to the east of the uk and pull down a cold NW'ly or N'ly later next week before high pressure and milder air pushes east the following week.

[NorthantsSnow]

Just to clarify, the NMM was in fact showing just shy of 15c, certainly didn't have a top temp of just 13c for yesterday. Top temp according to the meto was 15.3 @ Charlwood.

Well at the time of my post (12z the night before) the top temp it was showing was 13C! Here is the proof, thank you very much:

(chart courtesy of NW Extra)

Now I'm quite happy to admit I was wrong to go along with this model, because clearly that was a mistake, but I don't appreciate virtually being branded a liar.

Back to the models, as Stephen has outlined there are a laughable number of solutions showing just outside the reliable. It's a case of take your pick really. In the short term there is snow potential late Tues/early Wed for some, particularly in the NW but perhaps extending as far SE as the West Midlands.

Would be nice to see a bit more agreement in the medium to long term when the 12z runs roll out but I'm not holding my breath.