Model Output Discussion - 2nd March Onward

[IDO]

The GEFS showing from Tuesday for about 5 days a nice brief mild spell:

The GFS 0z op run then hugs the milder option (and wetter) and the UK is stuck in a trough with a stalled low(s).

The 850s mean continues to show from next weekend the cooling down:

with the control highlighting another possibility:

A clear split around D8-9 developing in the GEFS, that could bring a colder spell close to the UK shores. ECM T240 is close to another cold swan song. The synoptics appear to be there but it is whether the UK, as it does, just misses out again.

Certainly after the brief warm up a continued trend for a cooling down.

Edited March 2, 2013 by i'm dreaming of...

[Paul]

New thread for the model discussion (split the post out from above as it seemed a good place to start), so please continue here.

[winterof79]

If certain output verifies,it looks like we go from milder s/se mid week

http://www.wetterzen...ics/Rgem961.gif

http://www.wetterzen...ics/Recm961.gif

To cool/cold easterlies over the weekend

http://www.wetterzen...cs/Recm2161.gif

http://www.wetterzen...cs/Rgem1801.gif interesting for march.

Edited March 2, 2013 by winterof79

[mushymanrob]

i cant see anything else but normal, average march conditions on the models. yeah itll become pleasantly warmer this week, followed by a more changable mobile spell which will be slightly cooler. but theres no sign of anything cold (nor overly warm either). whilst we might get something easterly in about a weeks time, the uppers dont suggest itll be particually cold. probably more cloud...

its looking like a large area of low pressure will take up residence close to our wsw, keeping things changable, but never too cold.

suits me

Edited March 2, 2013 by mushymanrob

[TEITS]

Looking at this mornings output a cold E,ly continues to look favourite, how cold is still very uncertain. Appears around the 11th March is when this could occur so only 24hrs later than I suggested many days ago.

I won't bother you with posting the links but the GEFS mean again is very similar to last night and of course todays ECM shows an E,ly flow. If you look at the ensembles below you can clearly see the uncertainty how cold it could be.

http://cdn.nwstatic.co.uk/ensimages/ens.20130302/00/t850Cambridgeshire.png

[Frosty.]

Massive differences this morning between gfs and ecm 00z from early FI, ecm much improved from a cold perspective beyond T+168 with a trend to much colder although ultimately anticyclonic but with sharp frosts, the gfs 00z very west based with arctic air flooding into the atlantic for days and days and the uk on the mild side of the trough although it has a mid range reboot with a few colder, calmer days with overnight frosts before a similar west based pattern returns, the gfs 00z is pretty much a nightmare run for coldies hoping to tap into the coldest arctic air of the season, you would need to be on a ship in the atlantic to catch the arctic blast and snow showers.

The models do agree on the week ahead though, we will start next week in ridge conditions and increasingly mild SEly winds from the med, drier air so a lot more sunshine than recent times, during the week the high will drift away southeast and pressure will fall with bands of rain spreading north and east during the week and very mild air pumping up from the south, temps close to 13-14c later next week across southern britain, rather less mild further north but still on the mild side, the ecm shows the main low gradually being pushed away southwestwards and the cold block to the northeast getting closer and closer with more trough disruption over the uk, the mild uppers are drained away eventually and we end the run in cold anticyclonic conditions, it could evolve into something more significant than the op run shows.

[bluearmy]

Come mid march, the average temps are well into the forties. If we see max temps 38 to 41 then that's v cold. Whether it translates into any snowfall is another matter entirely.

[Gibby]

Good morning. Here is the report on the output of the big four from their 00z runs for today Saturday March 2nd 2013.

All models show signs of a change on the way. This comes in two phases as the current benign and cloudy weather with a little drizzle here and there as well as a few brief sunnier or clearer breaks continue for the next 24-48hrs. As the High responsible for these conditions gradually starts to slide away SE tomorrow the first phase of change sees a milder SE flow pick up bringing both drier and milder air NW from France with more sunshine over Monday and Tuesday than of late. Secondly as the High moves even further away from the East pressure falls from the SW and rain will arrive int the UK on a Southerly breeze by then.

GFS then brings this rain across all areas later in the week reinforced by a deeper Low pressure running North close to the West Cast with strong winds likely for a time. Then through FI the operational brings a typical March mix of weather with spells of rain and showers in occasionally strong winds which blowing from mostly a Southerly or Westerly quarter ensures temperatures stay close to the March average for all areas for most of the time.

The GFS Ensembles show the warmer uppers in association with the current High pressure gradually giving way to more average temperatures aloft as Low pressure takes hold midweek. Rain at times is then shown to occur throughout the rest of the run with the usual spread of values later on. The operational was one of the milder options on offer though both North and South later though more especially in the North.

The Jet Stream shows reluctance to move North anytime soon preferring to continue to flow East across Southern parts of the Northern hemisphere in the absence of the dominance of an Azores High.

UKMO for late next week shows Low pressure just to the west of Ireland with a cyclonic Southerly flow over the UK. It would of become steadily milder in the preceding days but cloud and rain would of already arrived by this point with some sunshine and heavy Spring showers the likely weather under this setup.

GEM today continues to want to keep a more SE airflow the dominant force later next week with rain held more into Southern and Western areas while the North and East see cool SE to East winds making it feel cold as well as cloudy. Late in it's run winds back further into the East bringing cold and dry conditions back later as High pressure shifts South down over the UK by the end of the run with the return of cold and rather cloudy weather with frost risk at night.

ECM too shows a similar evolution as GEM with High pressure re-establishing later in the run pushing down from the North and squeezing the Low pressure to the South of the UK away East and replacing the occasionally rainy conditions late next week with colder and drier conditions once more with overnight frost.

In Summary we are still on course for a change in the weather next week. The predominantly dry and rather chilly conditions will be replaced by a milder and wetter spell as Low pressure to the West and SW takes control for a while at least later next week. How long such a spell lasts is open for debate with GFS and UKMO looking like sustaining milder and unsettled conditions moving forward while GEM and ECM build High pressure back down from the North late in their output with the removal of rain from the South and a return to dry and rather cold conditions with night time frosts as we approach mid month.

[Methuselah]

Aye, judging from the projected upper-air conditions, 'normal' does indeed appear to be the 'form horse', for the foreseeable... After that, who knows? The ECM will no doubt 'default' to its favoured option (deep cold at T+X hours) and the GFS will faff about in FI...So, what's new? The 500mb anomalies would seem to be as good (if not a better) a guide as any...

[AWD]

The EC Op looks to be on the colder side of the De Bilt ens in FI;

But a cool down does look evident, just how cold a how long is unknown.

[Ian Brown]

i cant see anything else but normal, average march conditions on the models. yeah itll become pleasantly warmer this week, followed by a more changable mobile spell which will be slightly cooler. but theres no sign of anything cold (nor overly warm either). whilst we might get something easterly in about a weeks time, the uppers dont suggest itll be particually cold. probably more cloud...

its looking like a large area of low pressure will take up residence close to our wsw, keeping things changable, but never too cold.

suits me

Have to say I would much prefer a beautiful day like today than the damp murk promised by Lows parking themselves to the W/SW.

Hoping the ECM can verify for Cheltenham week !

[That ECM]

Come mid march, the average temps are well into the forties. If we see max temps 38 to 41 then that's v cold. Whether it translates into any snowfall is another matter entirely.

Agreed and the lack off posts clearly show what many actually look for when viewing the output. There is little doubt that it will cool down after what looks a pleasant few days for many at the beginning of next week. I have committed that this year I will continue to watch the output through the year and not start again in nov in the hope that I will continue my learning.

[Frosty.]

i cant see anything else but normal, average march conditions on the models. yeah itll become pleasantly warmer this week, followed by a more changable mobile spell which will be slightly cooler. but theres no sign of anything cold (nor overly warm either). whilst we might get something easterly in about a weeks time, the uppers dont suggest itll be particually cold. probably more cloud...

its looking like a large area of low pressure will take up residence close to our wsw, keeping things changable, but never too cold.

suits me

Yes mushy it looks like a mild/very mild week coming up, perfect for gardeners and growers with early sunshine and then rain with temps around 12-14c but a little cooler for northern britain.

[winterof79]

i cant see anything else but normal, average march conditions on the models. yeah itll become pleasantly warmer this week, followed by a more changable mobile spell which will be slightly cooler. but theres no sign of anything cold (nor overly warm either). whilst we might get something easterly in about a weeks time, the uppers dont suggest itll be particually cold. probably more cloud...

its looking like a large area of low pressure will take up residence close to our wsw, keeping things changable, but never too cold.

suits me

I take it that is according to the GFS or are you blatentley ignoring the charts,which you choose never to post,posted by others?

http://www.knmi.nl/exp/pluim/Data/pluim_06260_0_00_60.png?1362218294443

Definately shows "signs" of much colder weather than the coming week

http://www.meteociel.fr/modeles/ecmwf/runs/2013030200/ECH1-168.GIF?02-12

Another chart which shows signs of colder weather to follow.That is not to say it will happen.Your post refers to uppers in a weeks time http://www.meteociel.fr/modeles/ecmwf/runs/2013030200/ECH0-168.GIF?02-12

The origin of an easterly flow would be cold becoming colder.

Edited March 2, 2013 by winterof79

[Supacell]

I take it that is according to the GFS or are you blatentley ignoring the charts,which you choose never to post,posted by others?

I have to agree with Mushy here. The ECM charts that were posted above shows it turning cooler but would likely indicate temperatures in the region of 4-7c, which although colder than the mid-March average is not anything extreme and would not translate to widespread snow or anything unusual with temperatures. It would indicate the risk of overnight frost and possible snow on hills in any precipitation (of which those charts don't really show any), but isn't this normal March weather which is what Mushy stated?

Edited March 2, 2013 by Supacell

[winterof79]

I have to agree with Mushy here. The ECM charts that were posted above shows it turning cooler but would likely indicate temperatures in the region of 4-7c, which although colder than the mid-March average is not anything extreme and would not translate to widespread snow or anything unusual with temperatures. It would indicate the risk of overnight frost and possible snow on hills in any precipitation (of which those charts don't really show any), but isn't this normal March weather which is what Mushy stated?

My point is that these charts

http://www.meteociel...1-192.GIF?02-12

http://modeles.meteociel.fr/modeles/gem/runs/2013030200/gem-0-180.png?00

Are are colder than that of today or anything next week

http://www.meteociel...CH1-0.GIF?02-12 A widespread frost from this last night

I would be foolish to predict any precipitation at this stage wouldnt i?Indeed i have not mentioned snow either.

Edited March 2, 2013 by winterof79

[Frosty.]

The best thing about the ecm 00z op run is the trend and not the outcome, get the cold air first and hope for something more potent from the northeast, or even the north since the arctic is unusually cold and it would be lovely to have at least one good arctic outbreak before the sun becomes too strong and high, the gfs 00z was a road to nowhere as far as cold outcomes are concerned but there is still enough going on in the background to keep us in the hunt for cold towards mid month, no guarantees though.

[bradymk]

The best thing about the ecm 00z op run is the trend and not the outcome, get the cold air first and hope for something more potent from the northeast, or even the north since the arctic is unusually cold and it would be lovely to have at least one good arctic outbreak before the sun becomes too strong and high, the gfs 00z was a road to nowhere as far as cold outcomes are concerned but there is still enough going on in the background to keep us in the hunt for cold towards mid month, no guarantees though.

Slight change of viewpoint from yesterday I have to reinforce my point i made last night that come middle to late march, you need perfect conditions for snowfall to occur and especially accumulate and funny enough, conditions i have not managed to get all winter (ill stop moaning soon). Both Ens show the trend of it becoming colder, mean at around 5c which alone is cold for March but take out the milder cluster and the mean would probably be a lot lower. The ECM op was probably a good mean if you took the milder members out of the equation. Remember it does not need to be -5c/blizzard to be v cold. It has to also be relative to the month so v cold at the end of March is different to V cold in January. So when i have seen the posts this morning that all there is in the models is mild and then average, depending on which model you look at, this is wrong. The avg temp for March is around 7/8c so i believe you could class 3/4c as turning v cold. Some people seem to think we are still in January and that when other posters say chance of turning cold/v cold, they are taking those words and think snow/ice days rather than comparing v cold relevant to the month. With a very cold airmass to our North East, it could turn cooler, colder or v cold, certainly a lot of options and i would not rule out a bitterly cold N'easterly or easterly post 10th March (snow or no snow!!), just as i wouldnt rule out a trouvmgh over us or to our west, but still think Ely favoured option.

[tinybill]

http://www.meteociel.fr/modeles/gfse_cartes.php?mode=2&ech=204

i know its a long way off but could this be a start of another wet spell coming in fantasy world

[Tom Jarvis]

Just comparing the models over the last two days I would say they are clueless about what will happen.

[Bobd29]

Have to say I would much prefer a beautiful day like today than the damp murk promised by Lows parking themselves to the W/SW.

Hoping the ECM can verify for Cheltenham week !

Couldn't agee more, south west does NOT need a low parked anywhere nearby it would only take a day to undo all the draining achieved over the past week or two. As for Cheltenham....wholeheartedly agree, give me 15degs dry and preferably bright and I am Happy, chances....not great!!!

[No Balls Like Snow Balls]

Next week is still panning out to be mild with rain at times. Any potential very cold weather is still way out in FI (no change there then), and IMO is likely to remain so for some time. There are small signs in both the ECM and GFS ensembles that the temps may fall away again from the end next weekend, but only to values between 6-8c, no way near cold enough for snow unless your planning on being on the highest mountains.

[Frosty.]

Slight change of viewpoint from yesterday

I think i'm allowed to change my mind, being a coldie but also a weather fan and this mornings runs have lots of mild but also potential for cold later.

[nick sussex]

Putting aside the ECM in its later output which shows it a cold outlier there are marked differences at just T96hrs with what happens to those shortwaves to the north.

This effects any ridging extending sw from the Arctic, the UKMO and earlier GFS 00hrs were both in the same camp against the ECM which takes a shortwave westwards opening up a gap for ridging to extend sw'wards, so really its quite a confused picture.

If the GFS/UKMO are correct its a wet picture with that slow moving troughing and to a degree a stalemate.

We'll see this evening which model has called the earlier timeframe correctly.

Edited March 2, 2013 by nick sussex

[Frosty.]

It's worth remembering that this time last week the ecm was predicting a potent arctic blast for today whereas the gfs showed a benign pattern, it shows how the models have their ups and downs, the gfs is a very maligned model but it does have it's moments. It has no bearing on the post T+168 period though.