Model Output Discussion - 15th April Onwards

[Zenarcher]

The 12z ECM this evening has changed its idea on things from its 00z run this morning. With the low on Sunday in about the same position as where the GFS and UKMO place it. The high pressure gets a much better chance building over our North which is what the ECM is now showing and agreeing with this evening.

Edited April 26, 2012 by weathermaster

[Geordiesnow]

Interesting set ups, models are struggling slightly with the positioning of this low pressure system, it seems more and more likely Saturday will be drier for most people apart from the far South and parts of the NE where there might be a bit more rainfall but Sunday looks a wet one for most of England and Wales. As I said, the models are struggling regarding positioning of this low so could make all the difference where the rainfall will end up.

In terms of the GFS PPN charts, I am a little way about reading too much into them, you rarely see a front having the strength to stay that strong and they do normally tend to fizzle and die away from experience. That said, the trend is that despite warmer upper air temperatures, the outlook looks cool and cloudy, best of the sunshine may be in Western Scotland and Northern Ireland and if the sun does break through then the temperatures could shoot up to the dizzy heights of the mid-teens but for most, it will be cloudier and in some places, there will be more rainfall.

So I think overall, its a wet outlook but drier towards Scotland as its closer to the high pressure which looks like it may stay in situ over the Norwegian sea for a while.

[Summer Sun]

Well ECM is quite a high pressure dominated run tonight and it ends with high pressure keeping things settled if not a bit chilly for the time of year

[phil nw.]

I was rather takem aback when reading earlier posts regarding cold weather coming and remarks about crops failing etc.

Looking at todays 12z i tend to agree with Gavin in that the outlook for next week is similar to yesterday with a brighter and somewhat drier few days,especially for the north-some showery rain at times further south in the earlier part of the week.

OK not that warm but temperatures higher than recently with maxs in some spots aproaching 16C later next week which is a considerable difference to the impression that some views have given.

The GFS op was very much on the cold side in the medium term with the mean line around average.

Note as we enter May the 850 temp.mean runs above average.This would translate into some quite pleasant feeling days-enough perhaps for the beer garden after all.

[bluearmy]

ecm and gfs are now currently agreeing with a retrogression of the block to the mid atlantic/greenland with an associated 'plunge' of low uppers from the northeast, driven by a north scandi trough. whether, by the time we get to bank holiday weekend, the colder air misses to the east or not is the question. lets hope thereafter, that the block drifts back east.

[phil nw.]

ecm and gfs are now currently agreeing with a retrogression of the block to the mid atlantic/greenland with an associated 'plunge' of low uppers from the northeast, driven by a north scandi trough. whether, by the time we get to bank holiday weekend, the colder air misses to the east or not is the question. lets hope thereafter, that the block drifts back east.

It does look as if any polar air will be directed further east around that weekend Nick.

The mean hts for days 8-10

The way the block is modelled to our north west suggests this.

Mean 850hPa output for T240hrs.

GFS mean a little cooler than ECM but this probably skewed by the very cold -against the mean-Op run.

[damianslaw]

A very wet miserable Sunday ahead for England and Wales as we see a warm front moving slowly NE across the country.

All models are suggesting a more settled spell next week courtesy of heights building strongly to our north, these retrogressing NW by holiday weekend. The high is a 'cold high' so whilst we may see decent sunshine, nights next week look decidely chilly especially in the north with widespread air frosts very likely. However, maxes could get into the mid-teens, which is quite decent for early May, and will feel much better than recent weeks. Eastern coastal districts look like drawing the short staw with chilly northeasterly/easterly feed off the still very cold N Sea.

The charts have an air of May 96 about them... we remain locked in an airstream from the NW-E quarter. Indeed northerlies and easterlies are much more likely at this time of year than at any other time of the year, this is not a period of the year renowned for its raging atlantic westerlies nor its southerly plumes.

[jethro]

I think the springs over and summers over posts are being very hasty indeed!

It was not a few weeks ago we had unending high pressure & above average temperatures. All models kept the theme going and going. But look - it changed - and it will change again.

Completely understand the frustration and impatience - as a gardener (first year really having a proper go at it) it is very depressing seeing everything not growing and being stuck with plants all over the house. But change will come and the plants will catch up.

Yesterday we saw hints of something warmer coming in next week - today a northerly. The models are being very fickle as there is a lot of uncertainty in the relatively near time frame. Don't panic just yet!

Get some cloches or a cheap, plastic cold frame (wrap with bubble wrap if we get a really cold snap)- they'll be better off cooler but not growing much, than too warm and getting leggy. We might all end up with a later harvest this year but slower grown plants usually end up as healthier, more vigorous ones - when the weather warms up they'll romp away.

[mushymanrob]

oh dear.... after the hint of something warmer, even considerably warmer on some recent runs, there seems to be good agreement now that next weeks high will be positioned unfavourably for 'nice' weather. winds circulating with a strong northerly scource will bring alot of dull, cool, grey, overcast north sea dross across the uk. the further west you are, the better the chances of some warm sunshine whilst eastern areas will most likely miss out.

the charts are now resembling april/may 1974...

on the plus side at least it will be dry! (im talking into next week).

[ANYWEATHER]

oh dear.... after the hint of something warmer, even considerably warmer on some recent runs, there seems to be good agreement now that next weeks high will be positioned unfavourably for 'nice' weather. winds circulating with a strong northerly scource will bring alot of dull, cool, grey, overcast north sea dross across the uk. the further west you are, the better the chances of some warm sunshine whilst eastern areas will most likely miss out.

the charts are now resembling april/may 1974...

on the plus side at least it will be dry! (im talking into next week).

Really not sure about model outputs after this weekend. To much swapping and changing lately from the models to have much faith with anything past t72hrs! Looks as though the trend for the North to become more settled and the South to hang on to less settled /changeable conditions is what I can decifer from admist the muddle from what the model outputs or should I say "Muddle" Outputs are at the moment putting out!!!

[Bottesford]

Get some cloches or a cheap, plastic cold frame (wrap with bubble wrap if we get a really cold snap)- they'll be better off cooler but not growing much, than too warm and getting leggy. We might all end up with a later harvest this year but slower grown plants usually end up as healthier, more vigorous ones - when the weather warms up they'll romp away.

Want to continues with this point... please all gardeners join us in the gardening thread!

[MP-R]

Only problem with winds coming in from the east is the sheer difference of conditions depending on the source of the wind. Anything could happen from hot and sunny (May 2008), warm and sunny (May 2009) or cool and cloudy (May 2010).

The GFS does show a respite for about 5 days with high pressure extending down from the north pulling in cooler winds than the next few days. Then low pressure encroaches from the southwest with winds back southeasterly in FI so perhaps another convective spell with some actual thundery activity by the second weekend in May. All a long way out though.

[Weather Boy]

My take on the current ops model output, if they verify, which in the short term they surely will by and large, is that HP gives a brief respite for most places tomorrow before the Med-sourced Low gives a shockingly poor day for Sunday, for most of England and Wales extending into Monday for many places, especially in the SW. I would expect Scotland to escape by and large.

Thereafter, HP slowly takes control from the north, but due to its positioning, I don't fancy the East Coast much due to brisk and possibly quite raw E winds dragged off the North Sea. However, many in the west should fair better, especially in the NW. Things do tend to improve for all, though, and although these situations are extremely difficult to call, it looks as if there could be sunshine for all or nearly all by the end of the week.

FI is after about roughly Friday, and then it seems to me that both ECM and GFS don't really have much of a clue as the GFS moves into its low res and seems to just abandon trying to give a forecast with random isobars and synoptics that seemingly move around arbitrarily. It seems to me that in FI the models are just shrugging their shoulders.

[shedhead]

Well after a few days away from model watching it's nice to see a much drier looking setup developing next week, albeit not especially warm, with pressure building from the NW. Some of the charts towards next weekend offer up exactly what most of us craved through Winter, but alas that kind of blocking simply alluded us back then and it's perhaps no surprise it's appeared in Spring as it often does.

[bluearmy]

It does look as if any polar air will be directed further east around that weekend Nick.

The mean hts for days 8-10

The way the block is modelled to our north west suggests this.

Mean 850hPa output for T240hrs.

GFS mean a little cooler than ECM but this probably skewed by the very cold -against the mean-Op run.

that old chestnut phil. comparing the op means days 8 thru 10 against the ens mean for day 10. fwiw, i suspect the block to our nw is going to deflect most of any unsettled stuff to our east but the colder uppers are unliekly to miss us. also, not sure the op run is weighted to any extent in the gefs ens mean - infact, i'm not sure that the op run is represented at all in the gefs ens mean charts. a few less cold (even mildish) days next week will just make the cooler period to follow even less palatable.

[johnholmes]

Quite a change on the 500mb anomaly charts, especially the ECMWF-GFS version from when I was last able to get on the web (Monday am).

Gone is the +ve area with ridge to our east and trough to the west. Replaced by trough to our east and ridge to the west; oddly enough the end result in terms of temperature is perhaps about the same, not warm! It will be nice, for my area, if the monsoon went away for a while as well.

[bluearmy]

interesting fi on the gfs 06z. manages to find a way of delivering the scandi trough/greeny block for bank holiday w/end and then evolving to type of scenario talked about in the tech thread of scandi block and warmer se flow. a lot of chopping and changing in the op fi modelling reflecting the various solutions that are possible, none of which seems to be more favoured at the momernt.

[Summer Sun]

Not a bad 06z run from GFS high pressure continues to be much closer than it has been during April

http://www.null/ds/gfs.htm

ECM also has high pressure having more of a say, it looks like a northerly may set up later next week but rainfall should be much lower than of late

http://www.null/ds/ecm.htm

[summer blizzard]

Honestly not sure that some of you are looking past the 500hpa heights.

The only fine days for England look to be next Thursday and Friday (and it could well be cloudy). Before that and we have a stagnant front over Northern England with showers in the south and afterwards we get a northerly and the prospect of snow/hail.

You can cling onto whatever improvements you like but the general output is cool and wet if you live in England.

[Aaron]

Honestly not sure that some of you are looking past the 500hpa heights.

The only fine days for England look to be next Thursday and Friday (and it could well be cloudy). Before that and we have a stagnant front over Northern England with showers in the south and afterwards we get a northerly and the prospect of snow/hail.

You can cling onto whatever improvements you like but the general output is cool and wet if you live in England.

I agree with this.. GFS is showing high rainfall totals for most of England for Sunday and Monday with an inch of rain possible as far north as East Yorkshire..

Edited April 27, 2012 by Aaron

[Thundery wintry showers]

It looks like remaining on the cool side, but the weather pattern for next week is strongly up in the air, particularly for eastern and southern areas. Today and tomorrow look set to have sunny intervals and well-scattered showers across the north (except for the northern half of Scotland which is currently experiencing some sharp showers), although convective cloud may spread into stratocumulus may give relatively cloudy afternoons for some. For the Midlands and southern England it will be cloudier with a little rain thanks to slow-moving fronts.

Sunday looks like being a particularly cold dull wet day over England and Wales but with the brighter weather holding on across Scotland. On Monday the rain belt will move into northern England and southern Scotland with southern areas becoming drier, brighter and warmer. During next week that area of cloud and rain will weaken and probably hang around for a while but with dry and reasonably bright weather slowly pushing down from the north towards midweek, cold in the east but with daytime temperatures getting up to around average in the west.

For the long-term, the GEM 00Z is almost certainly a cold outlier but it would be likely to bring a mix of sun and wintry showers, with snow possible from the Midlands northwards- possibly the most widespread snow in May since 1997. The GFS 06Z outputs around T+180 are similar but less likely to be potent convection wise due to the less prominent Scandinavian trough, so only localised snowfall likely. However, the ECM and GFS ensembles point towards a rather more moderate and more stable north-easterly type which would most likely be dry, sunny and cool in the west, and cloudy and drizzly at times in the east.

[SP1986]

The FI period is quite clearly making it up as it goes along; there has actually been no consistency at all from FI.

The near timeframe suggest something a little milder into next week, but signals across the board suggesting a cold northerly into next weekend. The only thing we can deduce for certain, is that is will be cool for the forseeable future.

[Summer Sun]

The 06z ensemble's offer a bit of everthing this morning with some warm spells, but also some cooler periods, rainfall totals drop down slightly as we enter May

[AWD]

I notice the latest EC 32 dayer is painting a fairly average picture for May! ( according to Matt Hugo )

High pressure early may with temps around average, low pressure returning mid may with temps below average!

[mushymanrob]

Really not sure about model outputs after this weekend. To much swapping and changing lately from the models to have much faith with anything past t72hrs! Looks as though the trend for the North to become more settled and the South to hang on to less settled /changeable conditions is what I can decifer from admist the muddle from what the model outputs or should I say "Muddle" Outputs are at the moment putting out!!!

true, but the general trend is for high pressure to be somewhere around to our north, so whilst the detail is up for grabs, the general pattern is likely to be set.

it looks like after a succession of great springs (or at least periods of great weather) this year might return to a cooler mixed bag, similar to those of the 80's.