Model Output Discussion

[Milhouse]

theres certainly nothing tedious looking or boring from my perspective. At least we are soon to see the back of the cold evenings where the temperature drops well into single figures making it very hard to enjoy being outside much past 5pm. It may feel pleasant in the sunshine this morning but its only 7c and i'm getting a little fed up of it taking until early afternoon for it to warm up properly. Perfect weather for outdoor hobbies Eugene.

[Frosty.]

A cruel NW / SE divide looks probable if the GFS 06z verifies, high pressure will bring increasingly warm and sunny weather from later this week to southern britain, especially the southeast which could last a week and temps by sunday could be 22c 72f in london which will be hard for the marathon runners. NW Britain and more specifically NW Scotland will get the mucky end of the stick with strong sw'ly winds bringing outbreaks of rain and drizzle for much of the time and then the 6z gets into a bit of a frenzy once the high subsides with unsettled and cooler weather developing.

[Thundery wintry showers]

Again different people have different preferences and I think in fairness the people with differing views have given pretty strong reasons behind them.

I don't see much evidence of a 1994-style hairdrier on the latest GFS 06Z, the late April 1994 event had a very pronounced south-westerly in the last few days bringing sunshine towards the SE and cloud and rain towards the NW, whereas GFS/ECM both show high pressure centred a lot further north keeping the cloud and rain much further away to the NW.

GFS temperature outputs, given that they often underdo maxima slightly in these situations, are consistent with many places reaching 20C or above and the odd 23 or 24 can't be ruled out.

[Frank Trough]

Yes, wonderful looking charts for next week. The GFS was hinting at things warming up from the south for a while with the others not quite so sure - but now there is good agreement. I feel that it's a little bit wrong to be looking ahead to next week when, actually, it's been pretty glorious down here for a while when all things are considered.

I notice with some degree of chagrin that the GFS (in particular) has been consitent for a fair few runs now (i haven't been counting) in suggesting that some sort of breakdown will occur on Friday 30th. This is the first day of two weeks holiday for me! Actually, it's also bank holiday isn't it, so i guess i shouldn't be too surprised. I keep expecting it to shift back (like cold often seems to in winter) but it isn't...

[kold weather]

I think as Ian said given the models we are seeing today I'd imagine 23-24C would certainly be possible with the evolution by Monday/Tuesday. Still looks very dry as well it has to be said with a displaced Azores High dominating.

[summer blizzard]

GFS6z was a little cooler witht the high slightly further west, though still looking good for twenties and sunshine Monday-Thursday.

[Derp Patrol]

Eugene you must be joking lol. This time of Spring is usually not influenced by the atlantic, so you can expect winds from the south/east/north quite frequently.. nights will probably hold into double figures, maybe around 12C in the south.. but I think you'll be OK trying to get to sleep lol.. For me the warmer nights will be welcome, as at the moment as soon as the sun goes down it is too chilly to do much.

These past 2 weeks have offered a wide variety of wind directions here. It has been sunny and dry throughout, with northerly, easterly and brief southerly winds. Every day has been warm and pleasant though. It feels good that for the first time in a while I see 22C forecast for my area on Sunday Next week will be similar to this week in that it will be sunny and dry for most areas, but the only difference will be that it will feel much warmer and humid. I'd place a decent bet that we will reach 25C somewhere.

Edited April 21, 2010 by robthefool

[Thundery wintry showers]

Yes, I think you'd have to be sleeping in a room which is very exposed to sunshine and doesn't have any openable windows to have trouble sleeping in the sort of weather progged by GFS. In fact overnight minima may well fall close to the long-term normal at times in the progged setup- high pressure, clear skies and a warm airmass at this time of year usually translates to warmth emphasised through the daytime maxima. High minima are more likely when there's a strong maritime input, e.g. a humid south-westerly sucking tropical maritime air up from the Azores (admittedly if HP ends up further south and east than progged, we stand a chance of getting that, but the recent trend has been to place HP further north and west).

[Ben_Cambs]

I am liking the models very much at the moment, although I think the warmest air reaching the UK will only be a brief matter, as the HP retrogresses. In the meantime though, some unsettled weather for the NW of the UK at first later on this week, but elsewhere should be fine and dry, with plenty of sunshine with variable cloud amounts. Temperatures will slowly get warmer as HP builds northwards. 20C should be achievable from Sunday onwards. The latest output suggests that Tuesday and Wednesday being the warmest days of next week. Personally though I think there will be a breakdown to Atlantic weather by the first weekend of May, and this was suggested by the latest Met 6-15 day forecast, with a breakdown from the North-west spreading Eastwards.

[Stormyking]

I am liking the models very much at the moment, although I think the warmest air reaching the UK will only be a brief matter, as the HP retrogresses. In the meantime though, some unsettled weather for the NW of the UK at first later on this week, but elsewhere should be fine and dry, with plenty of sunshine with variable cloud amounts. Temperatures will slowly get warmer as HP builds northwards. 20C should be achievable from Sunday onwards. The latest output suggests that Tuesday and Wednesday being the warmest days of next week. Personally though I think there will be a breakdown to Atlantic weather by the first weekend of May, and this was suggested by the latest Met 6-15 day forecast, with a breakdown from the North-west spreading Eastwards.

Yes it does look that way, though not as warm as recent charts have shown but it looks very nice and yes 20c looks ncie might even hit a 21 or 22 in some parts

I think warmest looks next tuesday or wednesday.

[shaky]

would you believe it jus when think wer bout to have sum nyc weather on the way the ecmwf decides to do sum sort of u turn.its not lookin neraly as good as what it was showing a few days ago.it seems evrytym the ecmwf shows sumin that u want the gfs does not agree with it and vice versa whenever the gfs shows sumin that u want the ecmwf then decides to backtrack.has anybody else noticed this

[SP1986]

ECM was showing this this morning, I think we should take note of the ECM, I dont think it's to be ignored. A short, relatively warm spell for south and east but with copious amounts of rain in northwest and cool here, only real sunshine/brightness in the central areas/southeast.

I think this is a fair summary of what I expect to happen, I dont actually have much faith in the GFS outcome at the moment.

[Ben_Cambs]

Model performance stats from NOAA suggest that ECM is currently marginally the best perfoming model:

http://www.emc.ncep.noaa.gov/gmb/STATS/html/acz6.html

[Milhouse]

Going by the ecm which does become rather disappointing later on we would still get 5 dry and warm days which is certainly not to be sniffed at. Any breakdown cant be taken seriously at this point.

[damianslaw]

Signs that the atlantic is steeping into gear after a fairly lengthy period if inactiveness, nothing unusual for this time of year, indeed quite normal. Its influence will be felt in the far NW this weekend and probably more generally for the northern half of the country early next week, whereas the azores high wants to try and assert itself in the south - its a classic atlantic vs azores high battle, my money unfortunately is on the atlantic being more of the dominant force and eventually the south will feel its effects before we enter May, ECM seems to be onto this theme and the long range Met Office forecast also shows this, whereas the GFS wants to do one of its major switcharounds from dry settled to very wet and unsettled in the space of a day, whilst it will be much more gradual for many, again it is onto this theme. If the models continue to show a more unsettled atlantic theme developing next week in tomorrows outlooks then I think this the eventual theme has been set - goodbye dry and settled and hello wet cloudy and humid..still time for changes to this theme but the window is shortening..

[Thundery wintry showers]

Going by the ecm which does become rather disappointing later on we would still get 5 dry and warm days which is certainly not to be sniffed at. Any breakdown cant be taken seriously at this point.

Only for those of us who live in the southeast, and even in the SE, while it may be dry and warm it may not necessarily be particularly sunny. I must admit I really got taken in by those outputs earlier when there was cross-model agreement on high pressure extending well north and the murky tropical maritime airmasses being kept away to the far northwest of the country. The ECMWF shouldn't be taken as gospel but at the same time it shows that this warm sunny spell is not nailed on (the warmth is, but sunshine and even rainfall are subject to revision).

UKMO also allows SW'lys into the north and west but promises more in the way of warm sunshine for England and Wales in general.

[damianslaw]

Only for those of us who live in the southeast, and even in the SE, while it may be dry and warm it may not necessarily be particularly sunny. I must admit I really got taken in by those outputs earlier when there was cross-model agreement on high pressure extending well north and the murky tropical maritime airmasses being kept away to the far northwest of the country. The ECMWF shouldn't be taken as gospel but at the same time it shows that this warm sunny spell is not nailed on (the warmth is, but sunshine and even rainfall are subject to revision).

UKMO also allows SW'lys into the north and west but promises more in the way of warm sunshine for England and Wales in general.

Yes whilst a warmer theme is developing as we head into the weekend especially in the south east a switch from clean cold northerly airstream to a humid southerly/south westerly airstream with lots of moisture will probably mean much cloudier and murkier conditions and even under sunny spells the air will be much hazier, not the best direction therefore for guaranteed clear skies, for western and southern coasts misty murky weather could easily be the order of the day, eastern coastal districts will do best for sunshine I imagine.

[Costa Del Fal]

I hope the GFS is under estimating its temperatures! For example at Southampton on Monday. On the 12z it is expected to be 20c at 12pm. On the 18z its 18c at best by 12pm.

Seems like the classic downgrades on temps have begun. Still looks fairly good but at this rate it will jut turn out to be a normal spring day tbh!

Edited April 21, 2010 by Blizzards

[SP1986]

To be honest the whole patterns seems to be being downgraded, I expect this to be a case of cloudy and average temperatures soon, seems to be heading that way anyway.

I would not be surprised if a cold northerly pattern reasserted itself to be honest, within perhaps a week.

[Eugene]

Going by the ecm which does become rather disappointing later on we would still get 5 dry and warm days which is certainly not to be sniffed at. Any breakdown cant be taken seriously at this point.

Have to say i agree with you and lets not forget even though there has been a cool breeze this week and temps only 11C/12C yesterday it felt much much warmer in the blazing afternoon sun, was out walking about 15 miles in the lovely east warwickshire countryside yesterday and it was a magnifcent day with some amazing views, would recommend anybody to get out and about and visit ancient woodlands in their area or near me in the princethorpe/wappenbury area.

So if it felt really warm yesterday 18C is easily warm enough with sun.

[Eugene]

UKMO 00Z not looking so promising though with HP never really moving over the UK with LP moving in from the west, you cant complain though we've had lots of dry weather lately and the farmers do need some rain as the ground is rock hard with cracks showing, nothing like September 2008 when one member said the farmers were happy after those unseasonal floods in early September 2008.

http://www.wetterzentrale.de/pics/Rukm1441.gif

[Guest FireStorm]

goodbye dry and settled and hello wet cloudy and humid..still time for changes to this theme but the window is shortening..

I'm all for warm, dry & settled weather but wouldn't wet cloudy and humid weather suggest instability thus heightening the chances for thunderstorms (which is more preferred on a personal opinion)

[mushymanrob]

indeed eugene, this weeks weather (from tuesday) has demonstrated that temperature isnt the be all and end all. 11-13c here but in the sun it was gloriously warm and fresh. great weather for walking/working.

the dry theme continues, the 00z has a breif northerly in fi which might bring some precipitation as it changes but the spring drought continues. im getting concerned though that we will have to pay for this further down the line with dull wet weather dominating the summer again :lol:

[Thundery wintry showers]

I'm all for warm, dry & settled weather but wouldn't wet cloudy and humid weather suggest instability thus heightening the chances for thunderstorms (which is more preferred on a personal opinion)

Not if the wet, cloudy and humid weather is delivered by the tropical maritime airmass which is fundamentally stable, giving copious production of stratus and persistent light rain/drizzle. The longer-term outputs suggest that this airmass will be largely responsible for the cloudy wet weather, so convective/storm potential remains low (except for Sunday).

Thunderstorms are most likely to happen in a southerly type with low pressure trying to push in from the west and storms moving up from the continent, or a low-index pattern with pressure not too high, and storms kicking off due to solar heating of the surface, or the polar maritime type to the rear of cold fronts with cold upper air and a relatively warm surface leading to convection.

[Milhouse]

Have to say i agree with you and lets not forget even though there has been a cool breeze this week and temps only 11C/12C yesterday it felt much much warmer in the blazing afternoon sun, was out walking about 15 miles in the lovely east warwickshire countryside yesterday and it was a magnifcent day with some amazing views, would recommend anybody to get out and about and visit ancient woodlands in their area or near me in the princethorpe/wappenbury area.

So if it felt really warm yesterday 18C is easily warm enough with sun.

Not sure i agree with you. Towards the middle of the day it has warmed up significantly and has felt fairly pleasant. Either side of that however it has felt very cool indeed, and almost chilly in the morning in the breeze and out of the sun. We got down to -0.9 last night and with a max of just 12c forecast today its going to take a while to warm up to something approaching a respectable level. Mins of 7-9, maxes of 19-21c look quite likely early next week and in the sun that will feel lovely, and not too hot if you dont like the heat.