Model Output Discussion

[Coast]

Please use this thread to discuss the latest model output.

[Frosty.]

A cold weekend ahead according to the GFS 00z with wintry showers, falling as snow over hills and low ground in northern scotland, damaging frosts returning as well but no shortage of sunshine. By early next week it looks like becoming more settled but with an ongoing frost risk. The rest of this week shows today and tomorrow being warmest in the southeast with 21c today and possibly squeezing 23c tomorrow but for most it's a 16-19c temp range and lower than that in scotland and n.ireland with rain at times, the unsettled and cooler weather should reach all areas by friday.

[ANYWEATHER]

Well as we are approaching May ,Im sure some folks will be looking for signs of some heat! Well this chart sums it up really, looks more like a Winter chart rather than a May Chart! A cold outlook for the Bank Holiday weekend but having said that certainly not a wash out with high pressure nearby.

[Frosty.]

Good model agreement now between the GFS and ECM 00z for a strong N'ly flow for the holiday weekend with some improvement indicated by monday as a ridge topples across cutting off the cold air supply and therefore reducing the shower potential, over the weekend the airmass looks like being cold enough for snow showers in northern scotland and hills of northeast england but a mixture of rain/hail/sleet generally and a risk of thunder as the flow looks like being very unstable for a time and given the strength of the sun in early may, overnight frosts will also be a problem. As we look into next week, there are hints that the main centre of high pressure could remain out in the atlantic and the uk would then be open to attack from the north or northwest as the ecm 00z shows.

[rmc1987]

Good model agreement now between the GFS and ECM 00z for a strong N'ly flow for the holiday weekend with some improvement indicated by monday as a ridge topples across cutting off the cold air supply and therefore reducing the shower potential, over the weekend the airmass looks like being cold enough for snow showers in northern scotland and hills of northeast england but a mixture of rain/hail/sleet generally and a risk of thunder as the flow looks like being very unstable for a time and given the strength of the sun in early may, overnight frosts will also be a problem. As we look into next week, there are hints that the main centre of high pressure could remain out in the atlantic and the uk would then be open to attack from the north or northwest as the ecm 00z shows.

Sounds horrible...! Cold, frosts and wintery showers, what on earth! To me sounds bad if looking for even a half decent summer! Best enjoy today and tomorrow as what's to follow sounds plain nasty at this time of year after this!

[Archie_Lewis]

Good model agreement now between the GFS and ECM 00z for a strong N'ly flow for the holiday weekend with some improvement indicated by monday as a ridge topples across cutting off the cold air supply and therefore reducing the shower potential, over the weekend the airmass looks like being cold enough for snow showers in northern scotland and hills of northeast england but a mixture of rain/hail/sleet generally and a risk of thunder as the flow looks like being very unstable for a time and given the strength of the sun in early may, overnight frosts will also be a problem. As we look into next week, there are hints that the main centre of high pressure could remain out in the atlantic and the uk would then be open to attack from the north or northwest as the ecm 00z shows.

HORRIBLE... May bank Holiday and a chart like that... Could not think of anything worse.

Its actually boring, anyone who thinks that wintry precip will fall south of Scotland is living in dream land as the may sun is just too strong.

Maybe some hail in the heavier showers

Leave the wishing and looking for snow until next winter please.

In sunny breaks it will actually feel quite pleasant, even if the flow is from the North. Especially in sheltered southern areas. So not all bad.

[Stormyking]

I reckon Its quite Interesting of what could be coming up as I love all weather, though I hope this coldness coming won't last too long because even though I like some cold but prefer warmth or hot, but still the models are quite Interesting and i spose really good for cold lovers .

[reef]

HORRIBLE... May bank Holiday and a chart like that... Could not think of anything worse.

Its actually boring, anyone who thinks that wintry precip will fall south of Scotland is living in dream land as the may sun is just too strong.

Maybe some hail in the heavier showers

Leave the wishing and looking for snow until next winter please.

In sunny breaks it will actually feel quite pleasant, even if the flow is from the North. Especially in sheltered southern areas. So not all bad.

If people look forward to wintry showers at this time of the year (Im one of them due to the novelty factor) then that is entirely up to them. If everyone had the same views then it would be a very boring place. Some people are weather enthusiasts and enjoy unusual weather, not necessarily just cold in winter and warm in spring/summer.

That chart shown from the 00z would indeed produce wintry showers. If anything, the stronger sun would increase convection and increase the intensity of the showers making it more likely to produce sleet/snow. You have to bear in mind that solar heating only affects the bottom layer of the atmosphere, in 850hPa temperatures of sub -5C, theres every chance of wintry showers at any time of the year. In heavier showers that 0C isotherm would fall and snow could make it to the ground.

The 6z seems somewhat different to the ECM/GFS 00z runs, it will be interesting to see where it lies on the ensembles.

[BlueHedgehog074]

HORRIBLE... May bank Holiday and a chart like that... Could not think of anything worse.

Its actually boring, anyone who thinks that wintry precip will fall south of Scotland is living in dream land as the may sun is just too strong.

Maybe some hail in the heavier showers

Leave the wishing and looking for snow until next winter please.

In sunny breaks it will actually feel quite pleasant, even if the flow is from the North. Especially in sheltered southern areas. So not all bad.

Depends on the setup. A cold consitant Northerly wind can still bring in enough cold air to bring wintry weather to the South of Northern England, with cold 850 upper temperatures and very low Dewpoint temperatures (although I did learn this from one or two members). I think it either was in May or June in 1996, where some areas to the South some snow, so it's not impossible.

However, I think there would be a few too many obstacles in the way for the Southern areas to see some wintry weather this weekend, though, perhaps if the temperatures dropped enough during any spells of precipitation, some soft hail or sleety rain could fall for a time.

Mind you, the ECMWF 00Z update does look a little more favourable.

Edited April 27, 2010 by Rainbow Snow

[mushymanrob]

oak/ash update... this morning i saw loads of ash flowers appearing, especially on young trees. however the oak is well infront of the ash.

i know theres no law stating the a wet summer WILL follow a dry spring, indeed 75, 76 proves that wrong. over the years though i find that when a lengthy dry spell breaks, it often breaks with avengance. this has what happened in recent summers after pretty dry springs.

the models currently and broadly agree that over the weekend and after (ironically) some much needed precipitation, the general theme is cool and dry. i dont expect this pattern to shift with any haste, so its down to the detail to determine what we will get. its looking like with slackish northeasterlies low dull cloud will plague the east again whilst the west gets the best of any sunshine which will be very pleasant.

[Damp and dreary]

Well, my apple tree started blossoming the other day, ive heard that this can sometimes be seen as a sign of possible pork chops for my dinner....

Edit: sorry boredom got the better of me, my birthdays on may the 1st and i was going to have a BBQ dognamit!

Edited April 27, 2010 by jasonuk

[NorthantsSnow]

Sounds horrible...! Cold, frosts and wintery showers, what on earth! To me sounds bad if looking for even a half decent summer! Best enjoy today and tomorrow as what's to follow sounds plain nasty at this time of year after this!

What's to enjoy about today and tomorrow? Mild and mostly cloudy with a bit of hazy sunshine poking through occasionally?

I'm looking forward to the cooldown suggested by the models and some more interesting weather for the UK. I can't remember the last time it lashed it down with rain, looks like Sunday may bring an end to the dry spell.

[summer blizzard]

Personally, i see nothing major to worry about in the models at the moment.

The summary i would give of the model output is that from tommorow, it will turn showery and humid until next sunday/monday when pressure looks to build again to the north and east, though with high pressure values maxima will likely remain fairly high.

Outlook then looks fairly dry, quite sunny, and fairly average in temperature.

I have to laugth at some of the doom mongers on here, the nearest we get to anything other than high pressure is at 336 hours out, northing warm on the horizon, but nothing cold either.

[NW Leeds Russ]

Have to agree..

Im certainly very keen on the future models particulary Sat 8th May as Im doing the 40mile keswick to barrow walk / run that day.

My ideal conditions are slack N or NE flow, cool and sunny as i'm heading SW all the time. I particularly don't want a headwind...

At present this looks possible..

Any more thoughts anyone on that day. FI I know at present..

[Derp Patrol]

HORRIBLE... May bank Holiday and a chart like that... Could not think of anything worse.

Its actually boring, anyone who thinks that wintry precip will fall south of Scotland is living in dream land as the may sun is just too strong.

Maybe some hail in the heavier showers

Leave the wishing and looking for snow until next winter please.

In sunny breaks it will actually feel quite pleasant, even if the flow is from the North. Especially in sheltered southern areas. So not all bad.

Yes that is one good thing about northerlies at this time of year, they are rarely that cold and they tend to give a lot of sunshine which helps to keep temperatures up. I could only see snow falling on hills and mountains in Scotland if at all. But like you said, especially in southern areas, temperatures will stay in the low teens at least (which is still below average for the time of year). 10 days or so ago we did very well out of a northerly and got pleasant mild days of 16-17C in lots of sunshine.

[Thundery wintry showers]

HORRIBLE... May bank Holiday and a chart like that... Could not think of anything worse.

Its actually boring, anyone who thinks that wintry precip will fall south of Scotland is living in dream land as the may sun is just too strong.

Maybe some hail in the heavier showers

Leave the wishing and looking for snow until next winter please.

Depends on the setup. A cold consitant Northerly wind can still bring in enough cold air to bring wintry weather to the South of Northern England, with cold 850 upper temperatures and very low Dewpoint temperatures (although I did learn this from one or two members). I think it either was in May or June in 1996, where some areas to the South some snow, so it's not impossible.

The first post is a classic example of personal preferences dominating one's perception of the charts are showing, and, in particular, the swipe at those who don't follow the "ingroup"'s view that "frost and snow is great in winter, but the worst thing since World War II in spring" is the sort of thing that belongs in banter/whining threads, not in the Model Output Discussion.

The northerly with snow in the south Rainbow Snow refers to is probably the one on 6/7 May 1997, which saw sleet and snow showers over a large majority of the country- also the middle third of May 1995 had fairly widespread sleet and snow showers, but these were mainly reserved for the Midlands northwards. If 850hPa temperatures are around -8C or below over a wide area (as some runs have shown for the coming Sunday/Monday), sleet and snow showers can be expected to occur widely regardless of how late in the season it is.

The GFS's version of the northerly over the May Day weekend looks like it would bring a rather different outcome to many other progs because it has the low pressure further west and the precipitation outputs suggest a front draped around the low. Therefore, a good deal of "cold rain" and extensive cloud cover could be expected in the east, as opposed to other outputs which suggest sunshine and wintry showers- a similar thing happened at the end of March this year when an outlook for sunshine and wintry showers was turned into a dull raw wet one for most as LP ended up further west.

For the most part though the emphasis looks to be on dry sunny warm weather being pushed away south-eastwards over the coming couple of days with a cool showery regime establishing by Friday. It is notable that the cold northerly blast is set to coincide with the Bank Holiday weekend- but history teaches that this is nothing unusual, take the extreme instance in Easter 2008 for example.

[conor123]

Personally, i see nothing major to worry about in the models at the moment.

The summary i would give of the model output is that from tommorow, it will turn showery and humid until next sunday/monday when pressure looks to build again to the north and east, though with high pressure values maxima will likely remain fairly high.

Outlook then looks fairly dry, quite sunny, and fairly average in temperature.

I have to laugth at some of the doom mongers on here, the nearest we get to anything other than high pressure is at 336 hours out, northing warm on the horizon, but nothing cold either.

I wouldn't call single figure maximum's 'nothing to cold' http://www.wetterzentrale.de/pics/Rtavn12617.png

Very chilly weather for the time of year with high pressure staying to far west for things to settle down again.

[rmc1987]

What's to enjoy about today and tomorrow? Mild and mostly cloudy with a bit of hazy sunshine poking through occasionally?

I'm looking forward to the cooldown suggested by the models and some more interesting weather for the UK. I can't remember the last time it lashed it down with rain, looks like Sunday may bring an end to the dry spell.

Been sunny and 20c here today some cloud has bubbled up now but the day has been pretty good. Sunday was fairly wet and cloudy here...

Edited April 27, 2010 by rmc1987

[The PIT]

A very wintry GFS in FI land. It will be interesting the volcano goes pop again as the ash will be on it's way back. ECM on it way out now will it agree.

[Cheese Rice]

I wouldn't be surprised at all if there was snow from the upcoming northerly, even down south, as long as the -5 850's can establish itself then all we need is a decent northerly flow. Last spring (09) there was heavy now with a temperature of 3.5c all the way down to sea level, anyone that is dismissing snow needs to have look at past events to see it really is possible.

OT anyone see "the one show", they were at the meto and they showed computer screens with GFS charts on (and it looked like Net weather website!)

[Thundery wintry showers]

ECM keeps low pressure away to the east so eastern parts get two potentially wintry blasts out of this, the first would give widespread showers, the second probably light showers mainly for eastern areas.

A north-easterly btw will still tend to give bright showery conditions rather than low cloud, even in early May, if 850hPa values are around -6C or below- this was illustrated around 12 May 1995, 3 May 1996 and 16-18 May 1996. However if we start seeing more "stable" north-easterlies cropping up on later outputs then low cloud becomes a major possibility- stable northerlies/north-easterlies were frequent in the dull dry May of 1991.

Overall it shouldn't be too unexpected that we're seeing outputs like this- northerlies are traditionally more frequent in May and early June than at any other time of the year, and many recent Mays have been notable for their anomalous lack of northerlies.

[mushymanrob]

What's to enjoy about today and tomorrow? Mild and mostly cloudy with a bit of hazy sunshine poking through occasionally?

yeah terrible isnt it?

bizarre...

well next week is looking pretty cool but i reckon sunshine levels will be high after the weekends rain. a huge northern block eventually gives us some easterlies but these could end up being quite warm off a warming continent.

[Eugene]

What's to enjoy about today and tomorrow? Mild and mostly cloudy with a bit of hazy sunshine poking through occasionally?

I'm looking forward to the cooldown suggested by the models and some more interesting weather for the UK. I can't remember the last time it lashed it down with rain, looks like Sunday may bring an end to the dry spell.

Disagree with first sentence but agree with first part of second even though it did come down pretty heavy sunday morning but not for long here, i guess you missed it in northants which is a dry county.

19C on my car thermometer yesterday afternoon/early evening and it felt very warm outside, good job i have air conditioning in my car and can have it nice and cold inside

May be lots of sunshine next week with a cold northerly(potential for wintry showers too) but a completely different feel to the weather than yesterday and today with much colder dewpoints and a cold wind, i wont be seeing too many pasty legs next week good job

yeah terrible isnt it?

bizarre...

well next week is looking pretty cool but i reckon sunshine levels will be high after the weekends rain. a huge northern block eventually gives us some easterlies but these could end up being quite warm off a warming continent.

lol putting a very brave face on it arent you, GFS 00Z is a terrible run for you i agree

Looking forward to the cold nights with temps around 0C all next week?,,, i doubt it

Warming up easterlies isn't towards the end of FI, yes bizarre looking that far ahead and even then easterlies don't always deliver great sunny weather in May anyway, very poor run synoptically for the warm fans, the last few days must of got them in the mood but next week is a big shock to them and all the short wearers

Edited April 28, 2010 by Eugene

[Eugene]

Looks like a wet start to May, the first half of this week i think will give the public false hope that summer is here for good unfortunately not in the UK.

http://www.wetterzen...ics/brack2a.gif

Could be the first of three poor bank holiday weekends this May to September, never understand why they dont have them in the most reliable period for nice weather in the UK that being mid July to mid August, the Scots have more sense to arrange theirs for early August not at the end when the atlantic can pick up after a nice August.

Edited April 28, 2010 by Eugene

[phil nw.]

Yes good model agreement for this colder spell from the weekend.

Shame for me too as i was just enjoying my golf without wearing extra layers to keep out the chill of previous weeks.

With an upper ridge placed just to our west and troughs moving South over the weekend it looks quite chilly and damp by Saturday and then a few days of below average temps to follow with some night frosts.

Edited April 28, 2010 by phil n.warks.