Model Output Discussion

[k19]

I think if you held a vote here, the general concencus would be the fax charts are up

there as the most reliable.

Possibly in the very short range but I don't see the FAX charts as having any more reliability than the GFS or ECM when you long beyond 72 hours. Kind of like the nmm

[bluearmy]

PE - you are funny sometimes. posters can decide to believe you or to believe the ecm ens members from the 00z run.

http://www.meteogroup.co.uk/uk/home/weather/services/ensemble-forecast.html

op and control in good agreement that despite no rainfall, temps in london will just exceed 21c. i wouldnt have thought that the 'heat island effect' will play much part in london temps on tuesday. i'd say that your 19c will be closer to the mark for wednesday rather than tuesday. the T120 FAX due out soon and that will show how much the met office have altered their thoughts over the past 24 hours for monday. its a complex scenario with the shallow low moving ne over us. ecm still keenest to develop a shortwave, ukmo the least so.

[k19]

What front? Misleading nonsense, Stop it.

This chart shows a warm front pushing north, not a cold front pushing east.

No I believe a cold front does push over first, but then as you can see the centre of pressure over Paris 'pivots' a warm front back upwards. I believe this may be what people think may cause storms?

[Costa Del Fal]

Hmm the 18z GFS looks like pushing the warmer uppers etc further East with this run with the High pressure decaying quicker. Perhaps falling in line more with the ECM/UKMO now. :/

A Monday breakdown becoming a little more likely now. Still could change in which In hope it does but could of UKMO had this right all along?

There is one upgrade and thats the Greenland High.

Edited June 23, 2011 by Blizzards

[bluearmy]

What front? Misleading nonsense, Stop it.

This chart shows a warm front pushing north, not a cold front pushing east.

i'm sure that there will be a cf connected to whatever verifies, be it a defined shortwave or just a trough. and i expect it has to move west to east, clearing the hot uppers away as it passes through.

some of you getting excited by gfs cape values beware. they are notoriously unreliable several days in advance.

[PubliusEnigma]

Hmm the 18z GFS looks like pushing the warmer uppers etc further East with this run with the High pressure decaying quicker. Perhaps falling in line more with the ECM/UKMO now. :/

Agreed. certainly of late the GFS seems to be falling into line behind the UKMO the nearer one gets to T+0

[chionomaniac]

i'm sure that there will be a cf connected to whatever verifies, be it a defined shortwave or just a trough. and i expect it has to move west to east, clearing the hot uppers away as it passes through.

Yes, may be eventually. My annoyance arrives at the use of out of date fax charts two days running!

[feb1991blizzard]

Yes, may be eventually. My annoyance arrives at the use of out of date fax charts two days running!

Those were the latest ones available at the time. Thats like saying the 12z GFS is out of date because the 18z hasnt yet come out. Anyway anyway the longjevity of any hot spell is likely to be downgraded not upgraded on the 18z FAX.

[SP1986]

18z represents a disappointing runs for western areas (western England and Wales), especially on the main day, Sunday, low pressure moves in very quickly, and this everything is a little further east. For those further east it still looks good with some high temperatures and high humidity.

[Harry]

No I believe a cold front does push over first, but then as you can see the centre of pressure over Paris 'pivots' a warm front back upwards. I believe this may be what people think may cause storms?

Not entirely sure I agree...the low moving up from France with a CF attached is a continental, thundery Low spawned (I suspect) as a result of the mass surface heating/moisture rising under prevailing High pressure. The CF is a result of the low drawing in cooler air from the atlantic behind it, with the warm front pushing warmer air from the continent northwards.

That chart suggests to me (although in slight contrast with GFS) a threat of further thunderstorms moving towards the SE...in my view.

[mountain shadow]

There is one upgrade and thats the Greenland High.

Edited June 23, 2011 by mountain shadow

[SP1986]

I have to admit after the warm spell, the run does seem like one of the worst runs I've seen in recent time (not including FI). High pressure tries to ridge but it looks very chilly (5-6C below average day and night), especially with the dry air that follows.

I'm thinking this is more in line with signals? Although I hope not and I'd like to think the ECM is correct.

I suspect though that the 18z will be one of the coolest runs on its ensemble suite between the 28th June and the 4th July.

[feb1991blizzard]

GFS 18z even brings the 0c isotherm over NW Britain again although because of the range its probably odds against to verify.

[SP1986]

Ensembles show that the operation was not one of the cooler runs as I originally thought might be the case. Very very disappointing if you live in the west, a little better if you live in the east. This year has, and almost certainly will continue to contain many instances of NW/SE splits.

I cannot recall a summer when 20C has been so difficult to reach going into July (although to be fair my memory only goes back broadly 10 years), even 2007 delivered its fair share of days over 20C in June and July!

[Backtrack]

Ensembles show that the operation was not one of the cooler runs as I originally thought might be the case. Very very disappointing if you live in the west, a little better if you live in the east. This year has, and almost certainly will continue to contain many instances of NW/SE splits.

I cannot recall a summer when 20C has been so difficult to reach going into July (although to be fair my memory only goes back broadly 10 years), even 2007 delivered its fair share of days over 20C in June and July!

I'm not sure about you, but we've hit 20C on over 12 days this month.

[mushymanrob]

forget the iminant hot blip, for most itll be humid, milky skies/bright, becoming cloudier then wet... thunder? im not so sure that there will be alot of thunderstorms about dispite the synoptics.

the big three all agree though that from tuesday onwards the azores high will nudge in, so a proper area of high pressure should bring ever clearer skies for all as it drifts across us. maybe not as potentially hot as whats coming on sunday, but fresher, brighter, sunnier, skies will feel like summer proper.

into fi. IF the high centres to our east, then we might get a decent shot at a proper thundery spell, one that has time to build.

my only concern on the gfs 00z is that massive area of high pressure greenland/canada... that might push the weak jet south and not allow a euro high.

outlook... promising!

[mountain shadow]

You must be looking at different models to me Mushy, looks wet, wet and wet over here from now till doomsday.

[ANYWEATHER]

You must be looking at different models to me Mushy, looks wet, wet and wet over here from now till doomsday.

The Azores high is more dominant on the latest gfs run, however the latest Ecm run low pressure is certainly more dominant! :blink: Lots of changeable weather coming up in the days ahead, the Thunderstorm risk is still there ,notouriously difficult for the models to pick up untill the last minute, a little bit like snow in Winter!!

[Frosty.]

Having just looked at the latest gfs run today i'm seriously beginning to wonder whether there will be a summer this year in northern and especially nw britain because it appears like low pressure will continue to plague nw scotland well into july with hardly any respite from the cool cloudy rainy dross and this has been the situation since march/april. Southern britain should be ok with high pressure ridging up from the azores at times and a general band of high pressure to the south of the BI should ensure some dry and warm weather at times across the southern half of the uk and occasionally very warm in the southeast but for most of the north it looks like the mainly pathetic summer will continue to dribble away with low pressure dominant.

[Gibby]

Nearing the hot snap now. here's the latest from GFS, UKMO and ECM.

GFS makes for a humid damp start tomorrow but the overnight rain is shown to move off with brighter, sultry conditions spreading up from the south. Sunday would be dry and hot in England and Wales with more cloud and some rain in the NW. By Monday a trough moves gently east promoting some thundery activity, especially for the SE on Monday and Monday night as cooler air moves slowly in from off the Atlantic to other areas. By Wednesday cool NW winds cover the UK with some showers in the North and West with temperatures back down to normal values. High pressure rebuilds temporarily from the south delivering another fine second weekend before the Atlantic wins through again by the 4th. Thereafter until the end of the run winds maintain a westerly element with High pressure to the SW and Low to the North with rain or showers at times, chiefly in the North and temperatures not far from normal.

UKMO is very similar with a somewhat thundery trough lurking near SE England on Monday night into Tuesday. After a hot and sunny Sunday with perhaps the odd shower or storm overnight for many Monday will also be very warm or hot in the SE. Through the day cloud would increase from the west with thundery showers breaking out in the SE as cooler, fresher air invades Western Britain by Tuesday with winds turning towards the North. The thundery conditions may linger in the SE for a while but by the end of the run winds have settled into a fresher and cooler westerly as high pressure rebuilds from the Azores.

ECM continues to make more of a thundery breakdown for a larger portion of England as a closed centre of Low pressure develops to our south on Monday night/Tuesday meaning after Sunday and Mondays heat increasing amounts of thundery activity slide up from the SSW Monday evening and night giving locally very heavy rainfall for a while before fresher conditions move in on Tuesday as the Low transfers from Brest to the North Sea. Wednesday then sees much fresher conditions for all with westerly breezes and some showers in the North and West. By Thursday the Azores high builds back over Southern Britain temporarily giving a fine day or two before pressure falls once more as Atlantic Low pressure takes control to end the run with rain, showers and cool conditions returning.

In Summary this morning after a hot day or two things are set to turn much cooler by the middle of next week. The nature of the transformation between the hot and cool will be marked by a cold front. GFS and UKMO seem to make little of this as it moves east giving some rain and the possibility of thunder in the SE on Monday Night/Tuesday. ECM on the other hand shows a wave on the front developing a closed thundery Low pressure centre which would deliver more widespread thundery activity and heavy rain in the same time frame as it moves up through Southern Britain and then out into the North sea. Thereafter things simplify with things slowly getting back to normal as the Atlantic regains control with just brief ridges and associated fine weather mixed with periods of widespread unsettled conditions as per the ECM run and to a lesser degree with GFS.

[Downpour]

Having just looked at the latest gfs run today i'm seriously beginning to wonder whether there will be a summer this year in northern and especially nw britain because it appears like low pressure will continue to plague nw scotland well into july with hardly any respite from the cool cloudy rainy dross and this has been the situation since march/april. Southern britain should be ok with high pressure ridging up from the azores at times and a general band of high pressure to the south of the BI should ensure some dry and warm weather at times across the southern half of the uk and occasionally very warm in the southeast but for most of the north it looks like the mainly pathetic summer will continue to dribble away with low pressure dominant.

This post is a classic example of why the proper regional forums should be relaunched. The reality is that the SE and NW have very different climates – I remember being shocked last summer when I left London in glorious warm sunshine only to arrive in Manchester to very chilly temps and torrential rain. I just could not believe the difference – but there we are. The NW is wet and cold, the SE almost continental in its climate: semi-arid and rather pleasant.

The truth is most people in and around London don't really care if Manchester or Scotland are having rubbish weather. We simply want to know the prospects for the SE. Therefore, with the best will in the world, for many weather watchers down here, moans and grumbles from people in the rain-drenched NW are just noise.

[Eugene]

Not a very impressive hot snap at that gibby, its almost July so temps around 25C for most in england isnt exactly that hot, a blink or miss it affair really, ECM 12Z is horrific for those wanting extended hot weather.

http://www.wetterzentrale.de/pics/Recm2401.gif

[Bale]

The way the models are chopping and changing who knows what itl be like after the weekend the Meto update yesterday was for pretty unsettled weather to continue that said you cant even rely on them looking at back at some of the predictions they make...all i can say is enjoy the warmup if we get it and the sunshine...depending where you live and if it turns up at all...so in summery the charts are about as useful as a chocolate teapot....no wonder the ITV national weather only go to one day the majority of the time

[Nick F]

Not a very impressive hot snap at that gibby, its almost July so temps around 25C for most in england isnt exactly that hot, a blink or miss it affair really, ECM 12Z is horrific for those wanting extended hot weather.

http://www.wetterzentrale.de/pics/Recm2401.gif

I know that your posts are designed specifically to downplay anything hot or warm, but UKMet have a heat warning out for later this weekend/early next week, admittedly only going to be SEern UK that will probably see 30C+:

http://www.metoffice.gov.uk/weather/uk/heathealth/

I agree that it looks to turn somewhat cooler again everywhere by mid-week, though it looks like warming up again next weekend, as pressure falls to the west and NW again.

[chapmanslade]

Not a very impressive hot snap at that gibby, its almost July so temps around 25C for most in england isnt exactly that hot, a blink or miss it affair really, ECM 12Z is horrific for those wanting extended hot weather.

http://www.wetterzentrale.de/pics/Recm2401.gif

No but just over in central France as high as 41C on Monday with a mimimum of 24C !