Model Output Discussion

[snowmadchrisuk]

ECM flips again seems to flip every run these days. GFS still icebergs at dawn. Surprised the thread is so quiet.

Ecm does indeed take the Low further North , but I don't know if anybody here has actually looked but it still brings the cold uppers across the Country.

[Cheese Rice]

yep i did thanks.. its just the bbc forecast has 9c for wednesday and surely if it was under this cold it wouldnt be 9c even for glasgow! http://news.bbc.co.u...r/forecast/2190

I wouldn't take much notice of the 5 day forecasts, having said that for here it would be 3.c and snowing on Wed if the 5 day forecast is correct

[Eugene]

yea i can see why they are not on now.. this is only going to be a sleety spell of wet snow and temps around 4c with no frost due to cloud and it will be back to 9c on wednesday.....

Actually you are probably spot on with your analysis there apart from the no nighttime frost bit, temps can easily rise to 9C at the end of March, somewhere in the UK is bound to record it on wednesday onwards as this time of year it would be very abnormal not too even in a cold spell, night temps is where this time of year the real cold is as it almost always is.

[frostyjoe]

Actually you are probably spot on with your analysis there apart from the no nighttime frost bit, temps can easily rise to 9C at the end of March, somewhere in the UK is bound to record it on wednesday onwards as this time of year it would be very abnormal not too even in a cold spell, night temps is where this time of year the real cold is as it almost always is.

thats for glasgow too and much of northern ireland... and for leeds to have 3c.. hmm the gfs must be flicked over the wrong way lol!

[Ben_Cambs]

This is what GFS 12z said about Tuesday/Wednesday PPN wise:

http://expert.weatheronline.co.uk/daten/proficharts/en/2010/03/26/basis12/ukuk/rart/10033006_2_2612.gif

http://expert.weatheronline.co.uk/daten/proficharts/en/2010/03/26/basis12/ukuk/rart/10033012_2_2612.gif

http://expert.weatheronline.co.uk/daten/proficharts/en/2010/03/26/basis12/ukuk/rart/10033018_2_2612.gif

http://expert.weatheronline.co.uk/daten/proficharts/en/2010/03/26/basis12/ukuk/rart/10033100_2_2612.gif

Everywhere would see snow if GFS 12z pulled off.

[frostyjoe]

This is what GFS 12z said about Tuesday/Wednesday PPN wise:

http://expert.weathe...3006_2_2612.gif

http://expert.weathe...3012_2_2612.gif

http://expert.weathe...3018_2_2612.gif

http://expert.weathe...3100_2_2612.gif

Everywhere would see snow if GFS 12z pulled off.

why is there snow in south and hail in the north for a while?? thats rare!

[Ben_Cambs]

why is there snow in south and hail in the north for a while?? thats rare!

The grey dots represent the types of cloud cover, the map shows NI being affected by snow showers. If you are on the North Western flank of the front, you are likely to see something wintry. Scotland, NE England and NI will see snow showers interspersed with sunshine (If this run pulled off)

[Eugene]

Can't see 9C in glasgow on wednesday joe but you never know at this range.

This really is a fantastic chart for snow fans, this is the best kind of chart for heavy snowfall in late March.

http://www.wetterzentrale.de/pics/Rtavn842.png

[Cheese Rice]

*RAMP* *RAMP* *RAMP*

Smashing GFS run for Monday/Tuesday, for me I could be seeing very heavy snow from 9AM Monday to Wednesday 11PM, GFS snow depths show 20cm for parts of Yorkshire above 100m. But if the snow lasts for that long there could be over 35cm of snow!!!!

Edit: And half of the UK under at least 5cm of snow!

Edit: Max of 1.c on Wednesday even though it will be sunny!

Edited March 26, 2010 by 10123

[damianslaw]

I usually trend with the ECM model at least when it comes to the medium term except when a northerly scenario is programmed, if this is the case the GFS tends to perform much better.

Very difficuly to call where any low level snow may fall early next week if indeed at all. Certainly higher ground in southern scotland, cumbria and the Pennines in particular look in with a good chance of some heavy snow. Where the precipitation is heaviest this will add evaporative cooling which is most marked at this time of year than any other, lapse rates will be very high in the cold uppers so this will help lower temps at low levels very rapidly. Location will also be a determining factor, places on the north and west flank of the front will be in the colder air.. Just have to wait and see.

Longer term, signs of shortwave development to the north and north west near Icelan which looks conducive to another low developing to our north west probably on thursday taking a similiar track to Mondays and Tuesdays low, whether following this we are locked into a similiar pattern or not remains to be seen. Signs that heights will be ridging down from greenland killing off chance of shortwaves which would aid a deep seated prolonged northerly for easterly, equally we could see the jet flattening, however, those heights do look very robust over Greenland so a quick return to mild south westerlies doesn't look likely.

An interesting week ahead - best type of synoptics in my book at this time of year, such synoptics have potential to spring up some quite severe localised wintry weather most likely in the north.

Edited March 26, 2010 by damianslaw

[Geordiesnow]

Ecm does indeed take the Low further North , but I don't know if anybody here has actually looked but it still brings the cold uppers across the Country.

Those are the ECM 00Z runs uppers, the 12Z ones have not been updated yet but i suspect as the low is further north, the milder air will be aswell.

18Z GFS is the same as the 12Z regarding the low so thats some good news if you are hoping for the potential of seeing snowfall for perhaps the last time for many months.

[frostyjoe]

The grey dots represent the types of cloud cover, the map shows NI being affected by snow showers. If you are on the North Western flank of the front, you are likely to see something wintry. Scotland, NE England and NI will see snow showers interspersed with sunshine (If this run pulled off)

lol sorry silly me i thought that resembled hail... if this is the case that we will be getting snow showers and sun that would be quite good actually... nice sunshine then snow... thats everything i want.. heres glasgow forecast.. http://news.bbc.co.uk/weather/forecast/6

[ian34]

*RAMP* *RAMP* *RAMP*

Smashing GFS run for Monday/Tuesday, for me I could be seeing very heavy snow from 9AM Monday to Wednesday 11PM, GFS snow depths show 20cm for parts of Yorkshire above 100m. But if the snow lasts for that long there could be over 35cm of snow!!!!

Edit: And half of the UK under at least 5cm of snow!

Edit: Max of 1.c on Wednesday even though it will be sunny!

exactly ramp ramp ramp i hope this doesnt happen call it off!!!!!!!!!!!!

[Eugene]

Milder from thursday but still on the cool side with showery rain and lots of cloud cover.

[johnholmes]

probably on thursday taking a similiar track to Mondays and Tuesdays low,

eh?

Am I missing something?

The first low-the main one starts life way SW of the UK, the next one starts life w or sw of Iceland, so how can they follow 'a similar track', at least not until they have got east of the UK, assuming they both do that?

Maybe its just me being a bit thick?

[NorthantsSnow]

The 18z is actually an 'upgrade' if you like on snow potential for many areas given the snow tends to get its act together in the evening rather than the daytime, so more chance of accumulations. Upper temps look cold enough for snow even at lower levels, with rain turning increasingly to snow as the low gradually pulls away and the colder air digs in behind.

As far as the model inconsistencies go, the ECM has been changeable lately whereas the GFS has barely shifted at all in its output, so for that reason I am not too concerned about the ECM at the moment. The GFS also has support from the UKMO.

More outputs needed, but at the moment I'm very optimistic for another bash at winter proper before I give in to the prospect of months of mundane weather with the odd storm thrown in if I'm incredibly lucky.

I expect the Met Office are monitoring this closely and upgraded advisories will likely follow tomorrow / Sunday.

Edited March 26, 2010 by NorthantsSnow

[johnholmes]

In terms of model accuracy, using the NOAA checks, at 5 and 6 days UK Met was just leading. By day 6(T+144) none of the models have been doing that well recently.

IF, GFS/Extra verified, then there is no doubt that by Tuesday evening there would be a fair amount of wet low level snow at low levels. Take a look at the 850mb, zero isotherm, dewpoint and temperatures its forecasting.

By then, mind you, IF its correct , many low lying areas would have had well over 1 inch of rain, so flooding might well be something of a problem. Remember though, this far out, we only have GFS to go on. Its track record for getting amounts of precipitation and the area affected are far from good-very variable in fact. My experience as duty forecaster on here and trying to get rainfall amounts in the right area for preliminary Watches certainly showed this.

I expect the Met Office are monitoring this closely and upgraded advisories will likely follow tomorrow / Sunday.

there is already a Met advisory out for heavy rain with snow for some.

[Cheese Rice]

eh?

Am I missing something?

The first low-the main one starts life way SW of the UK, the next one starts life w or sw of Iceland, so how can they follow 'a similar track', at least not until they have got east of the UK, assuming they both do that?

Maybe its just me being a bit thick?

I think he means when the low is moving over the UK it will have a similar track of Mondays low.

...

Latest BBC forecast finished on Sunday with the snow globe at the end, long time no see

Edited March 26, 2010 by 10123

[NorthantsSnow]

In terms of model accuracy, using the NOAA checks, at 5 and 6 days UK Met was just leading. By day 6(T+144) none of the models have been doing that well recently.

IF, GFS/Extra verified, then there is no doubt that by Tuesday evening there would be a fair amount of wet low level snow at low levels. Take a look at the 850mb, zero isotherm, dewpoint and temperatures its forecasting.

By then, mind you, IF its correct , many low lying areas would have had well over 1 inch of rain, so flooding might well be something of a problem. Remember though, this far out, we only have GFS to go on. Its track record for getting amounts of precipitation and the area affected are far from good-very variable in fact. My experience as duty forecaster on here and trying to get rainfall amounts in the right area for preliminary Watches certainly showed this.

there is already a Met advisory out for heavy rain with snow for some.

Yes, I noticed this earlier John. But I suspect should the models continue with their output there will be some modifications made in the next couple of days in order to widen the coverage zone and also provide more detail on the expected weather types, precipitation amounts, etc.

[johnholmes]

I would imagine the first area to get a 'snow warning' will be Shetland, for heavy showers turning to snow through Sunday into Monday?

[davehsug]

Is it going to get colder? We seem to have gone from 1 page a day to 4 today! Also. now that winter is over & we're well into spring, would you mind not talking about charts that show colder weather as "upgrades", I assure you that for many of us, they are most definitely downgrades!

Spring weather will always swithch around from mild to cold. Snow is not uncommon in April, but please don't keep seizing on every model chart that shows a few flakes of snow as if it's January!

Rant over.

[johnholmes]

Is it going to get colder? We seem to have gone from 1 page a day to 4 today!

spot on Dave-I noticed that after being out today until mid afternoon; its always a good 'guide' to the type of weather checking the changes in people logging on, especially into the model thread.

[Cheese Rice]

Is it going to get colder? We seem to have gone from 1 page a day to 4 today! Also. now that winter is over & we're well into spring, would you mind not talking about charts that show colder weather as "upgrades", I assure you that for many of us, they are most definitely downgrades!

Spring weather will always swithch around from mild to cold. Snow is not uncommon in April, but please don't keep seizing on every model chart that shows a few flakes of snow as if it's January!

Rant over.

Not another post...

There is the "Anyone fed up of the cold?" thread to voice your opinon

http://forum.netweather.tv/topic/62030-anyone-fed-up-of-the-cold/

[Rob]

I would imagine the first area to get a 'snow warning' will be Shetland, for heavy showers turning to snow through Sunday into Monday?

i would expect so john and then the warnings further south and east late monday for the Tuesday Evening/Night event.

[Derp Patrol]

Looks like a brief cold spell from Tuesday to Thursday, possibly some areas recieving some snow, but most likely in northern areas, I see no chance of snow for anywhere down south thankfully. Thursday onwards looks set to get milder again and hopefully we can pull up some nice warm air from the south soon, I'm getting bored of shivering to death - it was cold all winter, and the last thing I need now is temps of 6C and cold rain..