Spring Model Discussion 18Z 9/3/13 onwards....

[Zakos]

My view is the GFS is underestimating the block to the NE, mainly because the GFS does this pretty much every time we get a set-up like this.

The UKMO is more like what I expect to verify, though it maybe not be as epic of course

This chart would be very hard to beat.

However, regardless of whether the Atlantic manages to make inroads, there is still no sign at all of a breakdown to the upcoming cold spell.

Even if the Atlantic manages to bring milder air to the UK, the only plausible scenario I can see is for the low to undercut and the cold air to swiftly flow back across the UK.

A mild blip perhaps, but no breakdown in sight. I cannot see the depression winning this battle, the northern blocking is simply too strong and extensive.

The outlook is rather bleak for mild weather fans.

Edited March 17, 2013 by Zakos

[TEITS]

Very tasty charts for E Scotland/ far NE of England.

http://expert-images.weatheronline.co.uk/daten/proficharts/en/nae/2013/03/17/basis12/ukuk/weas/13031912_1712.gif

For my location and others further S it could become very interesting towards the end of the week. However im still uncertain of the output at +144 and also you do have to take into account the notorious correction S that often occurs. What is crazy though is next week could be even colder than this coming week!

[bobbydog]

http://www.meteociel...44-21.GIF?17-17

Heavy snow for the SW & the south -

Thats a historic chart.

S

if we get heavy snow here in the south east i'll eat my hat. (off to make a hat-shaped cake, just in case.....)

[SMU]

remember the UKMO 144 has NO mild air reaching the UK-

Why? because the curvature of the isoline that curves in through france is bent so much - warm air doesnt go around courners-

Same as cold air doesnt go around corners when we look at high pressures from the east sometimes-

UKMO is a prolonged freeze up-

http://www.meteociel.fr/ukmo/run/U72-580.GIF?17-16

Look at the cold air building at 72- just 1c for norwich MAX on weds........

It will all pile west on thurs & friday...

S

[cooling climate]

Nearly choked when I saw the UKMO run, what a belter for more southern

regions of the country.After watching the GFS run come out you could

easily see future runs trending further south with more of a undercut

and disruption. The reason I say this is the block to the north is

holding its strength better and also the frigid cold uppers to the

northeast are a lot closer to us.It is therefore no massive surprise to

see what the UKMO model is now showing giving the extra forcing on the

energy to the southwest to disrupt etc.

More runs needed of course and will be eagerly awaiting the ECM run this

evening but as others have already said there could be a fair bit of

snow to come for the some areas this coming week.

[Cloud 10]

if we get heavy snow here in the south east i'll eat my hat. (off to make a hat-shaped cake, just in case.....)

Hope you have strong teeth...

[chris55]

http://www.meteociel...44-21.GIF?17-17

Heavy snow for the SW & the south -

Thats a historic chart.

S

UKMO is a peach of a run tonight. And with those record low AO values the foundations these very wintry charts are based on a more solid foundation than maybe at other times.

Edited March 17, 2013 by chris55

[Joe Levy]

Well based on current model output, whatever happens I will be very pleased for those snow-lovers in the North-East and Scotland who get cold and snow this coming week and beyond. For the rest of us, there are also some brilliant possibilities being shown and if we're lucky, who knows! But it's been very interesting watching this spell of weather evolve, either way

[tinybill]

Hope you have strong teeth...

looking at the radar for 2-night it could be a bit nasty south-east 2 night

[Summer Sun]

Hope you have strong teeth...

Straw Clutching coming here

A good run in FI from GFS in that it finally starts to erode that pesky northern blocking

A southerly develops as the low backs west and the high to the east drifts south (just in time for a wet but mild Easter)

Edited March 17, 2013 by Gavin.

[LeeSnowFan]

UKMO run is absolutely stunning! going to be a good week for quite a few people!

I am hoping it will reach my area of south yorkshire we seems to miss out on alot of the good stuff.

looking at very cold temperatures this week and even into next week at the moment but still alot to play for! can't remember last time we had a MARCH like this!

[chris55]

As others have said eastern Scotland could well be buried next week, UKMO at 48 highlights this well,

And come Thursday the cold air and PPN is heading south,

Then we have Friday and beyond, jaw dropping stuff for the Cotwolds in March, and plenty of other places as well I should think.

[SMU]

UKMO is a peach of a run tonight. And with those record low AO values the foundations these very wintry charts are based on are more solid than maybe at other times.

The AO index currently at -2 is set to plummet to near record levels ~ -5.2 with a few runs off the scale sub -6.

IIRC the record ( of all time ) is -5.8

S

[rory o gorman]

GFS is pumping back warmer uppers for a time at my location next week before its all shunted back south , signs still remain in F.I of falling heights over Greenland.hopefully the ecm will come on board later.

[MR EXTREMES]

remember the UKMO 144 has NO mild air reaching the UK-

Why? because the curvature of the isoline that curves in through france is bent so much - warm air doesnt go around courners-

Same as cold air doesnt go around corners when we look at high pressures from the east sometimes-

UKMO is a prolonged freeze up-

http://www.meteociel...2-580.GIF?17-16

Look at the cold air building at 72- just 1c for norwich MAX on weds........

It will all pile west on thurs & friday...

S

it would be best not to bother with ukmo its been pretty poor the last few weeks uppers dont look cold enough for the south or southwest but se and northeasterns areas including northern england and scotland look like the wintry weather could last into april i do feel a more northern correction coming in later outputs.

[SMU]

it would be best not to bother with ukmo its been pretty poor the last few weeks uppers dont look cold enough for the south or southwest but se and northeasterns areas including northern england and scotland look like the wintry weather could last into april i do feel a more northern correction coming in later outputs.

How can you forecast to warm uppers from a chart that doesnt give uppers-

id imagine the 144 is good for everyone snow bar the extreme SW without elevation-

ideally post 144 you want the track south of the UK along the channel

S

[mushymanrob]

well, theres some difference between the gfs and ukmo, but i have considerable doubts as to any snow falls....

why?

track the low @t144 from t120. it moves in off the atlantic, pushing ahead of it milder air (as per the uppers on the gfs), before it turns and heads north. the similar gfs 850 profile highlights this. so unless the actual uppers for the ukmo, (or what we get should the sea level synoptic chart for this ukmo varify ), are much colder then what the gfs currently predicts, chances of snow are remote. theres more chance of snow showers off the north sea for northeastern areas then a dumping for the south...

however, these charts are far from varifying. we will probably end up with something in between.

i dont want to argue this, ive stated my pov and supported it with reason. i might well be wrong, so be it.

[stratty]

remember the UKMO 144 has NO mild air reaching the UK-

Why? because the curvature of the isoline that curves in through france is bent so much - warm air doesnt go around courners-

Same as cold air doesnt go around corners when we look at high pressures from the east sometimes-

UKMO is a prolonged freeze up-

http://www.meteociel...2-580.GIF?17-16

Look at the cold air building at 72- just 1c for norwich MAX on weds........

It will all pile west on thurs & friday...

S

........and it's only been 2C max here all day with about 6 hours of falling snow today. Certainly not like last year! lol I reckon there could be some hype over the never few days....will it come to fruition????? What wonderful model viewing

[mushymanrob]

How can you forecast to warm uppers from a chart that doesnt give uppers-

S

but the gfs does, and to t144 they are pretty similar.

[Cloud 10]

This March could be heading for the record books regarding the Arctic Oscillation.

The most negative March AO on record in the last 62 years was 1962,with a value

of almost -3

www.cpc.ncep.noaa.gov/products/precip/CWlink/daily_ao_index/monthly.ao.index.b50.current.ascii.table

Anomaly chart for March 1962

Anomaly chart for the first two weeks of March 2013

[mcweather]

well, theres some difference between the gfs and ukmo, but i have considerable doubts as to any snow falls....

why?

track the low @t144 from t120. it moves in off the atlantic, pushing ahead of it milder air (as per the uppers on the gfs), before it turns and heads north. the similar gfs 850 profile highlights this. so unless the actual uppers for the ukmo, (or what we get should the sea level synoptic chart for this ukmo varify ), are much colder then what the gfs currently predicts, chances of snow are remote. theres more chance of snow showers off the north sea for northeastern areas then a dumping for the south...

however, these charts are far from varifying. we will probably end up with something in between.

i dont want to argue this, ive stated my pov and supported it with reason. i might well be wrong, so be it.

I love your posts mushy. You always have doubts as to any snow falls. I don't want to arguethis either it just makes me chuckle

[mushymanrob]

I love your posts mushy. You always have doubts as to any snow falls. I don't want to arguethis either it just makes me chuckle

because we never see what the posts on here suggest we will unless its within 24 hours! :lol:

[Captain Shortwave]

but the gfs does, and to t144 they are pretty similar.

I guess I may been seem as pedantic here but the UKMO has all bar the south of England under a very cold continental flow (-8 uppers probably in a line from Norfolk through Birmingham into Wales). GFS has an atlantic moderated South Easterly for all bar the north East. Quite a difference. Also add much low dew points. You might want to compare the 06z and 12z charts over the Scandinavia area, little difference between the two runs. Huge difference with the uppers.... being much colder this run.

As for snowfall from the UKMO I could probably find a similar chart on a low of that type and position....... last week

Edited March 17, 2013 by Captain shortwave

[snowking]

but the gfs does, and to t144 they are pretty similar.

Im very bemused as to how you can suggest (even from the reasoning in your previous post) that the 144 hour charts from the GFS and UKMO are similar

About the only similarity between the two is the geographic grid they show.

The two biggest differences between the two, which will make monumental differences to the surface conditions, are the source of the flow and the placement of the frontal boundary.

The UKMO clearly has a flow sourced from the near continent for almost all of the UK, meaning lower dew points (which will likely prove the deciding factor in snowfall in the upcoming scenario). The GFS, on the other hand, brings in more of a SWly flow across southern areas, hence the snow-line being Midlands northwards. GFS also pushes through frontal system far sooner than the UKMO, a clear cut sign that its not thinking there will be as much resistance from northern blocking as say the UKMO or the ECMWF (from 0z on the latter of course). We've been in this situation many times before, and the only time I can recall the GFS being proven correct in such a situation is Dec 2012...even then, the biggest difference here is the hugely more prevalent northern blocking.

SK

[chris55]

well, theres some difference between the gfs and ukmo, but i have considerable doubts as to any snow falls....

why?

track the low @t144 from t120. it moves in off the atlantic, pushing ahead of it milder air (as per the uppers on the gfs), before it turns and heads north. the similar gfs 850 profile highlights this. so unless the actual uppers for the ukmo, (or what we get should the sea level synoptic chart for this ukmo varify ), are much colder then what the gfs currently predicts, chances of snow are remote. theres more chance of snow showers off the north sea for northeastern areas then a dumping for the south...

however, these charts are far from varifying. we will probably end up with something in between.

i dont want to argue this, ive stated my pov and supported it with reason. i might well be wrong, so be it.

If we take the 00z ECM at 144 you can roughly see what sort of uppers the UKMO 120 would be showing as the charts are pretty similar. And they are colder then the GFS for the same time. With a cold surface feed and 850s below say -2 that would be heavy snow for many away from the far South West.

GFS on the other hand has things further north and as you say a snow to rain event for many away from the far north and Scotland. So it is a case of the Euros v GFS at present, lots more to run on this one though I should think.