Model Outlook Thread: January 2010

maquiladora

dloob wrote: »

Sky News weather at lunch time had widespread snow for sunday.

Good to see the GFS, BBC and Sky in agreement but Sunday is a long way off in terms of snowcasting....

WolfeIRE

Felixdhc wrote: »

Do we not need -8 uppers for snow? Certainly looks slightly milder for a couple of days.

As far as I know Felix, snow can fall when it is -2c at 850hpa. The 850 is regarded as about 1300 to 1500 metres. So, the lower it is the colder it is likely to be at the surface. I could have got that arseways but that is my understanding.

Timistry

Meh, not liking the charts for the west. 850 temps are too marginal and precip wont be intense enough to ensure snow at lower levels. We live in hope though. Sunday seems VERY interesting to say the least:D. Looks like our chance of some decent snow in the south. N, E, W have had theirs.... its our turn:p

munsterlegend

maquiladora wrote: »

Good to see the GFS, BBC and Sky in agreement but Sunday is a long way off in terms of snowcasting....

it is a long time alright but even issuing a warning shows a fair amount of confidence in the uk. look very good for southern ireland and might just be the big event we all hoped for on a countrywide scale. also at least its not coming from the atlantic which can just as easly be a wintry mix.

munsterlegend

Timistry wrote: »

Meh, not liking the charts for the west. 850 temps are too marginal and precip wont be intense enough to ensure snow at lower levels. We live in hope though. Sunday seems VERY interesting to say the least:D. Looks like our chance of some decent snow in the south. N, E, W have had theirs.... its our turn:p

yeah it will be very marginal but will have a better idea tomorrow how far inland it will make it. if only sunday was tomorrow...!

maquiladora

munsterlegend wrote: »

it is a long time alright but even issuing a warning shows a fair amount of confidence in the uk. look very good for southern ireland and might just be the big event we all hoped for on a countrywide scale. also at least its not coming from the atlantic which can just as easly be a wintry mix.

There are hints that the cold spell may be coming to and end in the middle of next week so this could indeed be our last chance at a nationwide snow event, it'll be interesting but a bit too far away to get excited about.

12Z ECM will be very interesting....

munsterlegend

maquiladora wrote: »

There are hints that the cold spell may be coming to and end in the middle of next week so this could indeed be our last chance at a nationwide snow event, it'll be interesting but a bit too far away to get excited about.

12Z ECM will be very interesting....

uk met office outlook have it cold for another two weeks and even then they have low confidence in a change!

maquiladora

munsterlegend wrote: »

uk met office outlook have it cold for another two weeks and even then they have low confidence in a change!

Oh I know, its only hints that it might be coming to an end next week, it only take a few runs for those to vanish again. :pac:

munsterlegend

maquiladora wrote: »

Oh I know, its only hints that it might be coming to an end next week, it only take a few runs for those to vanish again. :pac:

yeah i hope gfs is right about sunday though and wrong about mid week changes. i am getting a little tired of the crawling traffic though!

Scubadevils

Sunday night into Monday, pretty widespread but light precip?

dloob

maquiladora wrote: »

Oh I know, its only hints that it might be coming to an end next week, it only take a few runs for those to vanish again. :pac:

The Donegal postman says it will be cold for another two weeks at least.
The Foxes have come down from the hills and the blackbrids are nesting near the farms you see.

WolfeIRE

dloob wrote: »

The Donegal postman says it will be cold for another two weeks at least.
The Foxes have come down from the hills and the blackbrids are nesting near the farms you see.

he also reported that two hares were doing the siege of ennis in the barn, while a crow has built a nest in his hair (always a sure sign that the weather will be cold):P

Felix - yes that is light precip. Monday's chart is better though

maquiladora

Felixdhc wrote: »

Sunday night into Monday, pretty widespread but light precip?

GFS isnt good at nailing precip intensity, also, even if it remained light it looks like quite a long lasting period of precip so accumulations could build over time.

force eleven

maquiladora wrote: »

There are hints that the cold spell may be coming to and end in the middle of next week so this could indeed be our last chance at a nationwide snow event, it'll be interesting but a bit too far away to get excited about.

12Z ECM will be very interesting....

Well, for the mild weather to return, it will have to shift this really cold air. This sort of scenario rarely goes without a major battle somewhere between the mild and cold. Shades of 1947 in fact. Worth pointing out that 1947's winter didn't get going until the end of January....

Gonzo

also we have last 2 weeks of January, all of February and 1st week or 2 of March to play for. Could well be another cold snap or spell before winter is finished.

Deep Easterly

ECM 12z at 144hrs:



In line with this morning's UKMO, with low pressure attack from the SW. Significant wind chill despite a very slow rise in temps.

Snowaddict

The latest UKMO Fax Chart at T+72, shows an organised area of snowfall spreading Westwards from Central Britain, it also has a frontal system moving up from the Continent towards Southern England, which is expected to spread Westwards in the general Easterly flow. This is the current snow potential that is being discussed.

Renewed Snow Showers are almost a given with the setup being modelled - ''Deep cold pool over a body of open water''.. However, it is the more organised event that is still very uncertain.

ECMWF just about manages to avoid a breakdown in the Cold Spell, with continuous blocking and southerly tracking lows throughout. I have to check the 850mb temperatures in a while, however at T+144, the approach of that low is very favourable for sustaining cold. Notice the ''delfection'' in the angle of approach, as it comes up against a very cold block of air in situ over the UK & Ireland, with a slight easterly flow again at T+168.



SA

Those are warm fronts moving in from the continent-I don't like the idea of that
Look at the circulation origin thats throwing them up.
It's originally from the south jetstream and one of the lows that we would normally get thats currently are slamming into spain ,portugal and Italy.

That 528 dam line needs to be watched as they may drive it foward.
I'd also like to see even slightly sub 528 over Ireland

Anyhow shur we'll see thats a week away probably.

Deep Easterly

Both the UKMO and ECMWF runs keep the cold coming throughout their runs this morning, if somewhat less severe than in recent days. Both models continue to show a low pressure attack from the SW during the middle of next week, conflicting only in terms of strength:

UKMO 00z at 144hrs:


Bitter winds from the SE as low deepens to the SW. Temps will probably rise a little but wind chill will not make it feel any warmer, in fact, the contrary may well be the case.

ECMWF 00z 144hrs has the same theme, if a little less intense:


How near the frontal zone to the SW gets to our SW and S coast could well be the next big talking point next week; but between then and now, stay warm folks, and look after those are really becoming crippled by this ongoing cold the best ye can.

Prior to the above,if we in the short term end up looking south east for our weather,thats not initially as bad as it sounds given that the track is still over a now frozen UK and the track includes a frozen near continent.
Even Brittany is freezing with snow now.

Also I note that the M5 buoy is actually colder than M2 this morning and with a dp of -1.2c.

Snowaddict

Morning everyone

With regard to the potential weekend, event, ECMWF is showing this to be mainly an event for Eastern & Southeastern areas. More marginality is mentioned after Monday because as shown on last night's UKMO Fax Chart, a warm front will approach from the Continent later in the weekend, marking the boundary between very cold and less cold upper air. However, its worth bearing in mind that with all of the snowcover now, we can easily generate our own cold pool that can modify precipitation falling.

This does appear to be mainly an event for the above areas, as indicated on the overnight ECMWF charts, however small changes could bring the precipitation further north & inland.

At the moment, counties most at risk appear to be Waterford, Kilkenny, Wicklow, Wexford, Carlow, Kildare & Dublin, with Louth and Eastern areas of Northern Ireland also being at risk somewhat later on. County Kerry also appears to be at risk.



850mb temperatures will become less cold next week, with a more continental Southeasterly airflow being established. However, there will still be a significant wind chill factor, with much less of a diurnal temperature range.

SA

maquiladora

06Z GFS is showing snow showers for the east Friday, for the east and southeast Saturday and then on Sunday the east, southeast, south and midlands could see snow showers. From Monday to Tueday there is a risk the showers could turn more to rain.

maquiladora

I know it's not a very reliable model for our neck of the woods, but since this is the model thread, what the heck...from the US Navy... :pac:

arctictree

BB - you must be excited about these charts? Deep sourced siberian easterlies?



Isn't this what you've been talking about for years?!

A

Deep Easterly

maquiladora wrote: »

I know it's not a very reliable model for our neck of the woods, but since this is the model thread, what the heck...from the US Navy... :pac:

What a versatile bunch they really are. When they are not invading oil rich countries, poisoning our world with gross armaments and calling everyone "sir", they are churning out medium term weather forecasts.

Gee whizz....

arctictree

arctictree wrote: »

BB - you must be excited about these charts? Deep sourced siberian easterlies?

Isn't this what you've been talking about for years?!

A

Oh without a doubt,I'm keenly following Mt's thoughts on those.
Pressures a tad high but in these situations you can have and have had shallow areas of low pressure form in the irish sea that aren't modeled and form quickly.
I remember one of those in january '86 that formed off wexford and delivered several inches to the East coast counties including meath,Dublin,Wicklow and wexford.

Thats some thing to watch.

Snowaddict

On the Lunchtime Broadcast, it was mentioned by John Gormley that Gerard Fleming of Met Eireann was present at today's emergency meeting.

John Gormley also revealed that Gerard Fleming told them that is was conceivable that this could last for at least another ten days. Therefore, there must a good 40% + perturbations in the latest ECMWF Ensemble suite indicating a continuation of these conditions.

The overnight Operational ECMWF evolution was more bullish about this continuation also, with winds generally coming from a variable Easterly vector throughout.

For example: T+216



The crunch comes later next week as to how the evolution progresses, if low pressure does not make inroads across the country & there is no rapid breakdown, then this could easily redevelop and become potent again.

UKMO say there is a signal for slightly less cold conditions, beginning around the 17th, but that has been mentioned on & off with the past several days, with the date being continually pushed further out..

Next week is really the ''crunch''. If we see a favourable evolution, with undercutting lows not making inroads & a renewed displaced Polar Vortex, then this general pattern could be locked in for some time.

SA

Gonzo

I think it's best this cold spell ends early next week. Most of us have not been able to go out properly over past 3 weeks, Ive had many social events ruined/cancelled/postponed. The cold spell made this the quietest Christmas ever. College was cancelled this week and but we hope to attend our exams next week. Its been very difficult to walk over a mile to get to the village on a sheet of ice over past 3 weeks. There has been many accidents, people in hospital from broken bones after falling. I am hoping for a mild breakdown from Sunday and normality can resume for everyone as soon as possible. A this stage I really dont mind if we dont see a cold spell/snap again till next winter.

squonk

Gonzo wrote: »

I think it's best this cold spell ends early next week. Most of us have not been able to go out properly over past 3 weeks, Ive had many social events ruined/cancelled/postponed. The cold spell made this the quietest Christmas ever. College was cancelled this week and but we hope to attend our exams next week. Its been very difficult to walk over a mile to get to the village on a sheet of ice over past 3 weeks. There has been many accidents, people in hospital from broken bones after falling. I am hoping for a mild breakdown from Sunday and normality can resume for everyone as soon as possible. A this stage I really dont mind if we dont see a cold spell/snap again till next winter.

That sort of talk could get you banned

maquiladora

12Z GFS is a downgrade for snow showers from the Irish Sea tomorrow, compared to the 06Z, show a lot less precip on Friday.

Edit : Also less precip from the Irish Sea for Saturday morning on this run.