Winter Model Discussion - 12/01/13 06z Onwards

[BLAST FROM THE PAST]

Wat too much concern and clutter about will it snow here or there or anywhere. the cold is here, its getting colder and colder over coming days. This is just the start of it, enjoy.

BFTP

[johnholmes]

I suspect this has already been deleted by the mods but it really does need a reply

iowpompeylee, on 12 January 2013 - 13:19 , said:

With the ECM starting to swing.it looks like the temps. especially in the very south look a lot milder according to the met office.this cold snap might not be turning out to be what everyone thought.i do hope I'm wrong.been model watching for a week now chasing the holy grails of runs.....the runs tonight will rubber stamp the situations

Sadly it is a good example of what happens quite a lot on here and not just regarding quoting supposed Met O outputs.

Why on earth do you not read what is posted rather than making something up. Or maybe you are on a wind up which is perhaps why I can't find your original post?

READ and THINK BEFORE posting please?

[Methuselah]

Not a chance, JH!

[Paul T]

I have just had a trawl through all of the Weather charts from todays runs, and my main thoughts are:

-The ECM's evolution is very unlikely.

-Blocking to our North/North East is odds-on.

-The Low on Monday is modelled slightly differently on ALL models. Personnally, at present, anything West of Bristol doesn't have much of a chance, unless 250m+. However, just refer to the NAE charts for this along with the MO updates, and dont worry about other lower resolution charts in this time frame.

-Under cutting lows approaching from our NW will be likely from next Thrusday - driven by the power from the Polar vortex cold off greenland and Canada. This set-up usually drives horrid SW'rlys straight into the UK, but with sufficient blocking, France and Northern Spain are more than welcome to have them.

Have a good weekend,

Paul

Edited January 12, 2013 by Paul T

[Jezzer]

I suspect this has already been deleted by the mods but it really does need a reply

iowpompeylee, on 12 January 2013 - 13:19 , said:

With the ECM starting to swing.it looks like the temps. especially in the very south look a lot milder according to the met office.this cold snap might not be turning out to be what everyone thought.i do hope I'm wrong.been model watching for a week now chasing the holy grails of runs.....the runs tonight will rubber stamp the situations

Sadly it is a good example of what happens quite a lot on here and not just regarding quoting supposed Met O outputs.

Why on earth do you not read what is posted rather than making something up. Or maybe you are on a wind up which is perhaps why I can't find your original post?

READ and THINK BEFORE posting please?

John I think at times like these there are plenty of WUMs about. I think most members probably choose to ignore such statements, often the best way.

[iowpompeylee]

I suspect this has already been deleted by the mods but it really does need a reply

iowpompeylee, on 12 January 2013 - 13:19 , said:

With the ECM starting to swing.it looks like the temps. especially in the very south look a lot milder according to the met office.this cold snap might not be turning out to be what everyone thought.i do hope I'm wrong.been model watching for a week now chasing the holy grails of runs.....the runs tonight will rubber stamp the situations

Sadly it is a good example of what happens quite a lot on here and not just regarding quoting supposed Met O outputs.

Why on earth do you not read what is posted rather than making something up. Or maybe you are on a wind up which is perhaps why I can't find your original post?

READ and THINK BEFORE posting please?

hang on a minute the ECM has started drifting towards a milder outlook.and my met office temps for my area on the south coast are rising by the day.i love the cold more than anyone I can assure you.the things I have written on there are facts.ecm/temps and I said by tonight we should have a much better idea on snow chances for the uk on Monday and later in the week in my opinion. Edited January 12, 2013 by iowpompeylee

[stainesbloke]

There seems to be a warm sector on the second low which looks like hitting areas to the south of London, potentially ruining what would otherwise be a good snow event for me.

Too far away to be able to pinpoint snow with that degree of accuracy. No point stressing about it now.

[ChartViewer]

Anyway model related...NOGAPS 06Z........caveat that its NOGAPS

T72

T96

T120

T120 850's still cold

[Geordiesnow]

People got to bear in mind, the words "Some milder conditions and more persistent rain and hill snow though may fringe into western areas on occasions throughout the period." could very well be the classic case of an undercut with milder air coming from the Southerlies before switching to a SE'ly and perhaps Easterly and the UKMO model may hint at that.

I guess cold lovers got to hope the UKMO is onto something here but I would rather if the ECM come on board though but the ECM still does hint all is not lost even if it does turn a little milder by the end of the week.

[Frosty.]

It'd better be, or you're in trouble

As long as the internet works I would like 20 foot snowdrifts

I'm happy with the models so far today, the reliable timeframe is very cold with snow for many and sharp frosts with ice days, light years better than the drivel we have had so far this winter and it's an evolving situation, according to RJS the most severe wintry weather is yet to come so enjoy this taste of winter.. it's only an appetizer to the main event through late jan and throughout feb, GP and RJS are very respected posters and I am with them all the way

Edited January 12, 2013 by Frosty039

[lord stratus]

hang on a minute the ECM has started drifting towards a milder outlook.and my met office temps for my area on the south coast are rising by the day.i love the cold more than anyone I can assure you.the things I have written on there are facts.ecm/temps and I said by tonight we should have a much better idea on snow chances for the uk on Monday and later in the week in my opinion.

I agree you are only stating what's in front of you and it seems like eternity waiting for a cold spell that's being downgraded before its even started, however it maybe an idea to look at this evenings models to see how this is going. How many times have we heard that being said? Lol

[The PIT]

I agree you are only stating what's in front of you and it seems like eternity waiting for a cold spell that's being downgraded before its even started, however it maybe an idea to look at this evenings models to see how this is going. How many times have we heard that being said? Lol

Temps have been below average for the last few days so it's already started. What we're looking for now is how long it will last and this where the ECM and GFS earlier were/are throwing a spanner in the works. Thankfully we have moved away from a two dayer.

[fergieweather]

I've noticed that the GFS has consistently shown Monday's snow to change to rain for a time to the south of London only to then turn back to snow. Does anyone know why this might be?

Yes. It's an anomalous rise in WBFL: UKMO-GM had same issue yesterday for same time and area and was manually amended.

[manutdmatt1986]

Yes. It's an anomalous rise in WBFL: UKMO-GM had same issue yesterday for same time and area and was manually amended.

So are you saying you are currently expecting rain south of London, Ian?

[chionomaniac]

I agree you are only stating what's in front of you and it seems like eternity waiting for a cold spell that's being downgraded before its even started, however it maybe an idea to look at this evenings models to see how this is going. How many times have we heard that being said? Lol

How a cold spell can be downgraded when it is still in the process of being modelled I do not know! I suggest that you go and look at the predicted surface temps for the next few days. Even Portsmouth may see ice days on Tuesday and Wednesday.

[Snowman31]

Yes. It's an anomalous rise in WBFL: UKMO-GM had same issue yesterday for same time and area and was manually amended.

Sorry but what does this mean?

[Luke Best]

Yes. It's an anomalous rise in WBFL: UKMO-GM had same issue yesterday for same time and area and was manually amended.

WBFL = Wet Bulb Freezing Level

Extract taken from http://weatherfaqs.org.uk/node/64:

Wet Bulb Freezing Level

Because evaporative cooling is so important in rain versus snow forecasting (see the main FAQ entries, here and here), the wet-bulb 0degC level is a better guide to snow-risk level than the actual ZDL. The wet-bulb is the lowest temperature to which air can be cooled by evaporating water into a sample, which is a mechanism often important in determining whether it will rain or snow at or near the surface. However, note carefully that advection, both cold and warm must be taken into account - the former is particularly important in marginal situations in the vicinity of a well-marked cold front.

Edited January 12, 2013 by Luke Best

[fergieweather]

People got to bear in mind, the words "Some milder conditions and more persistent rain and hill snow though may fringe into western areas on occasions throughout the period." could very well be the classic case of an undercut with milder air coming from the Southerlies before switching to a SE'ly and perhaps Easterly and the UKMO model may hint at that.

I guess cold lovers got to hope the UKMO is onto something here but I would rather if the ECM come on board though but the ECM still does hint all is not lost even if it does turn a little milder by the end of the week.

They lean towards potential milder (of sorts) interlude later in week, as suggested by growing number of EC ENS with SW bias, followed by northerly outbreak. Exeter at pains to stress (again!) ongoing record Shannon entropy and whilst broadscale wig-outs continue from output across all NWP, they don't want us to veer from strong signal in FORMOST for cold to effectively characterise things through into early Feb.

[weatherguy]

So are you saying you are currently expecting rain south of London, Ian?

Sorry but what does this mean?

Essentially it means it's a model error, and they're expecting just snow rather than a random change to rain inbetween.

[Jason H]

Looks like it's been modelled incorrectly to rise hence why some forecasts showing raw data have it as rain.

[Iceni]

People also ought to bear in mind that even in a legendary winter like 62/63 there were milder periods where the top layer of snow actually melted then refroze a couple of nights later. As a girl, I can remember being able to walk on icy surfaces with a couple of foot of snow underneath.

Obsessing over milder interludes is rather silly when the snow took 3 weeks post thaw to completely disappear from some fields around here in 2010.

[cold snap]

Ive grown and learnt that looking where the ppn might fall is a utter waste of time.looking at the models is actually more benficial than ppn charts.

Lets see what happens once we get the cold in.remember over the years the models have backtracked from low presure systems and the main ppn providers have come from convection.

[Snowman31]

Essentially it means it's a model error, and they're expecting just snow rather than a random change to rain inbetween.

It can't be though as they have manually written that it will turn to rain in their warnings and forecasts. If they thought it was an error then they wouldn't have amended their forecast surely?

[fergieweather]

Next NAE run/modifications due around 1515hrs. Should be fascinating if last run was anything to go by!

[manutdmatt1986]

It can't be though as they have manually written that it will turn to rain in their warnings and forecasts. If they thought it was an error then they wouldn't have amended their forecast surely?

Maybe that's just because there's a bit of uncertainty? I don't know, I'm confused.