winter model discussion Winter Model Discussion 06Z 17/02/13 onwards.

[full_frontal_occlusion]

Never has so little meant so much to so few It's like Jesus is gonna make a speech to his disciples for the first time.

Jesus wept.

ffO.

[Average Joe]

Here's a brief summary of Met O very latest thoughts going forward (based now on 00z output) –

Weekend - Confidence remains high for conditions continuing cold, mostly dry and generally rather cloudy. There's some uncertainty concerning snow shower risk affecting mainly southern parts (the stratocumulus tops are forecast to be reaching up around -12C and thus broadly quite effective for producing PPN via the Bergeron-Findeisen Process), although any accumulations from these likely to be small and so broadly considered inconsequential (i.e., in formal scale of warning criteria etc.).

Next week: Mon-Weds – High confidence continues for cold, settled, mostly dry and largely cloudy story. There’s a low risk of snow showers still affecting some coastal areas of the south early in the period. Some likelihood of sunnier spells gradually becoming more widespread to the west. Temps might return to around normal in the NW

10-15d trend period: Initially remaining settled if mostly cloudy, mostly dry and rather cold. Ensembles agree that high pressure will tend to re-assert itself while sinking slowly S or SE over the UK next week – i.e., as in recent EC EPS output or moving SE into the near continent, as signalled per 00Z MOGREPS-15 and NCEP. Either way, the net result will be a relaxing of the much colder easterlies; a gradual recovery in temperatures next week by day (BUT with continuation of some very cold, frosty nights – this is of course dictated by cloud cover) and through into the 10-15d period, a migration slowly towards a milder anticyclonic SW’ly type. Equally, there’s an increasing likelihood of unsettled conditions spreading to NW’n parts in particular, albeit Exeter stress the timing of this change remains subject to “significant uncertainty†for now. Nonetheless, any snow signal during the eventual transition is showing as “quite weak generally†according to Exeter’s analysis. Meanwhile, the SE, especially, looks well-favoured to hang-on to dry, settled weather right through all; this phase, which bodes very well for that region into the start of March.

Hope this helps

Ian

Thank you so much for this. Whilst (sometimes) it's interesting to read the contrast in opinions in terms of what the models are showing, it's nice once in a while to get a summary of what that's likely to mean in terms of what's ahead in the coming week or so. This sums it perfectly.

[fergieweather]

PS - here's the 06z GFS profile for Heathrow at 06z on 22 Feb.... for comparison to the representative SE England tephi from UKMO-GM I posted earlier.

Edited February 18, 2013 by fergieweather

[Cheshire Freeze]

Meanwhile the CFS remains steadfast in its blocking scenario for March

Looks a close match to MJO phase 8

Edited February 18, 2013 by CreweCold

[Frosty.]

I think 'v slight risk' is underplaying it: I'm sure a few districts will see light snow showers periodically. As Exeter stress, there's inevitable uncertainty on this element of the forecast at current juncture - let's await the higher-resolution closer to the time. However, embedded UK4-km modelling extended into Fri-Sat showers very limited accumulations, it has to be said. But that's a consistent part of the story thus-far anyway.

Will there be major travel disruption Ian? We have some relatives coming up from london on friday, and my viewing of the latest models shows the peak period for wintry ppn being friday/saturday unless timings change. I think the windchill factor in the south is really worth highlighting as it will make temps of +1 or +2 celsius feel closer to minus 8 to minus 10c, very dangerous for some. Edited February 18, 2013 by Frosty039

[Don]

Meanwhile the CFS remains steadfast in its blocking scenario for March

No sign of Spring showing on that! A shame that it doesn't have much support currently?

Edited February 18, 2013 by Don

[Cheshire Freeze]

No sign of Spring showing on that! A shame that it doesn't have much support currently?

It's been showing the same blocking anomaly for the best part of a month. Obviously means little at this stage, though it's food for thought.

One common theme (along with a + pressure anomaly ranging from Greenland across Scandi) is lower heights across the continent.

Edited February 18, 2013 by CreweCold

[No Balls Like Snow Balls]

Well if the UKMO anaylsis rings true and the high sinks South then us soft Southerners can perhaps expect a fairly mild/warm start to spring (once this cold spell is out the way). Then all you Northerners can moan at us again for IMBY warmth comments - by the way only joking so don't take offence

Edited February 18, 2013 by No balls like Snow Balls

[BLAST FROM THE PAST]

Well yesterday the online forecasts from the MetO and the BBC were definately going for 4C Wednesday and 2C Thursda for London, so if anything they've added 1C to that foreacst. The 8C forecast was for Tuesday, which seems reasonable (GFS is even saying 9C under +3C uppers)

I know that because I was going to reply to your silly posts that seem to have an issue with virtually everything the Met Office says. Their forecasts seemed perfectly reasonable to me as I've experienced similar lapse rates, e.g 13.3C lapse rate under Feb 09 easterly with max of 1.3C from -12C uppers, and that was earlier in the year and with lower pressure and some snow showers about.

MetO are going for 1C max's widely in the SE on Friday and 1/2C on Thursday which sounds about right and is similar to what they showed yesterday, also slightly lower than the GFS shows.

Thats because the forecast I saw did show 8c for Wed and 4c was also muted by someone on here for the weekend although I didn't see that, so there we go. The forecasts now look right re temps and the drop is quick, bitterly cold outlook. Nice re lapse rates...

BFTP

Because destructive criticism of others is simpler and more self-serving than just accepting that one's own forecasts might sometimes be crap?

Thats rich coming from you Pete!!

Anyway 1c maxima is really really cold in my books indeed ice days are likely....not bad for back end of winter folks? Some whitestuff needed now to top it off

BFTP

Edited February 18, 2013 by BLAST FROM THE PAST

[Mac_SE]

Will there be major travel disruption Ian? We have some relatives coming up from london on friday, and my viewing of the latest models shows the peak period for wintry ppn being friday/saturday unless timings change. I think the windchill factor in the south is really worth highlighting as it will make temps of +1 or +2 celsius feel closer to minus 8 to minus 10c, very dangerous for some.

At this stage surely too far away to guess, especially given the models only suggesting shower activity for the SE corner rather than any organised bands of heavy snow across the UK.

[Panayiotis]

Meanwhile the CFS remains steadfast in its blocking scenario for March

I dont really follow these CFS maps but if you have, can you say they have performed well this winter?

[Timmytour]

I remember it being Thursdays in the winter of 1956. It happened week after week atleast on the IOW.

Isn't there a thing about the number 7 in nature...."every seventh wave" etc?

The far from disappointing snowfallls I've had this year have all been very weekend based. Could be more than just a coincidence i suppose?

I'm now hoping every seventh day there's a dramatic shift in the Meto's expectations of what lies ahead for us :lol:

[Interitus]

It's been showing the same blocking anomaly for the best part of a month. Obviously means little at this stage, though it's food for thought.

One common theme (along with a + pressure anomaly ranging from Greenland across Scandi) is lower heights across the continent.

The CFS is just rolling out the next run and it is completely different.

[PolarWarsaw]

Thanks Ian, as expected then. Dry for all bar 1-5%< of us, accumulations little to non and main threat, ice or slippy paths from frost. Not poor in the sense of there is cold in place, but snow chances very poor to minimal for virtually the entire country. Anticyclonic, cold, fry and occasionally foggy/misty.

Edited February 18, 2013 by PolarWarsaw

[Cheshire Freeze]

The CFS is just rolling out the next run and it is completely different.

Each actual CFS run will be. You need to look at the anomalies

http://www.meteociel...0&mode=4&run=10

At 700 hours out you don't want to be viewing every single run like you do the GFS. GFS FI is bad enough. The anomalies smooth all of this out.

Edited February 18, 2013 by CreweCold

[nicknacknoo]

Thanks Ian, as expected then. Dry for all bar 95%+ of us, accumulations little to non and main threat, ice or slippy paths from frost. Not poor in the sense of there is cold in place, but snow chances very poor to minimal for virtually the entire country. Anticyclonic, cold, fry and occasionally foggy/misty.

Should be excellent for most then!

[Interitus]

Each actual CFS run will be. You need to look at the anomalies

http://www.meteociel...0&mode=4&run=10

Yes, and?

[Timmytour]

It's clear we've had enough of those over- cautious dimwits at the Meto. They need to be replaced and I think I've come up with some good candidates....

http://www.express.co.uk/news/uk/277583/Arctic-blast-to-bring-snow

Below-average temperatures at the end of this month, next month and December will bring frequent heavy flurries across the whole country.

James Madden, long-range forecaster for Exacta Weather, said: “I expect the most frequent and heavy snowfalls to occur across many parts of the UK during November, December, and January.

“I also expect November, December, January, and February to feature largely below average temperatures. It is likely that temperature and snowfall records will be broken.â€

World forecasters World Climate Service said “unusual cold†and “disruptive snow†would arrive in weeks with a mini ice age set to last for decades, bringing bitterly cold winters.

Senior meteorologist Richard James said: “We expect another winter of unusual cold and occasionally disruptive snow from the British Isles and France across Germany and southern Scandinavia to the Baltic states.

“The highest likelihood of unusual cold appears to be in early to mid-winter (late November to January), with moderating conditions possible by February.â€

These two look the sort of guys who would be telling us what we want to hear from the current set of models. I particularly admire the way Richard James seemd to hit the nail with his head with his prediction for last year...

[Cheshire Freeze]

Yes, and?

Well it's a forecast tool so use it as you like (or don't in your instance). No need to be rude over the issue. Maybe you can bring some indications to the table as to where we may be headed through March?

Or are quips and a dismissive attitude your main focus?

Edited February 18, 2013 by CreweCold

[Interitus]

Each actual CFS run will be. You need to look at the anomalies

http://www.meteociel...0&mode=4&run=10

At 700 hours out you don't want to be viewing every single run like you do the GFS. GFS FI is bad enough. The anomalies smooth all of this out.

Yes, I looked at the anomalies and it is totally different.

[Methuselah]

Thats rich coming from you Pete!!

BFTP

That's not fair, Fred... But if I am guilty of ritually slating the Met, I 'umbly apologize!

The models are still indicating cold & dry, I see...

[Cheshire Freeze]

I dont really follow these CFS maps but if you have, can you say they have performed well this winter?

Have only really started paying attention since the back end of Jan.....well in enough depth to guage reliability.

There are inter run variations as you'd suspect given how often these charts update, however over the last 4 weeks or so there have been more runs suggesting heights somewhere between Greenland and Scandi than not. A recurrent theme for sure. I'm yet to see a run churned out that has core of +ve height anomaly across mainland Europe.

With the CFS you have to average the average in a sense. It did very well picking out last summer's washout from the end of Feb/early March.

Yes, I looked at the anomalies and it is totally different.

See my reply to Panaiyotis

Edited February 18, 2013 by CreweCold

[Mair Snaw]

Isn't there a thing about the number 7 in nature...."every seventh wave" etc?

The far from disappointing snowfallls I've had this year have all been very weekend based. Could be more than just a coincidence i suppose?

I'm now hoping every seventh day there's a dramatic shift in the Meto's expectations of what lies ahead for us

If only the weather would do what the Express say it will, us cold/snow seekers would be to busy building snowmen to come this forum.

Edited February 18, 2013 by bigsnow

[Average Joe]

If only the weather would do what the Express say it will, us codl/snow seekers would be to busy building snowmen to come this forum.

Ahh, Nathan Rao......weather reporter par excellence.........................

[BLAST FROM THE PAST]

That's not fair, Fred...But if I am guilty of ritually slating the Met, I 'umbly apologize!

The models are still indicating cold & dry, I see...

Fair do Pete, but it came with a smiley suggesting 'in gest' intent. Ok line drawn, Netw users are lucky to have Fergie post [seriously I mean that], of course the MetO lead their field.

BFTP

Edited February 18, 2013 by BLAST FROM THE PAST