Spring Model Discussion 18Z 6/3/13 onwards....

[johnholmes]

And me!

Coldies need to make the most of the next 48 hours by Tuesday the bitterly cold temperatures look like easing ever so slightly to around 4 to 6c

By Wednesday the change to milder air is underway in the southwest with highs up to 7c 5 to 6c in the east widely

But its Thursday when we see the milder air UK wide 7c widely 8c in the south west by this point only Scotland stays colder

By Friday we are back in double figures for the south coast 7 to 8c widely again only Scotland remains cold with 2 to 4c widely here

Into Saturday and most of the south is in double figures northern England to the midlands has highs of 6 to 8c once again Scotland remains the coldest with highs of just 4c

So if your a coldie my advice is pack your bags and head upto Scotland other wise for England and wales we will see a recovery of temperatures this week with Sunday and Monday the coldest period before double figure temperatures look like making a welcome return towards the end of the week which is to be expected after all this cold can't last long this time of year

Gavin, no mention of overnight values OR that this is the GFS version only. I have not looked at the later output on any model but if the anomaly charts are to be trusted then at the earliest it is after next week before any genuinely mild air may affect the country, then I suspect it will be post 14 days?

However, I have to agree with anyone hoping for mild, dry and sunny weather at last. I have forgotten when was the last time I saw the sun here-oh wait a tick SEVEN days ago!

Edited March 9, 2013 by johnholmes

[AWD]

Gavin, no mention of overnight values OR that this is the GFS version only. I have not looked at the later output on any model but if the anomaly charts are to be trusted then at the earliest it is after next week before any genuinely mild air may affect the country, then I suspect it will be post 14 days?

Yes. I have a feeling the GFS brings milder air in too quickly next week.

The ECM is a much slower evolution, with cooler than average conditions continuing for much of next week. Along with the updated Met Office medium range forecast, I have to favour a colder than average week still next week, albeit the cold moderated from midweek onwards.

[Captain Shortwave]

Excellent lunchtime forecast from the bbc for snow fans even before the potential main event for the south coast. This afternoons rain will turn quickly to snow giving a potential covering in places such as Lincolnshire, East Anglia and the East Midlands perhaps. Convective potential for Sunday looks pretty good on the forecast too with snow showers driving inland through Northern England and the Midlands with North East England down to East Anglia seeing possible good accumulations of snow tomorrow. I hope this is the case as I've experience nearly 24 hours of persistent moderate to heavy rain.

Edit - Went to put some stuff in the bin and the rain is starting to turn to sleet.

Edited March 9, 2013 by Captain shortwave

[Frosty.]

Today's meto update is a surprise, given how the spoiler low to the northwest later next week virtually seems to scupper the cold on the gfs and ecm 00z and then the gfs 06z, it's surprising to read that cold weather with wintry showers and frosty nights is set to persist, so perhaps the gfs eastward bias of shunting cold air away to the east is again guilty as charged, i'm pleased that the cold showery weather could last longer since we are almost at the time of year when inland convection really takes hold, clean cold polar air and sunshine with big wintry showers developing is more likely than milder atlantic type weather according to the latest update. :-)

Edited March 9, 2013 by Frosty039

[NickR]

Have to say posts like this do irritate me.

I do not seek praise but I do like credit to be given when its deserved. Remember a while back the arguments with regards to the anomaly charts when some of us suggested cold weather was on its way and you disagreed.

Here is a comment I made on the 24th Feb!

"LP moving up from the S bringing a big snow event as bitterly cold E,lys spread across the UK."

This is what I said on the 2nd of March.

"Looking at this mornings output a cold E,ly continues to look favourite, how cold is still very uncertain. Appears around the 11th March is when this could occur so only 24hrs later than I suggested many days ago."

http://forum.netweat...d-march-onward/

http://www.wetterzen...cs/Rtavn541.png

Unfortunately I cannot find the post when I referred to "Many days ago" but I do recall saying in late Feb that the 10th March was a significant date.

Fully expect this to be deleted mind you!

This must win some sort of prize for "overreaction to what was clearly a lightheated one-liner post" of the year".

Have a look at the whole exchange again TEITS and I think you'll see.

[IDO]

Today's meto update is a surprise, given how the spoiler low to the northwest later next week virtually seems to scupper the cold on the gfs and ecm 00z and then the gfs 06z, it's surprising to read that cold weather with wintry showers and frosty nights is set to persist, so perhaps the gfs eastward bias of shunting cold air away to the east is again guilty as charged, i'm pleased that the cold showery weather could last longer since we are almost at the time of year when inland convection really takes hold, clean cold polar air and sunshine with big wintry showers developing is more likely than milder atlantic type weather according to the latest update. :-)

Not too surprised, as the ECM ensembles for London highlights that the ECM op was probably the mildest permutation from D6 onwards till about D10 when it returned to the mean:

It looks like both the GFS and ECM ops are too fast with the breakdown of the cold uppers. Lots of scatter in FI and a relatively even split between milder temps and cool temps, with the cooler variety still on the UKMO radar.

Edited March 9, 2013 by i'm dreaming of...

[Cloud 10]

Today's meto update is a surprise, given how the spoiler low to the northwest later next week virtually seems to scupper the cold on the gfs and ecm 00z and then the gfs 06z, it's surprising to read that cold weather with wintry showers and frosty nights is set to persist, so perhaps the gfs eastward bias of shunting cold air away to the east is again guilty as charged, i'm pleased that the cold showery weather could last longer since we are almost at the time of year when inland convection really takes hold, clean cold polar air and sunshine with big wintry showers developing is more likely than milder atlantic type weather according to the latest update. :-)

That update seems to lean more towards the ECM ensemble mean than the GFS,with the ECM

having -4 uppers still across most of the UK by day 10.

ecm.. gfs..

[Purga]

Yes but as you would expect. We are now mid-march and we are not going to get several consecutive days of ice days so the ens are always going to trend milder as the temps next monday are as you say bitterly cold. However they only go to 5c, 5c mid to late March is certainly not mild and springlike. From a personal point of view, I would like to see a few days of cold/snow but then a warmup but I think we will stay cold and below avg for the whole of March. And by the way, for some people (cold and below avg does not mean blizzards)

Blast Brady you've now wrecked my life! Edited March 9, 2013 by Purga

[bluearmy]

The extended meto no surprise as the uk sits under a cold mean trough. What would lead to continued snowfall in mid winter will more likely be cold rain mid march. The north of the uk away from windward coasts, especially over high ground will still be at risk of snow.

[Frosty.]

Just a quick update on the snow, a large band of wet weather this afternoon across central/central southern britain is already turning sleety and to snow above 100m, it looks like the east midlands and lincs are in prime position for a good covering, maybe 2-4 inches and perhaps 4-6 inches overnight into tomorrow, the risk of snow tomorrow extends further south. NW england probably staying as rain since the rain will be turning lighter and fizzling out but as time goes on today and tonight, colder and colder air will be increasingly in the mix, most of scotland cold and dry but snow showers from tomorrow to n and e coastal areas and similar next week.

[Polar Maritime]

Just a quick update on the snow, a large band of wet weather this afternoon across central/central southern britain is already turning sleety and to snow above 100m, it looks like the east midlands and lincs are in prime position for a good covering, maybe 2-4 inches and perhaps 4-6 inches overnight into tomorrow, the risk of snow tomorrow extends further south. NW england probably staying as rain since the rain will be turning lighter and fizzling out but as time goes on today and tonight, colder and colder air will be increasingly in the mix, most of scotland cold and dry but snow showers from tomorrow to n and e coastal areas and similar next week.

Yes it's looking pretty good reg snow potential, already turned to sleet here. An interesting few days coming up, with lot's of last minute changes to come.

Fantastic chart's for March !

Edited March 9, 2013 by Polar Maritime

[Sussex snowstorm]

This happened in February where a channel low missed the coast and where I lived only had flurrys, I hate living in sussex because to much headaches from these channel lows , one minute it's moved north then last sec it's moved south , they always have trouble with anything coming up from the south , hint 1987 hurricane haha

[UV-RAY]

Just a quick update on the snow, a large band of wet weather this afternoon across central/central southern britain is already turning sleety and to snow above 100m, it looks like the east midlands and lincs are in prime position for a good covering, maybe 2-4 inches and perhaps 4-6 inches overnight into tomorrow, the risk of snow tomorrow extends further south. NW england probably staying as rain since the rain will be turning lighter and fizzling out but as time goes on today and tonight, colder and colder air will be increasingly in the mix, most of scotland cold and dry but snow showers from tomorrow to n and e coastal areas and similar next week.

It's been the story of the winter in these neck of the woods Frosty, abysmal winter for cold, frosts and snow for many in the NW. Looking good for those areas you highlighted though.

[damianslaw]

Reliable timeframe - notable cold period for the time of year with the 'coldest' synoptics of the winter 12/13 season despite it now being spring, we haven't seen uppers lower than -10 degrees all winter, but to see uppers approaching -14 degrees this late in the season is very notable indeed, all thanks to what is a very bitter cold pool over scandinavia. I just checked temps for Moscow maxima expected to be down to -8 degrees, which shows how cold the air is to our NE at present.

High pressure is projected to stick over Greenland for some time - deflecting the jet on a very southerly course, hard to say whether we will enter a west based NAO phase with attacks from the SW but as long as we maintain this overall upstream pattern there is a strong chance we will stay more on the northern side of the polar front jet than the southern and therefore exposed to arctic blasts.

So an easterly followed by a northerly - Meto FAX charts are showing trough formation in the northerly flow which could mean northern and eastern parts in particular could see more general snow on Tuesday.

We shouldn't pattern match, but its noteworthy how the only recent March's with notable snowy cold weather i.e. 1995, 1996, 2001 and 2006 and to a certain extent 2005 (cold start not that snowy) were all followed by good or very good summers in terms of sunshine warmth and dry weather...

[-uksnow-]

Hmm, latest NAE keeps anything significant away from the South for Monday

[ukpaul]

NAE totals suggest for 12z no snow or PPN at all apart from the very tip of NW France up to midday Monday (if they do picture that as snow), very much out of kilter with all other models.

EDIT: Yes, they do posit it as a heavy rain event for France until Monday.

Perplexing.

Edited March 9, 2013 by ukpaul

[shaky]

Hmm, latest NAE keeps anything significant away from the South for Monday

Plenty of accumulations from the snow showers of the north sea though!!

[Catacol]

I have just been drenched by a very spring like convective burst as the front pushes in to the SW. This will be the risk on Monday I think - within the overall pattern I suspect there will be the chance of some convective pepping up of the action, and some places might be surprised. A very interesting day coming up on Monday...

[Summer Sun]

Latest NAE

12:00 Sunday

18:00 Sunday

00:00 Monday

06:00 Monday

12:00 Monday

Snow accumulation totals upto 12:00 Monday

Edited March 9, 2013 by Gavin.

[ukpaul]

NAE has no snow accumulations in England at all this run by Monday, apart from the spine of Northern Pennines and a blob in Norfolk and South Pennines.

Massive variations at a very near timeframe.

[stratty]

Plenty of accumulations from the snow showers of the north sea though!!

........that will mostly be the rain/sleet and for some, snow, that is falling now

[nick sussex]

If this low decides to not deliver snow it may aswell be progged even further south to allow a quicker clearance of the high cloud, at least this might then allow some convection.

These Channel Lows are so frustrating because of their propensity to be a pain to model, in terms of the NAE we've seen it do some strange things in the past so hopefully this is the case now.

The low might edge a little further to the nw as it heads towards ne France but whether that is far enough north hard to say.

I'm not sure how closely the UKMO are following the NAE, they do have those other shorter term models which might show a different picture.

[mushymanrob]

Mushy, you said last week how you were looking forward to the Atlantic return in the week just gone but since Wednesday all we have had is unremitting gloom and drizzle - whereas this week should see plenty of sunshine in many places especially from Tuesday onwards.

With regard to the snow events, we can see the PPN building now to the East and it will be interesting to s

ee how the cold air undercuts the frontal this evening and tomorrow.

As for Monday, channel type lows are always fraught with difficulty for forecasters because until very late in the day it's very difficult to tell who will be in the milder air to the South, the snow band in the middle, and the dry cloudy area to the North.

the charts changed ian. there was a time when this cold was in doubt and the charts did suggest the atlantic return on a few runs.

[mushymanrob]

geordiesnow.

on tablet so hard to reply via quote im on crap tablet.

regarding downgrade, yesterday am models agreed on very cold uppers throughout the run. the gfs had us under -5c upper all through. the big two also strongly and persistently suggested reloads of -10 uppers thoughout. this morning these fi predictions have been replaced by average ones. so yes, id suggest that the duration of the cold based on current outputs in relation to previous ones are downgraded.

hope that clarifies that.

i dont see much sun either in the coming week, i might well be wrong on that butit wouldnt surprise me if it was largelydull. im happy to be wrong on that!

[ukpaul]

12z steady as you were, PPN pretty similar to 06z by 60h for the South East corner; in other words, as different to the NAE as you could imagine at this point.

Still clear as mud....

EDIT: UKMO seems to be a watered down version of the NAE.

Edited March 9, 2013 by ukpaul