Model Discussion And Chat 19th Feb.2012

[Troubleatmill]

Yes, i've never seen anything like this. In Jan 2011 pressure rose suddenly over Iberia and that killed off last winter and kept us dry, and ever since we have had relentless high pressure to our south. The pattern will break eventually, but after nearly 14 months no reason to think it will be anytime soon.

Nuts how for such a small country we have totally different weather top to north, here in Northwest England and im sure our pals north of the border will agree, its been horrible up here with loads of rain, waterlogged fields for weeks on end it seems, i would do anything for just a couple of weeks of dry settled weather.

Unfortunately the models are screaming zonality again with more of the same for both areas, north and south

Edited February 21, 2012 by arron123

[Frosty.]

The Ecm 00z has gone back into anticyclonic mode for most of the next 240 hours, this means there will be barely any relief for the southeast drought and it will just get worse and worse, high pressure building northeast this weekend and then sticking close to the south all next week. At least the Gfs 00z is a bit more mobile and occasionally pushes low pressure through the uk but always nw britain which catches most of the rain and windy weather, speaking of rain, the next 48-72 hours look like producing huge rainfall totals in more northwestern parts of the uk with 2-4 inches of rain and local flooding, a huge contrast with the bone dry southeast! Temps also look like hitting 17c later this week but a rather colder weekend with overnight frosts but at least some relief for the soaked northwest of britain.

Edited February 21, 2012 by Frosty039

[shedhead]

As Frosty as alluded too dry remains the theme across the south, while by contrast some northwestern areas directly beneath the SW rain train can expect very wet conditions at times, especially across the next 36hrs or so. Even deep into FI GFS appears reluctant to break the overall pattern, but as has often been the case this Winter T+384hrs offers up some decent eye candy.

[MP-R]

All model runs for the last two days have shown a pretty settled outlook for the rest of February, then turning much more unsettled into March with Atlantic lows coming a bit further south. The GFS 00Z certainly shows that so I await the 06Z to follow suit. No obvious ways into cold just at the moment though.

[picog]

Mild and dry. Same ensemble pattern for Manchester and Dublin too.

http://www.wetterzentrale.de/pics/MT8_London_ens.png

[legritter]

well my big straw clutch as gone down the drain .looking at charts i can see a possible lifeline perhaps lows will come further south eventually .or perhaps GFS will bring back the scandy high .chins up gang i still think something for all in march .regards legritter

[nick sussex]

Generally the models all agree on a continuation of low heights to the north and high pressure to the south or se.

The GFS 06 hrs run takes the high a little further north than the previous 00hrs, the ECM still suggests that troughing will become established in the mid Atlantic and in terms of looking for any chances for some colder snaps in March that would need to occur to give a chance for high pressure near the UK to ridge further north.

It's hard to see how any cold can come from anywhere but the east or ne given the HN pattern and the reluctance of heights to rise near Greenland.

In terms of the ECM ensemble maps there are more colder solutions this morning at 168hrs than on yesterday evenings, I'd say theres 10 out of the 50 but this would need a big change in the operational output and by and large the models have been solidly behind flattening the jet out at that timeframe.

http://www.ecmwf.int/samples/d/inspect/catalog/samplers/banner/mean_sea_level_pressure_and_temperature_at_850hpa!168!pop!od!enfo!enplot!2012022100!!/

[Timmytour]

Looks like a period of average weather coming up for the UK......dramatic regional variations but overall average!

reminds me a bit of how the ensembles were looking earlier this year with huge differences giving a mean which didn't really count for anything.

[Scorcher]

Looks like a period of average weather coming up for the UK......dramatic regional variations but overall average!

reminds me a bit of how the ensembles were looking earlier this year with huge differences giving a mean which didn't really count for anything.

It doesn't look too average to me- temperatures look like they will be above average and rainfall below average...

[WhiteFox]

It doesn't look too average to me- temperatures look like they will be above average and rainfall below average...

Indeed, looks strikingly similar to last year. Dry and warm March and April to come? We do get stuck in such patterns from time to time. The mid-nineties delivered a similar period of dry weather with persistent heights preventing meaningful rainfall to the South and East for long periods. This broke in spectacular style in June 1997. So, such patterns can easily persist for two to three years. The point is that average figures are just that; there will be years with above average rainfall and years with below average rainfall. This pattern will break at some point, but it cannot be accurately forecast.

[johnholmes]

I thought we might look at how close/far off the 500mb anomaly charts were 10 days ago to the upper air pattern for this morning?

On the left the NOAA predict for about this time and the actual to the right for comparison

To me the 500mb contour predicted is a fairly flat type of direction on it but with a hint of a ridge close by the UK then turning north of west into the continent.

The actual this morning (the 00z was almost identical) and the ridge is perhaps a shade more pronounced but with it again turning north of west into the continent.

Both show the idea of a fairly flattish westerly 500mb flow over most of the Atlantic.

The heights, the actual is the 550DM line, no 546 shown, with the forecast showing the more usual height at 546DM. Taking this into account and the forecast is a bit too low compared to the actual. This may affect what the surface chart would show as it infers somewhat colder air being over all the country.

Other than that it does seem to fit quite well. How would one have drawn the surface with this type of chart?

That is the interesting question. The chart below is how the model showed the surface isobars on this upper air chart.

[

Certainly one would have put low pressure at the bottom of the 500mb trough shown SSW of Iceland. This in spite of the anomaly suggesting that the 500mb height would be above average. I doubt I would have suggested it as deep as it turned out to be though, partly as a result of the suggested height anomaly. The overall idea of a surface ridge beneath the 500mb ridge into the continent would also have been an important feature on the charts. With these two in place then the isobar pattern would have been drawn as a shade south of west with low pressure dominant in higher latitudes. Thus the overall idea of the weather pattern we have today. Less settled and windier the further north in the UK with milder air flowing up the western side, possibly with some inference that rainfall in the NW and a temperature rise in areas east and SE of the main high ground would be the main weather features.

Overall then quite good guidance and a key element in seeing the colder spell last weekend as only a temporary feature.

Of the 6 or 7 of these charts I have tested over the past months 5 out of 7 have been as 'good' a guidance as this one in my view. One was poor, I recently commented on this. One was fair but not really as good as I would have liked. So not bad really and to my mind, as a forecaster, a far more reliable method than using just the 4x or 2x synoptic ouputs. Of course they cannot beused unless they are showing consistency with each other and themselves over several days. Neither can they be used in isolation from other data inputs, synoptic outputs and teleconnections in the next range.

sorry the charts are a poor size

Edited February 21, 2012 by johnholmes

[Timmytour]

It doesn't look too average to me- temperatures look like they will be above average and rainfall below average...

Fair enough about the temps I suppose.....but I think the NW looks a bit wet. And, in a tongue in cheek way, that's the point I was making.....the deficiency of wet weather in the south and east especially will be balanced elsewhere in the country.....not that it helps in any way!

[john mac]

Big differences again on the 12z at t144. Azores high much further to the south west.

FI could be interesting.

Nice bit of eye candy in deep FI.

Edited February 21, 2012 by john mac

[Summer Sun]

If GFS is proven to be correct then February will end settled and mild under high pressure and the first week or so of March which is of course in FI would be unsettled.

[IDO]

GFS 12z for the next 10 days gives most of the UK settled, HP based weather with mild temps.

Then in FI the jetstream goes AWOL (to our north) allowing the return of average temps. with a more unsettled outlook. Little sign of the return of anything wintry in this scenario:

http://nwstatic.co.uk/viewimage.pbx?type=gfs;date=20120221;time=12;ext=384;file=h850t850eu;sess=9b8ea6e0c99de5df0383fc1b6d18e002;

Another HP closing in from our SSW.

Any PV action a thousand miles plus to our east and west:

http://nwstatic.co.uk/viewimage.pbx?type=gfs;date=20120221;time=12;ext=384;file=npst850;sess=9b8ea6e0c99de5df0383fc1b6d18e002;

There is definitely a Global fall in temps from around 26th onwards:

http://policlimate.com/climate/gfs_t2m_bias.html

So it is likely that the UK temps next week will not be maintained at this week's relatively high marks. However the real cold is kept at bay, per the current GFS run. Yes, time for changes, but if anything, we are going to be even less favoured than when we missed out on the Jan/Feb strat. warming event.

[Polar Maritime]

The GFS is showing average or above temps for the next 10 days or so with the odd frost and some nice warm/dry weather on offer, while the far North stays unsettled at times, we have just had the 6th driest year in our catchment area since records began. So like most others on here, we really need some rain.

The blocking is still showing at the turn of the month and has moved closer into the timeframe today, so a cold end to the month is still highly likely.

[Cheese Rice]

Really like T192 on the GFS

I'm still edging towards a linkage with the high over Russia although the models don't seem too interested.

[nick sussex]

The ECM 12hrs operational output firmly shuts the door on even a hint of a change suggested by its two previous runs.

Gone is the mid Atlantic troughing which may have helped push the ridge further north to be replaced by even deeper low heights to the north, really its output this evening wouldn't look out of place in early winter, strong flat jet, low heights to the north and high pressure to the south.

If you're looking for even a chance of some colder conditions the ECM output is a horror show of epic proportions, indeed save for a deep FI tease by the GFS its shocking all round.

No appreciable rain for those areas that need it, although one does wonder what will happen when the PV eventually leaves its Greenland home. Once the NAO does eventually go negative I fear it might stay that way for some time!

Overall then winter looks to go out as it came in, what happens in March hard to say but if those low heights are maintained to the north then it's hard to see where any cold could come from.

Edited February 21, 2012 by nick sussex

[Cheese Rice]

We can still see low heights to the north as seen with the cold spell at the beginning of Feb, issue is though theres nothing stopping a high from sinking.

[nick sussex]

We can still see low heights to the north as seen with the cold spell at the beginning of Feb, issue is though theres nothing stopping a high from sinking.

Yes but as you head into March the best source of wintry weather is from the north or ne, easterlies at that point unless in conjunction with a piece of the PV dropping into western Russia lose their bite.

The Feb cold spell had some energy going into Iberia and the Med to support the high and also the the lower heights stayed further to the nw.

Edited February 21, 2012 by nick sussex

[cooling climate]

The ECM's 12z t240 chart must be a contender for one of the most cringe inducing charts we have seen this winter. The run has probably blown a fuse somewhere down the line and I would expect

this to be more of an outlier run. The PV at the end must be some sort of record for late February

I would have thought.

[legritter]

anybody out there ,pretty sure something will pop up soon .can this azores high keep on strangling our kneck of the woods .GFS keeps on throwing up some candy ,just waiting for ECM to deliver ,lets hope the arctic can throw us something in march .lets hope tonights GFS can give us some hope .in all my meteorological collections ,the last couple of years have certainly thrown up some different synoptics ,but where is that GRAIL ,HIGH TO THE NORTH LOW TO THE SOUTH ,LETS HOPE THE MODELLS SHOW SOMETHING MEATY SOON . IF YOURE FED UP WITH MODELLS pop over to winnipeg web cams ,plenty of the white stuff showing .

[bluearmy]

there are a few ecm members that blow up the ridge to our west and trough to our east by day 7. certainly in the minority but a wide spread of solutions at day 7 which are quite a way apart. i would be waiting a day or so to see this settle down. a mid lat high over the uk still seems the probable end game.

[Frosty.]

The ecm is consistant today and tonight for an anticyclonic outlook, at least for the southern half of the uk but possibly for all areas with just a few unsettled blips further north. A very mild few days to come, peaking at 17c on thursday but 15c on friday and then cooler air filtering southeast just in time for the weekend but with high pressure in control, plenty of sunshine and then overnight frosts, into next week more of the same, maybe a bit changeable in the north of the uk but fine and dry in the south which is bad news for the drought stricken south/southeast.

[LomondSnowstorm]

There's always next winter I guess: