Model Discussion - Spring approaches - how warm at the end of this week?

[Frosty.]

18 minutes ago, Scorcher said:

Eh? What exactly constitutes a 'special' mild spell for you in February? For a start, it's looking like the best spell of mild February weather since at least 2008. And tomorrow until at least next Wednesday would certainly be classed as prolonged and by no means 'quick'.

I agree, it's very exceptional and not a flash in the pan as some describe it..really spring-like spell this..close to the February record which is 19.7 celsius, we are probably looking just below that at 17 / 18c but it's the fact that we are looking at many days up around the mid teens celsius so early which is incredible.

[I remember Atlantic 252]

11 minutes ago, Frosty. said:

I agree, it's very exceptional and not a flash in the pan as some describe it..really spring-like spell this..close to the February record which is 19.7 celsius, we are probably looking just below that at 17 / 18c but it's the fact that we are looking at many days up around the mid teens celsius so early which is incredible.

Just hope we don't have to pay for it too much, obvious we'll have to during April, May

[MP-R]

12 minutes ago, I remember Atlantic 252 said:

Just hope we don't have to pay for it too much, obvious we'll have to during April, May

I think if we 'pay for it', it'll probably be in the form of the Atlantic returning into March, so nothing too unusual in that. There's quite often an Atlantic spell following a stand off between lows to the west and a block to the east. That then gives plenty of spring to establish a pattern change.

[MATTWOLVES 3]

Much cooler and more unsettled from the 18s as we head into March. 

[MATTWOLVES 3]

33 minutes ago, Mattwolves said:

Much cooler and more unsettled from the 18s as we head into March. 

And here are the 18z ensembles, Northern high ground could do well later in the period. 

[feb1991blizzard]

22 minutes ago, Mattwolves said:

And here are the 18z ensembles, Northern high ground could do well later in the period. 

I think we are buggered now to be honest.

[Weathizard]

32 minutes ago, Mattwolves said:

And here are the 18z ensembles, Northern high ground could do well later in the period. 

Even on high ground in the north they are pretty crap ensembles, cold rain for 99% and dire weather, my least favourite weather! I’ll be honest I’m hoping this conveyor belt of heights keeps control of our weather at this point.

[MATTWOLVES 3]

2 minutes ago, Weathizard said:

Even on high ground in the north they are pretty crap ensembles, cold rain for 99% and dire weather, my least favourite weather! I’ll be honest I’m hoping this conveyor belt of heights keeps control of our weather at this point.

Much higher ground like the cairngorms unfortunately! Yep the chances of seeing - 10+ uppers have all but gone 

[SLEETY]

Yeah looks like much more unsettled weather on the way, then I think the models will start showing attacks from the North in a week or just over, so hoping the ski  season can start properly at last! 

Edited February 21, 2019 by SLEETY

[BlueHedgehog074]

Looking at the latest NOAA/CPC 8 to 14 day 500mb anomaly chart, it looks like maybe the operational models (such as the 12/18Z GFS and 12Z ECMWF), are being a little too quick to breakdown the May-esque conditions. 

https://www.cpc.ncep.noaa.gov/products/predictions/814day/500mb.php

Guess it does depend on the transition period of any possible decline to more unsettled conditions, plus the speed to which the lower heights take over, which would affect how high the positive anomalies are over the U.K. Otherwise, either the likes of the ECMWF, GFS (including some GEFS ensembles) are being a bit too progressive with their breakdown mid next week (especially for Northern UK areas), or the anomaly chart may fall more into line with the operationals on its next run. 

While the surface UK High Pressure itself may lose some power next week, I suspect the upper UK High may cling on a bit longer before possibly getting pushed away further East by the Atlantic trough. 

[knocker]

outlook - In the more reliable short range major upper troughs, with a myriad of surface features, are generally confined to the Atlantic with the European high pressure remaining influential. So generally dry with temps at times considerable above average but sorting the cloud might be a bit tricky.

The NH 500mb and surface analysis for midnight and the WV for 0300

The deep low in the Atlantic is slowly filling and and drifting east of Greenland but the associated warm front is bringing cloud and patchy drizzle to the north west from Wales up. This will clear during the morning but cloud may linger in places in the north but generally where the cloud clears it will be a warm day with temps getting into the high teens in places.Perhaps in NE Scotland where they may get close to the Feb. record for Scotland.I'll post the WRF temps out of interest but they are not to be taken as gospel

Overnight low Stratus will drift north across the south coast into southern central areas with quite widespread mist.fog developing

This will clear slowly through Friday but as can be seen another low is tracking north west of Ireland and the associated cold front will bring some rain into N.Ireland and western Scotland by late afternoon.

Overnight Friday and through Saturday the above mentioned front moves away north only for another cold front to slide in from the west to bring some more rain to the north west. Elsewhere dry and another warm day with temps way above average.

Essentially over Sunday and Monday active systems continue to track north under the auspices of the upper trough to the west which, courtesy of this and the resilience of the ridge, ensures a continuation of WAA into the UK and thus a dry and very warm couple of days with any fronts kept on the periphery.

[knocker]

Given that last evening's runs were indicating a breakdown to more unsettled weather this mornings are not without interest.So continuing with the gfs. The next upper trough does duly arrive on the scene, courtesy of the Canadian factory, and tracks east to disrupt the incumbent trough and push fronts across the north on Thursday with quite strong winds.

The high pressure does put up some resistance but this is quickly swept aside by increasing upstream pressure as the Alaskan ridge and Canadian vortex make some fairly significant adjustments to their orientation. Whether this comes to pass is another matter

[knocker]

The GEFS mean illustrates what I meant by the above comment

 

[knocker]

The ecm similar to last night up to t168, thereafter still looking at a breakdown but significant difference in detail, not of coarse unusual. Temps much cooler but no surprise here either given likel forthcoming temps.

[Paul]

Little doubting the direction of travel on the GEFS ensembles this morning, a distinct downward turn in temperatures. 

Aberdeen

Derby

London

The pressure pattern tells a story too bringing lower pressure in, so cool/colder and less settled the likely outcome based on this run at least.

Vs climatology it's also quite striking, starting at much warmer than normal before slowly edging cooler, to end the run much closer to, or below normal. 

 

[North-Easterly Blast]

The chances of a spell of colder weather in early March look less likely on this morning's ensembles, although they still suggest a chance that temperatures will gradually decline from the notably mild levels in the second half of February.

[johnholmes]

12 minutes ago, Paul said:

Little doubting the direction of travel on the GEFS ensembles this morning, a distinct downward turn in temperatures. 

 

The pressure pattern tells a story too bringing lower pressure in, so cool/colder and less settled the likely outcome based on this run at least.

 

Vs climatology it's also quite striking, starting at much warmer than normal before slowly edging cooler, to end the run much closer to, or below normal. 

 

But as you remark Paul, it is one run. Did the same set of charts show similar yesterday once beyond say t+144?

 

[Badgers01]

14 minutes ago, johnholmes said:

But as you remark Paul, it is one run. Did the same set of charts show similar yesterday once beyond say t+144?

 

The general direction of travel looks like a return to around average conditions to me - anything after that is still up for grabs . Can’t see where a colder spell being called for is being shown yet ?! 

[IDO]

As we were.

UK HP until around D8-9, then the cyclonic westerly flood. 

At the moment it looks like when the gates to the Canadian vortex open it will be a rush of westerly cool zonality. That, of course, could change with some wave breaking, but more changeable D9-D? is the call.

No sign of colder than average temps, just a return from these warmer waters to climate. Certainly, very little sign of any HLB'ing to bring in the sustained cold, that is, according to the GEFS.

March could be a long & windy road with no sign of the trop PV wavering. No doubt the strat experts will advise on how the final warming is going, but the strat PV is looking resilient, and if there is coupling, maybe not a great early Spring, unless cold rain is your thing.

As for the MJO, although active, I will wait till it shows itself to more than just background noise, as it has been most of the Winter before it gets anything more than a cursory glance.

[Paul]

26 minutes ago, johnholmes said:

But as you remark Paul, it is one run. Did the same set of charts show similar yesterday once beyond say t+144?

 

It was similar yesterday I think John, albeit variations on a theme. 

[Nick F]

Extended 00z EPS (days 10-15) suggest a general downward trend in T850s and heights from the west across western Europe, indicative of westerlies featuring increasingly prolonged and colder Polar maritime airmasses visiting the UK. However, Pm flows in early March IMO likely more marginal than we saw back in late January/early Feb - so wouldn't expect as much snow away from northern hills as we saw a few weeks back! But the trend, for now, is increasingly unsettled and cooler/colder westerlies pushing out high pressure as we start March.

[johnholmes]

5 minutes ago, Paul said:

It was similar yesterday I think John, albeit variations on a theme. 

thanks Paul, could be a 'real' trend then

[Methuselah]

IMO things can only go one way, from here: given that we currently have the optimal synoptics for unseasonably warm weather, any deviation, in air-source, can only produce a cool down...? It is still February.

[legritter]

Its been painfull watching this very mild period unfold but i have accepted it and now looking forward to some gardening .Looking at todays charts March looks like starting more Zonal , so who knows we could get some polar or arctic flows ,with some snow about .Great forum on net weather , certainly a great place to learn , take care all and dont forget the Sun cream ,sausages are on ,brown sauce on table cheers .

[ANYWEATHER]

Why are people using the word cool down when it's not got even warm or hot yet? Wrong terminology for this time of year.....