Model output discussion - 20th Feb onwards

[knocker]

Rain pushing into the south west Thursday/Friday which could be thundery. Within the circulation of the low to the SW so temps significantly higher than at present and, it must be said, what is expected not long after.

[ANYWEATHER]

Good Evening Folks. Remarkable cold outlook from gfs and ecm...Some folks will moan that this situation is wasted! Not at all Spring this year is going to break records for all sorts of weather phenomenan

[The PIT]

Yeh the models do show a switch back to colder conditions however quiet a bit of differences between the ECM and GFS in the placement of the high. GFS has it further west than the ECM at 144 which shouldn't be too surprising at it's out of the reliable time frame.

[stodge]

Evening all

Plenty of interest in the night's output:

GFS 12Z OP at T+168:

ECM at the same time:

GEM at the same time:

The worry for those looking for warmth is all three models head the same way into FI with colder air pushing SW from Scandinavia on synoptics which, if ever shown in January, would crash the Netweather servers !!

To be fair, late April/early May is a time of huge contrasts - it can be very warm and sunny or the opposite and at the moment we're heading full pelt toward the opposite.

BUT we aren't there yet, it's still some way off and newer signals could emerge in the next few days...

[049balt]

35 minutes ago, stodge said:

Evening all

Plenty of interest in the night's output:

GFS 12Z OP at T+168:

ECM at the same time:

GEM at the same time:

The worry for those looking for warmth is all three models head the same way into FI with colder air pushing SW from Scandinavia on synoptics which, if ever shown in January, would crash the Netweather servers !!

To be fair, late April/early May is a time of huge contrasts - it can be very warm and sunny or the opposite and at the moment we're heading full pelt toward the opposite.

BUT we aren't there yet, it's still some way off and newer signals could emerge in the next few days...

It doesn't look that bad for the West/ Ireland. cool and dry.

[knocker]

The ens 850mb temp anomaly 6-10

Edited April 17, 2016 by knocker

[MP-R]

1 hour ago, ANYWEATHER said:

Good Evening Folks. Remarkable cold outlook from gfs and ecm...Some folks will moan that this situation is wasted! Not at all Spring this year is going to break records for all sorts of weather phenomenan

I fully expect snow in my location. If not, then it's very much wasted imo and may as well not happen lol.

[Singularity]

 

Just remembered I wanted to point this out before turning in for the night - those fingers of relatively warm air clawing their way into the Arctic while their counterparts take vacations toward the mid-latitudes.

Western Greenland has already seen one exceptional melt event this month (relative to the time of year; 11 April) and it could well see another before the hand-over to May. Meanwhile the Pacific side of the Arctic Ocean looks to be experiencing the consequences of unusually low snow cover across Alaska, which itself is looking mighty warm for the time of year.

This year is shaping up to be a very interesting one. I just hope that a decent UK summer can be a part of the puzzle!

[Thundery wintry showers]

A significant factor for us, regarding this northerly, is that the Svalbard/Barents Sea area of the Arctic is reporting similar temperatures to those of January 2016.  They were record or near-record warm back then, but now that we're heading into late-April, they are not far from the long-term average.  This gives us potential for a notably potent northerly for the time of year, although I have known widespread snow in May before (1979, 1982, 1987, 1993, 1995, 1997- the 1979 one was particularly noteworthy with some lying snow even in the West Country).  

With the main blast being a week away, there is still scope for it to be watered down nearer the time though, with snow showers restricted mainly to northern hills.  The NOAA 8-14 day outlook suggests that we may move towards more of a cyclonic/northerly type after the initial blast.  

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

Depending on the amount of frontal activity associated with the low, it could be bright and showery with widespread hail and scattered thunderstorms, or it could end up mostly cloudy and damp, especially in the east.  I expect the trough to retrogress westwards into early May bringing in warmer south-westerlies.

[knocker]

The GFS this morning is a work of art.

High pressure in charge for most of the week but Thursday/Friday a front pushes NE into the SW bringing intermittent rain, perhaps thundery at times. This rain 'belt' does not travel very far inland before petering out.

By Saturday we have the onset of the cold air from the north with shortwave forming north of Scotland, travelling down the east coast and then east to be west of Denmark by 12z Sunday. It then becomes reinvigorated and swings back up the North Sea anticlockwise  to sit over Glasgow 979mb by 06z Tuesday, This whole process introduces the cold air to all and a smattering of snow to most, probably in the form of convective activity. You couldn't make it up. Well you can, the GFS just has.

Edited April 18, 2016 by knocker

[Gibby]

HERE IS MY LATEST ANALYSIS USING DATA SUPPLIED BY THE NWP OUTPUT COVERING 5 OF THE WORLDS MOST POWERFUL WEATHER COMPUTERS ISSUED AT 09:00 ON MONDAY APR 18TH 2016

THE CURRENT GENERAL SITUATION A ridge of High pressure lies across the far South of England and will build further over the next 24 hours as well as extend further North tomorrow and Wednesday, killing off the weak trough currently moving South across Northern and Central areas

http://www.wetterzentrale.de/pics/Rtavn001.gif

CURRENT SNOW FORECAST AND FREEZING LEVEL OVER THE UK The freezing level across the UK will rise steadily through this week towards 6000-8000ft across the South later while the North will not be quite as high though comfortably above 3000ft in the North later 

http://www.snow-forecast.com/maps/dynamic/uk

http://www.natice.noaa.gov/pub/ims/ims_gif/DATA/cursnow.gif

MODELS-2 WEEK HEADLINE A lot of dry and bright weather this week with cool nights then even chillier weather with sunshine and showers look likely with a continuing night frost risk thereafter.

THE GFS JET STREAM FORECAST  The split flow in the Jet Stream will remain for a time through this week while later the flow simplifies by diving South across the UK and later still setting up a cyclonic flow around the UK.  

http://www.netweather.tv/index.cgi?action=jetstream

GFS OPERATIONAL The GFS Operational Run today shows a lot of High pressure influenced weather this week as the centre drifts North from Southern England to lie across the UK through the working week. Then by and over the weekend to come it is pulled West and NW over the Atlantic opening the door to cold and showery weather to arrive from the North with some longer spells of rain too as Low pressure centres across the UK early next week filling only slowly in situ over the UK thereafter while maintaining rain and showers across the UK to end the period.

GFS CONTROL RUN The theme of the Control Run is pretty much the same as the High pressure zone this week is also pulled West and NW out into the Atlantic with cold and showery North winds followed by cyclonic winds all bringing a mix of rain and showers with perhaps some snow on hills especially at first in this phase. Towards the end of the run a brighter and drier period looks possible as Low pressure weakens but further unsettled weather looks poised to flood down from the NW at the final day of the run..

http://www.wetterzentrale.de/pics/Rtavn1441.gif

http://www.wetterzentrale.de/pics/Rtavn3841.gif

http://www.meteociel.fr/modeles/gefs_cartes.php?code=0&ech=144&mode=0&carte=0

http://www.meteociel.fr/modeles/gefs_cartes.php?code=0&ech=384&mode=0&carte=0

GFS ENSEMBLE DAY 14 DATA  The GFS Clusters today once again appear to be a weak tool as there are few signals given this morning which give a clear guide as to where we might be meteorologically in two weeks time. Cyclonic conditions on the face of it seem more likely than not but infinite details about where pressure patterns will pan out in relation to the UK are unclear hence airflow patterns and sources make conditions at the surface hard to predict.

http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=euro&MODELL=gefs&MODELLTYP=2&BASE=-&VAR=cpre&HH=372&ZOOM=0&ARCHIV=0&RES=0&WMO=&PERIOD=

UKMO The UKMO model this morning shows High pressure well in control over much of this working week before it recedes to the West over the coming weekend with a chilly Northerly developing which brings the risk of showers, especially in the East but with plenty of dry weather still with some frost at night in the drier West and NW.

http://www.wetterzentrale.de/pics/Rukm1441.gif

THE FAX CHARTS The Fax Charts today agree with the theme of the Operational Run with High pressure through the week pushed out to the West by the weekend with a squeeze of troughs from both the South and North making the weather less reliably dry by the weekend as well as dropping temperatures downwards by the weekend as a North or NE wind takes hold.

http://www.weathercharts.org/ukmomslp.htm#t120

GEM GEM this morning also shows a largely dry and bright week to come before the same North winds develop by the weekend and accompanied by Low pressure moving in close to Eastern Britain rain and showers breaking out then too and under low temperatures some snow can be expected on the higher hills of the North. This pattern then largely remains locked into the midweek period next week with further rain or showers at times.

http://www.wetterzentrale.de/pics/Rgem2401.gif

NAVGEM NAVGEM too shows good support for a High pressure based week to come with fine days with some sunshine mixed with chilly nights with frost in places. It too by the weekend shows a slip into a colder Northerly wind though somewhat slacker than some other models but still capable of delivering showers as pressure falls across the UK and under any clear intervals overnight the light winds could give rise to night frosts.

http://www.wetterzentrale.de/pics/Rnvg1681.gif

ECM ECM today still maintains the theme of a relatively decent week of weather to come as High pressure across the UK slowly drifts West and NW by the weekend with a slow drift into a colder Northerly flow come the weekend with some showers breaking out in places. Then through the weekend and start of next week rather cold conditions with showers or rain at times looks more likely though on this run things might not turn quite as chilly as some of the previous versions of this model run has shown as the coldest temperatures become held further to the NW of the UK with more of an influence of Atlantic westerlies in the South though the overall weather pattern would become very unsettled for all.

http://www.wetterzentrale.de/pics/Recm2401.gif

ECM 10 DAY MEAN (12z) The 240hr mean Chart from last night shows n changes from the theme shown for days so the likelihood of a chilly North flow down across the UK is still a very likely one as we move towards the period 10 days hence.

http://www.wetterzentrale.de/pics/Reem2401.gif

NOTABLE TRENDS & CHANGES FROM PREVIOUS RUNS Changes are just small and subtle in the different ways in which a chilly Northerly flow is shown and as a result will likely be blowing down across the UK in the 10-14 day period.

31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKMO & ECM The verification Statistics of GFS, UKMO and ECM show at 24 hours ECM ahead at 99.6 pts with UKMO at 99.5 pts and GFS at 99.3 pts.  At 3 days ECM is leading with 97.3 pts to UKMO's 96.7 pts while GFS lags behind at 95.6 pts. At 5 days ECM leads with 89.2 pts to UKMO at 86.9 pts and GFS at 83.6 pts. Then at 8 Days ECM has the leading spot from GFS with 65.7 pts to 58.9 pts. Finally at Day 10 ECM has the lead from GFS with a score of 44.9 pts to 39.9 pts.

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day1_PMSL_MSL_G2NHX.png

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day3_PMSL_MSL_G2NHX.png

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day5_PMSL_MSL_G2NHX.png

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day8_PMSL_MSL_G2NHX.png

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day10_PMSL_MSL_G2NHX.png

MY THOUGHTS Still no major changes in the overall patterning between the models this morning. However, not all of the output is quite so strong in supporting really chilly air across the UK and ECM has thrown up a common scenario in this sort of setup where the coldest air stays to the NW of the UK as the Low pressure responsible moves across the UK from the NE and cuts off a direct Northerly feed that had previously been shown due to Low pressure holding out to the East. Nevertheless, this is just crumbs of comfort in an otherwise persistent pattern which nearly has a 100% of chance of verifying this morning. In the interim period High pressure lying across the UK will deliver some quite pleasant conditions this week with sunshine breaking out again by midweek after a couple of cloudy but largely dry days today and tomorrow. Then as winds freshen from the East later in the week there is still a decreasing threat of some rain moving up briefly from the South into the South though this looks a receding risk and it's not until winds back NE or North at the weekend when notable changes take hold. Colder air will plunge South again towards the weekend with an increasing risk of showers, first in the East and probably anywhere later and with air from such a cold source it will still be cold enough for some snow on Northern hills and mountains. The main concern for me is that once established there is little desire within the models to break us out of the pattern and as long as High pressure remains strong near Greenland it maybe that much of next week too remains cool and showery although there will be a fair amount of dry and bright weather too between the cold showers and it's at these times it will probably feel OK.

Next Update Tuesday April 19th 2016 from 09:00 

Edited April 18, 2016 by Gibby

[Singularity]

 

ECM (and GEM, not shown) having none of GFS' quite deep low development and draw into the mix of less cold air from the east. GEFS offer around 20% support to something to keep an eye on nonetheless.

By the end of the ECM run I believe we can see the signs of how we may escape the cold pattern in due course; the blocking is displaying a typical retrogressive tendency, with the trough following suit down the line but most likely in stages; jumping west with each new LP system. Could be a bit soggy for a time across the S in particular.

 

Quite a strong signal for a block to establish across western Asia too. This raises the potential for a warm incursion from the east sometime in the first week or so of May.

For a change, I just had to find something worth talking about in the longer range (the less cold conditions are not looking very interesting - temps barely making it above average) that isn't cold weather potential! 

[Summer Sun]

ECM ens keeps the cold lasting through the final week of April and most likely beyond

It may not be until week 2 of May that we see changes

 

Edited April 18, 2016 by Summer Sun

[phil nw.]

Certainly a disappointing outlook, cool and cloudy, in this persistent pattern.

No sign yet of us escaping the clutches of the Scandinavian troughing until month end. 

Eventually of course things will change as the remaining upper cold pools continue to fragment and we start to see a trend for cut off lows with mid latitude ridges.

At the moment though it does look like a wait until May for any signs of prolonged warmth.

 

 

[mb018538]

I was just going to ask the same thing....

Anybody with more knowledge than myself like to hazard a guess when this pattern will change? Looks like a huge block setting itself up right out until May at the earliest. Any teleconnections/signals that point to anything giving this northern blocking a kick up the backside, with higher pressure heading back to the azores where it should be??

[knocker]

Without claiming more knowledge the current thinking according to the anomalies for the end of April/beginning of May is for the highly amplified pattern currently forecast is become much less so and for the whole lot to retrogress somewhat, Particularly noticeable towards the end of the period.Thus weakened ridging over Greenland and the trough over the UK. This will back the upper flow to the NW/WNW thus still unsettled and temps probably still below average. There is not complete agreement on as the NOAA 8-14 is not following the GFS and EPS vis the amplification and retrogression but keep in mind here that is 8-14 and my comments above were mainly referring to the latter part of the 10-15 period. But NOAA has cyclonic conditions in situ over the UK

In a nutshell remaining wet and sometimes windy until the first week in May with temps rising from way below average to just below. Not a brilliant story I'm afraid.

For the experts view see the latest METO update which doesn't make pleasant reading.

Quote

Rain clearing from the far south early Saturday with a northerly airflow then expected to become established across the country as the weekend progresses, bringing showers, with snow over higher ground. The wintriness is also possible down to low levels, especially in the north where showers are expected be most frequent, with some gales possible along northern and eastern coasts. Cold conditions are then set to continue through to the start of May, bringing periods of sunshine and showers, these occasionally wintry and merging into longer spells of rain at times. It will also be windy for some, especially along the east coast where occasional gales are possible, making it feel especially raw. Temperatures well below normal of the time of year, feeling chilly by day with widespread overnight frosts.

http://www.metoffice.gov.uk/public/weather/forecast

[Penrith Snow]

1 hour ago, mb018538 said:

I was just going to ask the same thing....

Anybody with more knowledge than myself like to hazard a guess when this pattern will change? Looks like a huge block setting itself up right out until May at the earliest. Any teleconnections/signals that point to anything giving this northern blocking a kick up the backside, with higher pressure heading back to the azores where it should be??

Not sure about May but you can be sure that come late November  a 1050mb Azores High will be reaching out towards us while pressure over Greenland falls to that on Mars!

Andy

 

[knocker]

1 minute ago, Penrith Snow said:

Not sure about May but you can be sure that come late November  a 1050mb Azores High will be reaching out towards us while pressure over Greenland falls to that on Mars!

Andy

 

Wouldn't that be great . Something to look forward too.

[The PIT]

Well a downgrade on the latest gfs with the real cold uppers not making as progress down across the country. The -10c plunge never really makes it. Still going to be cold for the time of year but normal progress is to continue to downgrading so it could well end up just plain average by the time we get there.

[knocker]

Wind chill.

Sidney's prepared.

[Summer Sun]

25 minutes ago, The PIT said:

Well a downgrade on the latest gfs with the real cold uppers not making as progress down across the country. The -10c plunge never really makes it. Still going to be cold for the time of year but normal progress is to continue to downgrading so it could well end up just plain average by the time we get there.

Indeed

GFS 12z for April 24th 08:00 yesterday

And today

Lowest 850's on this run are around t168

Edited April 18, 2016 by Summer Sun

[knocker]

Tonight's GEFS 8-13 is very similar to last night's NOAA. A stationary cyclonic circulation in the North Sea portends some quite inclement weather, particularly down the eastern side of the UK. With temps 2-5C below average for the period, and quite windy at times, long Johns will the order of the day on Yarmouth pier.

[Thundery wintry showers]

Ironically maxima for the 25th and 26th are progged to be lower on the latest GFS run as the less cold air at 850hPa is associated with a trailing frontal system which would bring a couple of grey wet days and temps of around 5C.  

http://nwstatic.co.uk/viewimage.pbx?type=gfs;date=20160418;time=12;ext=171;file=ukmaxtemp;sess=82c70a3768d12d8fb95d5ec460be02e2;

The greater warmth would be felt entirely through higher night-time minima.  The GFS has a habit of sometimes overdeepening lows though, so I won't take too much notice unless we see a similar shift on tonight's ECM.

Edited April 18, 2016 by Thundery wintry showers

[stainesbloke]

1 hour ago, The PIT said:

Well a downgrade on the latest gfs with the real cold uppers not making as progress down across the country. The -10c plunge never really makes it. Still going to be cold for the time of year but normal progress is to continue to downgrading so it could well end up just plain average by the time we get there.

Wonderful news. Too late now for all that freezing crap, time for some nice warmth. Unlikely though for the foreseeable!

Edited April 18, 2016 by stainesbloke

[Summer Sun]

ECM continues to show the colder air moving down from the north

GFS and GEM at the same time

Edited April 18, 2016 by Summer Sun