Model output discussion - 20th Feb onwards

[Milhouse]

Well this is certainly an improvement over what was shown yesterday. Light winds and fairly pleasant with the southerly lasting long enough to bring some warmer air into the mix.

 

Yesterday ECM 0z

[Scorcher]

Yes those charts are much better if you're after something drier and warmer next week- I've noticed that the ECM has been gradually backtracking on the retrogression of that area of high pressure and the subsequent northerly. In fact, though the northerly is still there later on in FI, it keeps being pushed further and further back. Fingers crossed it never actually happens.

[stodge]

Morning all

Clear division in the GFS 00Z Ensemble membership between those keeping heights over Greenland and those not doing so. The OP is in the latter camp but plenty still keeping it very blocked over Greenland with a N'ly flow over the UK.

On a quick look, the GEM Ensembles seem to run against the majority and keep heights over Greenland as well so we'll see if a new trend is developing or not.

The better news is there does seem a window of fine and settled weather for many in the early part of next week with a feed of warmer air from the SE.

[johnholmes]

My take on the general weather type for 7-14 days ahead, see pdf link

thur 14 april 2016 upper air discussed.pdf

[knocker]

Although the ecm 5-10 this morning looks fairly benign with HP to the west, cut off low west of Iberia and a trough to the NE giving a cool NW this is a tad deceptive. The EPS 8-13 has retrogressed the HP a little and, more to the point there is now a deepening trough southern Scandinavia. It has been plugging this for a while now. The upshot of this is that the evolution from towards the end of the ten day period is to veer the streamlines ending in the northerly quadrant and with quite a long fetch this will drag some quite cold air down and and we'd be looking at 850mb temps around 6C below average  So if this was to verify, or come close, 4-5 days of quite chilly weather.

[BLAST FROM THE PAST]

Good post/spot Knocker and an outlook I certainly favour as plausible.  Could be a pretty chilly / even cold latter half/last ten days of April

 

BFTP

[Nouska]

5 minutes ago, BLAST FROM THE PAST said:

Good post/spot Knocker and an outlook I certainly favour as plausible.  Could be a pretty chilly / even cold latter half/last ten days of April

 

BFTP

Indeed. A very nasty (for time of year) EPS 850 mean on day 11.

It lessens over the next four days but still  below the seasonal norm.

[BLAST FROM THE PAST]

ECM reloads for another blast later in run, GFS not so.  I'll plump for ECM direction at this stage

 

BFTP

[stodge]

The likelihood of a colder than average spell in April has been well advertised and would echo the post-El Nino winter of 1998. GFS has however moved away slightly from some of the really cool options but there aren't many, if any, warm options on the 06Z Ensembles at T+240.

Basically, it's a toss-up between cool and dry under the influence of HP to the west or north-west or cool and wet with LP over us or close by to the east or south.

That's emphatically not to say we won't eke out some decent days - the last couple of days have been good for those areas which have missed the showers and I think early next week we could well see tho or three quite decent days but the warmth many on here want just isn't there (maybe 15-17c next Wednesday at best).

The two crumbs are first GFS 06Z OP in deepest FI turns much more settled and warmer but that's a very long way off. Second is that May 1998 was very warm (13.1c) and dry with 25c breached regularly so we could see a sudden and dramatic turn after any cooler spell.

 

[Frank Trough]

28 minutes ago, stodge said:

The likelihood of a colder than average spell in April has been well advertised and would echo the post-El Nino winter of 1998. GFS has however moved away slightly from some of the really cool options but there aren't many, if any, warm options on the 06Z Ensembles at T+240.

Basically, it's a toss-up between cool and dry under the influence of HP to the west or north-west or cool and wet with LP over us or close by to the east or south.

That's emphatically not to say we won't eke out some decent days - the last couple of days have been good for those areas which have missed the showers and I think early next week we could well see tho or three quite decent days but the warmth many on here want just isn't there (maybe 15-17c next Wednesday at best).

The two crumbs are first GFS 06Z OP in deepest FI turns much more settled and warmer but that's a very long way off. Second is that May 1998 was very warm (13.1c) and dry with 25c breached regularly so we could see a sudden and dramatic turn after any cooler spell.

 

It is only April - I think expectations are reasonably tempered aren't they? If it was June I could understand people wanting a bit more than 17c and sunshine - but in April? I think it's been a pretty average mixed bag of a spring so far and it looks like continuing in that vein over the next 10 days or so.

 

[knocker]

Blizzards on the Scottish mountains and a smattering as far south as Lynton-on- Ouse

 

[049balt]

West is best, and driest.

[049balt]

Dry theme continues.

Edited April 14, 2016 by 049balt

[Cheshire Freeze]

Euro4 model now showing the risk of a wintry mix of precipitation pushing S during the early hours of Sat morning

[Airedalejoe]

1 hour ago, 049balt said:

Dry theme continues.

Not here it doesn't. Everything soaked, fields have plenty standing water, all from rain over last few days!

And in relation to warmth? Another day of single figure max, 8C today, colder than most winter days,again. Yes I expect more from mid April.

[knocker]

The ecm run tonight is generally dominated by HP to the west but there are two things worth noting keeping in mind the last anomalies showing a cut off low west of Iberia and a deepening trough Scandinavia. On Wednesday the surface low associated with the former edges north and the frontal system pushes into south west England. And then at the end of the run, with the HP retrogressing a cold northerly sets in bringing some quite wintry conditions. Await the EPS with some interest.

Edited April 14, 2016 by knocker

[March]

18 minutes ago, Airedalejoe said:

Not here it doesn't. Everything soaked, fields have plenty standing water, all from rain over last few days!

And in relation to warmth? Another day of single figure max, 8C today, colder than most winter days,again. Yes I expect more from mid April.

Depends where you are. I've recorded double figures every day since March 23rd, and above 15C five times in April. 

[Cheshire Freeze]

Wow that's some wintry end to the ECM, wintry showers falling to modest elevation I would think

I remember snow falling in May 1998 at this location....also after a mega El Nino winter

Oops might be wrong on that one...looking at the archives it may have been 1997....but I was definitely in primary school at the time

Edited April 14, 2016 by CreweCold

[knocker]

The ecm 6-10 anomaly is still quite benign with HP to the west, cut off low Iberia and trough norther Scandinavia thus a cool NW upper flow. But as previously mentioned when discussing the ops this is a tad deceptive as the transition of the HP retrogressing and the Scandinavian trough extending and deepening covers the end of this period and the next. So looking at the EPS we have a cold northerly from around the 23rd to about the 27th with an 850mb negative temp anomaly of around 6C. There could well be some snow on them there hills. This evening's NOAA does tend towards this scenario although not deepening the trough to the extent of the ecm but still tending to veer the upper flow but perhaps not so chilly. Ditto GEFS.

Edited April 14, 2016 by knocker

[johnholmes]

3 hours ago, 049balt said:

Dry theme continues.

I assume you are taking a bit of the 'michael', not that wet but not dry either for most areas, even with the model you quote.

 

[knocker]

A quick look at the latest EC32 mean update. Not looking too far ahead as gets a bit vague and indecisive

By Tuesday an upper low has moved east to be west of Iberia with another trough over northern Scandinavia and ridging starting over the UK The Iberian trough could just impact southern Britain over the next couple of days.

By the 23rd the Iberian trough is gone and there is an increase in amplification over the eastern Atlantic with ridging into Greenland and the Scandinavian trough becoming more aligned N/S. During the next four days this trough deepens veering the upper flow to the northerly quadrant dragging down some very cold air with the 850mb anomaly in the -6C region.

After that the trough and HP both weaken fairly rapidly creating a much more zonal flow until the end of the month although temps still somewhat depressed.

[Polar Maritime]

As has been well advertised.. A chilly weekend coming up with a Northerly flow dragging -6/-7 850's over the UK, Bringing the risk of wintry precipitation for some especially upland areas as a front moves South during Saturday. 

Edited April 15, 2016 by Polar Maritime

[knocker]

The ecm this morning sticks with HP theme for most of the run with the centre to the west. A little blip around Thursday when fronts from the Iberian low push north into the south west. could produce some nice convective activity. And towards the end of the run the northerly does set in but the very cold air may be just to east.

[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 FRIDAY APR 15TH 2016

THE CURRENT GENERAL SITUATION Low pressure will move East along the English Channel today with a complex pattern of occluded fronts over the South and North accelerating away South tonight as a cold Northerly flow develops for all by tomorrow that in turn followed by a ridge of High pressure across the South on Sunday.

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

CURRENT SNOW FORECAST AND FREEZING LEVEL OVER THE UK The upper air temperatures are falling markedly across the UK over the coming days from around 5000ft to nearer 2000ft over much of the UK through the weekend before rising slowly across the North by the start of the new week. Patchy snowfall over modest high ground is possible for a time, mostly over the North today and on the highest hills of the South too tomorrow morning.

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

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

MODELS-2 WEEK HEADLINE Slowly becoming drier and brighter from the weekend but with the risk of cool nights and some frost for a time next week. Perhaps more showers again later especially across the South and East.

THE GFS JET STREAM FORECAST The Jet Stream pattern is changing as I type as the trough in the flow breaks up as the flow splits with a cut off Low to the South maintaining the main flow well to the South but with the UK lying under more of an influence to the Northern portions of the flow which is weaker and trending to move South across the UK at times.

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

GFS OPERATIONAL The GFS Operational Run today shows a lot of High pressure dominance across the UK over the next few weeks. A lot of dry weather is likely across the UK for much of the time but the one negative is the positioning of the High which is nearly always to the North or NW and allowing chilly Northerly winds to affect the UK for much of the period with some occasional showers especially in the East and South and more importantly some further frosts at night.

GFS CONTROL RUN The GFS Control Run is very similar with High pressure mostly dominant out to the West of the UK with some showery rain moving South or SE across the UK at times with temperatures generally ending up somewhat depressed with the risk of night frosts although it may be somewhat warmer in the South for a time early next week.

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 still show good support for High pressure to lie out to the West of the UK in 14 days with chilly Northerly winds likely at that time. The problem lies in how close High pressure is to the UK at that time and most members suggest not close enough with Low pressure close by with some rain or showers for many and only a total of 10 of members suggest High pressure close to the east of the UK offering a rather warmer and drier prospect.

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 a High pressure ridge just about holding on across the South to start next week with the North likely to see a little rain as troughs brush by to the North in a Westerly flow there. Then High pressure builds across the UK towards midweek with mostly dry weather for all with temperatures on the rise.

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

THE FAX CHARTS The Fax Charts show troughs clearing South tomorrow with cold Northerly winds briefly before a ridge builds across the South at the end of the weekend and for all by Day 5 with fine and dry weather but with frosts at night where skies stay clear.

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

GEM GEM today shows High pressure building across the South of the UK later in the weekend with a weak Westerly flow for a time across the North. Then a few days under High pressure brings fine and settled weather for all but with frosty nights before the High slips further towards the West and NW later keeping the door open for cold North or NE winds to re-invade the UK later with heavy and in places thundery and wintry showers with temperatures below average especially in the South and East.

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

NAVGEM NAVGEM also shows the same build of pressure at the weekend slowly giving away again by the middle of next week from the North as Low pressure troughs down from the North with a chilly North wind and showers to end next week.

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

ECM ECM today looks a bit better than recently although the theme of chilly North or NW winds is maintained. The difference is that this morning's run shows High pressure closer in to the West late in the run with lighter winds and less risk of showers though I think frosts would still be an issue by night especially in low lying areas. Before we get there though there is 4-5 days of fine and settled weather developing with some sunshine and settled weather with temperatures recovering a little for a time.

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

ECM 10 DAY MEAN (12z) The 240hr mean Chart from last night continues the theme of High pressure likely over the Atlantic in 10 days time with Low pressure to the East and NE meaning a cool Northerly flow likely over the UK with some showers by day and frost by night

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

NOTABLE TRENDS & CHANGES FROM PREVIOUS RUNS Still a lot of High pressure dominated weather in prospect for the UK with the trend for High pressure to finish up to the West or NW of the UK.

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 97.4 pts to UKMO's 96.8 pts while GFS lags behind at 95.7 pts. At 5 days ECM leads with 89.8 pts to UKMO at 87.6 pts and GFS at 84.7 pts. Then at 8 Days ECM has the leading spot from GFS with 65.1 pts to 59.9 pts. Finally at Day 10 ECM has the lead from GFS with a score of 42.6 pts to 38.9 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  There seems reasonable agreement on the fact that High pressure is going to play a large role in the conditions across the UK over the next couple of weeks as we lose the Low pressure based pattern centred down to the SW of the UK that we have had this week. So today sees the last of any warmth across the South along with the heavy and thundery showers as we pick up a cold Northerly tonight and tomorrow with some showers, wintry on hills for a time. With pressure rising quite quickly the cold Northerly soon gets replaced by lighter winds but with cold air aloft and near the surface night frosts look inevitable especially tomorrow night. After a little rain on a Westerly breeze over the North early next week the High pressure gradually exerts influence across more of the UK next week with some warmth returning for a time. However, it doesn't look the start of a long warm spell as the positioning of High pressure looks far from ideal in the longer term. It is likely to end up over the Atlantic or even further north to the NW keeping the door open to the North for chilly winds and potential showers from Low pressure over Europe to affect at least the South and East at times as well as maintaining the risk of cold nights with some unwelcome frosts. Nevertheless, for those planning outdoor activities there looks to be a sustained period of decent weather coming up with some sunshine and although record breaking high temperatures look unlikely, away from those pesky cold April showers conditions for most will end up acceptable through the period.    

Next Update Saturday April 16th 2016 from 09:00

[Frank Trough]

I'm still left wondering that if we don't manage a 20c somewhere next week (as almost advertised by the GFS) whether we might go all the way through to May without doing so? Certainly none of the modelling for the last third of the month suggests we will even get close.

 

I think I'm right in saying that would be the first time since 2006? And prior to that 1983?