Model output discussion - 20th Feb onwards

[Frosty.]

The Gfs 18z shows wintry weather through low res with arctic air flooding south along with some snow...so both the Ecm 12z and now the Gfs 18z are showing more interest for coldies beyond the next 10 days.

[knocker]

The ecm beyond ten days isn't showing interest in anything cold but I'm open to be corrected by those who are privy to more information than myself.

Edited March 14, 2016 by knocker

[Singularity]

 

 

To split or not to split? For that is the question that GFS cannot answer with respect to the polar vortex!

Given the destroyed nature of the stratospheric vortex, you'd think a split would be favoured. 

 

http://earth.nullschool.net/#current/wind/isobaric/70hPa/orthographic=-0.67,70.67,274

Looking here, we can see how the high pressure system affecting the UK extends right up to at least 70 hPa.

You can really see where Cohen's idea of an easterly from Siberia came from - but we have not seen a straight forward propagation of this pattern down to the troposphere.

Up at 10 hPa (either select that level on the site by clicking on 'earth' to bring up the variables panel, or click here - but be aware that having two tabs on that site at once will use a lot of computing power), the story looks rather different, with the polar vortex right over France. It won't have much effect on the pattern below though, as it's moving steadily west and will be in the middle of the North Atlantic within a few days time:

   

I've also posted the chart for when the 10 hPa pattern reaches the point at which a reflection at the surface some time later would produce unusually cold conditions for the time of year - but given how much cold looks to be displaced from the Arctic prior to anything affecting the UK, the extremity of such conditions may be watered down somewhat. The 18z GFS has a fair go at things yet maximum temps still reach the high single digits in the south - though this was helped along by a generally settled regime with some rather tame destabilisation affecting the south at times.

I do wonder what state this will leave the Arctic sea ice in - it's already at near record lows for the time of year, currently just above the record holder which happens to be 2015, and about to take the top spot again unless the extent manages to grow a bit in the next day or two. That, of course, is a matter for a different forum area and thread (a members-only area which can be accessed here).

[bobbydog]

16 minutes ago, Frosty. said:

The Gfs 18z shows wintry weather through low res with arctic air flooding south along with some snow...so both the Ecm 12z and now the Gfs 18z are showing more interest for coldies beyond the next 10 days.

hmm. reminds me of a quote from 'Wayne's World'

"yeah... and monkeys might fly outta my butt..."

[Frosty.]

6 minutes ago, knocker said:

The ecm beyond ten days isn't showing interest in anything cold beyond ten days but I'm willing to be corrected by those who are privy to more information than myself.

The Ecm 12z op run and the ensemble mean shows lots of potential for coldies by T+240 hours..Arctic blast beyond day 10?.hopefully it's still showing tomorrow morning and beyond!

[knocker]

3 minutes ago, Frosty. said:

The Ecm 12z op run and the ensemble mean shows lots of potential for coldies by T+240 hours..Arctic blast beyond day 10?.hopefully it's still showing tomorrow morning and beyond!

But as I've just said the EPS means past day ten do not and the anomaly doesn't support it. The 850mb flow chart for two days later indicates a westerly with temps a little below average.

Edited March 13, 2016 by knocker

[knocker]

The latest GEFS looks like average temps to me.

[feb1991blizzard]

3 minutes ago, knocker said:

The latest GEFS looks like average temps to me.

Yes, a few days ago, there was a slew of GEFS individual members going well below average for March, they trended back up, yes in the last 24-48 hours they have re-appeared in an earlier timeframe, but they are a lot less and more watered down, to get a proper cold spell, they really needed to have been trending near to -10 850mb temps and in significant quantity.

[knocker]

The GEFS anomalies are still retrogressing the HP during the next ten days but it digresses somewhat from previous scenarios by amplifying the pattern for a brief period starting on the 23rd. It runs the HP up into Greenland whilst at the same time swinging the European trough South west into the North sea. This would veer the upper flow NNW and introduce much colder air over the UK. How much credence to give to this is not easy to ascertain (the ecm will no doubt help later) because within two or three days this amplification disappears and a NW becomes the order of the day. And by the end of the we are talking zonal with the European  trough virtually non existent.

[knocker]

Strangely enough this morning's ecm ops retrogresses the HP in the latter stages of the run and at the end builds heights into Greenland And with LP to the east a NW flow ensues. It has to be said the air is not that cold and only a little below average and one suspects a transient rather than a long lived feature.

[IDO]

^^^Yes those teaser D10 charts! They keep coming this winter. 

An example is two days ago the D10 chart was amplified: 

 Today's run for the same time: 

The inevitable downgrade of the D10 charts, very predictable. However a caveat in this instance as the knock on effects of the upcoming  SSW (negative AO) would hint this may be when the exception proves the rule! Anything after D8 is open to change at the moment as we watch what happens to the trop PV as it moves away from it's short stay in Siberia. The GEFS suggest it will retrogress the UK high west and the trough will skirt with the UK. Mean at D10:

  Cold: 

But the cold uppers are in the wrong location at the moment^^^ for a period of intense cold and for the south pretty tame though below average 2m temps possible. After that the GEFS go in various directions so no comment at the moment.

 

 

Edited March 14, 2016 by IDO

[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 MAR 14TH 2016

THE CURRENT GENERAL SITUATION Pressure will remain very high over the UK in the coming days with a high centre across the North Sea responsible for fine and settled weather across the UK for the next few days. 

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

CURRENT SNOW FORECAST AND FREEZING LEVEL OVER THE UK The freezing level across the UK will remain in the range of 6000-7000ft asl under strong High pressure which as a result will not allow for any snowfall across the UK for some considerable time.

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

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

MODELS-2 WEEK HEADLINE  Mostly dry and bright with some frosts at night and near average temperatures by day.

THE GFS JET STREAM FORECAST  The Jet Stream is responding to a block of High pressure across the UK at the moment with the undulating flow over the Atlantic splitting into two arms one well to the South and the other well away to the NW of the UK both moving in an Easterly direction. The flow becomes more variable later with no definitive pattern as High pressure remains fairly close to the UK.

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

GFS OPERATIONAL The GFS Operational Run today shows High pressure in complete control of the weather across the UK for much of the next few weeks with the centre drifting slowly west or SW across the UK through the next week or so. This will maintain fine and bright weather especially in the NW whereas a chilly breeze and cloudier skies will likely affect the South at times. Then through the second week and as we move towards the Easter weekend it looks like there will be a change towards more unsettled conditions with rain at times especially in the South as Low pressure edges down across these areas from the North and then West but a High pressure ridge then returns again later in that weekend. 

GFS CONTROL RUN The theme of the Control Run shows the same High pressure moving West across the UK through this week with it's largely fine and settled conditions maintained but then accelerating quicker West from next weekend and allowing a cold second week with things turning more unsettled under Low pressure with rain and hill snow becoming likely for many through the second week and over the Easter weekend.

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 are back to their un-decisive nature again this morning with the 14 day point showing a mix of 4-5 options all with supporting members amounting to around 20% and ranging from unsettled conditions in association with Low pressure across the UK to a ridge with things much more settled and with temperatures closer to average. 

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 in control this week before retreating away towards the SW over next weekend. With much of the UK lying on the chilly side of the High it is left to the NW to receive some early Spring warmth while the rest of us might feel rather cold in a chilly NE breeze at times. Then at the weekend a Northerly flow looks likely for all and though still dry for many pressure will start to fall across the UK. 

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

THE FAX CHARTS The Fax Charts illustrate the High pressure 's movement West to the North of the UK through the week. With the UK lying on the Southern flank of the chilly NE winds are shown to drag weak troughs West in the flow with the ebb and flow of cloud amounts throughout.

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

GEM GEM this morning looks very settled too over the next week or so as High pressure remains in complete control with just patchy frosts and cloud disrupting the early Spring look of things. Towards the end of the run High pressure appears to be declining and moving away West to allow an attack from the North of cold and showery weather for what looks likely to be in time for the long Easter weekend.

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

NAVGEM NAVGEM also shows High pressure receding West later this week as it moves SW from it' current positions towards a point SW of the UK in a weeks time. A dry and fine week for many this week with varying amounts of cloud and sunshine looks under threat from the NW by the start of next week.

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

ECM ECM too looks to be setting up a disappointing Easter weekend as the High pressure under complete control of the UK weather over the next week slowly gives way to the West early next week and opening the door to the North for low pressure to bring very chilly North winds and wintry showers over Easter with frosts at night. 

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

ECM 10 DAY MEAN The 240hr mean Chart has strengthened it's theme of suggesting a cold and showery northerly airflow developing across the UK in time for Easter as High pressure recedes to the SW and Low pressure over Scandinavia drags colder and unstable air down from the North with the Jet stream easing South of the UK once again.

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

NOTABLE TRENDS & CHANGES FROM PREVIOUS RUNS The trend continues to show a protracted fine spell lasting for a week and possibly a lot more across the UK before signs of a chilly and showery Easter weekend looks equally likely on this morning's evidence.

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 99.4 pts.  At 3 days ECM is leading with 97.5 pts to UKMO's 97.1 pts while GFS lags behind at 96.4 pts. At 5 days ECM leads with 89.8 pts to UKMO at 88.9 pts and GFS at 85.7 pts. Then at 8 Days ECM has the leading spot from GFS with 64.8 pts to 60.7 pts. Finally at Day 10 ECM has regained the lead from GFS with a score of 46.3 pts to 45.3 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  The main focus on the models this morning is the growing theme of a rather chilly Easter coming up from the models as most output shows the grip that High pressure has on the UK weather lessens next week as it recedes slowly to the West of the UK. In the short term namely through this week and next weekend any changes will just focus around varying amounts of cloud day to day and the nagging and chilly NE breeze likely to be maintained across the South of the UK through the week. NW looks best for warmth especially early in the period while elsewhere daytime temperatures though near average might feel a bit cold at times but any rainfall will be very light and restricted to windward coasts and hills and from low cloud feeding in from the North Sea. Then we are increasingly seeing signs of change from the models as we move through next week as the High recedes to the West and opens the door for the UK to be under attack from the North. There are several differing versions of the way we might evolve through this period but there is sufficient evidence to say that there is a strong chance of Easter being rather cold and showery at least and a few members this morning illustrate something more generally wet and cold for a time with no doubt some snowfall over hills. It still is a fair way off and with the differing scenarios within the general theme on offer it suggests to me that nothing is guaranteed as yet so in the meantime we should enjoy the largely fine and dry conditions across the UK this High pressure is giving as it's a welcome break from the recent rains and strong winds. 

Next Update Tuesday March 15th 2016 from 09:00

[Frosty.]

Good continuity between the Ecm 12z and 00z with a strong Arctic blast arriving during next week, hopefully this trend will continue to firm up through this week!

[Frosty.]

It's an Anticyclonic week ahead but as the position and orientation of the high slowly changes, we can expect day to day variations in cloud cover and sunshine distribution but the main thing is it's largely dry, quiet and settled for a change which I'm sure many will welcome...there are growing signs that our UK based high will drift west into the Atlantic next week with colder and unsettled weather spreading from the north.

[knocker]

The ecm anomaly on the 24th also has ridging Greenland way but is not quite so ambitious with the trough to the east leaving it over Scandinavia. The resulting upper NW flow could well bring some fairly wintry weather, particularly to the north, as any systems could track SE into Scandinavia resulting in a transient cool northerly.

Within a couple of days the ridging to the west has gone, the trough to the east weakened resulting in a cool zonality, By the end of the period the trough to the east is gone, and the remnants of it, are down around Turkey and there is a trough in mid Atlantic running SE from the vortex over N. Canada. Temps remaining a little below average.

[Frosty.]

Plenty of eye candy for coldies to enjoy on the Gfs 6z op run through low res with repeated cold shots from the NW / N and a risk of snow.

[Frosty.]

There is clearly potential for a Pm / Arctic outbreak to develop next week according to both the GEFS 6z mean / Ecm 00z ensemble mean at T+240 hours with a large scandi trough favourably aligned for a cold shot to bring an increasing risk of snow to some parts of the uk as well as frosts and icy patches. 

[cheshire snow]

Unfortunately I think you may be correct Frosty. currently sat in the garden 14.8c crystal clear skies and warm sunshine if only it would continue. don't look forward to being sat inside with the fire on at the end of March 

C.S

Edited March 14, 2016 by Nick L
corrected weird formatting

[Frosty.]

2 minutes ago, cheshire snow said:

Unfortunately I think you may be

correct  Frosty.

currently sat in the garden 14.8c

crystal clear skies and warm sunshine 

if only it would continue 

don't look forward to being sat

inside with the fire on at the end

of March 

C.S

One of the things I love about March is the wide variety of weather when we can have warm sunshine like today but then potential snow within days..I'm not saying we will have a white Easter but it could be cold and unsettled before the end of next week. I don't see a typical Atlantic breakdown from the current anticyclonic spell with our high likely to drift west into the Atlantic which then opens the door to a Polar maritime  / Arctic maritime incursion (s). Compared to this time yesterday, the models do appear to be indicating an increasing chance of a cold shot during the second half of next week.

[knocker]

The GEFS 06z anomaly at day has realigned itself with the 00z ecm in not being so bullish with the Scandinavian trough. Ergo once the HP has moved sufficiently far west to initiate a NW upper flow the UK could experience some unsettled weather which could produce a transient N/NE and cooler conditions. This will only apply for a very short time as both the ridge and trough weaken and the pattern becomes much flatter.  So essentially an unsettled westerly with temps a little below average.

[Essex snowman]

On 29 February 2016 at 9:42 PM, bobbydog said:

well i've been keeping an eye on the models for the past few days (well actually all winter- but like everyone else, im now hoping we get a miracle and i am the eternal optimist).  however, in the real world, though we are facing a couple of chilly weeks, winter will not be arriving in force, to throw us into a media hyped 'snowmageddon'. if you want to see snow falling from the sky, thats a good probability. if you want (like me) a winter wonderland then give up now. we do have this label of "coldies" which is used often to describe winter lovers. now i do appreciate that some do like the cold but i just want snow. a proper winter.  a bit of frost is pretty in the morning but today was the final realisation for me. i was out in the garden today making a bunk-bed ladder for a customer. the weather was dry and sunny which meant i could do it outside rather than my workshop and i actually had to take my jumper off because i was too hot! 

to be honest, i'm not a 'coldie' i'm an extreme weather fan. bone chilling cold,  deep snow, powerful storms, floods, thunderstorms and tropical heat. that does it for me. the whole range. chilly with a bit of sleet does not.

sod the cold spring, if its not going to snow, the cold can bugger off and let the sun shine!

53 minutes ago, Frosty. said:

You are always having a go at what I post, am I not allowed to change my opinion?

As I said yesterday before the 12z, there was nothing cold showing but now there clearly is...hope you don't mind me discussing the possibilities next week! 

Karl u keep up the post me like many others on this forum love your posts so u discuss what u like my friend and in June we can discuss Decembers weather 

[phil nw.]

Come on guys no digs at others.If someone wants to put a different pov that's ok but not by childish sniping.

Early Spring is notorious for sudden changes and we are all entitled to reflect this in our views of the different model runs.

I have removed the posts involved.

Peace  all and back to friendly discussions,ta.☺

[Frosty.]

7 minutes ago, Essex snowman said:

 

Thanks Essex snowman

I'm pleased the models have changed since yesterday's 12z in favour of a colder incursion from the NW / N later next week, hopefully I haven't jinxed it by saying that!

[bobbydog]

12 minutes ago, Essex snowman said:

 

whats that about? i assume you have unintentionally quoted me there, as it makes it look like its me who is having a go at frosty!

it should be noted- i haven't!

[SLEETY]

looks like heading towards something similar to late march 1975 with snow even in South,if gfs is correct lol 

 

Edited March 14, 2016 by SLEETY