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Paul

Model output discussion - 20th Feb onwards

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The GEFS anomalies this morning are still looking at the hand over from our old friend the Canadian vortex and trough to the Siberian equivalent around the 15th. Prior to this HP will become more influential over the UK with temperature tending to rise from below average to above and certainly for a while a period of more settled weather.

Moving on the loss of the Atlantic trough and the emergence of the trough to the east does lead to the HP influencing  the UK to become far less influential with the upper flow tending to back westerly leading to periods of more unsettled weather with some interludes of wind and rain but interspersed with drier spells and temps around the average.

gefs_z500a_5d_nh_41.thumb.png.876ecf2bf9gefs_z500a_5d_nh_61.thumb.png.04f9150277

 

Edited by knocker

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Day 6 charts 

GFS/UKMO/ECM

gfs-0-144.png?0   UW144-21.GIF?05-06   ECM1-144.GIF?05-12

Looks like the ECM 12z was a rogue run with all the models taking the low north of the UK instead of through the UK with the Atlantic trough developing along with the corresponding Iberian based ridge. The ECM still the slowest here but in a similar ball park now.

Edited by Captain Shortwave

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Both the GFS and ecm are looking at a wet and windy day next weds.

ecmwf_z500_mslp_eu_5.thumb.png.f96ed64fagfs_ptype_slp_eur2_17.thumb.png.5a80d710

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Fasinsting mid term from GFS, warm and settled at first and then some very very cold air flooding down to the east!! 

If we could tap into this it would certainly be a month of extremes!!

image.gif

Edited by chris55

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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 SATURDAY MAR 5TH 2016

THE CURRENT GENERAL SITUATION   An occluded and weakening front across Central Britain this morning will pull away SE through the day clearing the east coast tonight and leaving a rather cold Northerly air stream across the UK for the weekend.

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

 CURRENT SNOW FORECAST AND FREEZING LEVEL OVER THE UK The freezing level across the UK will remain around about the 2000ft mark for much of the weekend but maybe a little lower than this under the occluded frontal zone at first. Snowfall amounts will be small or negligible for most through this weekend with any snow light and fleeting over higher ground exposed to the north once today's occluded front has gone.

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

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

MODELS-2 WEEK HEADLINE  Rather cold and breezy at first with rain or showers at times with snow on hills. Then becoming less cold but windy with rain at times especially in the North.

THE GFS JET STREAM FORECAST  The Jet Stream is shown to continue to blow SE or South across the UK and Western Europe in association with Low pressure moving East then SE to the North or east of the UK in the next 3-4 days. Thereafter the Thereafter the flow backs West to east across the UK late next week at least for a time before becoming less clear cut in positioning and strength towards the end of the period.

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

GFS OPERATIONAL The GFS Operational Run today shows the same pattern as has been shown for days now with the cold and changeable conditions giving way eventually to milder West or even very mild SW winds for a time by next weekend with rain at times towards the North. In week 2 the High pressure area to the South builds North through the UK with fine and settled weather for all. However, it looks like temperatures would fall back again with frosts at night before changeable Westerly winds return at the end of the run.

GFS CONTROL RUN The theme of the Control Run shows a variation on the same theme as the Operational today with chilly North winds backing to a milder West or SW flow by next weekend with the second week seeing High pressure build across the UK from the South or SW.

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 show a bias towards Low pressure close to northern Scotland or to the NE with cyclonic winds across the UK from the West or NW the most likely option with rain or showers at times. Up to 20% of members support a more High pressure based pattern centred near to the SW of the UK. 

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 has a much flatter look about it today meaning cold weather will depart to the East by midweek with a milder Westerly flow with rain at times especially across the north and West of the UK taking hold through the second half of next week.

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

THE FAX CHARTS The Fax Charts show good support for it's operational partner with fronts orientating more West to East across the UK towards midweek with rain at times and less cold air filtering in from the West.

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

GEM GEM this morning takes a different approach and instead of allowing milder westerlies midweek shows a Low pressure taking a more SE route down across the UK with more rather cold conditions with rain and hill sleet clearing as High pressure builds behind it across the South. This then extends across all areas later with dry benign days but frosty nights where skies stay clear.

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

NAVGEM NAVGEM takes the milder route with rain spreading from the West midweek replacing the rather cold conditions until then. rain will be most prevalent towards the North and West by next weekend with milder air by then for all.

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

ECM ECM today returns to it's milder roots this morning following last night's changes. Therefore although mild weather is shown to take until Thursday/Friday next week to take a strong foothold once it does temperatures could exceed average levels in the South with rain from fronts more restricted towards the North and West as High pressure builds to the South.

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

ECM 10 DAY MEAN Not released at time of publishing this morning's report.

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

NOTABLE TRENDS & CHANGES FROM PREVIOUS RUNS The pattern between the models appear to be continuing to give good cross model support for  a change to milder Westerly winds arriving across 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 99.4 pts.  At 3 days ECM is leading with 97.5 pts to UKMO's 96.9 pts while GFS lags behind at 96.2 pts. At 5 days ECM leads with 90.7 pts to UKMO at 88.2 pts and GFS at 86.1 pts. Then at 8 Days ECM has the leading spot from GFS with 65.3 pts to 61.5 pts. Finally at Day 10 GFS has the lead from ECM with a score of 49.5 pts to 47.1 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  Things may look very different synoptically by this time next week if this morning's output is anything to go by. The main culprit of the change to milder air next week is the re-orientation of the Jet Stream which has recently been pulled South over or to the West of the UK with Britain being on the cold side of this. By the middle of next week the jet flow backs West to East over the UK or even further North with the potential for some very mild weather to threaten the South at least on a week's time. In the meantime we still have 3-4 days of rather cold and rather changeable weather to come with a little rain or even snow at times over the hills before a band of wind and rain midweek opens the door to the Atlantic. thereafter there looks to be rain at times in strong west winds for the North, but less so for the South before all areas look like becoming dry and fine at some point through the second week as there appears sound support for pressure to rise strongly then at least for a time. This may mean of course temperatures falling back somewhat again with the re-introduction of a frost risk at night but any daytime sunshine should support temperatures still approaching normal values of not above dependent on where the resting place of any High pressure may end. Towards the very end of the period the usual variability of output is shown with the favoured Atlantic westerly option hinted at returning again by the GFS model in particular. So as I said yesterday a typical early Spring mix of weather across the UK in the next few weeks but on the face of it it doesn't look that bad.

Next Update Sunday March 6th 2016 from 09:00

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GFS shows what I warned about, albeit not as fast as feared.

ECM has gone from furthest south with the jet midweek to furthest north, which lowers confidence in proceedings - but a notable increase in temperatures does look the form horse for a time later next week. With luck that'll hold on into the weekend and feature enough high pressure to bring settled weather with it. The balance of play between the Azores/Euro High and those height rises across Svalbard will be important. 

npst30.png npst30.png

 

The split in the stratosphere has become better defined in the GFS output again after a couple of days where it became rather uncertain. The location is one that supports height rises N and NE of the UK. I'm inclined to pay most attention to the model runs that show the strongest height rises during the weekend, as this ties in best with the theoretical impact of this SSW event.

Interestingly the whole 30 hPa setup retrogresses during the rest of the run:

npst30.png npst30.png

 

That supports the idea of a long-fetch easterly as reverse zonality takes over from central/eastern Asia right across to the UK.

It may seem crazy but such an outcome could bring the UK at least a brief blast of deeply cold air (assuming a lot of modification with us at the western end of the line). After that, the pattern likely transitions to height rises NW of the UK, which I suspect ushers in a 'nuisance' period of chilly/cold (for time of year) but not all that snowy (if at all!) conditions for the southern half of the UK at least.

Oh I'm sorry, is that glass actually half full:rolleyes::laugh: For a positive take - at least it tends to be drier when easterlies are about as opposed to westerlies!

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ECM brings in spring proper from late next week could easily get into the high teens in the latter stages in the south if we got some sunshine

Recm1442.gifRecm1682.gifRecm1922.gifRecm2162.gifRecm2402.gif

 

 

Edited by Summer Sun

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10 hours ago, knocker said:

The EPS T360 850mb flow chart (along with the 500mb anomaly) has the HP pushing up mid Atlantic giving a flow just north of west over the UK with 850 temps around 0 -2C. The trough is way to the east.

indeed.... the noaa charts out to day 14 suggest, consistently, the azores ridge building to our near southwest. this keeps the uk in an upper flow from a north of west direction, but, originating from a more southerly mid atlantic source.  its looking like it might be a cloudy affair, but drier and milder by next weekend after a messy rather wet at times, unsettled week with temps gradually recovering.

whilst the noaa's never supported such a large ridging over scandinavia yesterdays 12z ecm suggested, and subsequently dropped, there are tentative signs of slight +ive rises over scandinavia on the 8-14 day chart coupled with -ive drops over central southern europe. so maybe the beginings of an easterly evolution IF these tentative signs  build pressure further over scandinavia.

interesting to note too, the noaa's do not support the azores high building across our south/southeast bringing the very warm weather some runs are suggesting. for what its worth, the gfs 00z looks likely to verify upto t240.

latest.thumb.gif.835edf9824148e2c79a419f


 

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ECMWF 0z shows WAA push into polar region via UK on the 14th March.image.thumb.png.3b0586994961debc44647c45If it goes through with purpose, it will close the door behind it and allow Siberian air to move westward towards UK. 

Whatever the outcome will be. It is going to be very fascinating to watch this process play out. 

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44 minutes ago, mushymanrob said:

indeed.... the noaa charts out to day 14 suggest, consistently, the azores ridge building to our near southwest. this keeps the uk in an upper flow from a north of west direction, but, originating from a more southerly mid atlantic source.  its looking like it might be a cloudy affair, but drier and milder by next weekend after a messy rather wet at times, unsettled week with temps gradually recovering.

whilst the noaa's never supported such a large ridging over scandinavia yesterdays 12z ecm suggested, and subsequently dropped, there are tentative signs of slight +ive rises over scandinavia on the 8-14 day chart coupled with -ive drops over central southern europe. so maybe the beginings of an easterly evolution IF these tentative signs  build pressure further over scandinavia.

interesting to note too, the noaa's do not support the azores high building across our south/southeast bringing the very warm weather some runs are suggesting. for what its worth, the gfs 00z looks likely to verify upto t240.

latest.thumb.gif.835edf9824148e2c79a419f


 

NOAA placement looks about right at the moment, backed up by the ECM ens

EDM1-192.GIF?05-12 EDM1-240.GIF?05-12

anomalies

EDM101-192.GIF?05-12   EDM101-240.GIF?05-12

Upper ridge located around the Meridian so moving forward it could go either way I think, plenty of signals to retrograde the pattern in the longer term but also we could see the pattern drift eastwards which could bring a potentially warm southerly. It certainly looks to be an interesting period coming up with the typical westerly pattern taking a back seat with some sort of blocking pattern emerging which isn't surprising given the situation in the strat. It could be a warm or cold one at the moment given the charts.

The GEFs anomalies are similar to day 10, beyond that there is a signal to pull heights westwards but recent suites have tended to put low heights a bit too far west to develop a cold pattern (Below average heights over Iberia but above average over the central Mediterranean).

Edited by Captain Shortwave

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46 minutes ago, mushymanrob said:

indeed.... the noaa charts out to day 14 suggest, consistently, the azores ridge building to our near southwest. this keeps the uk in an upper flow from a north of west direction, but, originating from a more southerly mid atlantic source.  its looking like it might be a cloudy affair, but drier and milder by next weekend after a messy rather wet at times, unsettled week with temps gradually recovering.

whilst the noaa's never supported such a large ridging over scandinavia yesterdays 12z ecm suggested, and subsequently dropped, there are tentative signs of slight +ive rises over scandinavia on the 8-14 day chart coupled with -ive drops over central southern europe. so maybe the beginings of an easterly evolution IF these tentative signs  build pressure further over scandinavia.

interesting to note too, the noaa's do not support the azores high building across our south/southeast bringing the very warm weather some runs are suggesting. for what its worth, the gfs 00z looks likely to verify upto t240.

latest.thumb.gif.835edf9824148e2c79a419f


 

If that chart does verify though, it could be setting up for a cold easter, although the caveat that there is less margin for error with any subsequent cold synoptics.

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Euro kept the high too far away bar day 9 for my liking. 

GEM looks great but you risk a cool, cloudy easterly. 

GFS is great from day 9.

..

Confidence building of a settled spell of some kind which given the March sun should get us a good durinal range. 

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The ecm this morning in the 6-10 range is very similar to the GEFS. Trough mid Atlantic with HP ridging over the UK backing the upper flow SW and indicating some more settled weather with temps rising above average.

It also makes the transition around the same time and in the ext period there is a rapid weakening of the Atlantic trough and the emergence of the trough down through eastern Europe. Initially the ridging over the UK is maintained but this weakens towards the end of the period leading to the upper flow veering westerly bringing periods of more unsettled weather with temps around average.

ecm_eps_z500a_5d_nh_11.thumb.png.6b03aa6

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15 minutes ago, feb1991blizzard said:

If that chart does verify though, it could be setting up for a cold easter, although the caveat that there is less margin for error with any subsequent cold synoptics.

well im not going to bother speculating about what might evolve, its not usual for milder weather to come in early/mid march and for us not to get a colder spell.

so a cold easter?... possible, its not unusual, but snow? i doubt that.

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BTW NOAA 500mb height forecasts on the weekends are automated with no human input (most of the time)

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16 minutes ago, mushymanrob said:

well im not going to bother speculating about what might evolve, its not usual for milder weather to come in early/mid march and for us not to get a colder spell.

so a cold easter?... possible, its not unusual, but snow? i doubt that.

I would say there is a good possibility of Snow at Easter - not saying snow on the ground but falling snow , a decent chance

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9 minutes ago, Banbury said:

I would say there is a good possibility of Snow at Easter - not saying snow on the ground but falling snow , a decent chance

based on what? easter is 4 weeks away, no modeling suite goes out that far with any degree of accuracy.

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Mushy

The charts I posted earlier in the thread shows a possibilty of colder weather after mid month - it snowed here yesterday with temps at 5c , so why cant it at Easter.?

You yourself said it could well be colder at Easter - so I assume you are saying HP sat directly over us,?

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21 minutes ago, mushymanrob said:

based on what? easter is 4 weeks away, no modeling suite goes out that far with any degree of accuracy.

Based on the SSW and final warming I would think. There will be a tanking -AO and the cold air has to go somewhere.  

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1 hour ago, mushymanrob said:

well im not going to bother speculating about what might evolve, its not usual for milder weather to come in early/mid march and for us not to get a colder spell.

so a cold easter?... possible, its not unusual, but snow? i doubt that.

Why not? It isn't an outrageous suggestion. In 2008 there was settling snow in London on 6 April.

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The ECM less interested this morning in building that stronger block although the overall pattern is similar.

The T168 and T192hrs is the timeframe to watch as that's when the Atlantic troughing starts to dig further south and this is when the models might force a stronger ridge north ahead of that.

Even if that happens though you still need some way to get the cold in from the ne, if theres to be a sudden change in the outputs with a quick trop response to the SSW then it will show up within the next few runs as the SSW is due within the next 24 hours.

 

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The Gfs 6z op run turns warm and anticyclonic for week 2 with plenty of sunshine and light winds with temperatures widely into the mid teens celsius and high teens for some! This would be very pleasant indeed and it would make a nice change to see high pressure building in and gaining a firm foothold and intensifying over the uk..:)

ukmaxtemp.png

h500slp.png

h500slp (1).png

ukmaxtemp (1).png

h500slp (2).png

ukmaxtemp (2).png

ukprec.png

h500slp (3).png

ukmaxtemp (3).png

ukmaxtemp (4).png

h500slp (4).png

ukmaxtemp (5).png

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13 minutes ago, Frosty. said:

 

Yes quite a bit of support for something of a warm up around mid-month Karl.

ensemble-tt6-london.gif

also the ECM/GFS mean outputs go with a high close to or over the UK around days 8-10.

EDH1-216.GIF?05-12gensnh-21-1-216.png

a few colder days still to get through first though.

It looks like the winds back westerly with some mid-week rain before the Azores high makes an approach to the UK next week end.

As you say it could well be quite warm in many areas for a few days so it will make a pleasant change after the cold start to March.

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1 hour ago, Banbury said:

Mushy

The charts I posted earlier in the thread shows a possibilty of colder weather after mid month - it snowed here yesterday with temps at 5c , so why cant it at Easter.?

You yourself said it could well be colder at Easter - so I assume you are saying HP sat directly over us,?

 

1 hour ago, solarcycle said:

Why not? It isn't an outrageous suggestion. In 2008 there was settling snow in London on 6 April.

guys, this is the model discussion thread, as the models dont go out to easter yet, arent predictions of what easter might hold be speculative? even ramping?

i have no idea what weather we will get in 3 weeks time, (my bad, not the 4 i mentioned earlier) im not expecting it to become mild and stay mild, spring is a season of mixed fortunes so after the likely warming up abit next weekend, im sure itll go colder again at some point. it might get cold enough for snow, but those events arent as likely as cold dry overcast easterlies - and thats assuming we even get an easterly.

by next weekend the anomaly charts will start to bring easter into their view, if, between now and then they start to suggest a large pressure rise over scandinavia - ill believe it. if they dont, i wont.

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