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Model Output Discussions 12z 03/05/2016

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1 hour ago, William Grimsley said:

Correct, Chris.R.

I've just had a look at both the GFS and the NMM charts, both show widespread heavy thundery showers/thunderstorms across my area through this weekend, not sure why some (very knowledgeable) aren't seeing this?

I feel both of us will do well this weekend. I think some are being cautious because of the lack of sheer and such like. Also it has to be said, sometimes there's not as much hype if certain parts of the country aren't in the direct firing line. 

Edited by Chris.R
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1 hour ago, William Grimsley said:

Correct, Chris.R.

I've just had a look at both the GFS and the NMM charts, both show widespread heavy thundery showers/thunderstorms across my area through this weekend, not sure why some (very knowledgeable) aren't seeing this?

Perhaps because the UKMO is sufficiently different - the unsettled stuff to the W/SW is a good 200-300 miles further away (not necessarily correct, of course!!)

By Monday there's a big variance - very warm on the UKMO, becoming unsettled on the GFS away from the north

gfs-0-120.png?12  UW120-21.GIF?04-18

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The GEFS 6-10 this evening incorporates the beginning of the process of rotating the HP to the NE and LP to SW anticlockwise which leads quite quickly to the trough over the Balkans and a transitory ridge over the UK . Thus a quick change of airmass but still relatively pleasant, dry, weather with temps holding up very well and still above average

gefs_z500a_5d_nh_41.pnggefs_t2ma_5d_eur_61.png

 

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2 hours ago, Chris.R said:

I feel both of us will do well this weekend. I think some are being cautious because of the lack of sheer and such like. Also it has to be said, sometimes there's not as much hype if certain parts of the country aren't in the direct firing line. 

Are you meaning anti "Londonocentric" forecasting - my new word!

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26 minutes ago, knocker said:

The GEFS 6-10 this evening incorporates the beginning of the process of rotating the HP to the NE and LP to SW anticlockwise which leads quite quickly to the trough over the Balkans and a transitory ridge over the UK . Thus a quick change of airmass but still relatively pleasant, dry, weather with temps holding up very well and still above average

gefs_z500a_5d_nh_41.pnggefs_t2ma_5d_eur_61.png

 

If only it were August..

Well, someone had to say it!

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ECM again favouring HP to the NE more than NW despite a move by GFS strongly in that direction.

Most intriguing - and suggestive that the models are next to clueless with respect to how the vague region N of the U.K. early next week shapes up by midweek.

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The theme of moving the HP west and the trough to the SW east is partly completed with the NOAA and ecm 6-10 anomalies. The ecm differs to the GEFS earlier in that takes the trough further east rather than SE.

610day.03.gifecm_eps_z500a_5d_nh_11.png

As mentioned before this continues in the 10 -15 period  with transient ridge over the UK so a continuation of the dry theme and temps though dropping as the period progresses but hold up quite well and are still a little above average.Towards the end of the period a more zonal flow ensues. Not sure where this is going so  put in the pending file for the moment.

All in all if something like this transpires not too bad.

Edited by knocker
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I think one thing that stands out in the outlook is that regardless if the winds do switch to a more Easterly then the feel of things will still feel quite mild even on the east coast with any low cloud.

I do think there is the potential for the outlook to stay more settled than perhaps the GFS is suggesting but its still not clear just how far Northwards that secondary low to the West of Portugal will get. The further South and West is better if you want it settled and warm but for those who wants something potentially a little more convective then the further North is more ideal but you want a case where its too far North that its just ends up grey and wet on a widespread level.

Some nice warmth coming up and in terms of the feels like, it will be by far the warmest with quite humid air but how much sunshine there will be is open to doubt and of course thunderstorm activity is also quite uncertain.

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Well it didn't last long - BBC weather for the week ahead is hinting a return to northenlies from end of next week. Back to square one we go 

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A lot of uncertainty come midweek. Latest GFS hinting at sustaining the warmth and thundery conditions with a much slower departure of the euro troughing, and then a possible return of high pressure and a potential reload of another plume. 

Best thing will be to concentrate on the weekend and early next week before any kind of conclusion can be made in the more long term scenario. 

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22 minutes ago, 40*C said:

Well it didn't last long - BBC weather for the week ahead is hinting a return to northenlies from end of next week. Back to square one we go 

So two weeks of warm weather? I'll take it.

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1 hour ago, 40*C said:

Well it didn't last long - BBC weather for the week ahead is hinting a return to northenlies from end of next week. Back to square one we go 

Your talking nearly 1 week of weather before any change, they might as well jaffa cakes in the wind when it comes to predicting weather that far out. It will change 

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I wont dwell on this weekend too much as no doubt it will be covered in the dedicated thread. Suffice it to say the low pressure to the south nudges north tomorrow so quite possibly some convective activity Tomorrow night/Saturday morning in the south west. But the main convective activity should be over the weekend and be quite general. Temps on Sunday looking quite impressive rising to around the mid 20s and the surface cape quite impressive as well.

For the rest of the week, with the low pressure still to the south the streamlines will be in the easterly quadrant with temps remaining above average, towards the end of the week the winds will briefly back NE as the LP moves east so temps a tad lower but by the following weekend high pressure is nudging in from the south west so a different ball game but still quite dry and pleasant with temps holding up quite well.

The story according to the GFS

gfs_ptype_slp_eur2_9.pnggfs_cape_mslp_uk2_16.pnggfs_t2maf_slp_eur2_39.png

 

 

Edited by knocker
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In general terms the ecm is along the same lines as the GFS. Next week the winds will have an easterly component so dry and temps above average. Towards the end of the week this breaks down as the low pressure to the south moves east with, by the end of the run, high pressure to the north and south west becoming more influential but temps still not bad.

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8 hours ago, 40*C said:

Well it didn't last long - BBC weather for the week ahead is hinting a return to northenlies from end of next week. Back to square one we go 

I wouldn't worry about it at this stage were a long way off what we had last week

Recm962.gifRecm1442.gifRecm1922.gifRecm2402.gif

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The Gfs 00z op shows an early taste of summer with temps into the 20's celsius, parts of the s /se could reach the magic 80F on Sunday and we can expect plenty of sunshine in the days ahead but also a scattering of heavy showers and thunderstorms and then the run ends pleasantly warm and anticyclonic...this is the type of spell which will whet the appetite for the summer ahead, hopefully there will be plenty of heat!:D

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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 THURSDAY MAY 5TH 2016

THE CURRENT GENERAL SITUATION Pressure remains high across the South of the UK with the weak frontal trough across the North of the UK continuing to weaken and decay over the coming day or so. With time an easterly flow will be developing across the South of the UK as pressure falls to the SW.

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

CURRENT SNOW FORECAST AND/OR FREEZING LEVEL OVER THE UK The UK continues to see the freezing level across the UK at around 5000ft over the NW and up to 8000ft over the SE. The level rises further in the coming days to as high as 10000ft over the South and 8000ft over the North by the weekend so no snowfall is expected anywhere over the coming days.

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

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

MODELS-2 WEEK HEADLINE Becoming warmer with the risk of some thundery showers in the South at times later.

THE GFS JET STREAM FORECAST  The Jet Stream currently moving NE across the NW of the UK will continue to weaken over the next day or so with the main flow held under a cyclonic pattern across Spain while the northern arm remains a long way to the NW. Later in the period the flow will remain weak and broken around our neck of the world.

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

GFS OPERATIONAL The GFS Operational Run today shows fine and warm weather developing for many over the coming days with humidity rising at the weekend as pressure falls to the SW of the UK with some thundery rain moving North on Friday night and thundery showers possible over the weekend in the South. Then next month winds back more and more towards the NE and eventually North with the warmest conditions likely in the West with further thundery showers around in the afternoons. Then as the Low complex to the SE moves away winds back towards the West with pressure still quite high with a lot of dry and benign weather likely. Towards the end of the run a new High pressure is shown to develop across the UK fine, warm and settled weather returning to all parts in two weeks time.

GFS CONTROL RUN The theme of events illustrated within the Control Run is largely the same as the Operational Run with just small but subtle differences later in the period. On this run the latter period is governed by quite slack pressure with High pressure further to the North and the risk of showers remaining across the South in particular in continuing rather warm conditions.

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 clustering today shows a lot of slack Low pressure over or around the UK with the risk of heavy showers continuing for many as we move through Mid May. With much of the air shown warm sourced the weather should continue to feel warm especially in sunny spells.

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 Low pressure developing down towards Spain and Portugal strengthening the airflow from the East and SE over the weekend. The air is inherently very warm and humid with an increasing risk of thundery showers in the South by early next week all this following a band of thundery rain moving North on Friday night.

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

THE FAX CHARTS The Fax Charts mirror the theme of the raw data well today showing persistent Low pressure down near Spain and Portugal with an ESE flow with troughs moving North close to the West on Friday night/Saturday morning and again towards the start of next week with pulses of thundery rain or showers at times but with a lot of dry, breezy and humid air across the UK at the weekend.

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

GEM GEM this morning shows the same sequence as the rest as the Low down near Spain and Portugal sends a risk of occasional thundery rain or showers across the South at times within the next week with warm and humid conditions developing for many. As the Low weakens later winds fall light and eventually revert to SW as pressure falls to the West and NW with rain and showers moving in from that direction towards the end of the period.

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

NAVGEM NAVGEM today shows the same Low pressure area down to the SW of the UK by the weekend pumping warm East to SE winds up across the UK with warm sunshine and well scattered thundery showers. With time the pressure gradient falls out making for quiet and humid weather with slow moving thundery showers at times across many parts, a process that continues through to the end of next week.

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

ECM ECM shows a very similar path to events as NAVGEM today as the warm and strong ESE flow developing following a band of thundery rain moving North on Friday night brings humid and thundery conditions in places. Then as we move through next week the Low pressure to the South weakens with winds falling light and making for a lot of dry conditions but with slow moving thundery downpours for some as well. This pattern remains for Southern areas until the end of the period whereas further North a High pressure belt lying SW to NE will bring drier and slightly cooler conditions here to end the period.  

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

ECM 10 DAY MEAN (12z) The 240hr mean Chart from last night shows chances of a 'col' area developing over the UK in 10 days time. By definition an area between two low pressure areas and two higher pressure zones can often bring any type of weather with the best guess scenario leaning towards some showers but a lot of dry weather too in temperatures close to or slightly above average looking most likely.

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

NOTABLE TRENDS & CHANGES FROM PREVIOUS RUNS The theme remains for a warm and humid period of weather across the UK which could last for quite a while as Low pressure remains likely to lie across Southern and Eastern mainland Europe and to some extent near the UK too.

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 99.4 pts and GFS at 99.3 pts.  At 3 days ECM is leading with 97.2 pts to UKMO's 96.3 pts while GFS lags behind at 95.6 pts. At 5 days ECM leads with 88.9 pts to UKMO at 86.8 pts and GFS at 83.3 pts. Then at 8 Days ECM has the leading spot from GFS with 61.9 pts to 51.7 pts. Finally at Day 10 ECM has the lead from GFS with a score of 45.6 pts to 37.5 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 general theme of the weather over the coming two weeks remains largely unchanged from that which was shown yesterday. True there are small and subtle differences between the models the further out into the future we go but the general message remains that a lot of rather humid and showery weather is on the way to most areas perhaps most prominent over the South with the best conditions likely towards the NW. As mentioned yesterday the East coast could be a place to avoid over the next week as a sea fret and haar looks likely to develop north of the Humber but this does look like becoming less of a problem as we move into the second week when the Easterly or SE drift becomes less dominant. In the meantime the warming process is already well under way although the night's are still currently very chilly and it won't be until we get behind a band of thundery rain moving up the West side of the UK over Friday night that the risk of frost becomes entirely eliminated with winds too brisk by then and the air sourced from too warm and humid a source. Looking out into the far reaches of the output today there are still various scenarios on offer but in general it looks like staying on the warm side for many always with a risk of showers and in all honesty the charts look very seasonal this morning with ideal growing conditions underway across the UK over the coming few weeks once we can get rid of the risk of the present borderline night ground frosts.

Next Update Friday May 6th 2016 from 09:00

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Looking good to me - even though it breaks down somewhat, the milder air stays firmly entrenched over the country, so there doesn't look to be a return to that freezing cold muck we had last week. Summer is on the way :D

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Looks at this setup from the GFS at t384! Yes, I know it's at that "fantasy island" stage, but this looks like a very nice plume waiting to happen:

1614349d4ea1562d408fb8669d230462.png

Edited by William Grimsley

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What a difference a week makes, the Ecm 00z shows summery charts with increasingly warm and humid air wafting up from the near continent in the days ahead, really great charts within the reliable timeframe with temps rising further during the weekend, into the mid 70's F across southern UK and a chance of 80 F in the s / se on sunday....so, plenty of very warm sunshine but triggering thundery showers in places during the afternoons and evenings and some mist / fog lapping onto eastern coastal areas at times but really it's a very nice spell for early May...enjoy!:)

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...and GFS vote shifts in favour of the ridge to the NE again. Meanwhile ECM remains steadfast with this outcome - though I'm still keeping in mind that it was pointing very strongly the other way the evening before last!

 

Anyway, this weekend seems to be looking even warmer on the latest output, with increased sunshine amounts and 23*C more widely on Sunday - but still with that heavy shower and thunderstorm potential.

Next week, advection of air with (very?) high moisture content from the southeast and into a sharp convergence line on Tuesday needs watching. GFS has been consistent with stalling this across the south to bring a very wet day which could even reach severe levels depending on just how much moisture import there is. One to keep an eye on, for sure. The 00z GFS has up to 30 mm generally, but a region of over 60 mm in the Dover Straits belies the potential - I think the model 'wrings out' a bit too much moisture as the air moves onto the land. I'm not predicting anything drastic at this stage of course.

By Wednesday this breaks down and it becomes generally pleasant again but still with some showers to contend with.

Edited by Singularity
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The ecm anomalies this morning paint a similar picture to one I posted yesterday. The latter pert of the 6-10 begins the transition of the upper trough moving east and the HP south west ending with a ridge over the UK. Not too bad at all with dry weather the order of the day and temps holding up above normal.

Into the 10-15 period the ridge proves to be transient and moves east as a trough mid Atlantic enters the fray, The light variable winds become westerly/SW westerly thus more unsettled with temps returning to  average.

ecm_eps_t850a_5d_natl_11.png

Edited by knocker
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Afternoon all

By D10, a weak Scandi ridge seems favoured - the mean doesn't tell the whole story as the values are massively suppressed by a couple of outliers which have a deep low over Scandi - 16 out of 20 ens members have better ridging centred over Denmark than is shown by the mean below:

gens-21-1-240.png

Makes you wonder if the same has happened on the ECM ens, except with the whole pattern shifted slightly further west, and a few better troughs over E Europe

EDM1-240.GIF?05-12

So by next weekend, settled/warm weather just about the favourite for the UK, but a number of possibilties for a breakdown, particularly a trough to the S moving up, and trough dropping into Scandi. Probably not as warm as the upcoming weekend, but keep that t-shirt handy.

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Greater risk of some rain by mid week should still be warm for most

Rukm961.gifRukm1201.gifRukm1441.gif

Edited by Summer Sun
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As summer sun mentioned, there is an increasing risk of some rain by the middle of next week but there should be no complaints regarding the temperatures that the Gfs 12z is showing which look very respectable next week, following the very warm spell this weekend into early next week with lots of dry and sunny weather and isolated thunderstorms pretty much nationwide...a very welcome early taste of summer.:)

Rtavn7217.gif

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Rtavn14417.gif

Rtavn19217.gif

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