The first new model thread since 5th February; the last one must be a contender for the title of longest-lasting model thread in the history of this forum I'd have thought!

Take it away folks.

HERE IS MY LATEST ANALYSIS USING DATA SUPPLIED BY THE NWP OUTPUT COVERING 5 OF THE WORLDS MOST POWERFUL WEATHER COMPUTERS ISSUED AT 08:00 ON THURSDAY APRIL 9TH 2015

THE CURRENT GENERAL SITUATION High pressure will move slowly away East as a light Southerly flow ahead of troughs over the East Atlantic develops across the UK tomorrow.

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

MODELS-2 WEEK HEADLINE  Becoming more changeable over the North with rain at times next week while the South and East stays largely dry and bright and possibly quite warm at times. Possibly rather colder for all later with frost at night.

THE GFS JET STREAM ENSEMBLE FORECAST The Jet Stream forecast shows the flow well to the Northwest  of the UK tracking NE between Scotland and Iceland. It sinks slowly South travelling NE across England at Wales at the weekend before drifting back slowly North early next week. Towards the end of the run this pattern becomes much more complex and unclear as the pressure pattern around the UK and NW Europe at that time is undecided as yet.

http://www.theweatheroutlook.com/twodata/datukgfshires.aspx?display=jetstream&model=gfs

GFS OPERATIONAL The GFS Operational this morning shows High pressure continuing to move away to the East and SE with a couple of frontal systems over the weekend affecting the UK with cooler weather with some rain. Then as the period continues a drier spell early next week especially across the South will be replaced by Low pressure moving up from the South bringing rain at times and maintaining cooler weather than currently. Towards the end of the run a vigorous Low develops near Scandinavia sending a cold and showery NW to North airflow down across the UK with wintry showers across the hills and in the North.

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

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

THE GFS CONTROL The GFS Control Run broadly follows the course of the operational in the short term with further rain towards the middle of next week following the colder and dry phase across the South after the weekend trough clearance. It looks like being very windy in the North early in the week with some rain before colder weather with showers move down over all areas late next week, these wintry in places. The rest of the run shows a lot of rather chilly weather with showers at times and a cold North wind as High pressure builds North across the Atlantic Ocean.

THE GFS CLUSTERS The GFS clusters show the message that the UK could well become more unsettled by two weeks from now and rather chilly too as most members show Low pressure in control just to the North of the UK with a NW flow delivering rain and showers at times. A reasonable 35% group show something slightly different with a trough just to the West with rain at times there and drier conditions to the East.

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 UKMO shows High pressure recovering across the UK early next week as a new centre close to the South moves to the SE too as it's predecessor did and allowing warm continental air to waft North over the UK by midweek with rising temperatures again especially in the South.

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

THE FAX CHARTS The Fax Charts illustrate weakening troughs affecting parts of the UK across the weekend especially on Sunday when some rain and thick cloud can be expected for all for a time. As we move into next week pressure is shown to have rsen sufficiently across the troughs to weaken them and allow some bright and fine weather to return for the South of the UK at least.

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

GEM GEM today shows High pressure generally in control of the weather over the next 10 days but a few flys in the ointment at the weekend in the shape of troughs could bring some cloud and rain for a time and the positioning of the High pressure areas as shown would not provide the warm and settled weather currently being experienced but more likely bring colder breezes sourced from a Northerly direction with a lot of fine and bright weather by day but more unwanted night frosts.

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

NAVGEM NAVGEM too shows a lowering of temperatures soon as fresher West winds develop across the UK especially over the North where further rain at times is likely at times next week. In the South dry weather will largely prevail with less warmth than recently and a chage for all to a cold and showery flow from the North looking very possible late next week as this run too shows the desire to rise pressure over the Atlantic sending cold air South across the UK.

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

ECM ECM today is much like UKMO today moving forward to retreat High pressure away from the UK towards the North and NW late next week and the weekend with colder winds from the North and NE threatening the UK and contrasting conditions markedly from those we have at present. Before that happens most of next week will be fine and pleasant with respectable temperatures though a little rain could be introduced into the South for a time from troughs sliding East and SE from the Atlantic and ahead of the colder air filtering in from the NE.

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

ECM 10 DAY MEAN(12z) The ECM 10 Day Mean Chart shows very flat conditions across the UK in 10 days made up of a variety of options though with a bias of High pressure not far from the UK and relatively pleasant conditions for many.

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

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The trends this morning are beginning to show an increased risk of rather cold air moving down from the North after the next week with GFS, GEM and the ECM operational all hinting that cold North winds could be present by 10-14 days.

31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKM & ECM The current verification statistics for the past 31 days shows ECM leading the way at 3 days with 97.6 pts followed by UKM at 97.1 pts and GFS at 96.4. At 5 days ECM  continues to lead the field at 90.6 pts over UKMO at 89.5 pts and GFS at 87.2. At 8 days ECM remains the leader with 66.2 pts over GFS's 62.3 pts. Then at Day 10 ECM retains superiority at 48.2 pts over GFS at 43.1.

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.prig
 

MY THOUGHTS The models continue to show the collapse of High pressure away to the SE tomorrow and the weekend allowing fresher air to cross the UK from the West with a little rain in places, this especially on Sunday. It's as yesterday the events that follow on next week which are yet to be fully determined by the models with something of a North/South split in the weather looking more or less likely with the South seeing some fine and potentially warm conditions for a time while the North looks less assured of this with stronger winds and occasional rain looking feasible from some output. Then comes the main theme this morning that the weather could turn rather cold from the North later next week and beyond as pressure is shown from many model runs to build at Northern or Western latitudes and longitudes sending chilly North or NE winds down across the UK as pressure builds over the Atlantic. This could provide the risk of some showers, wintry on hills and possibly more significantly frost at night which is something gardeners and growers do not want to here at this stage in Spring. This at the range shown is of course not a guarantee at the moment as positioning of High pressure then could develop more favourably in bringing the UK less cold conditons than some of the output shows this morning. The one constant from all models once more today is that there looks unlikely to be any particularly unpleasant conditions within the next few weeks anywhere across the UK with the theme of a much drier start to the year than last year maintained for many through the period.   

Issued at 08:00 Thursday April 9th 2015

New thread, same old disagreement between ECM and GFS for Sunday... if anything it's even bigger this morning:

The GFS 00z op brings a small 1010mb low - as strong as the model has shown it to be on any op run - through the central belt of the UK during Sunday daytime, bringing a spell of heavy rain and holding down maximums in the low teens. To the south of that, it's a fair day with maximums in the mid-teens.

By the start of Monday, this run (above left) has high pressure starting to build in from the SW behind the feature.

By contrast, ECM has the high a lot more advanced into the UK, with the peak pressure close to 1034mb - some 8mb higher than GFS has for the same time. This implies that the Sunday disturbance is either very weak and fast moving (and probably tracking more toward Scotland) or not existent at all; there's nothing holding the ridge back.

UKMO is very similar to ECM for day 4, just as it was yesterday evening, and it also continues to give some suggestion of a weak disturbance racing across the UK on Sunday, a little further north than GFS has it and clearing sooner.

Overall, it seems that the adjustment to a slower feature yesterday - arriving Sunday evening - has been undone this morning, and it could even end up being something that clears through by the afternoon judging by UKMO.

The chance remains that it could turn out to be little more than some nuisance cloud, and there seems to be good odds on anywhere on a line from London southward escaping dry, with some sun to be enjoyed for at least part of the day.

Saturday has seen better model agreement of late, and currently looks to bring a wet morning followed by a dry afternoon across the far SW, Wales and Northern England. SE of there, it's a dry morning and wet afternoon.

So as things stand, Saturday's the better looking day for northern parts of Wales and most or all of Northern England thanks to a dry afternoon, with Sunday looking a bit soggy for much of the daytime.

The southeast appears to be lined up for a disappointing Saturday - likely after a promising start - but a decent - or at least very usable - Sunday.

The southwest and at least the southern half of Wales could see a reasonable weekend overall, despite a soggy morning on Saturday.

I wonder if we are having are summer now!

Looks like staying settled for quite some time to come.

Temp a little up and down though.

Hi all,

Here's today's video update;

Spanish Plume On Today's GFS;

http://www.gavsweathervids.com/

After a thundery push late next week, ends with a northerly! 

The cooler weather mid month onwards is not very welcome. Especially with the sunshine of the past few days...

Looking  cooler and more changeable in about a week.

ECM going scorchio next week could be 24c+ if it comes off

http://www.wetterzentrale.de/pics/Recm1442.html

The ECM 12z looks tasty for some sultry warmth and in some places thunderstorms occurring unusually early in the year. Probably a lot of pollution with that as well though... the curse of our vehicle-laden existence.

GFS continues to break things down more quickly, with the 18z the quickest yet - though this still allows for temperatures to widely reach into the 20's on Tuesday and Wednesday and I daresay 25*C would not be out of the question in one of the usual hot spots such as Gravesend, St. James' Park or Charlwood.

Past experience suggests a more gradual progression is more likely - but this is based on the performance of GFS prior to its major upgrade early this year. So confidence is low... frankly I'd be okay with either outcome, as some appreciable rain wouldn't go amiss in these parts, so long as it didn't keep coming for too long (an important caveat after what took place in 2012... though that was dry on a wider scale prior to the dramatic turnaround in April).

Would be nice to eventually see some warmth down here, with the exceptions to last Monday it's been rather average at best, in fact rather chilly at times.
Can't complain to much though as it's been quite sunny, and after a rather cloudy start to spring the sun has felt nice.

Dead calm, potentially humid, a risk of homegrown thunderstorms... it could feel more like July than April if this ECM chart verifies.

Obviously there's no telling at this end what the small scale details are in the above chart - it could be largely cloudy for all I know (not enough parameters available for free public access).

Even so, I will dream of this becoming a reality - hopefully without too much air pollution attached.

GFS has trended less progressive with that low to the SW and comes pretty close to the above on the 00z op run.

While ECM maintains the status quo right on through the following weekend, GFS has a new ridge from the Atlantic taking over. It actually manages to retain the warm air and then pull it back NW, so after a cooler day on Thursday for all but the far south, it warms up again, with maximums widely into the 20's during the following weekend.

I'll be watching this with great interest over the coming few days, as it looks like very unusual conditions for the time of year.

Hi all,

Here's today's video update;

Going Into May With JMA Friday

http://www.gavsweathervids.com/

Still the idea with JMA and CFS that April end cool and unsettled.

Well what do we have here then... having seen GFS and UKMO develop some agreement on the cut-off low developing to the south of the UK and sticking around there for a few days, somehow I'm not surprised to see ECM trying out something a bit different.

A very weak disturbance to the west of the UK at +96 hours is associated with a weak frontal boundary, and GFS and UKMO avoid any appreciable development of that feature as it moves into the UK and interacts with another area of instability to the south of the UK to create a cut-off low there by Thursday.

ECM gives the feature to the west a bit more of a circulation and this means it's able to act as the acorn from which the cut-off low grows, instead of the unstable region to the south of the UK. So we end up with the low being to the southwest of the UK, which is a better position for bringing a greater amount of warm air up from the south and then keeping it in situ for a longer period of time.

This is a simpler way toward a warm outcome next weekend than GFS and UKMO, which rely on a new ridge from the mid-Atlantic building over the top of the cut-off low and dragging the warmer air back in from the southeast. Both routes start to break down on Sunday though, so it seems that BH Monday may turn out to be a rare exception to the usual rules - fine weeks, dodgy weekends 

That breakdown exists on nearly all model output, and is driven by the broad scale pattern taking a big step west, with the new cut-off low locating between the Azores and Bermuda, the ridge between the Azores and the UK, and the major trough either right over us or not far to our east.

I remember a few runs exploring that idea for the second half of the coming week, so there's a chance that the pattern won't pull back west so hastily, but let's face it, 10 or more days widely hitting the high teens to low 20's in April is about as much as any sane person should dare to hope for 

I don't think it means anything other than short-term statistical anomaly. People often cite 2007 as leading to a crap summer but then look at 2012. April was a shocker and led to a crap summer. The UK climate is far to complex to pattern match months ahead so comments about danger signals are pure speculation. 

We always pay dearly for nice weather in this country you should know that by now.

Looking at the latest model output for the rest of April, it might not turn out to be that warm overall. Quite a cool down after next Thursday and wetter too.

HERE IS MY LATEST ANALYSIS USING DATA SUPPLIED BY THE NWP OUTPUT COVERING 5 OF THE WORLDS MOST POWERFUL WEATHER COMPUTERS ISSUED AT 08:00 ON SUNDAY APRIL 12TH 2015.

THE CURRENT GENERAL SITUATION A wave depression will move East across Central Britain today clearing away tonight as a milder SW flow establishes tomorrow.

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

MODELS-2 WEEK HEADLINE A lot of dry and settled weather across the UK. A little rain is likely at times especially later in week 2 when colder air from the North might arrive.

THE GFS JET STREAM ENSEMBLE FORECAST The Jet Stream forecast shows the flow blowing NE across Central Britain currently. It then weakens over the UK and realigns well to the NW later this week and increase over Iceland. through the second week it weakens again for a time before changinging orientation to a NW to SE direction across the UK towards the end of the two week period.

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

GFS OPERATIONAL The GFS Operational this morning shows High pressure maintained to the SE of the Uk through the first half of this week with some warm sunshine and dry conditions developing for many. A weak cold front moves into the High pressure later in the week with the risk of a few showers before High pressure reforms across the UK with dry and settled conditions next weekend before it retreats out into the Atlantic opening the door to the North and NW to the risk cold Arctic winds to blow down over the UK with rain or showers at times wintry on hills especially in the North and East.

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

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

THE GFS CONTROL The GFS Control Run differs only in as much as High pressure doesn't retreat as much West in Week 2 protecting the UK from any colder and changeable conditions from the North and giving rise to plenty more fine and at times reasonably warm weather under High pressure with any encroachment from Atlantic fronts only shown by the very end  day of the run.

THE GFS CLUSTERS The GFS clusters show a predominant risk that Low pressure will lie close to the North of the UK in two weeks time with resultant cloud and rain at times for the UK with temperatures near average in the predominantly Westerly flow.

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 UKMO shows High pressure to the SE until Thursday bringing increasingly warm SW wnds across the UK before a weak trough moving across from the West by Thursday brings the risk of some showers for a time before High pressure reasserts itself across the UK by next weekend with dry and fine weather for all then with sunny spells.

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

THE FAX CHARTS The Fax Charts reflect the raw data of UKMO well with the warm SW winds close to High pressure this week but with a lot of cloud at times towards the North and West from weak troughs. The showery disturbance on Thursday is then replaced by High pressure building over the top of the UK by next weekend.

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

GEM GEM today is similar to the GFS operational in that this week follows popular consensus of mild and dry weather with just a few showers later as High pressure at first to the SE and later over the UK commands control. Then through the beginning of next week this recedes West into the Atlantic with a dual attack from both the South and North of Low pressure threatening cold and showery weather next week with snow showers over the hills.

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

NAVGEM NAVGEM too shows High pressure to the SE brnging fine and warm conditions at times this week but on this run High pressure is maintained near or close to the UK at the end of the run maintaining largely fine and dry weather though it's centre to the North at times could make the South a little fresher in an Easterly wind component perhaps with the odd shower.

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

ECM ECM today is showing High pressure domination reigning across the UK over the 10 days as a whole with the positioning changing from a point to the SE to be over the UK next weekend spliced by a showery disturbance across Southern Britain on Thursday. Towards the very end frames of the run although the benign and reasonably warm conditions over the UK look like continuing there is rumblings to the NW of the cold and showery NW or North flow that other output shows might be waiting in the wings just outside of the outputs range

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

ECM 10 DAY MEAN(12z) The ECM 10 Day Mean Chart  from last night shows High pressure to the SW and varying degrees of a NW flow across the UK some with a showery theme as far as the UK is concerned but also quite a few with High pressure still maintaining a largely dry theme with the warmest conditions to the South and West.

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

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The trends this morning continue to show the risk of a cold NW flow in Week 2 but it remains an uncertain aspect with  some support for continuing High pressure domination as well.

31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKM & ECM The current verification statistics for the past 31 days shows ECM leading the way at 3 days with 97.6 pts followed by UKM at 97.0 pts and GFS at 96.3. At 5 days ECM  continues to lead the field at 90.7 pts over UKMO at 89.0 pts and GFS at 87.2. At 8 days ECM remains the leader with 65.2 pts over GFS's 60.2 pts. Then at Day 10 ECM retains superiority at 46.8 pts over GFS at 41.4.

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.prig
 

MY THOUGHTS The models continue to focus on the development of a High pressure pattern across the UK over the coming week. Not all is straightforward though with a small and inclement area of Low pressure crossing Central districts today bringing a mix of gales, rain and hill snow for a few with cold Winter air still over Scotland with a milder SW flow over the South. This feed moves North tonight and tomorrow with all areas settling into several days of mild SW winds with some warm sunshine across Southern Britain in particular. then another small disturbance is shown by most output to increase the risk of showers by Thursday but still with some warm sunshine in between. Then over next weekend as High pressure strengthens, this time across the UK any showers will evaporate to leave all areas dry, bright and sunny and reasonably warm again especially in the South and away from windward coasts. Through next week the models go one of two ways with some support that the High will retreat out into the Atlantic or worse still to the NW with a cold late season plunge of cold air down across the UK with wintry showers and unrequired frosts by night. there is though reasonable support for the High to remain close to the UK cutting off any cold injection and maintaining fine and dry weather with Spring sunshine by day but not excluding slight grass frosts overnight under the clear skies and light winds. All in all with the exception of today in Central Britain benign is the word I would use to describe conditions across the UK for the coming few weeks with plenty of dry and bright weather with some warm sunshine and temperatures especially in the South with only a risk of a few showers for a time later this week and again later in Week 2 when something rather colder could arrive from the North and NW with showers more widespread and wintry on hills and frost at night. However, that is a long way off and far from a certainty so lets enjoy what is fast becoming for many quite a dry and pleasant Spring April month this year or will be if most of this morning's charts verify.

Next update from 08:00 Monday April 13th 2015

Thanks Martin.  I always read your reports and your plain speaking interpretation of the output is invaluable to people like me who haven't much of a clue about models.  So, thank you very much!