Model Output Discussion - Spring 5th March Onwards 6z--->

[knocker]

Yesterdays EC32 update.

 

The anomaly at T240  has the LP NE Canada and Alaskan ridge and also LP over the Pole troughing SE into N. Europe with a quite strong Azores ridge SW pushing into the UK.  Perhaps slightly above average temps for certainly the southern half of the UK.

 

By T408 one or two significant changes. The European trough has gone as has the Alaskan ridge . The surface analysis has  a low Greenland and the Azores ridge pushed a tad south giving a mainly south of west flow over the UK with temps a tad above average.

 

By T576 the Azores HP pushed even further south with the LP Iceland more in control so back to Pm airstream NW/SW and more unsettled weather with temps about average.

 

The end of the run shows no significant change with a continuation of the above airstream.

 

So in summation I would say a brief period of more settled HP weather but then it’s back to a familiar story of the airstream in a westerly quadrant and basically an unsettled picture with no sign of any lengthy HP domination with around average temps.

 

Looks like a typical April.

[Polar Maritime]

The GFS this morning again shows quite a potent Northerly around Easter. With -10 850's touching Scotland and Snow showers pushing South.

 

 

[Frosty.]

Gfs 0z shows a prolonged very pleasant spell for the south from Sunday until late next week with high pressure becoming centred just to the south of the UK with tropical maritime air pumping around the top of the high and across the southern half of the BI. Temperatures go up and up, at the peak of the warm spell they are around 19-20c 67f.

Edited March 24, 2015 by Frosty.

[Captain Shortwave]

Indeed, quite a contrast on the GFS with temperatures reaching 18/19C during the middle of next week (mid to high teens from Sunday)

 

Before a cold front pushes south and introduces an Arctic blast with wintry showers even to low levels by day 10.

 

Unfortunately the other models are less keen on either of these scenarios developing with a stronger westerly jet with temperatures varying less from the seasonal norm. Quite unsettled for the north, but the south remaining much drier due to the influence of the Azores high which will weaken any rain bands pushing through.

Edited March 24, 2015 by Captain shortwave

[Gibby]

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 TUESDAY MARCH 24TH 2015.

 

THE CURRENT GENERAL SITUATION A cold and showery NW flow covers the UK today followed by a ridge of High pressure moving across from the West tomorrow.

 

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

 

MODELS-2 WEEK HEADLINE After an unsettled start the South should become drier and milder while the North stays unsettled with strong winds and rain at times.

 

THE GFS JET STREAM ENSEMBLE FORECAST The Jet Stream is currently projected to flow across the Atlantic and over the British Isles as a more mobile Westerly regime sets up from the weekend. Later in the period the pattern becomes more confused and less clear.

 

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

 

GFS OPERATIONAL The GFS Operational this morning shows a more mobile westerly regime developing across the UK from late this week with a strong but milder Westerly flow and occasional rain especially over the North. The pattern then becomes more changeable later in terms of temperatures and rainfall for all with another cold interlude shown to move South down over the UK in Week 2 with more unceratin conditions expected to end the period.

 

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

 

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

 

THE GFS CONTROL The GFS Control Run is very similar in theme to the operational in the short to medium term before diversifying slightly late in the period. A westerly based weather pattern continues to show occasional rain and milder weather with rain at times especially over the North. The run also shows another chilly period early in Week 2 before the gradual return to Westerly winds and occasional rain looks possible by the end of the period.

 

THE GFS CLUSTERS The GFS clusters this morning offers several different options mostly revolving the extent and influence of High pressure looking likely to lie to the SW or West of the UK in 14 days time.

 

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 today shows a steady increase in Westerly winds as we move through the weekend and into next week. The air will become milder as tropical maritime air is shown to lie over the South early next week with most rain bearing fronts held over more Northern areas where rain will be far more likely.

 

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

 

THE FAX CHARTS The Fax Charts show the next 5 days as rather unsettled over the UK as a series of fronts and small depressions track slowly East across the UK, first into rather cold air before milder air becomes more prominent towards and then over the UK by the end of the weekend.

 

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

 

GEM GEM this morning shows a similar evolution to the GFS model today in introducing strong but milder Westerly winds next week with rain at times especially across the North before colder air looks likely to come down from the NW at the start of the second week in NW winds and showers following a band of rain.

 

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

 

NAVGEM NAVGEM shows stiff Westerly breezes with occasional rain across the UK next week, chiefly over the North while the South sees a lot of dry, rather cloudy, breezy but mild weather lasting out until the term of the run.

 

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

 

ECM ECM today shows the same pattern as the rest with the theme of milder and Atlantic Westerly winds with occasional rain from later this week on and following the next few days worth of more general rain at times for all in rather cooler air. Next week will see some mild air across the UK for some considerable time especially over the South before the threat of rather colder air looks like possibly moving down from the NW at times later.

 

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

 

ECM 10 DAY MEAN  The ECM 10 Day Mean Chart shows High pressure lying over Northern France in 10 days time with a mild Westerly flow across the UK with rain at times largely restricted to the North.

 

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

 

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The models continue to show a milder theme next week and the possibility of another chillier phase of weather from the NW in Week 2.  

 

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 97.8 pts followed by UKM at 97.4 pts and GFS at 96.6. At 5 days ECM  continues to lead the field at 91.2 pts over UKMO at 89.8 pts and GFS at 88.2. At 8 days ECM remains the leader with 66.8 pts over GFS's 62.4 pts. Then at Day 10 ECM retains superiority at 48.6 pts over GFS at 44.9. 

 

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 Today's models continue to project a milder phase of weather under a strong Westerly breeze next week following the current rather unsettled and chilly period up to the coming weekend. Once this westerly wind is established High pressure is likely to edge up close to the South while Low pressure crosses East to the North of the UK with their attendent troughs affecting mostly Northern areas where rain at times next week will be commonplace. With the High close to the South a lot of dry weather is likely here although even here we are not immune to at least a little rain as troughs edge down from the North at times. Temperatures though should reach very respectable levels next week for almost all and if any brightness in the more sheltered East occurs then the temperatures could reach the mid teens or so. So where do we move too from there. Well the message I read from the output this morning is that from late next week and into the second week while a Westerly based theme looks like persisting colder air from the NW is hinted at from many models to move SE across the UK briefly bringing a return to chilly winds and showers, wintry on hills in the North. This is of course a long way off and will likely be changed many times over the coming days but the one constant again this morning is the lack of any disruptive type weather of any kind shown anywhere within the next few weeks with a very typical mix of different early Spring conditions likely over all areas with some rain and showers, chiefly in the North but a lot of fine and dry weather over the South in temperatures overall close to or even somewhat above normal at times over the South and East. 

 

Issued at 08:00 Tuesday March 24th 2015

[johnholmes]

If the anomaly charts are anywhere near close to the upper pattern for days 6-15 then some kind of flow from north of west, quite strong over the northern half seems likely. This would probably mean a NW-SE splt in weather type. More changeable, even unsettled for the NW and more settled for the SE. Just how much of the unsettled will affect the SE corner and how often is going to be the main interest for model watching I suspect. With air being shown to be sourced from the Canadian/US border in the far west much of the time temperatures will be around or somewhat below normal?

links below

http://www.cpc.noaa.gov/products/predictions/610day/500mb.html

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

[Frosty.]

Good support from the GEFS 00z mean for drier, brighter and much milder / rather warm weather to spread across the south of the UK and last until around the middle of next week, cooler and unsettled for the north throughout.

Edited March 24, 2015 by Frosty.

[Summer Sun]

Looking at the ECM ens high pressure begins to edge up from the south during next week temperatures here could easily get into the mid teens maybe even close to 20c for a time if conditions were right.

 

Whilst the south starts to see the high becoming more of an influence its a different story further north as your closer to the low so temperatures here would be lower with some rain around as well

 

 

If the D10 chart from the ens is right the Easter weekend would start on a dry note for England and Wales

 

[Frosty.]

Yes Gavin, lol you beat me to it. The ecm 00z ensemble mean, as with the gefs 00z mean, shows high pressure building in across France with its influence extending across the south of the UK with tropical maritime air feeding around the top of the anticyclone. A spell of very pleasant weather is on the way for the south of the BI from the end of the weekend and for much of next week, if the ecm is right, high pressure will have an even bigger influence longer term. :-)

[Frosty.]

The Gfs 06z shows an increasingly very mild spell from Sunday until later next week with a Tm airmass set to bathe southern uk with temperatures into the 60's F on most days during that period and mostly dry with variable cloud and sunny spells thanks to high pressure further south. Later next week there is a cooler blip with a few showers but it then starts to turn fine and milder again. The north of the UK looks generally cooler and unsettled but occasionally fair and milder.

Edited March 24, 2015 by Frosty.

[mushymanrob]

If the anomaly charts are anywhere near close to the upper pattern for days 6-15 then some kind of flow from north of west, quite strong over the northern half seems likely. This would probably mean a NW-SE splt in weather type. More changeable, even unsettled for the NW and more settled for the SE. Just how much of the unsettled will affect the SE corner and how often is going to be the main interest for model watching I suspect. With air being shown to be sourced from the Canadian/US border in the far west much of the time temperatures will be around or somewhat below normal?

links below

http://www.cpc.noaa.gov/products/predictions/610day/500mb.html

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

 

far be it for me to question you john, the airflow might be sourced from the us/canadian border, but doesnt it take a dip to more southerly latitudes before rising over the azores high to cross us from the northwest? wouldnt surface winds be sourced from west of the azores? which is why the current runs are suggesting periods of warm 'uppers', so temps varying either side of average depending on the front we are on....

[Frosty.]

The GEFS 06z mean shows the change to more settled and much milder conditions as a large anticyclone develops across France / Spain and slowly pushes further north to influence southern UK. I think the highest temperatures of the spring so far will be recorded across the south during early / mid next week with 18-20c range being a distinct possibility.

Ps. Just heard about the horrific plane crash in the French alps and the very poor weather conditions in the area tonight & tomorrow with heavy snow and strong winds but with high pressure gradually replacing the current low / trough, the search and rescue team are likely to see a huge improvement in conditions as time goes on.

Edited March 24, 2015 by Frosty.

[johnholmes]

far be it for me to question you john, the airflow might be sourced from the us/canadian border, but doesnt it take a dip to more southerly latitudes before rising over the azores high to cross us from the northwest? wouldnt surface winds be sourced from west of the azores? which is why the current runs are suggesting periods of warm 'uppers', so temps varying either side of average depending on the front we are on....

 

quite right mushy, the airflow does take a long long sea track before arriving in the UK. However the source is still Polar rather than Tropical as a general rule. That is not always the case though as the strong Atlantic flow, and the quite large temperature contrast either side of it, will generate weather systems. On the southern flank of these lows some Tropical sourced air will be around, especially for southern areas, but much of the time the air will be RPm (returning Polar maritime, even possibly Polar Maritime. Basic meteorology suggests lowish dewpoints so out of the sun and in any breeze it will not feel warm regardless of what 'number' our thermometer may show when this airmass is over the UK. 

Edited March 24, 2015 by johnholmes

[Captain Shortwave]

The GFS again wants to play around with some sharp temperature contrasts around the Easter period.

Again the first part of next week looks mild with temperatures hitting around the 17C

 

Then by the end of the week

Strong northerly plunge with 850s of -8C engulfing the country by Good Friday

White Easter still on according to the GFS

[Polar Maritime]

Yes once again following this mornings GFS, A cold Northerly with -10 850's digging even further South into Northern England for the Bank Holiday weekend. Plenty of scope for change yet..

 

Edited March 24, 2015 by Polar Maritime

[Frosty.]

Yes once again following this mornings GFS, A cold Northerly with -10 850's digging even further South into Northern England for the Bank Holiday weekend. Plenty of scope for change yet..

 

I think that Arctic maritime blast is a strong possibility, the latest met office update mentions the chance of a colder interlude, the Gfs could be on the right track this time.

[Frosty.]

Quite a settled end to the Ecm 12z with high pressure building in from the west, nothing as dramatic as the earlier Gfs 12z.

[Summer Sun]

ECM looking pretty settled again this evening with some milder weather at times especially for the south, still unsettled at times for the far north but even here it would be drier at times

 

 

 

Meanwhile the GFS ens doesn't bring in the colder blast like the Op

 

Edited March 24, 2015 by Summer Sun

[mushymanrob]

quite right mushy, the airflow does take a long long sea track before arriving in the UK. However the source is still Polar rather than Tropical as a general rule. That is not always the case though as the strong Atlantic flow, and the quite large temperature contrast either side of it, will generate weather systems. On the southern flank of these lows some Tropical sourced air will be around, especially for southern areas, but much of the time the air will be RPm (returning Polar maritime, even possibly Polar Maritime. Basic meteorology suggests lowish dewpoints so out of the sun and in any breeze it will not feel warm regardless of what 'number' our thermometer may show when this airmass is over the UK.

Cheers john... Well hopefully soon theyll change to support something pleasantly warm!

[ANYWEATHER]

Given the success of the gfs lately , this model is predicting a cold Easter, Ecm  is not.! Where shall I put my money    

[Frosty.]

I think I would put money on high pressure being very close to the south during easter as shown on tonight's Ecm 12z ensemble mean with pleasant holiday weather, at least for the south of the BI. :-)

[ANYWEATHER]

I think I would put money on high pressure being very close to the south during easter as shown on tonight's Ecm 12z ensemble mean with pleasant holiday weather, at least for the south of the BI. :-)

Please explain why you go with ecm  and not gfs which as been a winner of late

[johnholmes]

If one looks at the anomaly charts then all 3 suggest that ridging close to the SW of the UK is the most likely pattern at 500mb. This would suggest that surface high pressure will be somewhere close to that area as well. Overall these charts suggest more settled than unsettled in the 6-10 day time scale with less settled for areas well north, central/n Scotland and possible N Ireland? It is quite finely balanced though and may explain why one model makes more of this idea whilst the other has the centre of gravity of both upper and surface highs further west. This allows a plunge of Arctic air just east of the country but close enough for some parts to have a rather chilly spell. This detail is not going to be settled for a few days yet.

[damianslaw]

Reliable timeframe - a rather unsettled outlook as we see the atlantic crashing through. Wet for the north and cool, a little drier in the south. The weekend promises a change to something a bit milder but still unsettled in the north.

 

Next week - lots of scatter amongst the models, all show high pressure in some form to the SW, but differ in its proximity and strength. ECM supporting a stronger high with ridge movement into southern Britain enabling a mild feed to envelope the country and mostly dry benign conditions away from the far north - a promising lead up to Easter. GFS conversely is markedly different, suggesting weaker heights further to the SW allowing for another plunge of cold air from the NW, with quite significant cold pool around Good Friday - wintry showers would be the order of play, thereafter it shows a collapsing ridge of high pressure in cold air - a frosty but more settled easter weekend would be in store.

 

Met Office update is in interesting, it too suggests a far bit of uncertainty in the outlook as we move out of the easter period, with hints of a colder theme emerging possibly, could it be picking up on northern heights developing? On balance a meridional topsy turvy flow of weather looks on the cards - all very seasonal standard average fayre for the time of year.

[picog]

Presumably the potential white Easter has disappeared or there might be more posts?

Personally, I'm hoping the high will ridge towards the south and give us some decent settled weather for Easter.