Model Output Discussion - 3rd May Onwards 00z--->

[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

FRIDAY MAY 8TH 2015

THE CURRENT GENERAL SITUATION A complex set of fronts will move NE over the UK today, tonight and at first tomorrow in a freshening SW flow.

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

MODELS-2 WEEK HEADLINE Changeable with some rain at times but a dry and warm period across the South and East early next week.

THE GFS JET STREAM ENSEMBLE FORECAST The Jet Stream will ridge North across the UK to be blowing in a NE direction across the British Isles over the next 4-7 days. It then is shown to change trajectory at the same time as moving back South under a UK trough in Week 2 before becoming less defined in both strength and location at the end of the period.

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

GFS OPERATIONAL The GFS Operational this morning shows a period of warmer and more humid conditions developing over the latter half of the weekend and start to next week as pressure builds to the SE sending rain bearing troughs towards the North and West only in a Southerly or SW flow. This lasts for a time before more unsettled and cooler weather on a Westerly wind develops across the UK by next weekend with week 2 looking generally quite cool and unsettled at times.

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

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

THE GFS CONTROL The GFS Control run is quite similar in many respects with a warm and dry period across the SE giving way to generally cooler and unsettled weather later as Low pressure becomes stationed over Scandinavia for a timesends cool and showery NW winds down over the UK only slowly watering down at the end of the run as a conversely block of High pressure then develops to the NE bringing Easterly winds across from Europe.

THE GFS CLUSTERS The GFS Clusters show as yesterday that the majority thought is for High pressure likely to be close to the West or near the UK in 14 days time with winds from between West and North across 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 UKMO this morning still shows things warming up at the start of next week as High pressure to the SE sucks up some warm and humid air across Southern and Eastern Britain. However, it looks unlikely to last long as the orientation of the airflow across the UK changes with Low pressure sliding ESE towards Southern Britain later next week with rain at times in cool conditions for many.

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

THE FAX CHARTS The Fax Charts show a warm up early next week with warm SW winds across the South and East. The then expected push of Low pressure from the SW later next week has reduced in significance for a time.

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

GEM GEM this morning also shows the surge of warm air across the South and East early next week still showing as rather slower to give way to more unsettled conditions from off the Atlantic. In fact in the latter stages of the run High pressure looks like rebuilding back towards or even over the South with fine and dry conditions.

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

NAVGEM NAVGEM shows a much more UKMO type evolution with Low pressure gradually becoming more established across the UK in a change of air source to a more NW source later driving Low pressure across the UK from the WNW.

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

ECM ECM shows High pressure near the SE early next week with some warm humid air over the South and East of UK slowly giving way to somewhat more unsettled conditions but on this run High pressure never strays far away from the South shifting the emphasis of wind, rain and the coolest weather to the North.

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

ECM 10 DAY MEANThe ECM 10 Day Mean Chart shows a shift in emphasis this morning back towards a more North/South split in the weather with High pressure to the South having a greater push on the Jet Stream North and less cool or unsettled generally.

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

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The models continue to suggest that changeable conditions look likely to continue for the next two weeks but with more emphasis to High pressure closer to the South than has been shown on runs previously.

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 97.2 pts followed by UKM at 96.6 pts and GFS at 95.9. At 5 days ECM leads UKMO with 87.7 over UKMO's 86.5 pts with GFS at 84.2. At 8 days ECM remains the leader with 57.2 pts over GFS's 54.4 pts. Then at Day 10 ECM gains superiority at 38.5 pts over GFS at 37.5.

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 There is a gentle shift back towards rather less unsettled conditions at least for the South of the UK in a week to 10 days time. The changes being are the shift away from the cool uppers and Low pressure to a maintained outlook that keeps High pressure closer to the South later in the period which should keep winds from a Westerly point and consequently remain more average temperatures across the South at least longer term.

Next update from 08:00 Saturday May 9th 2015

Edited May 8, 2015 by Polar Maritime
Quickly posted report.

[knocker]

I've only just noticed that the GFS has the little cut off low as well

Edited May 8, 2015 by knocker

[Frosty.]

The Gfs 6z shows lots of positives, for one thing, next midweek looks fine and pleasant for an extra day, more unsettled and cooler from thursday and longer term it's High pressure domination. In the short term, the south of the UK warms up and becomes settled for a few days, Sunday and Monday look dry and warm with sunny spells, Monday is the warmer day in the south and east, 21-22c, Tuesday not as good as earlier runs but could still change again but it's the longer term trend that interests me most, we could be looking at an anticyclonic second half of May..I hope.

[049balt]

ECM and Gfs hinting at something much dryer from 18th. on.

[Summer Sun]

ECM and Gfs hinting at something much dryer from 18th. on.

 

Yes ensembles from GFS and ECM both showing higher pressure at day 10

 

 

Closer timeframe Tuesdays highest temperatures are no better than the mid maybe high teens in the south it was only last the beeb were showing highs in the London area of 26c on Tuesday

 

 

Edited May 8, 2015 by Summer Sun

[Frosty.]

The Gfs 12z shows a nice spell coming up across the southern half of the uk with 4 days of largely fine and pleasantly warm weather with good sunny spells from sunday, warmest in the south east with 22c 72f on monday, generally cooler and unsettled across the northwest of the UK throughout. The south and east briefly turns unsettled and cooler from the west on thurs/fri but high pressure then starts ridging in from the south west by the end of next week and early following week, really this is not bad at all out to T+240 hours away from the northwest.

Edited May 8, 2015 by Frosty.

[Milhouse]

ECM and Gfs hinting at something much dryer from 18th. on.

 

The GEFS 12z mean shows this too

 

[Milhouse]

Not a bad outlook i suppose with a bit of everything to come over the next 10 days. Initially a pulse of warm air spreading northwards to bring a warmer but not totally dry few days, then a drier and fresher interlude on Tuesday/Wednesday before the Atlantic comes back in with associated wind and rain to end the week. Signs still there for the final frames of the ECM for high pressure building from the south bringing more of a north south split. Its from here that we potentially could see high pressure building in more widely such as shown by the GEM.

[Frosty.]

The GEM 12z does look the best from the 12z runs this evening in the T+240 range and today's met office update mentioned a weak signal for a settled spell through the last week or so in May and first week or so of June, fingers crossed the settled signal will strengthen in the days ahead.

[Summer Sun]

ECM ens still hinting at a rise in pressure from next weekend

 

 

[DAVID SNOW]

ECM ens still hinting at a rise in pressure from next weekend

 

 

 

 

All models have now gone off the idea of any 'hot' spell next week,and we are left with average spring weather(GFS ECM)  nice days and chilly nights

[049balt]

ECM ens still hinting at a rise in pressure from next weekend

 

 

Yes, the jet really is shunted North, at long last.

[knocker]

The beginning of the next week the 00z GFS is still looking at a squeeze between the low running NE between Scotland and Iceland and the HP to the south giving a quite warm south westerly/westerly flow over most of the UK but damp and cooler in Scotland. Brief ridging on Wednesday before the next depression arrives on the scene on a more southerly track en route to northern Europe. Thereafter it's a story of HP building from the SW.

Chart weatherbell

 

[Polar Maritime]

The GFS this morning shows a continued Atlantic influence with Low Pressure systems spinning in from the West. By the 14th a Low tracking S/E over the UK (pushing the Jet with it) will push High Pressure North blocking the Atlantic for a short while bringing a slack N/Ely over the UK to end the working week.

 

Edited May 9, 2015 by Polar Maritime

[bluearmy]

Looking quite difficult to call whether we will manage to establish a more settled regime or if the jet will continue to keep us close to the shallow upper trough on an axis nw/se into Eastern Europe. Recent experience would tend towards the answer that we will see a alternating weather type where the Azores ridge pushes ne for a short while followed by a return south of the jet with associated troughing.

the gfs 00z showing the probable best case scenario post day 6/7 and the ECM 00z the worst. one will be closer to what transpires.

[mushymanrob]

ECM ens still hinting at a rise in pressure from next weekend

 

 

 

indeed, and the noaa 8-14 day anomaly charts supports this solution

but it currently isnt really close enough to bring any real warmth, at least it suggests the jet will track further north of the uk, so it wont be as wet as its likely to be this coming week at times. but with an upper flow north of west, temps possibly struggling to reach average especially if we get cloud (which is likely?)

[seaside 60]

Looking quite difficult to call whether we will manage to establish a more settled regime or if the jet will continue to keep us close to the shallow upper trough on an axis nw/se into Eastern Europe. Recent experience would tend towards the answer that we will see a alternating weather type where the Azores ridge pushes ne for a short while followed by a return south of the jet with associated troughing.

the gfs 00z showing the probable best case scenario post day 6/7 and the ECM 00z the worst. one will be closer to what transpires.

Seeing as we have had the Azores high in its place all winter pretty much.

Is this something that could persist for a long while yet.

Often said by many forecasters that a strong azores high gives us our good summers and if missing early spring its often looked for for signs of summer.

Personally I prefer the Scandi summer high.

[Summer Sun]

00z GFS ens again shows pressure rising towards next weekend and into the following week

 

 

00z ensemble for London shows the mean going above 1020mb between the 17th and 21st possibly the 22nd as well, temperatures would be around average at this stage

 

 

The Aberdeen ensemble also shows the mean getting above 1020mb between the 17th and 21st

 

[Captain Shortwave]

Not overly keen on where the Azores high is being predicted to set up if I am quite honest.

 

Not a good position for warmth and it tends to be close enough to kill of the majority of the rainfall from any passing whether systems and capping convection between the rainbands. So in the end the trend seems to be turning drier in week 2 with near normal temperatures and possibly a fair amount of cloud at times.

[knocker]

The anomalies this morning have the upper trough moving into Scandinavia and the Azores HP pushing NE from the SW. The GEFS and ECM  have slightly different interpretations of the exact alignment of these systems and this may be crucial regarding the evolution. The further east the upper trough moves it would probably then allow further development of the HP with the jet (although not that strong) nipping around the HP before turning SE on the western flank of the trough just east of the UK.

 

It's a bit of a knife edge situation which will hopefully work in our favour.

Charts weatherbell

 

Edited May 9, 2015 by knocker

[Eugene]

All models have now gone off the idea of any 'hot' spell next week,and we are left with average spring weather(GFS ECM)  nice days and chilly nights

 

 

Yes tuesdays southerly plume has been pushed way into europe, ECM 00Z has cyclonic Northwesterlies later in its run which i think will be correct, GFS 00Z seems most optimistic but other runs not so, chasing HP and warmth is a futile task.

[mushymanrob]

Not overly keen on where the Azores high is being predicted to set up if I am quite honest.

 

Not a good position for warmth and it tends to be close enough to kill of the majority of the rainfall from any passing whether systems and capping convection between the rainbands. So in the end the trend seems to be turning drier in week 2 with near normal temperatures and possibly a fair amount of cloud at times.

 

yep...i fully agree, im no fan of the azores high being sat there , if its sun and warmth youre after. hence i refer to it as the azores enemy! but it is preferable to a 07/08 style washout summer.

[I remember Atlantic 252]

 

yep...i fully agree, im no fan of the azores high being sat there , if its sun and warmth youre after. hence i refer to it as the azores enemy! but it is preferable to a 07/08 style washout summer.

 

those charts are FI, i will settle for that, just sick of low pressure and rain/wind, if sun comes out will feel warm at times, so I hope it comes off

[knocker]

It may not be ideal but one alternative is the upper trough a tad further west allowing the jet nearer the UK and depressions slide in with the HP pushed even more to the SW. 

[mushymanrob]

those charts are FI, i will settle for that, just sick of low pressure and rain/wind, if sun comes out will feel warm at times, so I hope it comes off

 

lol... but its only just turned wet!

yes those charts are fi, but theres good support from the mean charts and the noaa anomaly charts, detail to be decided of course, but itll be a fairly safe bet the the azores high will build to our southwest after next week.