Model Output Discussions 12z 03/05/2016

[Frosty.]

The Ecm 12z Northerly at the end of the week really is a blink or miss it affair but it does turn much cooler for next weekend but mainly dry with sunny spells and slight night frosts but high pressure ridges across the UK and temperatures start to recover post T+144 hours...so, a warm week ahead for the time of year with some sunshine but also showery rain at times further south which could be heavy and thundery in places and then very briefly much cooler from the north but only a glancing blow, in my opinion this turns into a better run than the 00z as far as week 2 is concerned.

[Summer Sun]

As Frosty says the cooler air (which will still see temps around the seasonal average) is a blink and you'll miss it event before milder air returns plenty of dry weather on offer too the main positive to take is we have no low pressure systems in the Atlantic steaming towards us

[Singularity]

I am certainly interested in seeing how high the temperatures turn out to be on Saturday versus the low teens maximums that GFS keeps putting out for that date. 

Looks like a classic 'get away from me, old trough' situation going into the following week, as the residual lower heights to the northeast try their best to cling on. They must be warmed out and banished! They may facilitate height rises NE of the UK which could turn out nicely or unpleasantly depending on how the flow aligns and to what extent there continues to be a trough to the south of the high.

[Polar Maritime]

The GFS this morning is showing the slack Northerly for the weekend again re-establish by Wednesday next week, Towards the end of the run into the following weekend (20th) Lows spin in from the S/W bringing some unsettled weather especially for the South.

 

Edited May 9, 2016 by Polar Maritime

[Gibby]

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 MONDAY MAY 9TH 2016

THE CURRENT GENERAL SITUATION Low pressure to the South of the UK will push troughs North across Southern Britain over the next 48 hours in an Easterly flow which will be maintained for many for several days before backing NE later in the week.

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 range between 8000-10000ft over the following three or four days with a steady fall off of values later in the week from the North and NE.

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 cooler and drier from the weekend especially in the South.

THE GFS JET STREAM FORECAST  The Jet Stream's main core is situated well South of the UK near Southern Spain and North Africa in association with a large depression down there. This remains for some while this week before weakening by the weekend as the Low pressure down there moves slowly away ENE over mainland Europe. A weak flow then runs South just to the East of the UK next weekend before in the second week the flow rejuvenates moving Eastwards just South of the UK again with Low pressure close by to the British Isles.

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

GFS OPERATIONAL The GFS Operational Run today shows Low pressure down to the South moving slowly ENE later this week with the South seeing a lot of heavy showers or longer outbreaks of rain on most days. Higher pressure in the North will maintain drier conditions for the most part and with the air inherently mild it should feel warm in the sun. Later in the week the winds will back Northerly for all and it will be cooler but drier for all next weekend. Then in the second week Low pressure is shown to feed in from the North and West with cyclonic winds countrywide then through Week 2 with rain at times in average temperatures.

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

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

NEW GFS PARALLEL RUN The Parallel Run this morning shows Week 1 the same as the Operational with a trend towards cooler and drier weather last to reach the South by next weekend. Then the drier weekend follows on to a better week of weather than the Operational shows as High pressure to the South keeps those areas largely dry with some rain from Atlantic fronts further to the North. However, the run does show all areas becoming more unsettled in cyclonic conditions by the end of the run.

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=144&mode=0&runpara=1

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=384&mode=0&runpara=1

GFS CONTROL RUN The Control Run looks more like the Operational Run rather than the Parallel Run with an unsettled and cyclonic pattern through the second week too with the same sequence of events through this week leading to an interlude of drier, cooler conditions over the weekend under a brief Northerly flow.

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 for day 14 continues to show no definitive patterning at that time showing instead a slight bias towards lower pressure giving rise to rain at times but also plenty of better options under higher pressure patterns as well.

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 the slow transition towards drier and cooler conditions moving down from the North by the weekend as the Low to the South currently takes away the risk of thundery showers or rain by the weekend with a fairly decent if cooler weekend for all looking likely as a weak ridge moves East across the UK.

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

THE FAX CHARTS The Fax Charts show quite a complex scenario of troughs across Southern Britain for all of this working week as they move North at times in the next few days and then slowly away South towards the end of the week as the warmth of recent days is gradually squeezed out under cooler Northerly winds by the weekend flooding South.

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

GEM GEM this morning shows the same thundery Low pressure to the South moving away ENE across Europe later in the week backing the winds towards the North and introducing cooler and fresher conditions in time for the weekend. The rain and showers in the South through this week reduce later with a dry weekend looking likely for many as something of a ridge crosses East. Then as we move through the start of next week a Westerly flow is shown to develop with rain returning on Atlantic troughs, this time heaviest in the North and West and driest towards the SE.

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

NAVGEM NAVGEM too shows a showery week to come in the South and fair weather in the North as the Low to the South takes until the weekend to move away far enough to lose it's grip over the UK. Then the weekend looks set fair as the cooler Northerly develops ahead of a ridge making the weekend a decent if cooler one for many with perhaps some rain on Atlantic troughs reaching the NW soon after the start of next week.

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

ECM ECM today also shows High pressure inching in from the West next weekend and into the second week but it still looks a painfully slow task and although all parts should see a lot of fair and dry weather in cooler air than of late across the UK next weekend it's longer term survival looks fraught as we move into next week with Low pressure from both the NW and SE squeezing the life out of a ridge over the UK and possibly re-introducing showery rain late in the period.

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

ECM 10 DAY MEAN (12z) Last nights 10 day Mean Chart is showing a trend towards a return to a more traditional Low to the North and High to the South pattern but there are many other options shown within members too with the chart as a result much less reliably accurate than usual.

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

NOTABLE TRENDS & CHANGES FROM PREVIOUS RUNS The theme is for cooler and drier conditions to move across the UK under a ridge next weekend with a lot of indecision still on the longer term prospects.

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 99.2 pts.  At 3 days ECM is leading with 97.0 pts to UKMO's 96.2 pts while GFS lags behind at 95.5 pts. At 5 days ECM leads with 88.2 pts to UKMO at 86.6pts and GFS at 83.1 pts. Then at 8 Days ECM has the leading spot from GFS with 61.0 pts to 51.2 pts. Finally at Day 10 ECM has the lead from GFS with a score of 44.2 pts to 36.5 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 There is some coming together of the models in the theme that covers this week's weather and now the weekend's too as the demise of the thundery Low to the South later this week has been agreed upon as well as the weak ridge of High pressure across the UK next weekend with fine and cooler conditions looking more likely next weekend now rather than anything else. Through this week there will be a fair amount of showers and heavy rain across the South especially tomorrow before the winds begin to back NE after midweek and pulls cooler air down from the North by the weekend. It now looks that the worst of this cold plunge will be to the east of the UK with the British isles having a quiet and dry weekend with some chilly night but some decent daytime weather when temperatures should reach average levels. As we look towards the second week things are less clear cut with GFS looking quite unsettled again across the UK with Low pressure close by bringing rain at times for all although the New Parallel Run is somewhat less supportive of this with the Clusters offering no clear patterning either at the 14 day time point. ECM shows the road towards a more traditional NW/SE pattern at the end of its run with some rain developing across the NW while the South and East sees something rather brighter, dry and warmer weather although the day 10 chart itself is a little less supportive of this pattern. So as you can tell from a reliably accurate prediction of this weeks likely conditions confidence falls away rapidly for next week and I feel we need a few more days runs yet before conditions predicted for next week can be accurately foreseen.

Next Update Tuesday May 10th 2016 from 09:00

[Summer Sun]

ECM again shows a short lived northerly before the high returns

Not as warm / hot as the weekend but still very pleasant in any sunshine rain fall amounts remain very low over the next 10 days for many looking at ECM

 

[johnholmes]

Differences arising in the anomaly charts from ECMWF-GFS this morning but NOAA keeping a similar idea to what it showed several days ago. The odds are probably on a somewhat coollish, possibly unsettled 6-10 day outlook, although it may turn out more settled, but still markedly cooler than the weekend and today has/will be for many.

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

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

Edited May 9, 2016 by johnholmes

[Eugene]

16 hours ago, Singularity said:

I am certainly interested in seeing how high the temperatures turn out to be on Saturday versus the low teens maximums that GFS keeps putting out for that date. 

Looks like a classic 'get away from me, old trough' situation going into the following week, as the residual lower heights to the northeast try their best to cling on. They must be warmed out and banished! They may facilitate height rises NE of the UK which could turn out nicely or unpleasantly depending on how the flow aligns and to what extent there continues to be a trough to the south of the high.

 

Puzzling comment as the May CET average max is only 16C so max temps a few degrees cooler are easily achievable in a cool northerly flow, looks much cooler by Saturday, upto 10C cooler, dewpoints much cooler too.

 

 

[March]

My most trusted forecast only showing below average on Saturday. 

[Summer Sun]

Looking at UKMO the northerly flow won't really affect the UK much temps back down to the seasonal average but nothing worse

GFS very close to UKMO

[wishingforsnow]

ECM has the best output at the moment as opposed to the GFS - the 'Northerly' and cooler/unsettled conditions happily looking like a weekend blip and nothing unsettled on the horizon for the end of the week as opposed to a long lasting pattern which is what I was wary of. GFS on the other hand is once again playing Dr Evil bringing in notably cooler and unsettled weather for mid May, although this outlook does not have much support. Hopefully ECM ends up being the form horse and it's good to see the Northerly reduced to nothing particularly wintry with only slightly cooler temperatures but closer to the seasonal average, and dry weather. Met Office encouragingly is still backing another above average period temperature wise at the end of the month too. 

Edited May 9, 2016 by wishingforsnow

[Fourty Point Three Degrees]

The BBC weather website have published their Monday outlook and its not a good one - no sign of a return of the current warmth for the rest of this month as the door is open for a constant battering of atlantic lows

http://www.bbc.co.uk/weather/2635167#outlook

 

[weatherguru14]

No return of the current warmth?? hold on a moment 25c at the start of May?? and you think its a disappointment that it wont be happening again? looking at the charts and the temps that are showing up.. I am very pleased nothing outwardly cold showing. just above  actually..

[wishingforsnow]

21 minutes ago, 40*C said:

The BBC weather website have published their Monday outlook and its not a good one - no sign of a return of the current warmth for the rest of this month as the door is open for a constant battering of atlantic lows

http://www.bbc.co.uk/weather/2635167#outlook

 

I don't see anything too bad from that forecast, yes there could be some low pressure systems at times but not frequently,  and a lot of bright and dry weather on offer too even if it's not as warm for a while. Nothing too cold and unsettled on offer and BBC are also hinting at perhaps more settled and warmer weather at the end of the month to return  For me the real warmth and longer periods of 20-25 degree + weather can wait until June.

The model output apart from GFS at the moment would also suggest nothing too horrible is on the cards for the foreseeable and the rest of May, unlike May 2015 which was awful.

Edited May 9, 2016 by wishingforsnow

[mb018538]

Indeed, remember the average for May is only around 16-17c, so temps in the mid to upper twenties are like getting 15-17c in the depths of winter! Doesn't look disastrous, nor does it look like a scorcher. Typical May weather, which is fine by me!

[mb018538]

ECM shows the northerly not lasting too long, before a ridge builds in from the west, after which things flatten out and look a bit more zonal. N/S split, with the S being drier and warmer. 850s recovering to above average too.

[cheese]

49 minutes ago, mb018538 said:

Indeed, remember the average for May is only around 16-17c, so temps in the mid to upper twenties are like getting 15-17c in the depths of winter! Doesn't look disastrous, nor does it look like a scorcher. Typical May weather, which is fine by me!

And that's for the month of May as a whole - the average high in early May will be lower than that. In Leeds we reached 26C on Sunday, average high for all of May is 16.0C so that's a good 10C above average at least. It's the earliest 25C+ temp we've had in ages. I think the earliest I recall personally is 26C back in April 2003 (reached 24C in April 2011).

Edited May 9, 2016 by cheese

[Man With Beard]

ECM and GFS parallel with plenty of cheer for summerites. Cut Saturday out (and Friday in the north) and they are excellent runs, especially GFS(P). The Azores High builds in nicely from Sunday and quickly warms us up - back up into the 20s by Monday, and 22-25C for midweek on the parallel. Less settled on the ECM by D10 for NW areas but that's way off.

[Frosty.]

The Ecm 12z shows a cooler blip at the weekend but it also looks largely dry by then, bar the odd shower with sunny spells but briefly cold enough overnight for grass frosts and a nice ridge of high pressure gradually topples southeastwards across the uk with temperatures recovering to pleasantly warm levels, at least for the south but then a typical NW / SE split develops with northwest of the uk becoming more changeable / unsettled. Looking much further ahead, the experts, despite much uncertainty, are still hinting at a return to nationwide settled and warmer weather from the end of May.

[Singularity]

@Eugene I should have made clearer - GFS was showing low-teens maximums even in the south, which is what I found hard to believe (for example I average a little over 17*C by day in mid-May). Since then the projections have been adjusted upward and now show mid-teens maximums, in line with the expectations of many on here. Sunday might well climb higher, with high-teens returning to the far south - but ECM remains slower to push the cool air aside so best not to pin hopes on such temperatures just yet.

Looking beyond the weekend, it's a real dogs breakfast with the modelling; we've seen everything from a lingering cool N/NE flow (ECM 00z) to brisk, quite warm westerlies (ECM 12z). 

GFS has taken to driving a low right through a building ridge early-mid next week, which is less than appealing. It's still finding ways to build heights to the NE in the 9-10 day period though, which is intriguing. ECM has no interest in that at all this evening, with low heights grouping together in the Arctic, almost as if the ghost of polar vortex is coming to haunt us. Except it could be a blessing in disguise for southern parts at least, provided the jet takes on a typical latitude for the time of year (north-south divides are very common for the UK in mid-May, or so it has seemed to me this past decade!).

[Scorcher]

1 hour ago, cheese said:

And that's for the month of May as a whole - the average high in early May will be lower than that. In Leeds we reached 26C on Sunday, average high for all of May is 16.0C so that's a good 10C above average at least. It's the earliest 25C+ temp we've had in ages. I think the earliest I recall personally is 26C back in April 2003 (reached 24C in April 2011).

Where in Leeds was 26C recorded yesterday? That sounds very high with an easterly element to the wind. I know you've been far enough inland to avoid any North Sea cloud but that's as warm as places on the coast of NW England managed. I didn't see Leeds in the BBC list of warmest places.

But yes we do need to manage expectations now, it's pretty remarkable to be getting above 25C away from the SE in the first 10 days of May. It looks like a more traditional outlook for the next week or so which is fine by me- weather systems tracking just to the north of the UK, which won't produce perfect summery conditions but there will be plenty of good, dry weather on offer.

I certainly prefer that to the feast or famine that seems to have become more common in UK springs in recent years.

 

 

[cheese]

1 hour ago, Scorcher said:

Where in Leeds was 26C recorded yesterday? That sounds very high with an easterly element to the wind. I know you've been far enough inland to avoid any North Sea cloud but that's as warm as places on the coast of NW England managed. I didn't see Leeds in the BBC list of warmest places.

But yes we do need to manage expectations now, it's pretty remarkable to be getting above 25C away from the SE in the first 10 days of May. It looks like a more traditional outlook for the next week or so which is fine by me- weather systems tracking just to the north of the UK, which won't produce perfect summery conditions but there will be plenty of good, dry weather on offer.

I certainly prefer that to the feast or famine that seems to have become more common in UK springs in recent years.

 

 

There is no weather station in Leeds, that's why - I have my own PWS, which I compare with Linton on Ouse, north of York, which reached a rounded figure of 26C and was in the top 100 warmest places in Europe on Sunday. I have no reason to doubt the validity of either figure. Even the BBC were forecasting 25C as the high on Sunday - the easterly wind didn't really have much of an effect on our temperatures, nor did they today. I used to use Church Fenton as the nearest point of reference but that weather station is no longer in operation.

The precise figure for myself was 25.6C.

Edited May 9, 2016 by cheese

[Scorcher]

Cheese I have seen that Linton on Ouse managed 26C on Sunday- I do find that surprising as it wasn't really mentioned by the BBC. Impressive for early May. The west did fare better temperature wise yesterday though.

[Chris.R]

A max of  26.7°C here yesterday, a little warmer than forecast out of interest. Quite exceptional for the time of year here. 

[Polar Maritime]

If we could keep discussion around the 'Model Output' in here that would be great, There is Spring thread open for more general chat, Cheers.

The GFS continues to sing from the same sheet this morning, With the Northerly by at the weekend re-establishing by midweek before unsettled conditions move in off the Atlantic around the 20th.