Model Output discussion 1st September 00z------->

[knocker]

The anomalies tonight are looking to lose the HP cell around Monday the 5th, the ecm a day earlier than the GEFS, with a transition to a flat zonal westerly with a weak trough Iceland area.

http://www.tropicaltidbits.com/

 

[Singularity]

 

These two seem simply unable to come to agreement with respect to how the ridge shapes up over Scandinavia during the middle part of next week (ECM on the left, GFS on the right). We're talking just four days away now - surely this has to be resolved tomorrow?

 

With ECM the outcome by Friday is cool air diving south toward Italy (below-left) and warm air rising north to the UK, whereas GFS (below-right) has the cool air heading west to southern parts of the UK, leading to instability and low pressure development to our south, with the warm air being held out in the middle of the North Atlantic.

 

So they're worlds apart in terms of 850 hPa temperatures - though cold nights and perhaps fog lingering well into the day could bring conditions from the ECM run that are about as chilly overall as GFS' rather cloudy, nagging easterlies. So the signs are that for the third time in a row we'll see a month starting off with temps some way below the LTA. 

 

 

It's fair to say that ECM's following two charts would probably lift temps back up to at least average for the first five days of October as a whole, but GFS is another story with some remarkably low temperatures possible for a time on the 12z. Then there's the 18z which has taken things a number of steps further and bears a fair bit of resemblance to the 00z operational. The coldest chart of the run looks like this:

 

 

 - but I feel like it's a little early for this sort of thing 

[Frosty.]

The Gfs 00z shows an anticyclonic week ahead but then there is quite a dramatic change from the northwest to much colder and unsettled conditions, cold enough for sleet and snow on northern hills. High pressure then builds in across the south for a time but the run ends unsettled with further cold shots from the northwest looking likely. It's been a regular feature of the gfs recently for a colder and unsettled early october with polar maritime incursions, I hope we see plenty of it next month!  

Edited September 27, 2015 by Frosty.

[knocker]

The latest fax charts

 

[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 SUNDAY SEP 27TH 2015

 

THE CURRENT GENERAL SITUATION A High pressure area will continue to dominate the weather across the UK through the period.

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

MODELS-2 WEEK HEADLINE Mostly settled and fine well into October.

THE GFS JET STREAM FORECAST The GFS Jet Stream Forecast shows the main arm and core of the flow remaining well to the North of the UK for the reliable future with a return slowly South later towards Northern Britain as it links with a somewhat less pronounced Southern arm at the end of the period.

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

GFS OPERATIONAL The GFS Operational Run today shows High pressure across Northern Britain for all of the coming week while the South sees an increasing Easterly flow with perhaps a few showers come next weekend. warm days and cool misty night will last throughout the week in the North. Then pressure falls across all of the UK with more changeable and often cool weather in the second week with some rain at times especially over the North and West.

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

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

THE GFS CONTROL The theme of the GFS Control Run this morning follows a similar route in the next week as the operational with a fine week to come as High pressure remains positioned close to or over the North of the UK. by next weekend some showers look like breaking out over the South ahead of a more changeable second week as a gradual shift to deep Low pressure close to the North brings the risk of gales and heavy rain at times especially in the North while the best of any drier spells look likely further to the South and East.

http://www.meteociel.fr/modeles/gefs_cartes.php

THE GFS CLUSTERS(14 Days) The GFS Clusters this morning indicate a largely favourable position of a NW/SE split in the weather in two weeks time with an almost 90% chance of a ridge lying over or close to the South of the UK with a more unsettled and changeable WSW flow more likely across the North and West.

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 is again rock solid in promoting High pressure persisting across the UK throughout this coming week, lying far enough South to prevent too much incursion from a strong East flow in the South and totally eliminating any risk of showers there too later in the week.

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

THE FAX CHARTS The Fax Charts this morning show a blocking High to the East with a ridge stretching across the UK throughout this week warding off all Atlantic fronts well to the West and NW.

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

GEM GEM this morning also shows High pressure over the North maintaining a dry and fine week but with the risk of showers in the South late in the week as an easterly flow develops, fresh at times in the extreme South. Then through next weekend and the start of the second week a more general fall of pressure could bring more changeable conditions for all but with rainfall amounts likely to be small and restrictive in nature and most likely over the North and NE.

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

NAVGEM NAVGEM this morning has High pressure dominant across the North of the UK over the next week with an increasing Easterly flow across the South through the week. It should stay largely dry though with just a risk of more cloud and a few showers brushing the South at times late in the week and again late next weekend towards the SE.

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

ECM ECM this morning follows the course of much of the output today in ensuring a week at least of fine and settled weatehr especially across the North as High pressure remains anchored there. In the South a nagging East wind looks likely at times and while it should stay largely dry a few showers are possible for a time later in the week. By the end of next weekend signs of a more general pressure fall across the UK develops with the run ending with a deep Atlantic Low knocking on the door of the West with rain bearing fronts moving NE across the UK on warm and moist SSW winds.

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

ECM 10 DAY MEAN The ECM 10 Day Mean Chart from last night is gradually changing to somewhat more changeable pattern with a trough of Low pressure possible close to the West by Day 10.

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

NOTABLE TREND CHANGES FROM PREVIOUS RUNS The models remain little changed from yesterday with the majority showing sustained High pressure based weather across all areas but with a more definitive move to more changeable weather being shown now through the second week although how this develops is unclear at the moment.

31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKMO & ECM The Verification Statistics of GFS, UKMO and ECM show at 24 hours ECM ahead of UKMO at 99.5 pts to 99.4 with GFS closely behind at 99.3 pts.  At 3 days ECM is tied with UKMO at 96.5 pts  while GFS lags behind at 95.6pts. At 5 days ECM leads UKMO at 86.6 pts to 86.3 pts then GFS at 84.6 pts. Then at 8 Days ECM still leads at 58.4 pts over GFS's 52.6 pts. Finally at Day 10 ECM leads GFS at 34.8 pts to 33.2 pts from GFS.

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  Another good set of output this morning if it's fine weather your after as High pressure without exception from any model is scheduled to block any attack from Low pressure over the next 7 days. the only fly in the ointment is how much influence an increasing East wind across Southern England has on masking daytime warmth and setting off any showers late in the week which is just about possible though looking unlikely from a UKMO point of view. Night's will remain chilly and while the South may escape much in the way of mist and fog due to the increasing breeze there the North looks likely to see quite a bit at night along with a continuation of cool temperatures and patchy frosts. Then as we look further ahead into week 2 there is some signs of change as it looks likely that Low pressure in one shape or another will feature rather more although how and to what extent this develops is still largely unclear. The general theme would probably see the North and West become more unsettled while the SE remains the most likely area to stay drier for longer although the ECM 10 day chart would ensure wind and rain for all. There remains a hint of cold cyclonic winds from the North in week 2 by GFS though the clusters are less supportive of this. So with all this speculative talk of a phantom breakdown as of yet we should be enjoying the here and now over the next 7 days as a lot of fine and very pleasant weather looks like being shared for all through that time and while that goes on the path may become clearer in what direction the weather will take thereafter.  

WORST CHART OF THE DAY 00z RUN 

http://www.wetterzentrale.de/pics/Rtavn2161.gif

A nasty little Low to the North of Scotland at day 9 holds the mantle for the worse chart of the day as it would fire cool and very windy weather to the North and East with rain and cold showers rattling through in the very strong breeze.

BEST CHART OF THE DAY 00z RUN

http://www.wetterzentrale.de/pics/Rukm1201.gif

Once again the best chart of the day has to be from UKMO at day 5 which illustrates a persistent area of High pressure locked solidly across the heart of the UK ensuring all areas continue to enjoy a sustained period of fine and settled weather for several more days at least beyond that point.

Next update from 09:00 Monday Sep 28th 2015

Edited September 27, 2015 by Polar Maritime

[knocker]

The ecm ops this morning has the centre of the HP moving from the North Sea to N. Ireland during the week before scooting away to the east early next week as the Atlantic intrudes. Much along the lines the anomalies have been indicating. Still a good week.

Edited September 27, 2015 by knocker

[Polar Maritime]

The GFS continues to show High Pressure domination next week, With some cool wintry Northerly shots into week 2 of October again this morning. 

Edited September 27, 2015 by Polar Maritime

[Summer Sun]

2 completely different options at d10 this morning ECM is going for a deep low dragging up some warmer air

 

 

GFS on the other hand has a deep low centered close to Norway leaving us open to some cooler air

 

[knocker]

At day ten range I don't find the two scenarios SS has posted above at all incompatible. If, as seems likely, we have the evolution of the HP scooting east with a weak trough to the west and the Atlantic becoming the main driver then depressions tracking NE would seem likely. The timing of the transition of said depressions is crucial as to whether the UK is in a S/SW airstream or, with the passage of the low, a northerly one. Ten days hence they are bound to differ as 24/48 hours is crucial to the exact position.

 

Anyway this morning's anomalies confirm the above scenario

http://www.tropicaltidbits.com/

Edited September 27, 2015 by knocker

[MR EXTREMES]

It would seem that a possibility that high pressure over UK may stick around a bit longer that suggested.

With such a different set up to recent years it's possible that the model are finding it hard to pin down an actual outcome.

There for heights hold for a bit longer than suggested.

I remember 09/10 well it was the Azores heights that became the friend for collides and retrogressed into a favoured area similar to now but it took what seemed an eternity there after blocking was stubborn for such a period of time which gave us a great winter.

So in my opinion it's likely high pressure could be the dominant player and that the models could well be to progressive.

Until the jet vortex and arctic area settles into a pattern I'd be thinking more of our most recent type of weather will continue nothing overly stormy or disruptive showing yet.

But I must say it's beautiful and I'm enjoying this weather fresh in the mornings and warm by day nice seeing frost this will do just for now.

[johnholmes]

An idea of how similar in some ways and yet how different for the ECMWF-GFS anomaly chart this morning

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

both have the upper low about the same place, one=S'ly 500mb flow, the other north of west flow. One has a ridge e of UK and in about the same place the other has a low!

Until they stop changing I would not place too much reliance on these two. This especially so while the NOAA 6-10 remains fairly sequential and consistent, see last evening below.

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

If it also starts to switch then forget all 3!

Edited September 27, 2015 by johnholmes

[Frosty.]

The Gfs 6z shows an anticyclonic week ahead with pleasant spells of sunshine and chilly nights with patchy mist and fog where skies clear and winds fall light but as with the 00z it's to the northwest where we see quite a change to colder and unsettled conditions sweeping SE and becoming cold enough for sleet and wet snow across northern high ground for a time. Looking further ahead, the run up to  mid october looks generally unsettled and i'm hoping october will bring a nw/se aligned jet with regular polar maritime and even arctic incursions as time goes on..    

Edited September 27, 2015 by Frosty.

[Zenarcher]

Daily comparison using the GFS, ECM, UKMO, JMA, ICON, GEM, NAVGEM, NASA, CMA, FIM and the CFS all up to 240 hours along with the ECM and GFS ensembles. For each day whatever model has the most support will be shown for that time.

 

24 Hours Monday (GFS)

High pressure of 1030 to 1035mb covers all of the UK and Ireland while a low pressure system develops in the Atlantic.

 

48 Hours Tuesday (GFS)

High pressure remains over the UK while the low pressure system moves North into Iceland.

 

72 Hours Wednesday (NAVGEM)

The high pressure now starts to move West and still covers all of the UK and Ireland.

 

96 Hours Thursday (GFS)

The high pressure continues to move West.

 

120 Hours Friday (GEM)

High pressure now sits mainly to the West side of the UK and Ireland.

 

144 Hours Saturday (ECM)

The high pressure now begins to weaken while staying in the same position.

 

168 Hours Sunday (NAVGEM)

The high pressure shifts back East while it continues to weaken in strength while a low pressure system develops in the Atlantic.

 

192 Hours Monday (GFS)

High pressure still remains at this point but it continues to weaken. The low pressure system deepens in the Atlantic.

 

216 & 240 Hours Tuesday and Wednesday (ECM & GEM)

Signs of high pressure building up to or near to Greenland while low pressure starts to take control over the UK and Ireland.

 

[Polar Maritime]

The GFS 12z certainly shows the much touted Easterly flow for Thu/Fri sink to far South to effect the UK. With High Pressure taking control well into the 1st week of October, And holding on a good few days longer than previous runs. It's not until the end of week 2 we see the projected Northerly shots.

Edited September 27, 2015 by Polar Maritime

[Milhouse]

The UKMO is also showing the strong area of high pressure set to persist over the UK until the end of the coming week. If the GFS 12z is correct we may see temps reaching 20c

 

[Frosty.]

Most of the Gfs 12z is showing warm anticyclonic conditions with plenty of sunshine and chilly nights with mist and fog patches until around the middle of week 2 but it then turns much colder and more unsettled from the North, (from the arctic actually) with snow on high ground in scotland although it takes longer for the cold air to reach the south before a cold high builds across the uk with night frosts, the high becoming centred across the northern half of the uk with a chilly easterly flow becoming established further south so it's a very interesting run to say the least, warm and settled then much colder and unsettled then staying relatively cold for the time of year and becoming settled again...winter is coming    

Edited September 27, 2015 by Frosty.

[ANYWEATHER]

Evening all. High pressure controls the Nation this week although a nagging wind develops across the southern half of Britain from the East or north east which may produce a lot of cloud cover. So I would say Scotland will all in all have some very pleasant temperatures, Probably the highest temperatures in the Uk.  So we go out to T+168 and models disagree vastly, Gfs keeps the high pressure scenario, Ecm shows the return of the Atlantic...    

[lorenzo]

First 192 bias learning of the season.

 

One of these models is wrong...

 

 

Interestingly it is the classic GFS bias of toppling east displayed on the ECM.

 

GFS going for the longevity on the block.

 

Nice time range 192 open to all sorts of interpretation, on the edge of where 184 fax charts never verify. Where ECM skill score hits 3 times out of 10 where GFS is a law unto itself and where we cannot see UKMO.

 

This winter will be a helluva lot of fun..go ENSO

[legritter]

Evening all. High pressure controls the Nation this week although a nagging wind develops across the southern half of Britain from the East or north east which may produce a lot of cloud cover. So I would say Scotland will all in all have some very pleasant temperatures, Probably the highest temperatures in the Uk.  So we go out to T+168 and models disagree vastly, Gfs keeps the high pressure scenario, Ecm shows the return of the Atlantic...    

Just about to post a similar post ,anybody on uk holiday over next week have i think picked a good time ,after that well i,v waited 63 years to see blackpool illuminations and ECM as tracked me down as we are their October the 5th ,but at 8 days away we could be in luck ,time will tell .

But certainly looking like some interesting norther Hemisphere weather in the outlook .  

[Summer Sun]

GEM is taking the stormy route like ECM as we move into the first full week of October

 

 

The ECM ens shows the high gradually declining later next weekend and into the following week

 

 

The coming week looks fairly quiet cloud amounts will be tricky to get correct though pleasantly warm where its sunny but cooler which the cloud persists

Edited September 27, 2015 by Summer Sun

[cheese]

Most of the Gfs 12z is showing warm anticyclonic conditions with plenty of sunshine and chilly nights with mist and fog patches until around the middle of week 2 but it then turns much colder and more unsettled from the North, (from the arctic actually) with snow on high ground in scotland although it takes longer for the cold air to reach the south before a cold high builds across the uk with night frosts, the high becoming centred across the northern half of the uk with a chilly easterly flow becoming established further south so it's a very interesting run to say the least, warm and settled then much colder and unsettled then staying relatively cold for the time of year and becoming settled again...winter is coming    

Wow, that's a cold high pressure. Would like to see that verify.

[knocker]

Tonight's anomalies go some way to understanding the the ops output. At the beginning of next week they both have a trough to the west but the ecm is more progressive with this and the GEFS keeps the Scandinavian ridge. This is a bit deceptive as it moves rapidly to join forces with the ecm within 24hrs and into the ext period indicating the arrival of the trough influence by the beginning of next week. A matter of timing. It also might well illustrate the fallacy of reading too much into one run

http://www.tropicaltidbits.com/

 

[johnholmes]

184 fax charts never verify

Can't say I have ever seen a Fax chart that far out, 144 hours is the max that I have seen. Can you post a link please to where you found them?

thanks

[lorenzo]

184 fax charts never verify

Can't say I have ever seen a Fax chart that far out, 144 hours is the max that I have seen. Can you post a link please to where you found them?

thanks

 Sorry John typo meant to write 144. This is the link for the meto ones anyway useful as time stamped, although at peak viewing the NOAA .tif chart arrives more quickly..

 

Either way, we do not get to see enough of UKMO d7-10 - would be good to see it at the party this winter.

[Singularity]

There's a critical change between the GFS 12z and 18z det. runs (it's about time I started calling the operational runs the deterministic runs); the jet no longer engages with a deepening low exiting Canada to create a trough there, meaning it creates one over Greenland instead.

 

That brings GFS in line with ECM's 12z det. output with the Atlantic romping in by day 8 (ECM on the left, GFS right):

 

 

It also seems to bring the guillotine blade down on potential height rises around Greenland. At least GFS isn't as vicious with the storms as ECM is... that model really powers up the jet stream as cold polar maritime air, less modified than usual thanks to the unusually low Atlantic SSTs west of the UK, meets warm tropical maritime air, itself being enhanced by anomalously high SSTs in the subtropics (in fact they're at record high levels in some parts).

 

It's easy to see where I'm going with this - I can see where ECM's coming from with its suggestions of a particularly vigorous jet stream.