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Model Output Discussion - Into Autumn 2019.


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Posted
  • Location: Crymych, Pembrokeshire. 150m asl
  • Weather Preferences: Extremes of all kinds...
  • Location: Crymych, Pembrokeshire. 150m asl

For those interested in the accuracy of the operational models, it is sometimes worth comparing the predictions for a single date and time separated by a week of evolution.  The track and influence of Dorian was perhaps a more complicated issue than most for the models to resolve but they didn't all perform badly.....

Predictions for 02:00 12/09 as shown on the....

                                     03/09/19.....                                         today....

ECM   image.thumb.gif.e5ae9277a76b057ee6b4980893b8364e.gif   image.thumb.gif.018d2ffedc12b145a0ec108358f82fde.gif

GEM   image.thumb.png.6d4372b8bf7c649362047af9f8d2f3d6.png   image.thumb.png.7a6c04f7d2c7666117ed3b2940759000.png

GFS    image.thumb.png.f3a6ec2a2d55b0d697fae6b09bad8daa.png   image.thumb.png.d93ba154027dff7fb53187093605ad73.png

The models today are all in pretty close agreement as to the conditions expected in 72 hours, but a week ago there were considerable differences.  For my money the ECM has performed well, getting all the major features in the right general area meaning that the weather conditions we can actually expect were being predicted correctly by the ECM 9 days ahead.   The GFS, on the other hand, was quite wide of the mark showing the remnants of Dorian tracking into the North Sea, forecasting much more unsettled conditions than we can now expect.  This single example doesn't prove much except that even with the aid of these very powerful computer models the weather remains pretty unpredictable much beyond 120 hours ahead.  Sometimes quite significant changes can occur in the patterns within as little as 96 hours so trying to predict how and when major weather events will develop and evolve still involves a lot of guesswork.  No doubt we will see plenty of this in the coming season as we all try to detect the first major snowfall of Winter.....but if it was too easy, many of us wouldn't even be here....

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Posted
  • Location: Cambridge, UK
  • Weather Preferences: Summer > Spring > Winter > Autumn :-)
  • Location: Cambridge, UK

image.thumb.png.50daf5e95e89646453cb33cb702f535e.png

With ensembles mean sea level pressure not dropping below 1020mb on the 00z GFS runs, we could be looking at 2 weeks of dry and settled weather after Wednesday. Been quite a while now since we've had such a lengthy spell dominated by high pressure. Mainly down to the crazy stretch of negative NAO from late spring right through the summer:

nao.sprd2.gif 

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Posted
  • Location: leicester
  • Location: leicester
49 minutes ago, JON SNOW said:

It may be Monday morning but the Ecm 0z ensemble mean has given me a happy face with a predominantly settled / anticyclonic outlook..very warm at times too for early autumn further south where the best of the weather is indicated..pop larkin likes it too!

EDM1-96.thumb.gif.f185db680b8e7ced34477294bcb46c20.gifEDM1-120.thumb.gif.e89732973efd42797f01e602c7eea65a.gifEDM1-144.thumb.gif.8ebaf48f5e07f2241baed5d57058f5c1.gifEDM0-144.thumb.gif.98ed3521dbbe65fa77941540efe910ef.gifEDM1-168.thumb.gif.c2744a685408a2e0c24d5f07653f5e3a.gifEDM0-168.thumb.gif.5a7db55398742e6a72c0a1ec32120257.gifEDM1-192.thumb.gif.10195c6655d1ecc2228bdce50719dffb.gifEDM1-216.thumb.gif.6580550e041a9f75c39480ed74729ac7.gifEDM1-240.thumb.gif.c9824b46927ecb21f1d427232dccfc98.gifBRAND_SMILEY_MAIN.thumb.jpg.7e5b3113fc08c826e44d0a7862556e1a.jpgperfick.thumb.jpg.caa275b4fac87fb669b9163c99dd397c.jpg

 

Yup looks like the op was an outlier from 144 hours onwards which is good news if you want warmer temperatures!!

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Posted
  • Location: Manchester
  • Location: Manchester
1 hour ago, sundog said:

Well these charts from the ecm for next week would put a smile on my face if they came to fruition.  Cooling down with cool night's I would imagine. Perfect autumn weather.

ecm500.192.png

ecm500.216.png

ecm500.240.png

Just one run and an outlier. The odds are still strongly favouring a warm up rather than a cool-down.

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Posted
  • Location: Ashbourne,County Meath,about 6 miles northwest of dublin airport. 74m ASL
  • Weather Preferences: Cold weather - frost or snow
  • Location: Ashbourne,County Meath,about 6 miles northwest of dublin airport. 74m ASL
17 minutes ago, Scorcher said:

Just one run and an outlier. The odds are still strongly favouring a warm up rather than a cool-down.

The odds are certainly favouring a warm up no question.  But anyway next week is a bit far off yet as to know how long the warm up lasts .

 

Fwiw ,latest gfs going for a cool down later next week. Too far out of course at this stage to know what will happen by then.

h500slp.png

h850t850eu.png

Edited by sundog
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Posted
  • Location: Mynydd - Isa , Nr Mold - North Wales
  • Weather Preferences: Foggy autumn days are the best! Although I does enjoy a good thunderstorm.
  • Location: Mynydd - Isa , Nr Mold - North Wales
10 minutes ago, Scorcher said:

Just one run and an outlier. The odds are still strongly favouring a warm up rather than a cool-down.

But remember that we are now in September, and whilst we could very well get a late burst of summer, the longer nights mean that the temperatures will soon drop away! The season of mists and mellow fruitfulness is now well and truly up on us. :oldsmile:

... And swerving swiftly back on topic...
Morning everyone, here is a look at what the CFS is showing for the next four weeks...
Now I'm no professional, but my take on these charts is that high pressure is gonna be anchored pretty close to us here in the UK. So I think it feel rather pleasant by day, but with the obvious cool down come evening time.
Now then is it gonna be warm? Or is it gonna be cool? Time will tell on that... But I do know that I've seen far worse looking in June! Early June this year being a classic example! 
So lets see how things pan out, but I'd say that we looking at a very fine and settled autumn period, with nothing much to complain about. :oldgood: 

wk1.wk2_20190908.z500.gif

wk3.wk4_20190908.z500.gif

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Posted
  • Location: Camborne
  • Location: Camborne

the clusters at T168 and 192 illustrate very well the battle between the eastbound energy and the amplifying subtropical high. One would have to say the latter is struggling to stay in there

ec-ens_nat_z500scenarios_2019090900_168.thumb.png.89da692d3eb686062fc8a04b3a12c24d.pngec-ens_nat_z500scenarios_2019090900_192.thumb.png.414bfbadebb9659a03eadf9d652ec32b.png

 

Edited by knocker
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Posted
  • Location: Cambridge, UK
  • Weather Preferences: Summer > Spring > Winter > Autumn :-)
  • Location: Cambridge, UK

This morning's ECM OP run (a cool outlier by day 9/10) doesn't really fit with the ensemble clusters:

ec-ens_nat_z500scenarios_2019090900_240.

Perhaps close to the 4th and smallest one, but the majority still keep things with the ridge over the UK rather than backing west.

This is shown well at T300:

ec-ens_nat_z500scenarios_2019090900_300.

Day 15:
ec-ens_nat_z500scenarios_2019090900_360.

Form horse at the moment is high pressure sitting over, or very close to the UK. Dry for most, temperatures dependent on where the high sits. Next Monday potentially looks very warm if the ECM mean is to be believed (850 temps around 15c). Could be nudging 80f in the south.

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Posted
  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.

The GEFS 06Z ensembles do look, on the face of it, a tad less appetising than did the 00Zs...But then, knowing just where a future HP will set-up shop is a pretty hapless task...?

 prmslLondon.png   t850London.png

t2mLondon.png   prcpLondon.png

At least high pressure and near-zero rainfall seem to be a consistent theme?

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Posted
  • Location: Crymych, Pembrokeshire. 150m asl
  • Weather Preferences: Extremes of all kinds...
  • Location: Crymych, Pembrokeshire. 150m asl

The major models are all promising some lovely late summer conditions coming our way in around a weeks time:

                                          500s:                                                     850s:

ECM     image.thumb.gif.92503c03c3d797c985d347251819785e.gif image.thumb.gif.389012bd7fe5362a02ac2bf68b417582.gif

GFS     image.thumb.png.414775d7567a5e8239eb4705680690b2.png image.thumb.png.3c9be4a9ced427b8193967d5406e4baf.png

GEM    image.thumb.png.d795f694e72c6fb20347bb0244f8b010.png image.thumb.png.9736de1d97720c788acec816662aed72.png

....but saving the best till last, in only 6 days time, the UKMO is boasting the following charts:

            image.thumb.gif.a10796aa11274ba03b8928c903bf088e.gif image.thumb.gif.53cd85ac6d518ae2394e4149baf4b00f.gif

Cor!!  Could be looking at July there.  No records likely to be broken, though.....

And there really isn't any reason to worry that a few warm days in September will mean a lack of snow in January.  If you don't believe me, read the Sun.....

https://www.thesun.co.uk/news/9887058/uk-weather-forecast-coldest-winter-years/

(courtesy of dbaloo)

 

Edited by Sky Full
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Posted
  • Location: Camborne
  • Location: Camborne

An interesting observation by John Homenuk. This also promotes the downstream ridge over the UK as previously noted

Quote

Both the Euro and GFS ensembles continue to suggest that a sprawling ridge of high pressure will develop from the Eastern US into the Western Atlantic in 5-7 days. This would be a concerning synoptic setup should any tropical development occur in the Atlantic Basin.

EEBiekSX4AEvMma.thumb.jpg.d41ec0da75269a49d326a4fdde6b3e08.jpg

Edited by knocker
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Posted
  • Location: South Norfolk, 44 m ASL.
  • Weather Preferences: Varied and not extreme.
  • Location: South Norfolk, 44 m ASL.
4 hours ago, Dangerous55019 said:


So lets see how things pan out, but I'd say that we looking at a very fine and settled autumn period, with nothing much to complain about. :oldgood: 

wk1.wk2_20190908.z500.gif

wk3.wk4_20190908.z500.gif

...except if you're in an ongoing drought as we are here.  With the Norfolk and Suffolk countryside already brown, another four weeks of dry weather will probably see shortages...in bloody autumn!  Certainly, the anomaly outputs Malcolm linked earlier today would support this.

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Posted
  • Location: Wildwood, Stafford 104m asl
  • Weather Preferences: obviously snow!
  • Location: Wildwood, Stafford 104m asl

EC flirting with this, now GFS, hope this stays away, any further West then it could be potentially vile

gfs-0-156.png?12

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Posted
  • Location: leicester
  • Location: leicester
3 minutes ago, I remember Atlantic 252 said:

EC flirting with this, now GFS, hope this stays away, any further West then it could be potentially vile

gfs-0-156.png?12

Stil will feel reallly  pleasant in the sun!!and a serious lack of rainfall!!atlantic is blocked!

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Posted
  • Location: Wildwood, Stafford 104m asl
  • Weather Preferences: obviously snow!
  • Location: Wildwood, Stafford 104m asl
4 minutes ago, shaky said:

Stil will feel reallly  pleasant in the sun!!and a serious lack of rainfall!!atlantic is blocked!

not if pattern moves west

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Posted
  • Location: Manchester Deansgate.
  • Weather Preferences: Heavy disruptive snowfall.
  • Location: Manchester Deansgate.

Various points of the 12z GFS are threatening a potent for the time of year early season Northerly.

image.thumb.png.7a1bbfccf6836ea78da5dd09cd98628f.pngimage.thumb.png.9d4f8f8597146cad8d97a6e51b17f6d6.pngimage.thumb.png.7319f2dd40c64cf07e0ecef14bae22ef.png

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Posted
  • Location: Windermere 120m asl
  • Location: Windermere 120m asl

A bit of change in the models today, they have been showing heights building strongly over the UK as we move through the week, with the jetstream well to the north, enabling them to position further east and maintaining a warm flow. Recent runs are showing heights possibly coming unstuck and instead of building over the UK, they will quickly retract westwards aided by heights building north to the east of the USA coastline, allowing a deep downstream long wave trough to push south just to our east, which would usher in much cooler uppers. 

In terms of the reliable though, the coming weekend could deliver one of those late bursts of summer warmth that often happens in September, with widespread maxes in the 20s. Indeed it would be odd for such a spell not to happen in September any more.

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