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Mid-winter - models, teleconnections and nowcasting

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Here we go with a new thread that we hope will become a regular one. This is the spot for those who want to discuss the current and upcoming weather, but don't necessarily enjoy the cold hunting rollercoaster style drama which can happen in the model discussion threads. 

This thread has a quite wide remit, and is open for anyone to discuss the current models, teleconnections and even the current weather and nowcasts. Posts don't have to be really in depth or technical, and you're welcome to make the same post into the model discussion thread if you'd like to (assuming it's model related!). This idea for this thread is for it to be a quieter, more balanced and maybe less cold slanted discussion though, so please use the model discussion thread if you prefer the cut and thrust of the annual hunt for cold in there.

Interested in teleconnections and their impacts?
Head to the teleconnections discussion

If you're wanting to learn more about the weather and meteorology, it's definitely worth taking a look at our new Learning and Research area.

Model Output And Charts On Netweather:
UKV (Extra subscribers)
GFS
GEFS Ensembles
ECMWF
ECMWF EPS
NetWx-SR (3km)
NetWx-MR (9km)
Met Office (UKMO)
Fax
GEM
GFS Hourly

Model Comparison
Golbal Jetstream
Stratosphere

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Using examples from the GFS 12Z, looks like the High Pressure that has brought some chilly, frosty and bright conditions will slip away to the East and South of the UK, allowing some more changeable conditions to spill in from the West. 

High Pressure should, at least, hold on for another day over the South and Eastern portion of the UK tomorrow:

1FDF8C84-EBAD-4A5A-BA23-443091E6F715.thumb.png.59a4acb6d030c2c7b66c62ee75202ae0.png4A9870DA-8183-4239-8FE1-B2ADD103858A.thumb.png.b20e4a8e6e96c66210aed09fa19b2461.png

Should be a mostly dry and bright day over Central and South-Eastern areas, though some mist/fog and frost patches could still be possible. Some rain over North-Western areas of the UK, where the pressure is lower. And probably quite cool for those under the rain in the South-Westerly to Westerly winds.

Models then show Low Pressure to the North becoming more dominant on Thursday and Friday over the UK with Westerly and North-Westerly winds. The best of the driest and less-cool conditions over South-Eastern areas of the UK. But some rain is likely to sweep through most areas during Friday with colder, brighter and showery conditions tucking behind from the North-West.

70C02FDF-7279-4A39-AD7D-502F7EFFC7E2.thumb.png.cdc837a2a311861ab12bb55e82b592ba.png6E2AB1B8-1152-4CD2-AA60-A828345DD136.thumb.png.e75976217a61a439aa61e08b55607177.pngE613C289-1462-4BF1-8A84-C6B66465E361.thumb.png.eecf257714d7c72b27346d27231b1a09.png379D59B1-D761-4D4A-9270-AD07D6E7B1A2.thumb.png.9712928cfd3e34830101d9525d1cc611.png

There is then likely to be a transient ridge in the West from the Atlantic tracking Eastwards through the UK on Saturday. This delivering a calmer day with sunny spells in places. Especially towards Southern UK.

EF28469F-0593-4F32-9280-DFED5FCB5168.thumb.png.6979caf1fca41a2542d9ca21fe8122de.png0FC96AB5-7055-445A-A00E-80CEF7E7A1DA.thumb.png.854f5d5c09a1162b6462c6bd6a170205.png

Though with the GFS showing a Low Pressure system approaching Western areas of the UK from the Atlantic, Ireland, Wales (especially North-Western parts) and Scotland could see a wet afternoon and evening.

AFEF874A-65DF-4DA4-9A81-9FD72246AEC8.thumb.png.2422e95a680a6502dd169ba902585695.png6423B8DB-00D9-4F1D-BFFE-445C0A32FE9E.thumb.png.496c3f4c7061dadd2831519e4f51ef05.png
 

After that, there could be a possibility for a colder flow to develop from the North for a time early next week.

Examples from the 12Z GFS, 12Z GEM and 12Z ICON below. (In that order):

17552A17-12AA-4FAA-AF21-8445B14FDA62.thumb.png.e6a41b8264e9461665c3865066b45b5a.png9EDB36A0-91AB-4AC0-89A0-93446B2E7256.thumb.png.113e510ca35269993263b0ba716f4ad5.png84E58F82-72B2-4ADB-AD04-DE5EB2AC5AD7.thumb.png.e919a5413667eb849b9a2b3724b18108.png

GFS 12Z above being the most keen on this. Shows the most pronounced Northerly over the UK at 144 hours thanks to some fairly decent amplification in the Atlantic (though nothing too major). Likely to be cold enough for some wintry showers over Northern UK. 

7D5B2BAE-7DDA-418D-AD4E-63C1AACBCFD5.thumb.png.92438c4904f93b8b1932624e2ad7925b.png2AED8342-F413-4243-BF3B-28B86B67EAC3.thumb.png.e1f4b2da8228db69ff559b3977d25c44.png

The other 2 models a little less keen and pronounced with their North-Westerly and Northerly flows at the same time-frame, particularly on the 12Z ICON. 

However, the GEM is very similar to the GFS 12Z above at 138 hours:

5DC7C876-F3EF-47A2-A45F-D73094B1B033.thumb.png.b160d037c6bfae25aede1d1dea9765b0.png
 

As such, the timing partly having something to do with it as well as the duration of the chillier plunge from the North-West and North. 

And with the 12Z UKMO, either it just pushes any colder plunge from the North-West or North too quickly East around 144 hours (the one that would appear to affect Scandinavia at that time-frame), or it really isn’t buying into it at all.

25D3E6FD-1363-4516-BF32-18E15E5E3319.thumb.png.ad6769dd07dac87ce1b20de8092c5df9.png

What ever happens, any chillier flow from the North early next week is likely to be transient (it’s also possible the GFS may be over-doing the Northerly a bit). Does also depend whether High Pressure can amplify enough in the Atlantic with enough of a gap between the Eastern UK and Western Atlantic Low to provide a potent enough Northerly for some wintry weather, before it crumbles away. Inland areas of the UK, such as Central Midlands areas, would likely see a lot of bright, sunny weather should the possible Northerly be a direct straight one from the North.

Some further chilly weather could be possible beyond that - a prospect to see the Jet Stream taking an increasingly more North-West to South-East path through the UK (or perhaps just to the South of it), which could encourage Low Pressure to dive to the South of the UK and squeeze the Azores High out West. A bit far away to be sure enough of this yet. The deep(ish) trough of Low Pressure could always stall just to the West of the UK quickly encouraging High Pressure to build to the East of it over mainland Europe and maybe draw up some milder air from the South and South-West. This seems unlikely at the moment, but not impossible. 

Seeing Low Pressure becoming more Southerly tracking is a possibility anyway. And is something that could provide excitement for the cold and snow weather enthusiasts (if those Lows do behave themselves 😉). 

8E3013D7-0A14-4EF4-B3C3-5D9FFD8B188C.png

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An overview As said above Friday is looking unsettled widely with a spell of heavy rain and strong winds from an active cold front with showery conditions behind this also windy too with very windy conditions in particular for Scotland..

GFS_072_UKD0_SFC.thumb.png.954b9478c0fe65130952f0180a4c5e0d.png

 A wave depression moving through on Thursday for the north bringing heavy and persistent rain for Scotland leading to localised flooding. 

GFS_048_UKD0_SFC.thumb.png.1d5a37f0a235907f604f139a83fa8e1a.png

Saturday very showery but some sunshine too. 

Another weather front bringing heavy rain to most throughout Saturday night into sunday that timing isn't nailed on ofcourse but with clearer showery but colder conditions behind this. 

GFS_108_UKD0_SFC.thumb.png.7aa82477c7f8c1b555a8c871c0e351bf.png

Edited by jordan smith

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Displacement of the Canadian vortex alongside intense WAA has an affinity with the lower strat this evening according to the ecm det run

ecmwf-deterministic-nhemi-z500_anom_5day-6173600.thumb.png.ce5db10433f0aa7a480e68a5d524c9bd.pngecmwf-deterministic-nhemi-z50_anom-6173600.thumb.png.096a6ec18827ac7cd798baec09332b6a.png

Edited by knocker

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There are significant differences between the ext mean anomalies this evening, particularly relating to the upstream amplification off the GEFS so until this is sorted little point in worrying about detail

ecmwf-ensemble-avg-nhemi-z500_anom_5day-6584000.thumb.png.c7a3b616052c373521be7147d1abd9b4.pnggfs-ensemble-all-avg-nhemi-z500_anom_5day-6584000.thumb.png.98c9caf5b6478dec6a73a3c98252039d.png814day_03.thumb.gif.1b5d480af33ce592db49b38364b14012.gif

Edited by knocker

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53 minutes ago, knocker said:

There are significant differences between the ext mean anomalies this evening, particularly relating to the upstream amplification off the GEFS so until this is sorted little point in worrying about detail

ecmwf-ensemble-avg-nhemi-z500_anom_5day-6584000.thumb.png.c7a3b616052c373521be7147d1abd9b4.pnggfs-ensemble-all-avg-nhemi-z500_anom_5day-6584000.thumb.png.98c9caf5b6478dec6a73a3c98252039d.png814day_03.thumb.gif.1b5d480af33ce592db49b38364b14012.gif

Knocker the NOAA/CPC have not updated today,it says so in the heading but are yesterdays ones(2nd) on the chart,very strange.

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11 minutes ago, Allseasons-si said:

Knocker the NOAA/CPC have not updated today,it says so in the heading but are yesterdays ones(2nd) on the chart,very strange.

Thanks I should have noticed. The 6-10 has showing the upstream amplification and why the det runs are having difficulty pinning down the detail/ And actually the ext one isn't a million miles from the EPS so I'm wondering whether the date on the chart is wrong

610day_03.thumb.gif.90e479dca202547dcc05ae3e34450c99.gif

Edited by knocker

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18 minutes ago, knocker said:

Thanks I should have noticed. The 6-10 has showing the upstream amplification and why the det runs are having difficulty pinning down the detail/ And actually the ext one isn't a million miles from the EPS so I'm wondering whether the date on the chart is wrong

610day_03.thumb.gif.90e479dca202547dcc05ae3e34450c99.gif

They are def yesterday's Knocker because i can remember that little green error/scribble over in the med on the 8-14.

814day_03.thumb.gif.7b6cb16d498bf15b503cde8569a6c455.gif

there is no mention of this on there discussion either.

Edited by Allseasons-si

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Thanks again and actually I think they just sorted it

noaa.thumb.JPG.95ed70720dc55cd145f63c570db2707b.JPG

 

Edited by knocker

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4 minutes ago, knocker said:

Thanks again and actually I think they just sorted it

814day_03.thumb.gif.a1173c298e2446082142fcd2e30b419e.gif

Knocker,that's the same one i have just posted!^

Edit:you have corrected,cheers.

Edited by Allseasons-si

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1 minute ago, Allseasons-si said:

Knocker,that's the same one i have just posted!^

? I had to screen grab as for some reason it just gave me the previous one. Anyway to move on 🙂

Edited by knocker

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Some composites based on recent torque action..

gwo_40d.thumb.gif.c88f67f15845a33c611c0c437f48b096.gifgltaum.90day.thumb.gif.4b6c39a18456b1d1a005993c2c51f34c.gif

Based on individual dates between 20th -30th November > then rolled forward in time. Clearly the Aleutian ridge is a big watch out and then perhaps on a secondary basis the Scandi Block and Jet angle.

All of these manifesting in various mid term modelling now so let's see how well the AAM does for predictability... given the core vorticity vacating the Scandi locale as the vortex centroid position pivots back to Pacific I think the scandi high solution would be a interesting catch for this build, given it's not something you would have rightly called out lookng in NWP / ENS etc..

1269123830_GWOEndNovP4and5.thumb.png.085f68e0ad8c36fa2e01aa4cc7b94fc2.png1865920155_GWOEndNovP4and5rolledforward15daysOrth.thumb.png.e87ce5d4fa009c96d8d424b96f989153.png

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The North Atlantic 500mb and surface analysis for midnight and th 0400 UK surface chart

gfs-deterministic-natl_wide-z500_anom-5417600.thumb.png.b9a978da3ea3f7dd59b8cb5100480524.pngPPVA89.thumb.gif.59f24b04f42ad5e069f476b2878a271d.gif04.thumb.gif.219e73bcb9dec6a9af3b1e0b25d225a6.gif

The cold front associated with the complex area of low pressure to the north west has already brought rain to N. Ireland and western Scotland and this will track south east during today, fizzling out en route. Frequent squally showers will follow in it's wake over northern Scotland. Further south fog in central and south east regions will be slow to clear but eventually another quite sunny day here

PPVE89.thumb.gif.deaba2c8241e2ad60df38319fe4674f9.gif2mtemp_d02_20.thumb.png.fe732d1c6f0429c9695a2d43f395101c.pngmeanreflec_d02_24.thumb.png.c844557d5c1c42d11e2709dd670697ea.png
A much cloudier night to follow in the south courtesy of the weak front so any fog will be patchy with a continuation of showers over northern Scotland in the stiff westerly wind

PPVG89.thumb.gif.1bee290a7158dfc6a5d440e9602225d7.gifprecip_d02_31.thumb.png.dff0bdb548384df0c1c4ee3b0c40127c.png
Meanwhile a further trough have developed into the Atlantic and the frontal system associated with it is tracking quickly east and bringing heavy rain and strong winds into western Scotland by Thursday morning which will persist all day and spread south to N. Ireland and NW England. Dry further south but perhaps a tad cloudier than of late

gfs-deterministic-natl_wide-z300_speed-5547200.thumb.png.877a9b833a86a11ade3d5c71e82223de.pngPPVI89.thumb.gif.7dfee638459b9ba669ee9c586bccf6f5.gif2mtemp_d02_44.thumb.png.7e361b665bf8b59bd288721ded5f0439.png

precip_d02_39.thumb.png.b3d0efc5c5e410ff2efce5358ef98836.pngprecip_d02_43.thumb.png.d4cdd25de4ddb45d6492500147652004.pngprecip_d02_48.thumb.png.f90e6edc8d55e26ea90c3f72915731df.png
By Friday the trough will have merged with the trough to the north resulting in a windy day with showers and longer spells of rain, which could be heavy in the north and west, albeit much milder than of late

gfs-deterministic-natl_wide-vort500_z500-5633600.thumb.png.b8e12dc3bb795b63f5fcc3e1a69b25c0.pngPPVK89.thumb.gif.dcad5783df055cc38cd3ef66c10511fe.gifgfs-deterministic-uk-t2m_c_max6-5655200.thumb.png.fe5e5de27a780d7421171bc913b875f9.png

By Saturday the analysis is becoming quite complex as rapid cyclogenisis takes place in the western Atlantic as a ridge builds in eastern Greenland, whilst a transient ridge over the UK soon gives way to the next frontal system

gfs-deterministic-natl_wide-z300_speed-5720000.thumb.png.aa7127385acc02707023f3f3f87ef755.pngPPVM89.thumb.gif.2651ff66a760cb5bd664a01646bf6c4d.gif

gfs-deterministic-uk-precip_1hr_inch-5741600.thumb.png.77fabb225c4628a6b02b18fc771e8db6.pnggfs-deterministic-uk-t2m_c_max6-5741600.thumb.png.bbeb4466acc884edf1454128fce8ce96.png

The rain should clear over Saturday night, possibly some transient snow in the mountains, leaving a very windy day on Sunday with frequent heavy showers, mainly concentrated in western regions.

gfs-deterministic-natl_wide-vort500_z500-5806400.thumb.png.5673522932b06f9db85f20f31ec369af.pngPPVO89.thumb.gif.050f6fab0481126b20c0730dd5a49145.gifgfs-deterministic-uk-t2m_c_max6-5828000.thumb.png.7acd8b1e4397c094d072ada244df84d2.png

EDIT

I've no idea why the link at the top is there or the underlined links and I don't know how to clear it.

Edited by DiagonalRedLine
Fixing underlining text problems

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To say the evolution following on next week is tricky is an understatement with the conflicting energy flows as colder air is introduced into the north of the UK as can be seen on Monday

gfs-deterministic-natl_wide-vort500_z500-5914400.thumb.png.69690cd01650aaf150f1eded03c2f102.png132.thumb.png.cba349077cfe0178b654fe64ebb6ce99.png

But by Tuesday the Atlantic predominates as fronts associated with the deep low sweep across the country bringing some heavy rain and strong winds and snow in the colder air in the north but whether it reaches low levels remains to be seen. Quite a tricky call and not one to be made at this range

gfs-deterministic-natl_wide-vort500_z500-5979200.thumb.png.dedfaa2869316880887b8eb876e2f9fd.png156.thumb.png.b3a73cf065c71b539e0fcbcea594cc38.pnggfs-deterministic-uk-dew2m_f-5979200.thumb.png.cc5d2799143346f72dc71c3e2914d492.png

Once the fronts clear continuing unsettled but this getting too far ahead

180.thumb.png.0b50a7c705f4babd91c985c8b45c5bfe.png

 

 

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Still highly amplified upstream this morning on the ext GEFS with the Alaskan ridge/Canadian vortex trough and a negatively tiled trough into the NW Atlantic beneath the east Greenland ridge, But with strong westerly upper flow exiting the eastern seaboard across a negatively anomalous Atlantic it is likely to be unsettled with temps a tad below average. The usual caveats apply

gfs-ensemble-all-avg-nhemi-z500_anom_5day-6627200.thumb.png.71270daa49ee1447a797a094bafaa0d5.pnggfs-ensemble-all-avg-nhemi-t850_anom_5day-6627200.thumb.png.e0ffad85f2612d5a771b1cadd60f99ec.pnggfs-ensemble-all-avg-eur-t2m_c_anom_5day-6627200.thumb.png.f065be50acb3b9b94b71ca0ef097fce8.png

Edited by knocker

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According to the ecm after some transient ridging on Monday with showers down coastal regions fronts sweep through on Tuesday as it becomes very windy courtesy of the very strong jet exiting the eastern seaboard

ecmwf-deterministic-natl_wide-z300_speed-6022400.thumb.png.9bdb114c39a7c6b19c02e95ca966d365.png132.thumb.png.e125412dcf5f6805a4f3f3e248687c96.png156.thumb.png.8f6a331155a81da4903d9ee5d4dc3254.png180.thumb.png.821d3d481027f3287b133c8eda4aba89.png

Edited by knocker

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Pleased I’ve found your analysis Knocker. Much more down to earth than some of the overnight “the sky is falling” posts on the other thread!

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Cheers Lottie. The ext EPS has some minor differences upstream compared to the GEFS but the main different is downstream where it retains much more of a trough over the UK and thus one suspects is more susceptible to some wintry stuff during the day to day variation of the unsettled weather Temps below average

ecmwf-ensemble-avg-nhemi-z500_anom_5day-6627200.thumb.png.8cd6ac1299a29c7ac3eb226310d3e92e.pngecmwf-ensemble-avg-nhemi-t850_anom_5day-6627200.thumb.png.f81e81435d1e2f1527409319b87c5312.pngecmwf-ensemble-avg-eur-t2m_c_anom_5day-6627200.thumb.png.ffff3e63ecdb0da2807f6e88e3eab29c.png

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13 hours ago, knocker said:

There are significant differences between the ext mean anomalies this evening, particularly relating to the upstream amplification off the GEFS so until this is sorted little point in worrying about detail

ecmwf-ensemble-avg-nhemi-z500_anom_5day-6584000.thumb.png.c7a3b616052c373521be7147d1abd9b4.pnggfs-ensemble-all-avg-nhemi-z500_anom_5day-6584000.thumb.png.98c9caf5b6478dec6a73a3c98252039d.png814day_03.thumb.gif.1b5d480af33ce592db49b38364b14012.gif

Updates aside, to my eye they look pretty similar and suggest a cool unsettled mobile pattern dominating for the next two odd weeks. Yes we will get occassional colder blasts, but no pattern chance. All over the tinternet there hyperbole at one or two GFS runs that suggested snow. Theres no pattern change though, just a 48odd hour cold blast that might deliver some transitory snow for some.

Nothing to get excited about imho.

As i see it, theres too much energy for blocking and a lengthier cold spell to emerge going off current outputs and the timeframe they pertain too.

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8 hours ago, knocker said:

EDIT

I've no idea why the link at the top is there or the underlined links and I don't know how to clear it.

Had the same issue before. Not something that used to happen (or was at least a rarer issue). Should be all sorted now, though 🙂

Edited by DiagonalRedLine

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The cold front over Lerwick at midday but still very cold aloft with -85C at 30mb

 PPVA89.thumb.gif.c78dc6dd789bb4574ac9f9b2e2722f28.gif2019120412.03005.stuve10_parc.thumb.gif.2f4964fe89748446d8f1a0585035235f.gif

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Nice depiction of the weak front currently straddling the country but in particular the next and more intense system that is likely tp bring a ;ot of rain to western Scotland

meteosat-msg_naturalenhncd_overlay-ne_10m_coastline_overlay-ne_10m_admin_0_boundary_lines_land.thumb.jpg.8b459cab859f366cfee172d9dfa6e609.jpgtotalprecip_d02_48.thumb.png.9674cf46a49f980973f1a215669e9360.png

 

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