Model thread discussion - cold spell looming

[Tim Bland]

[sheikhy]

Didnt expect that from ukmo!!!high further north and much better than yesterdays 12z!!maybe all is not lost!!

[KTtom]

Its that time of year where many peoples preferences start to edge towards the warmer weather, early next week sees a long drawn out southerly, yes it will take a day or so to remove the surface cold, but you cant have snow at this time of year you may as well have 14 degrees (which is what Met show for my area)

 

[That ECM]

7 minutes ago, sheikhy said:

Didnt expect that from ukmo!!!high further north and much better than yesterdays 12z!!maybe all is not lost!!

T144 all 3.  The next potential is later down the line. The one that stands out is gfs.  

[sheikhy]

Any snow events for the weekend before the cold fights back from the east?!

[That ECM]

5 minutes ago, sheikhy said:

Any snow events for the weekend before the cold fights back from the east?!

Well that’s the thing. You look at the output and you read the met extended and you think eh. What is that they are seeing that the output isn’t showing. Ukmo and ecm don’t show cold coming back from the east. Gfs has a chance but gfs against Ukmo and ecm. Interesting to see how this pans out.  Here is ecm T192 doesn’t scream of their extended to me. 

Edited February 10, 2021 by That ECM

[chris55]

59 minutes ago, KTtom said:

Its that time of year where many peoples preferences start to edge towards the warmer weather, early next week sees a long drawn out southerly, yes it will take a day or so to remove the surface cold, but you cant have snow at this time of year you may as well have 14 degrees (which is what Met show for my area)

 

If the cold does come back in, a period of warmer dry weather would be a nice interlude!  

[sunnijim]

A look at the updated ukmo fax chart is quite a thing.

Gone is the spoiler short wave in the North Sea at the weekend that allowed an easier Atlantic attack.

We now have a straight battle between an intensifying High over Southern Scandanavia 1044mb and a set of fronts ambling across the uk.

Imo still room for upgrades to the cold persisting over the weekend,it may never leave the East and North before a renewed surge from the East later next week.

[JimBob]

The models have further firmed up on the milder trend for next week, large parts of the UK into double digit temperatures by early next week. 

[Jock Bingham]

58 minutes ago, JimBob said:

The models have further firmed up on the milder trend for next week, large parts of the UK into double digit temperatures by early next week. 

I think you could be right for the far South West Jim Bob, but are you calling that as a Uk-wide outcome?

Edited February 10, 2021 by Paul

[JimBob]

1 hour ago, Jock Bingham said:

I think you could be right for the far South West Jim Bob, but are you calling that as a Uk-wide outcome?

Good morning  Jock Bingham, yes I think the southerlies will get pretty far North next week.

[nick sussex]

The shorter term is still subject to some small changes in terms of how protracted any breakdown is.

The UKMO is an improvement on its 12 hrs from last night .

The surface cold not leaving the far east till the early hours of Monday , the ECM however takes over today’s grinch spot which is more bullish on that front . Although the ensemble spreads show a largish amount for that time period .

In terms of snow , two attempts to remove the surface cold , the first an occlusion  won’t make much progress east ne and will weaken as it does so  , so this should favour sw parts with any heavier precip .  Looking at the fax chart the next attempt and likely at this stage to be too much for the high to the east makes slow progress east ne. 

The GFS has 3 attempts with a wintry mix of snow and freezing rain.

 

[Tim Bland]

Not much uncertainty around the fact it is going to warm up on the ensembles ..

[That ECM]

Hmmm

[IDO]

I think the gfs and ecm ops are at the extremes of the envelope as we proceed in the next 10-days. The gfs the coldest and the ecm the mildest. It is no surprise that the means for each are closer at d10:

The gem is also showing this. The ecm op is progressive in killing the cold compared to its op and the opposite for the gfs op, so maybe somewhere in the middle and effectively the negative uppers leaving the east during Sunday?

The gfs op is flat as a pancake upstream all the way to d16 so we are getting to the point of calling the model's MJO forecast a bust for any NH high-latitude forcing. So probably need to rely on wedges again to get some potential colder spells, which is indeed what the gfs op shows in FI?

Sadly, the lack of Tropical forcing this winter when the tPV has been predicated to disruption and destruction has meant what could have been astonishing has instead has been just a good winter? Enjoy the next 4-5 days of guaranteed cold for most.

[Climate Man]

9 minutes ago, That ECM said:

Hmmm

Just shows how long a week is in weather watching and we get so hung up on output well beyond this.

Edited February 10, 2021 by Climate Man

[Jason M]

Well looking through the output this morning I think the curtain is coming down on this cold spell now. The GEFS had a decent cluster last night wanting to bring in a renewed easterly but that has largely vanished on this set.

So, cold uppers leaving us but maybe a few extra days of surface cold but a warming trend looks the most likely option now. Wouldn’t absolutely rule out another easterly before months end but with the low sat in the Atlantic a period of winds from a southern quadrant now very likely.

Edited February 10, 2021 by Jason M

[carinthian]

45 minutes ago, nick sussex said:

The shorter term is still subject to some small changes in terms of how protracted any breakdown is.

The UKMO is an improvement on its 12 hrs from last night .

The surface cold not leaving the far east till the early hours of Monday , the ECM however takes over today’s grinch spot which is more bullish on that front . Although the ensemble spreads show a largish amount for that time period .

In terms of snow , two attempts to remove the surface cold , the first an occlusion  won’t make much progress east ne and will weaken as it does so  , so this should favour sw parts with any heavier precip .  Looking at the fax chart the next attempt and likely at this stage to be too much for the high to the east makes slow progress east ne. 

The GFS has 3 attempts with a wintry mix of snow and freezing rain.

 

This chart from Arpege shows the slowest transition to remove the embedded cold away from the UK. Sunday into Monday will feel cold in that strengthened surface SE wind , especially in Central and Eastern Britain with temps still close to freezing. Looks like little in the way of precipitation at this stage. As you @nick sussex say shorter term still subect to changes. One things for sure some real cold temps over the coming nights/ days over much of Northern Europe. Lets see how easily it dissipates  ?

C

[Timmytour]

1 hour ago, Jock Bingham said:

I think you could be right for the far South West Jim Bob, but are you calling that as a Uk-wide outcome?

With reference to this post which was in response to......

 

1 hour ago, JimBob said:

The models have further firmed up on the milder trend for next week, large parts of the UK into double digit temperatures by early next week. 

 I see Tamara has liked JimBob's post which I assume is an indication she has come off the fence and is thinking along the same lines?

[Nick F]

Morning. 

Looking likely it will slowly turn less cold at the surface early next week, uppers turning milder first before the wind switches at the surface to turn it less cold too. Uncertainty how far east occluding fronts moving in from the Atlantic will get and how much they will weaken with eastward progress too, as they move into high pressure to the east. But, could be some snow from these fronts for the west, for those that have missed out from the easterly, and maybe snow reaching central and eastern areas too before it peters out. Could also be a risk of freezing rain where upper layers are above freezing with rain falling onto frozen surfaces.

Worth noting the ensemble means keeping Atlantic troughing to the west of Britain in the extended, while blocking ridge / HP holds over NE Europe / Norwegian Sea. The 00z EPS mean even hints at the mean Atlantic trough retrograding in the extended:

Trouble is, most of the jet energy going north to the west of the Uk and looping over the top of the ridge close to the E and NE - which keeps the block sunk too deep into Europe to benefit us.

Ideally want the jet energy to going east over the Atlantic and under the block into Europe, as 00z GFS op hints at in the extended, with jet loop to the north weakening/cut off - 

Or, jet loops round to the north then over Scandi then back SW like EC op at day 10, but ideally the block need to be further north than this for UK to benefit from tapping into cold air from the east:

But, with the Atlantic lows held at bay to the west by blocking, and potential the jet may eventually  undercut blocking to the N/NE rather than all the energy going north over the top, there's certainly potential to bring back cold from the east or northeast later this month.

Edited February 10, 2021 by Nick F

[Don]

 

5 minutes ago, Nick F said:

But, with the Atlantic lows held at bay to the west by blocking, and potential the jet may eventually  undercut blocking to the N/NE rather than all the energy going north over the top, there's certainly potential to bring back cold from the east or northeast later this month.

The latest ECMWF 42 day forecast showed a less cold interlude next week but for it to then turn colder again the following two weeks.  Will be interesting to see what tomorrow's update brings.

Edited February 10, 2021 by Don

[sheikhy]

Early stages but gfs more amplified at only 66 hours!

[johnholmes]

Interesting post from Nick F above, here is my usual mix of ECMWF and 500 mb anomaly charts

Wed 10 feb

Ecmwf and the deep cold is clearing east by sun as the milder air associated with the atlantic fronts edges in; the 500 mb ec chart shows a trough-ridge-trough pattern through the 10 day period. The deep cold trough is way east over the eastern med, with the shallow ridge sharpening a little with time just east of the uk, the rear trough is fairly shallow in the atlantic but has the surface low in the Iceland region slowly filling and the two together developing a noticeable s-sw surface flow.Monday shows +5C 850’s over most of the uk with slightly colder air returning, briefly, to western districts, The 10 day closes with all above 5C and areas quite well north showing indications of almost double figures by day 10.

Assuming the ecmwf is close to the mark then in the coming 10 days we go from the freezer to spring!

The anomaly charts

Ec-gfs show the deep trough in about its normal place and more n-s than for some time with a marked s-sw flow into the uk, on to the ridge n Scandinavia area and into the trough over the eastern med. Little sign of any change in wavelengths in the far west.

Noaa has a very simila chart to what it has shown, for 6-10 days, for several days now. Near the uk its main features are the main trough, unlike ec-gfs, still aligned more ese from its base in ne Canada and over that the marked ridge from n Scandinavia west to Greenland; beneath this it keeps the atlantic flow turning s of west over the uk into the ridge and down to the eastern med trough.The 8-14 follows on again as in previous days.

So 2 show one idea and one continues to show another option. I am reluctant to ditch the noaa version, it is sometimes wrong v the ec-gfs but not very often. So which will win, probably based on 10-12 years with these charts, just about 60:40 on noaa, but fence sitting time for me for another couple of days. By that time it should be clearer IF ECMWF, as outlined above, has the right idea.

One final comment is looking at the UK surface and 500 mb progs T+144-168 and their charts support the ECMWF outputs!

Yes, their 6-15 day outlook seems a half way house between EC and noaa. Like I said fence sitting time.

ECMWF/GFS DAY 8-10 MEAN 500MB HEIGHT COMPARISON

WWW.METEO.PSU.EDU

Climate Prediction Center - 6-10 Day 500mb Outlook

WWW.CPC.NCEP.NOAA.GOV

 

 

[Nick F]

15 minutes ago, Don said:

 

The latest ECMWF 42 day forecast showed a less cold interlude next week but for it to then turn colder again the following two weeks.  Will be interesting to see what tomorrow's update brings.

If we can get the ridge to the E/NE and Atlantic trough to retrograde, as the 00z EPS and GEFS means in the extended suggests later this month, we could end up with something like the 00z EC control shows at day 15

But there seems some uncertainty to the MJO forecast atm, so not sure we can trust the models extended direction of travel at the moment.

[sheikhy]

Even better at 96 hours!!cold continental air still well and truly across the uk!