Model Output Discussion - Into February

[Daniel*]

Clear imprint there. Evidence to support colder polar maritime in NW Europe.

10mb temperature anomaly this is the real deal unlike previous warnings…

 

 

Edited February 5, 2023 by Daniel*

[Ali1977]

So it seems that all the data available now points to a significant strat warming event (not just GFS) , so now it’s just a case of waiting for the signs of a change in the NH patterns -  whether or not the U.K. is in the mix for something decent for coldies to be determined of course. 
 

 

[ItNeverSnowsInWindsor]

Hope this trend is wrong

[SLEETY]

45 minutes ago, Alderc said:

How silly, it was really only the GFS Det for a couple of days and a handful of its ensembles that supported the idea of the really cold conditions, the mean never went cold and a milder Euro was always a decent shout. 

While not fully out the winter woods yet with ensemble charts like this it won't be long until I'm fully out of my dark season model hibernation. 

 

So your basically saying dont believe the gfs if its showing cold in the ensembles but believe it if its trending mild in the ensembles like it is now,and you are,how silly....

Edited February 5, 2023 by SLEETY

[Ali1977]

3 minutes ago, prolongedSnowLover said:

Hope this trend is wrong

It’s probably correct , or not far off for the next 6-9 days or so.  I’m hoping to get some impressive cold from the east before the months out though - nothing more than hope and everything pinned on a SSW

Edited February 5, 2023 by Ali1977

[damianslaw]

Its a unusual set of affairs recently, GFS usually the model that wants to steam roll the atlantic in at any opportunity, continues to show a very blocked set up, and ignoring just how strong the polar vortex to the NW is, alas the recent debacle is leaving me reluctant to look much into it any more..

Conversely its ECM which is showing more atlantic energy, this has been a theme of recent runs, high pressure pushed aside early next week, and we see a westerly, then cold north westerly flow - indeed sub 522 dam uppers much of the country, wintry is the picture. There is much severe cold bottled up to our NW, and this shoudl in theory fuel the jet, the ECM evolution seems more logical to me, than the high simply staying in situ as per GFS.

[Mike Poole]

14 minutes ago, Ali1977 said:

So it seems that all the data available now points to a significant strat warming event (not just GFS) , so now it’s just a case of waiting for the signs of a change in the NH patterns -  whether or not the U.K. is in the mix for something decent for coldies to be determined of course. 
 

 

12z GEFS has SSW percent = 90%.

So I think we’re nearly home and hosed with a technical SSW around 15/2/23.  

What happens next, as you say, is to be decided.  Look out for interesting trop patterns in the last week of Feb.  

Edited February 5, 2023 by Mike Poole

[Met4Cast]

Quite a few comments re: GEFS trending mild, that is also well supposed by the ECM ensemble suite. 

The GEFS suite as a whole offers good guidance, the GFS det is worthless. 

[reef]

2 hours ago, Weather-history said:

"February fill dyke"

Could be a very dry February for numerous locations. 

Yes, absolutely no rain at all on the GFS 12z here out to T+384! ECM has nothing out to the 14th. We've only actually had 3.4mm since 17th January so if anything, its looking quite likely to be notable dry spell regardless of whether its cold or mild.

These prolonged dry spells seem to be quite a common theme in recent years.

[Vikos]

The SSW probability in GEFS is: 90%

well... why not

[damianslaw]

1 minute ago, reef said:

Yes, absolutely no rain at all on the GFS 12z here out to T+384! ECM has nothing out to the 14th. We've only actually had 3.4mm since 17th January so if anything, its looking quite likely to be notable dry spell regardless of whether its cold or mild.

These prolonged dry spells seem to be quite a common theme in recent years.

Yes I've noted many a time how we've endured long very dry spells since about Dec 2020 on and off, I wonder if it is the La Nina base state. The dry spells lasting easily upwards of 3 weeks or more.

[Ali1977]

18 minutes ago, Met4Cast said:

Quite a few comments re: GEFS trending mild, that is also well supposed by the ECM ensemble suite. 

The GEFS suite as a whole offers good guidance, the GFS det is worthless. 

I wouldn’t say the GFS Det is worthless, it’s just had a wobble here and there lately; as have the other systems .

You’d think FI will be creeping closer over the next few days as the strat changes, so maybe nothing beyond day 10 is offering much guidance at the minute - even the METO long range!! 

Edited February 5, 2023 by Ali1977

[ItNeverSnowsInWindsor]

25 minutes ago, damianslaw said:

Yes I've noted many a time how we've endured long very dry spells since about Dec 2020 on and off, I wonder if it is the La Nina base state. The dry spells lasting easily upwards of 3 weeks or more.

Let’s hope we see a wetter summer instead this year then!

[bluearmy]

1 hour ago, Mike Poole said:

12z GEFS has SSW percent = 90%.

So I think we’re nearly home and hosed with a technical SSW around 15/2/23.  

What happens next, as you say, is to be decided.  Look out for interesting trop patterns in the last week of Feb.  

Second consecutive eps run with no mean ssw after three runs with one. Infact I’d say the three runs that had ssw were more marginally negative than the two runs today have been positive. Not a great deal in it but those assuming that we are certain of a tech ssw should be aware of the eps trend.  But we are seeing a displaced spv into Asia with a mean signature not far from the gfs op. (Of course without the reversal).  Looking at this hemispheric pattern, I’m not convinced that we need a tech ssw if we lose the westerlies. Even without a tech ssw, we will see the atmosphere north of 70 reversing and as long as we lose that stronger zonal flow in the trop above 55N, the Asian trough/Canadian ridge set up is surely positive for cold if Imprinted below. 
 

     

Edited February 5, 2023 by bluearmy

[Mike Poole]

2 minutes ago, bluearmy said:

Second consecutive eps run with no mean ssw after three runs with one. Infact I’d say the three runs that had ssw were more marginally negative than the two runs today have been positive. Not a great deal in it but those assuming that we are certain of a tech ssw should be aware of the eps trend.  But we are seeing a displaced spv into Asia with a mean signature not far from the gfs op. (Of course without the reversal).  Looking at this hemispheric pattern, I’m not convinced that we need a tech ssw if we lose the westerlies. Even without a tech ssw, we will see the atmosphere north of 70 reversing and as long as we lose that stronger zonal flow in the trop above 55N, the Asian trough/Canadian ridge set up is surely positive for cold if Imprinted below. 

With the EPS, do you mean the mean does not go negative, or that less than 50% show a SSW?  (I don’t think I have access to this data on the EPS?) It matters because if all members show a SSW at different times and then rebound positive, then the mean could stay positive throughout.  

[January Snowstorm]

If the reversal does happen and we get Easterly winds we will likely see out the rest of February without a named storm.

No named storm during winter would be extraordinary!!

[feb1991blizzard]

must admit eps are indicative of another fizzler, rather than a sizzler.

[Ladyofthestorm]

9 minutes ago, January Snowstorm said:

If the reversal does happen and we get Easterly winds we will likely see out the rest of February without a named storm.

No named storm during winter would be extraordinary!!

And that's considering we have such a positive NAO and the SPV over Canada and Greenland! 

[bluearmy]

26 minutes ago, Mike Poole said:

With the EPS, do you mean the mean does not go negative, or that less than 50% show a SSW?  (I don’t think I have access to this data on the EPS?) It matters because if all members show a SSW at different times and then rebound positive, then the mean could stay positive throughout.  

The mean 

[Singularity]

From what I’ve read in the past week, the events of Jan have primed the polar vortex for absorbing vertical wave activity flux and taking a big hit.

The trouble for those seeking cold UK weather as a result this side of end Feb / early March is that any resulting SSW looks to be a displacement type.

Even if the majority vote outcome for where it displaces to - Scandinavia - comes about, the typical time taken for displacement-driven anomalies to propagate down to the troposphere is 2-4 weeks.

By then we should be seeing AAM reaching positive territory with GWO in phases 5-6. That’s usually conducive to strong high pressure slowly retrograding from Europe to the Atlantic at the mid-latitudes, but *if* there has been a zonal wind reversal and that propagates down as the MJO reaches phase 6, then we could see more of a high latitude block take shape. 

This, however, would mean an extended winter, delaying spring. Some would enjoy that but a larger number wouldn’t when compared to such events playing out in late Jan or early Feb.

 

Im not convinced by recent ECM runs suppressing and retrograding the subtropical high so much. Where does the forcing come from to drive such alignment with the stratospheric pattern so soon?

[damianslaw]

36 minutes ago, January Snowstorm said:

If the reversal does happen and we get Easterly winds we will likely see out the rest of February without a named storm.

No named storm during winter would be extraordinary!!

Yes noteworthy, perhaps the first storm will come in March - a snowstorm!

[bluearmy]

More amplification in the day 15 eps than for a while 

hopefully indicative of the flushed down westerlies dissipating 

would seem to favour mid Atlantic ridging on this suite 

[BLAST FROM THE PAST]

43 minutes ago, January Snowstorm said:

If the reversal does happen and we get Easterly winds we will likely see out the rest of February without a named storm.

No named storm during winter would be extraordinary!!

And a very ‘mild by day’ Feb…that’s the idea

 

BFTP

[Don]

10 hours ago, Met4Cast said:

So.. end of Feb/early March at the earliest, if we even see impacts from any potential SSW. 

It’s not the magical path to certain cold many seem to believe it to be. 

Are you no longer expecting colder weather during the second half of the month?

[Met4Cast]

9 minutes ago, Don said:

Are you no longer expecting colder weather during the second half of the month?

In a word, no. Things haven’t come together as expected and instead it seems mid-latitude blocking is more likely vs high latitude. 

My idea of a colder/blocked mid-2nd half of February looks dead in the water now.