Model Output Discussion - Spring Has Sprung

[Chesil View]

 Just keep twisting the knife winter of 2024 why dont you..  

Edited March 8 by Chesil View

[andymusic]

GFS 12z the freezer makes an attempt from the north

[Cloud 10]

GFS at it again with the Northerly on the 12z.

 

[RJBingham]

Hints of something a bit milder on the GFS

[Anthony Burden]

Evening all,GFS in fantasy island smelling the products of SSW ie northern blocking with polar blast over UK,would match the 10/14 day usually taken after a major SSW to show it’s hand  regarding northern blocking.Very interesting in weather terms to find the final outcome of this situation.

[Metwatch]

A blizzard for half of Spain and the 25c 850hPa isotherm reaching Sicily on the March Equinox, the GFS never fails to make me laugh with its output in the extended time frame sometimes.

[WYorksWeather]

 Metwatch Not just at the 850hPa level either. Some crazy surface temperatures for south-eastern Europe, especially when you add the usual degree or two for under-reading.

[Mike Poole]

4 hours ago, bluearmy said:

Given that gfs has done a decent job in the strat this winter, I’d be expecting some impressive fi output from some ens members across the models.  Be interesting to see how the AI models get on with this if it does gain momentum

My bet is the AI models won’t catch on to any post-SSW patterns quickly.

Given that SSWs are rare, it is unlikely that the AI models will suss the evolutions with an SSW in play from the current pressure patterns over the evolutions without, from the training dataset that they are based on.

No sign on the latest AIFS run, of the kind of pattern that GFS has been playing with in deep FI, T360:

[Metwatch]

22 minutes ago, WYorksWeather said:

Some crazy surface temperatures for south-eastern Europe, especially when you add the usual degree or two for under-reading.

The chart below holds the March record for Palermo, Sicily reached nearly 35C, and 0.1C warmer than April's one and the airmass is still less warm compared to the output! Classic -NAO there with very warm air advection into southern Europe.

http://climaintoscana.altervista.org/italia/stazioni-wmo/palermo-punta-raisi/

Edited March 8 by Metwatch

[CoventryWeather]

That's a ridiculous plume for south eastern Europe at the end of the GFS run.

If that came off, we would see some remarkable heat records. And it's only late march at that point. 

[Methuselah]

 CoventryWeather But it's something we are seeing all too frequently, these days.

[Mike Poole]

 TwisterGirl81 There are about 6 SSWs every 10 years.  Whether that is considered rare or not probably depends on the point of view - but my post was about the training dataset for AI models, and for most of that training dataset there won’t be a SSW happening.

Edited March 8 by Mike Poole

[Summer8906]

 Jordan S A truly horrific outlook for the south by the looks of things, and the second exceptionally poor March in a row. Hoping GFS 12z with its drier northerly is closer to the mark otherwise the south may well see devastating flooding of the 2014 type.

just hope this pattern abates soon, it's persisted with only short breaks since the end of June and we just cannot take any more rainfall.

Edited March 8 by Summer8906

[minus10]

Crazy spread...from +14 to - 13 850s !!

[WYorksWeather]

If like me you'd appreciate some early warmth (I appreciate to some this would be more of a nightmare), then 12z GFS P28 is the one.

More realistically, temperatures still hovering about average (a bit below for the next few days, then a little above to mid-month), and then still too much scatter for the second half.

Overall though, the second half does show quite a bit more scatter away from the mean even adjusting for how far away it is, so I think more chance of something interesting (be it either warm or cold) than looks likely for the first half. I'd prefer warm myself, but appreciate others are still looking for cold.

[stodge]

Evening all

The pattern for next week has resolved. The collapse of heights to the north east aided by residual energy in the Atlantic allows heights to rise over Iberia and consequently a long positively aligned trough ushers in a run of south west TM air. The one thing that won't bring is a prolonged dry spell - indeed, more soaking rain forecast over the next 7-10 days for the south west of England, Wales and especially the north west of England - the usual suspects.

Beyond that, some idea the trough will finally clear through to the north east ushering in a colder spell with perhaps heights building to the west.

The 10 HPA vortex temperature profile looks like final warming to me but little sign of a tropospheric impact in tonight's charts - again, as some have argued, the impacts of the SSW may be far from clear as yet. Longer range CFS charts play with northern blocking around Easter - nothing desperately unusual in that, April can be prone to E'ly or blocked evolutions. 

Edited March 8 by stodge
my terrible spelling

[WYorksWeather]

 stodge To be fair, the ECMWF chart disagrees that this is the final warming, so definitely not nailed on yet.

Of course a lot of uncertainty in what will happen afterwards in any case.

[bluearmy]

 Mike Poole this was my first thought 

but then the starting data includes reverse flow higher up so the model should be looking for data with that in place 

will certainly be interesting 

[Addicks Fan 1981]

 bluearmy I think other things we need to look out for are how quickly el niño declines.  Mind you we have had years where we have gone into la niña and actually the shape of the weather hasn't changed all that much.    

Also I believe that the MJO will be in the west Pacific later on this month another thing to keep our eyes on to whatever synoptic pattern we get.   

[Addicks Fan 1981]

This was a very sensible tweet from someone on twitter/X who is very well respected and knowledgeable.     

 

 

https://twitter.com/MetRyan96/status/1766215758541979958?t=Qs4dvrkUlMn53mKFAEv5Vw&s=19

[Lukesluckybunch]

8 hours ago, andymusic said:

12z the freezer makes an attempt from the north

Could do with a laugh on a Friday night.!

[IDO]

I am not seeing any changes from what the mean has been saying over the last eight days for the upcoming period. A west-based Atlantic trough means any cold is pushed away, and scraps are the best we can expect. EC for the next ten days, but GEM and GFS are similar:

 

We are still getting random outlier colder runs but not supported by the mean, so they are best ignored until they gain support and consistency.

The 2m London ens:

Nothing cold or snowy there.

The Bering Sea surface high is still evident on the mean D8-16 and has been for a few days on the GEFS:

But the mean tPV looks like it is splitting, so I am not sure this will take the UK out of no man's land, caught between an Atlantic and Scandi trough. The mean defines this well as a mean out in FI.

It looks like March is going out with a whimper, assuming we do not get any forcing of the pattern, being tropical waves or SSW sPV impacts.

[Cloud 10]

Overnight ECM det. run keen on another scandi high at only day 6 with good ensemble support as well.

 

Maybe a less unsettled outlook than what looked liikely a couple of days ago?

 

[Rain All Night]

On 08/03/2024 at 09:37, Rain All Night said:

0z deterministic runs, out to Fri 15th (day 7)

0z ensemble means, out to Sat 23rd (day 15)

The Atlantic height rise signal in deep FI on the ECM ensemble mean doesn't seem as strong this morning.

0z deterministic runs, out to Sat 16th (day 7)

Yes please ECM. The other models also show more heights to the east than were evident yesterday, so there's more hope of less rain for us.

0z ensemble means, out to Sun 24th (day 15)

The ECM mean resembles its op earlier on, and while the signal isn't as strong as a few days back, it still has interest in an Atlantic height rise later. The other two means look like garbage unfortunately.

[feb1991blizzard]

Very good split in the 6z.