IDO

Alderc 2.0 ...still hot for the south on Sunday:

nick sussex Yes. But we needed a lot more disruption and undercutting like the EC from two days ago: GFS 18z: The synoptic needed is simple, but the likely reality of no undercut is massive. There has been no change today, and we see the likely pattern established, with no light at the end of the tunnel for the rest of February. The mean from D8-16 is terrible, and we will need to see that change via some background signal to save the final rites of Winter:

I am not interested in FI, assuming we have confirmed that the undercut has failed. It is unlikely to be a rinse and repeat as the Siberian high, again well-modelled on the GFS, means there is no Scandi trough as there was on this current spell; T192: So, on the GFS D16, we are still only here: It is hard to spot any potential; again, there is no possibility of an Atlantic ridge (our main hope). A re-run of another Scandi high too far east in early March is not enticing. For the record, the GEM mean at D8 and D16 matches GFS: ECM in the same ballpark.

By D8, EC is looking a lot like GFS has for the last two days:

Sadly, EC has the cut-off low that GFS has had for six runs and the 18z keeps. EC: GFS 18z:

The GFS Control follows the op. T144: Interestingly, the mean does not have the cut-off low, so there is still some support in the ensembles for the other solution, that is, undercutting and disruption, keeping the HP further south for a little longer. The mean:

GEM went with the GFS route on its 0z. Let us see if it switches sides. The 0z at T180: At T144 it looks like no change and if anything more progressive with the breakdown:

UKMO at T144 is going under with the western low. Blocking the Azores high from flattening the pattern: GFS has a cut-off low off the western trough, with HP breaking through and flattening the pattern more. So GFS keeps to its guns for the sixth op in a row:

GFS and EC at D7 re the upper wedges/highs: The GFS is still keen on blowing up the Siberian high, which squeezes the Scandi trough--the EC allows that trough more breathing space, which undoubtedly has knock-on effects in our quadrant. The first phase is essential, and if GFS moves in that direction, we can worry less, as Arctic heights are notoriously fickle and can change in a heartbeat. Of course, the whole mechanics of this pattern are intertwined so it's interesting to see where we go on the next run.

From then, it goes wrong due to the GFS having a different Arctic/Greenland high profile:

northwestsnow Yes. And you can see the net result on the next frame. Whereas the 0z cut off the low allowing the Atlantic high in, the 06z blocks it with an undercut of sorts:

You can see the better undercut on the GFS 06z at T132 compared to the 0z:

I found only four GEFS close to the EC op run, less than yesterday. Most were similar to the GFS op, though that looked progressive: Meteociel - Panel GEFS WWW.METEOCIEL.FR The GFS and EC are similar at T120: But by T144, we have them reacting differently: GFS cuts a low off the western trough, sending it south, while the EC sends energy SE, dragging the mother low SE for a short period before it disrupts and goes under the high, which is sliding down from Greenland. By D8, that high is in the Mediterranean on the GFS but in Scandi on the EC, supported by the remnants of that undercutting low. We will learn how each model handles the Atlantic undercutting, whichever way it goes. We need the GEFS and op run to move toward EC today; otherwise, by 6.30 pm, I fear we will see EC move closer to GFS. Original post: https://community.netweather.tv/topic/101220-into-february-forecast-and-model-discussion-commentary/?do=findComment&comment=5246907

northwestsnow Logic says GFS, but maybe it's not as bad as the 0z run. AO- I am not hopeful it will be well represented.

I found only four GEFS close to the EC op run, less than yesterday. Most were similar to the GFS op, though that looked progressive: Meteociel - Panel GEFS WWW.METEOCIEL.FR The GFS and EC are similar at T120: But by T144, we have them reacting differently: GFS cuts a low off the western trough, sending it south, while the EC sends energy SE, dragging the mother low SE for a short period before it disrupts and goes under the high, which is sliding down from Greenland. By D8, that high is in the Mediterranean on the GFS but in Scandi on the EC, supported by the remnants of that undercutting low. We will learn how each model handles the Atlantic undercutting, whichever way it goes. We need the GEFS and op run to move toward EC today; otherwise, by 6.30 pm, I fear we will see EC move closer to GFS.