psuhoffman

Everything is almost identical to the 6z run that gave us a lot of snow. The one difference is the SS wave had simply trended less amplified

I didn’t get 4 flakes

They were progressive waves in a fast pac flow. We just had cold and got lucky.

If that Nino can alter the N pac flow such to get true cold into the pattern it would work. If not…I doubt the results will be any better.

If by chill you mean the pac jet stop being amplified with waves racing into N America I don’t think we will see much of that ever because it’s an effect of the expanded Hadley cell compressing the flow and increasing the jet. That seems to be a new permanent base state due to…something.

@Heisy the next pac wave hasn't really trended that much faster...it did trend significantly more amplified at 6z v previous runs...and it's slightly faster...but the bigger problem is the SS wave is a little slower which narrows the window between the two NS waves. But here is the bigger issue with that...and one we have run into in the few split flow blocking regimes we have had lately (this killed us several times in January 2021 for example) is the awful thermals of the mid latitude airmass stuck under the blocking...means we need such a suppressive northerly flow that it ends up suppressing the storm also. The reason the SS wave is slowing down is the increased confluence in the flow behind the first NS wave. We have been celebrating that trend because we know cold is going to be iffy at best and so we wanted that...but there has been a correlated slowing of the SS wave as that trend happens that has resulted in a suppressed solution. Basically...our path is so narrow because with such a marginal airmass we need so much northerly flow to get enough cold down here...that it becomes too suppressive for a SS storm to amplify at our latitude. Yes part of that problem right now is the time of year. But we have also had that problem in mid winter. January 2021 we had a couple waves where we had a great split flow longwave pattern but the airmass was putrid and we had this same equation...we were rooting for more confluence and we got it...but both waves ended up suppressed and torn to shreds by the flow even though we were barely cold enough to get snow even had the storm not been suppressed. For us to have a good chance for any given storm to work...the airmass has to be cold enough to survive some southerly flow ahead of the wave. If we need the flow to be out of the north to be cold enough...that usually isn't going to work because in a split flow that is going to suppress a SS wave 90% of the time.

The euro has been too amplified with most everything. It’s hard to quantify the March effect since we don’t necessarily know what the same wave looks like earlier. It’s already baked unto the models. The Gfs is under done. The euro over. That’s the most typical error at this range.

Things have to trend good now. If it falls apart this far out it won’t hurt enough. It has to get better and better until we actually believe, truly allow ourselves to think this is the one, it’s really finally happening, then and only then can it be the total soul crushing knock us to our knees and make us sob uncontrollably like March 2001 and December 2010 were a fun day at the park experience that is the only fitting way this can end.

Huge improvement

Euro is just over amplified. Typical bias at this range

Gefs better

It's not that simple... because we are also dealing with the timing of other features...its the play between the NS wave before and after the SS wave that matters also. There is a window between the two where space is open for a SS wave. If you slow down or speed up either of those NS waves it changes the window. This run the SS wave was towards the very end of that window...but the bigger problem was it was too slow and not amplified enough...got caught under the flow and cut off down there.

yes...ggem was perfect except it was just a few degrees too warm. We just have to hope it goes down like the GGEM and its simply a few degrees colder. Not going to over analyze it.

It was 12 hours too slow...lost it's window. Cuts off too far south and slides east. But the GFS has the setup we need...just needed a slightly faster more amplified SS wave and it would have been a good outcome.

It's taking too long... flow ahead of the next main pac wave is starting to erode the cold. Storm could also end up suppressed...but this was close enough to a monster solution (the only kind that can work for us really) that I am fine with it. If that SS wave was 12 hours faster and slightly more amped it would have been the exact result we wanted.

It looks like its coming up now...but the 12-18 hours slower is offsetting a lot of the improvements up top from 6z. But then again 6z was a huge win so...that balancing act isnt necessarily a bad thing. But yea if the SS wave had the same timing as 6z this would have been a monster run.

It's starting to get its act together in the northeast gulf now...snowing in north Georgia at 168.

through 150 I still like 12z better than 6z. High is back over IN vs already over MD last run. Storm is slightly slower getting going but SS wave is more amplified and the NS flow over the northeast has a lot more confluence. Money frames are coming up though...

out to 133 the GFS is showing the two trends I want...more suppressive NS flow and more amplified SS

The high is also positioned further west which will be helpful later on

so far so good...as far as I can see so far both a better cold push AND a stronger STJ wave.

12z GFS slowed down and amplified the next wave (the one ahead of our storm threat) quite a bit. That is a good thing imo...but we need a healthy STJ wave that can amplify despite a more suppressive flow. That is the win imo. Rooting for a weaker STJ wave is kinda pointless since we need a qpf bomb for this to really work. Our win is to have both a stronger SS wave AND a more suppressive flow and let the two fight it out.

According to a press release I found the GEFS was upgraded to the FV3 core in 2020 with version 12. But perhaps one of our model experts could clarify how aligned the GEFS and GFS op are at this point. Regardless though I do think this is an example where resolution matters a lot. We know it's going to be very marginal and the lower resolutions models will struggle with getting the boundary layer exactly correct in a dynamic situation. And since that is the only win scenario here...I can see why the ensembles would struggle to see the snow threat more here. It would be a bigger problem if the ensembles had a completely different synoptic solution, suppressed or a cutter...but the fact several of them take a similar track to the op but simply are too warm bothers me a little less. I mean the whole March 22 thing bothers me plenty enough...just saying the ensembles being a bit warmer than the op isn't shocking imo.

The SS was suppressed by the NS. For now (the next NS wave is starting to get dangerously close) the NS is out of the way and its simply a matter of how much the SS amplifies.